Patent Application
20220395821
Harnessing the energy of light to make and break chemical bonds usually involves semiconducting photocatalysts, with titanium dioxide being the benchmark.1-4 Recently, organic photoredox catalysts have been acknowledged in a myriad of chemical transformations due to their diverse synthetic modularity, promising for the discovery and optimization of new reaction routes.5-7 While impressive advances have been achieved, engineering the optical properties to improve efficiency through the direct functionalization of chromophore moieties is often cumbersome and synthetically challenging. In addition, the molecular photoredox catalysts often suffer from photobleaching, compromising their long-term stable outputs.8 Alleviating the deactivation and enhancing control over the conversion of light into chemical energy are essential in furthering this technology.9-19
Described herein are covalent organic frameworks. The covalent organic frameworks have unique structural and physical properties, which lends them to be versatile in a number of different applications and uses. In one aspect, the covalent organic frameworks are composed of a plurality of fused aromatic groups and electron-deficient chromophores. The covalent organic frameworks are useful as photocatalysts in a number of different applications.
The advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the aspects described below. The advantages described below will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive.
The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate several aspects described below:
Before the present materials, articles and/or methods are disclosed and described, it is to be understood that the aspects described below are not limited to specific compounds, synthetic methods, or uses, as such may, of course, vary. It is also to be understood that the terminology used herein is for the purpose of describing particular aspects only and is not intended to be limiting.
In the specification and in the claims that follow, reference will be made to a number of terms that shall be defined to have the following meanings:
It must be noted that, as used in the specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the context clearly dictates otherwise. Thus, for example, reference to “a solvent” includes mixtures of two or more solvents and the like.
“Optional” or “optionally” means that the subsequently described event or circumstance can or cannot occur, and that the description includes instances where the event or circumstance occurs and instances where it does not. For example, the compositions described herein may optionally contain a hydrophilic compound, where the hydrophilic compound may or may not be present.
Throughout this specification, unless the context dictates otherwise, the word “comprise,” or variations such as “comprises” or “comprising,” will be understood to imply the inclusion of a stated element, integer, step, or group of elements, integers, or steps, but not the exclusion of any other element, integer, step, or group of elements, integers, or steps.
As used herein, the term “about” is used to provide flexibility to a numerical range endpoint by providing that a given numerical value may be “a little above” or “a little below” the endpoint without affecting the desired result. For purposes of the present disclosure, “about” refers to a range extending from 10% below the numerical value to 10% above the numerical value. For example, if the numerical value is 10, “about 10” means between 9 and 11 inclusive of the endpoints 9 and 11.
As used herein, the term “admixing” is defined as mixing two or more components together so that there is no chemical reaction or physical interaction. The term “admixing” also includes the chemical reaction or physical interaction between the two or more components.
As used herein, “aryl group” is any carbon-based aromatic group including, but not limited to, benzene, naphthalene, etc. The term “aryl group” also includes “heteroaryl group,” which is defined as an aryl group that has at least one heteroatom incorporated within the ring of the aromatic ring. Examples of heteroatoms include, but are not limited to, nitrogen, oxygen, sulfur, and phosphorus. In one aspect, the heteroaryl group is imidazole. The aryl group can be substituted or unsubstituted. The aryl group can be substituted with one or more groups including, but not limited to, alkyl, alkynyl, alkenyl, aryl, halide, nitro, amino, ester, ketone, aldehyde, hydroxy, carboxylic acid, or alkoxy.
As used herein, a plurality of items, structural elements, compositional elements, and/or materials may be presented in a common list for convenience. However, these lists should be construed as though each member of the list is individually identified as a separate and unique member. Thus, no individual member of any such list should be construed as a de facto equivalent of any other member of the same list based solely on its presentation in a common group, without indications to the contrary.
Concentrations, amounts, and other numerical data may be expressed or presented herein in a range format. It is to be understood that such a range format is used merely for convenience and brevity and thus should be interpreted flexibly to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range was explicitly recited. As an example, a numerical range of “about 1” to “about 5” should be interpreted to include not only the explicitly recited values of about 1 to about 5, but also to include individual values and sub-ranges within the indicated range. Thus, included in this numerical range are individual values such as 2, 3, and 4, the sub-ranges such as from 1-3, from 2-4, from 3-5, from about 1-about 3, from 1 to about 3, from about 1 to 3, etc., as well as 1, 2, 3, 4, and 5, individually. The same principle applies to ranges reciting only one numerical value as a minimum or maximum. The ranges should be interpreted as including endpoints (e.g., when a range of “from about 1 to 3” is recited, the range includes both of the endpoints 1 and 3 as well as the values in between). Furthermore, such an interpretation should apply regardless of the breadth or range of the characters being described.
Disclosed are materials and components that can be used for, can be used in conjunction with, can be used in preparation for, or are products of the disclosed compositions and methods. These and other materials are disclosed herein, and it is understood that when combinations, subsets, interactions, groups, etc. of these materials are disclosed, that while specific reference to each various individual combination and permutation of these compounds may not be explicitly disclosed, each is specifically contemplated and described herein. For example, if a fused aromatic group is disclosed and discussed, and a number of different electron-deficient chromophores are discussed, each and every combination of fused aromatic group and electron-deficient chromophore that is possible is specifically contemplated unless specifically indicated to the contrary. For example, if a class of fused aromatic groups A, B, and C are disclosed, as well as a class of electron-deficient chromophores D, E, and F, and an example combination of A+D is disclosed, then even if each is not individually recited, each is individually and collectively contemplated. Thus, in this example, each of the combinations A+E, A+F, B+D, B+E, B+F, C+D, C+E, and C+F is specifically contemplated and should be considered from disclosure of A, B, and C; D, E, and F; and the example combination A+D. Likewise, any subset or combination of these is also specifically contemplated and disclosed. Thus, for example, the sub-group of A+E, B+F, and C+E is specifically contemplated and should be considered from disclosure of A, B, and C; D, E, and F; and the example combination of A+D. This concept applies to all aspects of the disclosure including, but not limited to, steps in methods of making and using the disclosed compositions. Thus, if there are a variety of additional steps that can be performed with any specific embodiment or combination of embodiments of the disclosed methods, each such composition is specifically contemplated and should be considered disclosed.
Described herein are covalent organic frameworks. The covalent organic frameworks have unique structural and physical properties, which lends them to be versatile in a number of different applications and uses.
In one aspect, the covalent organic frameworks are assembled with a plurality of fused aromatic groups and electron-deficient chromophores as described herein. In one aspect, the organic framework comprises a plurality of structural units comprising the formula I
wherein Ar is a fused aromatic group, and
EC is an electron-deficient chromophore.
The squiggle line placed on the bonds in formula I represents a bond to another group (Ar or EC). For example, the structure of formula I is a monomeric unit (i.e., repeat unit) used to produce the organic frameworks described herein. Thus, the formulae described herein where squiggle lines are depicted represent units used to produce the organic framework.
The dimensions and physical properties of the organic framework can vary depending upon the number of structural units as depicted in formula I and the way in which the structural units are arranged in the framework. For example, the structural units of formula I can be positioned to produce the framework with the repeating structure
The structure above is represented as a square configuration; however, other configurations can be produced such as, for example three-sided, five-sided, six sided, seven-sided, or eight-sided structures.
The fused aromatic group Ar is a group that possesses two or more aromatic groups that share two carbon atoms. The fused aromatic group can consist entirely of carbon atoms or, in other aspects, can include one or more heteroatoms (e.g., oxygen nitrogen, sulfur, or any combination thereof). In one aspect, the fused aromatic group has from 2 to 10 fused aromatic groups, or 2, 3, 4, 5, 6, 7, 8, 9, or 10 aromatic groups, where any value can be a lower and upper end-point of a ranger (e.g., 2 to 8, 3 to 5, etc.).
In one aspect, the fused aromatic group comprises naphthalene, anthracene, acenaphthene, acenaphthylene, fluorene, phenalene, phenanthrene, benzo[a]anthracene, benzo[a]fluorine, benzo[c]phenanthrene, chrysene, fluoranthene, tetracene, anthanthrene, benzopyrene, pyrene, benzo[a]pyrene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, corannulene, coronene, dicoronylene, diindenoperylene, helicene, heptacene, hexacene, kekulene, ovalene, pentacene, perylene, picene, or tetraphenylenepentacene. In another aspect, the fused aromatic group comprises a pyrene.
The organic framework comprises a plurality of fused aromatic groups. In one aspect, two or more different fused aromatic groups can be present in the organic framework. In another aspect, the fused aromatic group in the organic framework is the same fused aromatic group (e.g., pyrene).
The fused aromatic group can be substituted with one or more different groups. In one aspect, the fused aromatic group is substituted with one or more aryl groups. In another aspect, the fused aromatic group is substituted with 2 to 8 aryl groups, or 2, 3, 4, 5, 6, 7, or 8 aromatic groups, where any value can be a lower and upper end-point of a ranger (e.g., 2 to 6, 3 to 5, etc.). In one aspect, the aryl groups are symmetrically positioned around the fused aromatic group. In one aspect, the aryl group is the same group bonded to the fused aromatic group; however, two or more different aryl groups can be positioned on each fused aromatic group. In other aspects, the fused aromatic group can include a fused aromatic group substituted with one or more first aryl groups and a second fused aromatic group with one or more second aryl groups, where the first and second aryl groups are different.
In one aspect, the fused aromatic group comprises the structure of formula II
Referring to formula II, the fused aromatic group is pyrene, where four phenyl groups (i.e., aryl groups) are symmetrically positioned about the pyrene structure. In one aspect, the organic framework includes only the structure of formula II with respect to the fused aromatic group.
The organic frameworks described herein also include an electron-deficient chromophore. In one aspect, the electron-deficient chromophore comprises a thiadiazole, a triazine, a heptazine, or an oxadiazole. In one aspect, the electron-deficient chromophore comprises a molecule incorporating thiadiazole. Thiadiazole has the structure
When electron-deficient chromophore includes thiadiazole, thiadiazole can include additional groups that permit covalent bonding to the fused aromatic group as well as enhance the properties of the organic framework. In one aspect, the chromophore can have the structure
wherein L is not present or L is a fused aromatic group as defined herein comprising 1 to 10 aromatic groups.
In another aspect, the chromophore has the structure of formula III
wherein L is not present or L is a fused aromatic group defined herein comprising 1 to 10 aromatic groups.
In one aspect, the structural unit used to produce the organic framework has the formula IV
wherein L is not present or L is a fused aromatic group comprising 1 to 10 aromatic groups. In another aspect, the organic framework comprises a plurality structural units having the structure depicted in
The structural units present in the organic framework include an imine group (—C═N—) that covalently bonds the fused aromatic group to the electron-deficient chromophore. In one aspect, a Schiff's base reaction can be used to covalently bond the fused aromatic group to the electron-deficient chromophore.
In one aspect, the organic framework is produced by reacting a fused aromatic group substituted with three or more amino groups with an electron-deficient chromophore comprising two aldehyde groups. In one aspect, the fused aromatic group has four amino groups symmetrically positioned around the fused aromatic group. In one aspect, the fused aromatic group is 1,3,6,8-tetrakis(4-aminophenyl)pyrene.
In one aspect, the electron-deficient chromophore comprising two aldehyde groups comprises the formula V
wherein L is not present or L is a fused aromatic group as defined herein comprising 1 to 10 aromatic groups.
In another aspect, the organic framework is produced by reacting a fused aromatic group substituted with three or more aldehyde groups with an electron-deficient chromophore comprising two amino groups. In one aspect, the fused aromatic group has four aldehyde groups symmetrically positioned around the fused aromatic group. In one aspect, the fused aromatic group is 4,4′,4″,4′″-(pyrene-1,3,6,8-tetrayl)tetrabenzaldehyde.
In one aspect, the electron-deficient chromophore comprising two amino groups comprises the formula VI
wherein L is not present or L is a fused aromatic group as defined herein comprising 1 to 10 aromatic groups.
Non-limiting procedures for producing organic frameworks described herein are provided in the Examples.
The organic frameworks are crystalline, porous, extended polymers with highly ordered and periodic two-dimensional (2D) or three-dimensional (3D) framework. In one aspect, the organic frameworks described herein comprise an AA stacking structure.
In one aspect, the organic frameworks described herein are two dimensional structures that possess a plurality of square or rhombus channels. In one aspect, the channels have a pore size of about 0.5 nm to about 4 nm, or about 0.5 nm, about 1.0 nm, about 1.5 nm, about 2.0 nm, about 2.5 nm, about 3.0 nm, about 3.5 nm, or about 4.0 nm, where any value can be a lower and upper endpoint of a range (e.g., about 1 nm to about 3.5 nm, about 2 nm to about 3 nm, etc.).
In one aspect, the organic frameworks described herein have a Connolly surface area of about 2,500 m2/g to about 3,000 m2/g, or about 2,500 m2/g, about 2,550 m2/g, about 2,600 m2/g, about 2,650 m2/g, about 2,700 m2/g, about 2,750 m2/g, about 2,800 m2/g, about 2,850 m2/g, about 2,900 m2/g, about 2,950 m2/g, or about 3,000 m2/g, where any value can be a lower and upper endpoint of a range (e.g., about 2,600 m2/g to about 2,900 m2/g, about 2,650 m2/g to about 2,850 m2/g, etc.).
In one aspect, the organic frameworks described herein have a Brunauer-Emmett-Teller (BET) surface area of about 600 m2/g to about 800 m2/g, or about 600 m2/g, about 610 m2/g, about 620 m2/g, about 630 m2/g, about 640 m2/g, about 650 m2/g, about 660 m2/g, about 670 m2/g, about 680 m2/g, about 690 m2/g, 700 m2/g, 710 m2/g to about 720 m2/g, or about 730 m2/g, about 740 m2/g, about 750 m2/g, about 760 m2/g, about 770 m2/g, about 780 m2/g, about 790 m2/g, or 800 m2/g, where any value can be a lower and upper endpoint of a range (e.g., about 610 m2/g to about 790 m2/g, about 650 m2/g to about 750 m2/g, etc.).
In one aspect, the organic frameworks described herein have a total pore volume of about 0.10 cm3/g to about 0.70 cm3/g, or about 0.10 cm3/g, about 0.15 cm3/g, about 0.20 cm3/g, about 0.25 cm3/g, about 0.30 cm3/g, about 0.35 cm3/g, about 0.40 cm3/g, about 0.45 cm3/g, about 0.50 cm3/g, about 0.55 cm3/g, about 0.60 cm3/g, about 0.65 cm3/g, or about 0.70 cm3/g, where any value can be a lower and upper endpoint of a range (e.g., about 0.20 cm3/g to about 0.60 cm3/g, about 0.35 cm3/g to about 0.55 cm3/g, etc.).
Due to their unique structures and physical properties, the frameworks described herein can be used in numerous applications. The frameworks described herein possess optoelectronic properties. Not wishing to be bound by theory, the organic frameworks described herein have favorable electron delocalization on the polymeric backbone with extended 7-conjugations and layer stacking architectures, forming periodic columnar 7-arrays with significant electronic overlap.
In one aspect, the organic frameworks described herein can generate singlet oxygen when irradiated. The development of methodologies for efficiently producing 1O2 has numerous applications in photodynamic applications. In one aspect, the organic framework can produce singlet oxygen when irradiated by a laser or a xenon lamp at a wavelength of about 200 nm to about 2,000 nm, or about 200 nm, about 300 nm, about 400 nm, about 500 nm about, about 600 nm, about 700 nm, about 800 nm, about 900 nm, about 1,000 nm, about 1,200 nm, about 1,400 nm, about 1,600 nm, or about 2,000 nm, where any value can be a lower and upper endpoint of a range (e.g., about 300 nm to 1,800 nm, about 500 nm to about 800 nm, etc.). The Examples provide techniques for producing and detecting singlet oxygen produced from the organic frameworks described herein.
In one aspect, the frameworks described herein are useful as photocatalysts. In one aspect, described herein are methods for oxidizing an organic compound comprising exposing the organic compound to oxygen in the presence of the organic framework as described herein and irradiating the organic framework.
In one aspect, the organic frameworks described herein can be used to convert toxic chemicals to inert compounds. One such toxic chemical is nerve agents. As one of the most broadly used and notorious chemical weapons, sulfur mustard can cause grievous skin blisters and irritation to the respiratory system or even death at high doses.64 In one aspect, the nerve agent is a halo-sulfo compound. In another aspect, the nerve agent is 2-chloroethyl ethyl sulfide or bis(2-chloroethyl) sulfide, diisopropyl phosphorofluoridate, dimethyl methylphosphonate, diethylsulfane, or 3,3-dimethylbutan-2-yl methylphosphonofluoridate. As demonstrated in the Examples, an organic framework oxidized a sulfur mustard simulant 2-chloroethyl ethyl sulfide (CEES) within 1 hour.
The organic frameworks described herein can be incorporated or used in batch or continuous processes.
Due to the ability of the organic frameworks described herein to oxidize certain organic molecules such as harmful sulfides, the organic frameworks can be applied to fibers used to produce textiles, where the textiles can be worn by personnel that are exposed to harmful compounds such as, for example, mustard gas.
The fibers can be coated with the organic framework using techniques known in the art. In one aspect, the fibers are immersed in a solution of the organic framework then subsequently died. In certain aspect, the fiber can be pre-coated to enhance adhesion of the organic framework to the fiber. In one aspect, the fiber is coated with poly-dopamine followed by coating with the organic framework. Exemplary procedures for producing coated fibers are provided in the Examples. In one aspect, the fiber is a synthetic fiber such as, for example, a polyester, a polyamide (e.g., nylon), a polyalkylene oxide fiber, a glass fiber. In another aspect, the fiber is a natural fiber such as, for example, cotton, wool, or silk.
The following listing of exemplary aspects supports and is supported by the disclosure provided herein.
Aspect 1. An organic framework comprising a plurality of structural units comprising the formula I
wherein Ar is a fused aromatic group, and
EC is an electron-deficient chromophore.
Aspect 2. The organic framework of claim 1, wherein the fused aromatic group comprises 2 to 10 fused aromatic groups.
Aspect 3. The organic framework according to aspect 1, wherein the fused aromatic group comprises naphthalene, anthracene, acenaphthene, acenaphthylene, fluorene, phenalene, phenanthrene, benzo[a]anthracene, benzo[a]fluorine, benzo[c]phenanthrene, chrysene, fluoranthene, tetracene, anthanthrene, benzopyrene, pyrene, benzo[a]pyrene, benzo[e]pyrene, benzo[b]fluoranthene, benzo[j]fluoranthene, benzo[k]fluoranthene, corannulene, coronene, dicoronylene, diindenoperylene, helicene, heptacene, hexacene, kekulene, ovalene, pentacene, perylene, picene, or tetraphenylenepentacene.
Aspect 4. The organic framework according to aspect 1, wherein the fused aromatic group comprises a pyrene.
Aspect 5. The organic framework according to aspect 1, wherein the fused aromatic group is substituted with 2 to 8 aryl groups.
Aspect 6. The organic framework according to aspect 1, wherein the fused aromatic group comprises the structure of formula II
Aspect 7. The organic framework according to aspect 1, wherein the electron-deficient chromophore comprises a thiadiazole, a triazine, a heptazine, or an oxadiazole.
Aspect 8. The organic framework according to aspect 1, wherein the electron-deficient chromophore comprises the structure of formula III
Aspect 9. The organic framework according to aspect 1, wherein the structural unit has the formula IV
Aspect 10. The organic framework according to aspect 9, wherein L is not present.
Aspect 11. The organic framework according to aspect 1, wherein the framework comprises a plurality structural units having the structure depicted in
Aspect 12. An organic framework produced by reacting a fused aromatic group substituted with three or more amino groups with an electron-deficient chromophore comprising two aldehyde groups.
Aspect 13. The organic framework according to aspect 12, wherein the fused aromatic group is 1,3,6,8-tetrakis(4-aminophenyl)pyrene.
Aspect 14. The organic framework according to aspect 12, wherein the electron-deficient chromophore comprising two aldehyde groups comprises the formula V
Aspect 15. An organic framework produced by reacting a fused aromatic group substituted with three or more aldehyde groups with an electron-deficient chromophore comprising two amino groups.
Aspect 16. The organic framework according to aspect 15, wherein the fused aromatic group is 4,4′,4″,4′″-(pyrene-1,3,6,8-tetrayl)tetrabenzaldehyde.
Aspect 18. The organic framework according to aspect 15, wherein the electron-deficient chromophore comprising two amino groups comprises the formula VI
Aspect 18. The organic framework according to any one of aspects 1-17, wherein the framework comprises an AA stacking structure.
Aspect 19. The organic framework according to any one of aspects 1-18, wherein the framework comprises a plurality of channels, wherein the pore size of the channels is from about 0.5 nm to about 4 nm.
Aspect 20. The organic framework according to any one of aspects 1-19, wherein the framework has a Connolly surface area of about 2,500 m2/g to about 3,000 m2/g.
Aspect 21. The organic framework according to any one of aspects 1-20, wherein the framework has a Brunauer-Emmett-Teller (BET) surface area of about 600 m2/g to about 800 m2/g.
Aspect 22. The organic framework according to any one of aspects 1-21, wherein the framework has a total pore volume of about 0.1 cm3/g to about 0.7 cm3/g.
Aspect 23. The use of the organic framework according to any one of aspects 1-22 as a photocatalyst.
Aspect 24. A method for generating singlet oxygen, the method comprising irradiating the organic framework according to any one of aspects 1-22.
Aspect 25. The method according to aspect 24, wherein the organic framework is irradiated by a laser or a xenon lamp.
Aspect 26. The method according to aspects 24 or 25, wherein the organic framework is irradiated at a wavelength of about 200 nm to about 2,000 nm.
Aspect 27. A method for oxidizing an organic compound, comprising exposing the organic compound to oxygen in the presence of the organic framework according to any one of aspects 1-22 and irradiating the organic framework.
Aspect 28. The method according to aspect 27, wherein the organic compound is a diene or sulfide.
Aspect 29. The method according to aspects 27 or 28, wherein the method is conducted in a batch process or continuous process.
Aspect 30. A fiber comprising a coating of the organic framework according to any one of aspects 1-22.
Aspect 31. The fiber according to aspect 30, wherein the fiber comprises a synthetic fiber.
Aspect 32. The fiber according to aspect 31, wherein the synthetic fiber comprises a polyester, a polyamide, a polyalkylene oxide fiber, a glass fiber.
Aspect 33. The fiber according to aspect 30, wherein the fiber comprises a natural fiber.
Aspect 34. The fiber according to aspect 33, wherein the natural fiber comprises cotton, wool, or silk.
The following examples are put forth so as to provide those of ordinary skill in the art with a complete disclosure and description of how the compounds, compositions, and methods described and claimed herein are made and evaluated, and are intended to be purely exemplary and are not intended to limit the scope of what the inventors regard as their invention. Efforts have been made to ensure accuracy with respect to numbers (e.g., amounts, temperature, etc.) but some errors and deviations should be accounted for. Unless indicated otherwise, parts are parts by weight, temperature is in ° C. or is at ambient temperature, and pressure is at or near atmospheric. Numerous variations and combinations of reaction conditions (e.g., component concentrations, desired solvents, solvent mixtures, temperatures, pressures, and other reaction ranges and conditions) can be used to optimize the product purity and yield obtained from the described process. Only reasonable and routine experimentation will be required to optimize such process conditions.
Solvents were purified according to standard laboratory methods. Other commercially available reagents were purchased in high purity and used without further purification.
1,3,6,8-tetrabromopyrene (1): To a mixture of pyrene (5.05 g, 25.0 mmol) and nitrobenzene (200 mL), Br2 (110 mmol in 100 mL of nitrobenzene) was added dropwise. After the addition was complete, the resulting yellow suspension was heated at 120° C. for 18 h and then cooled to room temperature. The precipitate was filtered off, washed with ethanol, and dried under vacuum to yield 1,3,6,8-tetrabromopyrene as a pale yellow solid. The product was found to be insoluble in all common organic solvents, limiting characterization.
1,3,6,8-tetrakis(4-aminophenyl)pyrene (2): 1,3,6,8-tetrabromopyrene (2.96 g, 5.72 mmol), 4-aminophenylboronic acid pinacol ester (6.0 g, 27.4 mmol), K2CO3 (4.4 g, 31.6 mmol), and Pd(PPh3)4 (0.66 g, 0.589 mmol) were introduced into a mixture of 1,4-dioxane (100 mL) and H2O (20 mL). The resulting mixture was refluxed under N2 atmosphere for 3 d. After cooling to room temperature, the solution was poured into water. The formed precipitate was filtered off, and washed with water and methanol, which was further purified by flash chromatography with acetone as eluent to afford the title compound as a yellow-brown solid. 1H NMR (400 MHz, d6-DMSO, 298K, TMS): δ 8.13 (s, 4H), 7.79 (s, 2H), 7.35 (d, 8H, J=8.4 Hz), 6.77 (d, 8H, J=8.0 Hz), 5.32 (s, 8H) ppm.
4,4′,4″,4′″-(pyrene-1,3,6,8-tetrayl)tetrabenzaldehyde. 1,3,6,8-tetrabromopyrene (2.96 g, 5.72 mmol), 4-formylphenylboronic acid (4.12 g, 27.4 mmol), K2CO3 (4.4 g, 31.6 mmol), and Pd(PPh3)4 (0.66 g, 0.58 mmol) were introduced into 1,4-dioxane (100 mL). The resulting mixture was refluxed under N2 atmosphere for 3 d. After cooling to room temperature, the solution was poured into water. The formed precipitate was filtered off, and washed with water and acetone. After dying, the resulting solid was Soxhlet extracted with chloroform for one weak. The title product was obtained as a yellow solid after evaporating CHCl3. 1H NMR (400 MHz, CDCl3, 298K, TMS): δ 10.17 (s, 4H), 8.18 (s, 4H), 8.10 (d, 8H, J=8.0 Hz), 8.05 (d, 2H), 7.86 (d, 8H, J=8.0 Hz) ppm.
1,1,2,2-tetrakis(4-nitrophenyl)ethane (4): To a solution of fuming nitric acid (40 mL) and acetic acid (40 mL) at 0° C., 1,1,2,2-tetraphenylethene (5 g) was added in portions. The resulting mixture was allowed to warm to RT and stirred for another 3 h. The solution was poured into ice water and the precipitate was filtered off, washed with water and recrystallized from 1,4-dioxane to yield 4 as yellow crystals. 1H NMR (400 MHz, d6-DMSO, 298K, TMS) δ 8.1 (d, 8H, J=8.0 Hz), 7.36 (d, 8H, J=8.4 Hz).
1,1,2,2-tetrakis(4-aminophenyl)ethane (5): A suspension of 1,1,2,2-tetrakis(4-nitrophenyl)ethane (2.5 g, 4.88 mmol) and Pd/C (5 wt. %, 0.25 g) in ethanol (80 mL) was heated to reflux. Hydrazine hydrate (15 mL) was added dropwise, and the mixture was refluxed overnight. The hot solution was filtered through Celite and all volatiles were evaporated under vacuum, yielding the title compound as a yellow powder. 1H NMR (400 MHz, d6-DMSO, 298K, TMS): δ 6.57 (s, 8H), 6.26 (d, 8H, J=8.0 Hz), 4.86 (s, 8H) ppm.
4,7-dibromobenzo[c][1,2,5]thiadiazole (6). A solution of Br2 (35.2 g, 220.3 mmol) in HBr (100 mL) was added dropwise to the mixture of benzothiadiazole (10.0 g, 73.4 mmol) and HBr (150 mL, 48 wt. %). The resulting mixture was heated at reflux for 6 h, yielding a dark orange solid. The mixture was cooled to RT and poured to a NaHSO3 saturated solution to consume any excess Br2. The resulting mixture was filtered and washed exhaustively with water. The obtained solid was then washed with cold Et2O and dried under vacuum to afford 6 as a light yellow solid. 1H NMR (400 MHz, d6-DMSO, 298K, TMS): δ 7.92 (s, 2H) ppm.
4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dianiline (7). 6 (1.67 g, 5.7 mmol), 4-aminophenylboronic acid pinacol ester (3.0 g, 13.7 mmol), Pd(PPh3)4 (0.23 g, 0.2 mmol), and K2CO3 (3.8 g, 27.4 mmol) were introduced into the mixture of 1,4-dioxane (60 mL) and H2O (10 mL). The resulting mixture was stirred at 110° C. for 3 d under N2 atmosphere. The residue was extracted with ethyl acetate, washed with brine, dried over Na2SO4, and evaporated under reduced pressure, giving the crude compound which was purified by flash chromatography with hexane/ethyl acetate (1:1) as eluent to afford the title compound as a yellow solid. 1H NMR (400 MHz, CDCl3, 298K, TMS): δ 7.74 (d, 4H, J=8.4 Hz), 7.60 (s, 2H), 6.77 (d, 4H, J=8.4 Hz) ppm.
4,4′-(benzo[c][1,2,5]thiadiazole-4,7-diyl)dibenzaldehyde (6) (1.67 g, 5.7 mmol), 4-formylphenylboronic acid (2.06 g, 13.7 mmol), Pd(PPh3)4 (0.23 g, 0.2 mmol), and K2CO3 (3.8 g, 27.4 mmol) were introduced into the mixture of 1,4-dioxane (60 mL) and H2O (10 mL). The resulting mixture was stirred at 110° C. for 3 d under N2 atmosphere. The residue was extracted with dichloromethane, washed with brine, dried over Na2SO4, and evaporated under reduced pressure, giving the crude compound which was purified by flash chromatography with hexane/dichloromethane (2:3) as eluent to afford the title compound as a red solid. 1H NMR (400 MHz, d6-DMSO, 298K, TMS): δ 10.06 (d, 2H, J=17.2 Hz), 8.24 (d, 2H, J=8.0 Hz), 8.00-8.07 (m, 4H), 7.92 (d, 2H, J=7.6 Hz), 7.48-7.68 (m, 2H) ppm.
A Schlenk tube (5 mL) was charged with 3 (20.6 mg, 0.033 mmol) and 7 (21.2 mg, 0.066 mmol) in 1.1 mL of a 5:5:1 v/v/v solution of 1,2-dichlorobenzene/n-butylalcohol/6 M aqueous acetic acid. The tube was flash frozen at 77 K (liquid N2 bath), evacuated, and sealed. The reaction mixture was heated at 120° C. for 3 days to afford a red brick precipitate which was isolated by filtration and washed with anhydrous CHCl3 using Soxhlet extraction for 3 d. The product was dried under vacuum to afford the Py-Td COF. CHN calculated for C40H23N4S: C, 81.2; H, 3.9; N, 9.5%. Found: C, 80.5; H, 4.0; N, 9.4%.
A Schlenk tube (5 mL) was charged with 5 (19.6 mg, 0.05 mmol) and 8 (34.4 mg, 0.1 mmol) in 1.1 mL of a 5:5:1 v/v/v solution of 1,2-dichlorobenzene/n-butylalcohol/6 M aqueous acetic acid. The tube was flash frozen at 77 K (liquid N2 bath), evacuated, and sealed. The reaction mixture was heated at 120° C. for 3 days to afford an orange-red precipitate which was isolated by filtration and washed with anhydrous THF using Soxhlet extraction for 3 d. The product was dried under vacuum to afford the Etta-Td COF. The product was dried under vacuum to afford the Py-Td COF. CHN calculated for C16H10NS: C, 76.7; H, 4.4; N, 8.0%. Found: C, 76.2; H, 4.6; N, 7.8%.
A Schlenk tube (5 mL) was charged with 2 (28.3 mg, 0.05 mmol) and 3 (30.9 mg, 0.05 mmol) in 1.1 mL of a 5:5:1 v/v/v solution of 1,2-dichlorobenzene/n-butylalcohol/6 M aqueous acetic acid. The tube was flash frozen at 77 K (liquid N2 bath), evacuated, and sealed. The reaction mixture was heated at 120° C. for 3 days to afford an orange precipitate which was isolated by filtration and washed with anhydrous CHCl3 using Soxhlet extraction for 3 d. The product was dried under vacuum to afford the Py-Py COF. The product was dried under vacuum to afford the Py-Py COF. CHN calculated for C21H12N: C, 90.6; H, 4.4; N, 5.0%. Found: C, 90.5; H, 4.6; N, 4.8%.
A Schlenk tube (10 mL) was charged with 3 (75.6 mg, 0.24 mmol) and 5 (48.0 mg, 0.12 mmol) in 2.2 mL of a 5:5:1 v/v/v solution of 1,2-dichlorobenzene/n-butylalcohol/6 M aqueous acetic acid. The tube was flash frozen at 77 K (liquid N2 bath), evacuated, and sealed. The reaction mixture was heated at 120° C. for 3 days to afford a yellow precipitate which was isolated by filtration and washed with anhydrous CHCl3 using Soxhlet extraction for 3 d. The product was dried under vacuum to afford the Etta-Py COF. The product was dried under vacuum to afford the Etta-Py COF. CHN calculated for C35H21N2: C, 89.5; H, 4.5; N, 6.0%. Found: C, 98.5; H, 4.9; N, 5.9%.
To the mixture of 3 (50 mg, 0.08 mmol) and 7 (51.4 mg, mmol) in a Schlenk tube, DMSO (4 mL) was introduced. After being stirred at room temperature for 12 h and then 120° C. for 3 d, the title product was isolated by filtration, washed with anhydrous CHCl3 using Soxhlet extraction for 3 d, and dried under vacuum at 50° C. The product was dried under vacuum to afford the Py-Td COF. CHN calculated for C40H23N4S: C, 81.2; H, 3.9; N, 9.5%. Found: C, 80.3; H, 4.1; N, 9.3%.
To achieve the title composite materials, the melamine foam and nylon-66 fabric were coated with a layer of poly-dopamine, by soaking in a dopamine Tris-HCl solution (pH=8.5) for 24 h. After that, the substrates were filtered, rinsed with deionized water and acetone, and dried under vacuum to yield the poly-dopamine coated materials. The Py-Td COF crystals coated melamine foam/nylon-66 fabric was achieved by immersion the corresponding poly-dopamine coated materials into the Py-Td COF synthetic system as described above.
General Procedure for Photocatalytic Transformation of α-Terpinene to Ascaridole. A Schlenk tube (5 mL) was charged with CHCl3 (1 mL), α-terpinene (1 mmol), and photocatalyst (5 mg). The mixture was saturated with 02, and magnetically stirred at room temperature under irradiation of blue LED modules with a power of 10 W/m (total 10 W). Once the reaction was completed, the photocatalyst was collected by centrifugation and the solvent was removed under vacuum. The yields were determined by 1H NMR.
General Procedure for Photocatalytic Oxidation of Sulfides. A Schlenk tube (5 mL) was charged with CH3CN (1 mL), sulfides (5 μL), and photocatalyst (5 mg). The mixture was saturated with 02 and magnetically stirred at room temperature under irradiation of 280 W white Xe lamp. Once the reaction was completed, the photocatalyst was collected by centrifugation, and the solvent was removed under vacuum. The conversions and selectivity were determined by 1H NMR on the basis of the ratio between integrated peaks of products and substrate after dissolving in CDCl3.
General Procedure for Photocatalytic Reactions in Flow Employing Py-Td. The fix-bed reaction system was prepared as follows: 0.5 g of silica gel was placed at the bottom of the glass column, and then the mixture of 20 mg of Py-Td and 1 g of silica gel (200 mesh) was introduced, which was covered by another 0.5 g of silica gel. The column was fitted to a light source, and the solution was pumped through the column at 1.0 mL h−1. Concurrently, oxygen was pumped through a second pump at a flow rate of 1 mL min−1. The solution was collected at an interval of 1 h, and the yield was analyzed by 1H NMR.
The Natural Transition Orbital (NTO) particle-hole representation of the repeat units of COF materials (Py-Td, Etta-Td, Py-Py, and Etta-Py from top to bottom, respectively), were optimized with B3LYP/6-31 G(d) basis set implemented in Gaussian 09 program package.
The density functional theory (DFT) calculations associated with band structure were carried out by CASTEP. [Cryst. Mater. 2005, 220, 567-570.] The generalized gradient approximation (GGA) of Perdew-Burke-Ernzerhof (PBE) [Phys. Rev. Lett. 1996, 77, 3865-3868.] was used, and dispersion interaction was considered by Grimme's DFT-D correction [J. Chem. Phys. 2010, 132, 154104.] during the geometrical optimization with Gamma point (1×1×1) for Brillounin Zone integrations. In the band structure and density of state calculations, the 1×1×2 (Etta-Td) and 3×1×1 (Py-Td) Monkhorst-Pack grid was utilized for Brillounin Zone integrations along with ultrasoft pseudopotentials. The SCF tolerance was set as 5×10−7 eV/atom, and the energy, force, stress, and displacement were converged to 5×10−6 eV/atom, 0.01 eV/A, 0.02 GPa and 5×10−6 Å during the optimization.
The Mott-Schottky plots were carried out with a CHI660E workstation (ShangHai ChenHua, China) via a conventional three-electrode system in a 0.2 M Na2SO4 aqueous solution. The working electrode was prepared as follows: A COF material (2 mg) was dispersed in a mixed solution of ethanol (1 mL) and Nafion D-520 (10 μL) to form a homogeneous slurry. Subsequently, 200 μL of the slurry was transferred and coated on an ITO glass plate (1 cm×2 cm), and then dried at room temperature. The Ag/AgCl electrode was employed as the reference electrode, and a platinum plate was used as the counter electrode, respectively.
Cyclic Voltammetry: The working electrode was prepared by drop casting an ethanol suspension of the COF material, carbon black, and polytetrafluoroethylene (PTFE) (2:7:1 by weight) onto a glassy carbon electrode. Tetrabutylammonium hexafluorophosphate (0.1 M, acetonitrile) was used as an electrolyte. The counter and reference electrodes were Pt wire and Ag/AgNO3. Ferrocene was used as a standard to calculate the energy levels vs. vacuum.
Powder samples: Approximately 1 mg of Py-Td was loaded in a borosilicate capillary tube (0.70 mm i.d./1.25 mm o.d.; VitroGlass, Inc.). Both ends of the tube were sealed with wax. The sealed sample was then mounted in a Varian E-109 spectrometer fitted with a cavity resonator. The continuous wave (CW) EPR spectrum was acquired with an observe power of 12.5 mW and modulation amplitude of 2 G. The main frequency is 9.550 GHz. The scan range is 100 G, from 3300 G to 3400 G. Signal average time is about 20 min. The sealed sample was then irradiated with a 457 nm visible lamp for 60 min, followed by the same EPR studies.
Spin trapping studies for O2.− detection: Approximately 1 mg of Py-Td was suspended in 50 μL of acetonitrile containing 50 mM DMPO and loaded in a borosilicate capillary tube. Both ends of the tube were sealed with wax. The sealed sample was then irradiated for 60 min, followed by mounting in a Varian E-109 spectrometer fitted with a cavity resonator. The continuous wave (CW) EPR spectrum was acquired with an observe power of 12.5 mW and modulation amplitude of 2 G. The main frequency is 9.550 GHz. The scan range is 100 G, from 3300 G to 3400 G. Signal average time is around 20 min.
Spin trapping studies for 1O2 detection: The experiments were performed followed the same procedures as for O2.− detection except that 50 mM TEMP was used instead of 50 mM DMPO.
The crystalline structures of the COFs were constructed using Materials Studio and the geometry and unit cell were optimized by Forcite method. Universal force field and Quasi-Newton algorithm were used for calculation. The XRD pattern simulations were performed in a software package for crystal determination from PXRD pattern, implemented in MS modeling. We performed Pawley refinement to optimize the lattice parameters iteratively until RWP value converges. The pseudo-Voigt profile function was used for whole profile fitting and Berrar-Baldinozzi function was used for asymmetry correction during the refinement processes. The final RWP value was 2.1, 5.6, 5.8, and 7.0 for Py-Td, Py-Py, Etta-Py, and Etta-Td, respectively.
Physiochemical Characterization and Local Structure Analysis. These materials were synthesized under acid-catalyzed solvothermal conditions. The formation of the imine linkage in all synthesized COFs was verified by Fourier-transform infrared spectroscopy (FT-IR), where we observed the appearance of characteristic C═N stretching modes at 1620 cm−1, as well as a complete disappearance of N—H stretching of the primary amines (3370-3210 cm−1) and aldehyde band (2800-2720 cm−1) from the monomers (
aThe Connolly surface area was determined by Platon.
The powder X-ray diffraction (PXRD) pattern of Py-Td contains several prominent diffraction peaks, indicating the high crystallinity of the material. The identification of the resulting structure was done through a comparison of structures modeled using Materials Studio (
The Py-Py and Etta-Py COFs are also highly crystalline frameworks, as established by the intense reflections in the PXRD patterns. Structure elucidation revealed that these two COFs shared the same symmetry of P2/m with a similar pseudo-quadratic geometry as that of the Py-Td COF. Both samples showed reversible type I isotherms, indicative of the uniform microporous structure of these materials. Fitting these isotherms gave BET surface areas of 958 and 1858 m2 g−1 and pore size distributions peaking at 1.50 and 1.30 nm for Py-Py and Etta-Py, respectively. With respect to the Etta-Td COF, the PXRD analysis revealed that it crystallized in the P6m space group with a structure that was in excellent agreement with the proposed AA-stacking mode of a dual-pore Kagome structure. Derived from N2 sorption isotherms, the calculated BET surface area for this material was 749 m2 g−1 with two different pore sizes predominantly distributed at ca. 3.8 and 1.5 nm, assignable to the hexagonal mesopores and triangular micropores, respectively.
Optical Property Investigation. Given that a material's optical bandgap and energy level alignment have profound consequences on its photoreactivity, these properties of the resulting COFs were investigated through a combination of UV-vis spectroscopy, Mott-Schottky analysis, cyclic voltammetry (CV) measurement, and DFT calculation for cross-validation. In order to examine optical absorption profiles, UV-vis spectroscopy measurements were carried out, showing distinct differences among these COFs. Etta-Py exhibited an absorption maximum at 470 nm, with an absorbance edge at around 563 nm. In comparison, the spectra of the other three COFs are extended to broader regions, with a comparable maximum absorption peak of 514 nm; the absorption onsets are redshifted in the order of Etta-Td>Py-Td>Py-Py (
To gain detailed information about the energy level alignment of the COFs, Mott-Schottky electrochemical measurements were performed (
Catalytic Performance Evaluation. Among the developed photocatalytic transformations, molecular oxygen (O2) involving oxidation reactions have been of great interest, whereby active oxygen species can be generated via the energy or electron transfer pathway from photocatalyst to O2. Given the oxidizing and electrophilic properties of 1O2, this species has been under scrutiny and proven useful in a variety of applications58. These materials were thus initially examined as triplet photosensitizers in the 1O2 production. To evaluate the efficiency in photogenerated 1O2, their performances in the Alder-Ene reaction with α-terpinene as a trapping reagent were tested, as this only proceeds with 1O2, therefore facilitating comparisons59. The production of 1O2 over various materials was monitored by calculating the conversion of α-terpinene into ascaridole (Table 3). To confirm the 1O2 generation mechanism, three control experiments were first conducted as follows: (i) in the absence of any photosensitizer; (ii) in the dark and in the presence of photosensitizing material; and (iii) in the dark and with heating with the COFs. Each of these controls showed no ascaridole yield, which is, therefore, indicative of no 1O2 generated under the above conditions (Table 3, entries 1-3).
a Standard reactions were conducted with 1 mmol of α-terpinene, 5
b Yields were determined by 1H NMR analysis.
An 84% conversion of α-terpinene to ascaridole was detected after 3 h of irradiation in the presence of Py-Td under the 420 nm LED modules (Table 3, entry 4). Under otherwise identical conditions, its amorphous counterpart, Py-Td-POP (BET: 477 m2 g−1,
To experimentally prove this, the performance of all the struts involved in the COF syntheses were evaluated, resulting in inferior or comparable activities to the COFs (Table 3, entries 9-11). Taken together, the divergent outcomes of these COFs may not be pinpointed to a single factor change but rather considered a result of a complex interplay of several aspects. An increase in photoabsorption and proper energy level alignment can be used to explain the superior performance of Py-Td in comparison with Etta-Py and Py-Py. However, in the cases of Py-Td and Etta-Td, only a very weak correlation between the catalytic performance and the photoproperties could be established, given that Etta-Td with a broader photoabsorption range and lower LOMO energy level than Py-Td offered an inferior result. Therefore, their activity discrepancy may be ascribed to their differences in charge carrier lifetime, another critical parameter for an efficient photocatalyst. Indeed, computational studies reveal that Etta-Py with P6m symmetry exhibits a nearly flat and overlapped top valence band, resulting in high charge-carrier effective masses60. In contrast, the top valence band of Py-Td with C2/m symmetry displays a significant dispersion, giving superior charge-carrier mobility (
Considering the efficiency in the generation of 1O2, this prompted investigations into the potential of these materials in other chemical transformations. Among the developed catalytic reactions that involved triplet photosensitizers, we were interested in the photooxidation of organic sulfides. Given the superior performance, Py-Td was our choice for detailed investigations. The reactivity of Py-Td under visible light was investigated by the photooxidation of thioanisole61. A full conversion of thioanisole to the desired mono-oxidized product methyl phenyl sulfoxide with a selectivity of 96% was obtained (Table 4, entry 1). Photooxygenation of sulfides involves either an energy-transfer process, whereby 1O2 reacts with sulfides to afford the sulfoxides, or an electron transfer process, whereby a superoxide radical (O2.−) acts as an electron mediator in the photoredox cycle. To detect the generated reactive oxygen species by Py-Td, electron paramagnetic resonance (EPR) measurements were carried out. Both EPR signals for 1O2 and O2.− were unequivocally detected when 2,2,6,6-tetra-methyl-1-piperidine (TEMP) and 5,5′-dimethyl-1-pyrroline N-oxide (DMPO), respectively, were used as trapping agents (
aGeneral reaction conditions: Py-Td (5 mg), thioanisole (1 mmol), acetonitrile (1 mL), Xe lamp, O2, and RT.
b The selectivity was calculated based on the ratio of methyl phenyl sulfoxide and methyl phenyl sulfone in the products, which were determined by 1H NMR.
c Reuse.
d Recycled for 5 times.
To obtain more information about the reaction pathway, the role of each reactive oxygen species was investigated. When p-benzoquinone (BQ), an O2.− scavenger, was introduced to the reaction system, the conversion of thioanisole decreased to 72%, indicative of the role of O2.−. To identify the role of 1O2, the singlet oxygen scavenger, sodium azide (NaN3), was introduced to the reaction system, and the conversion of thioanisole decreased slightly to 93%. Using ethene-1,1,2,2-tetracarbonitrile as a hole scavenger, only 7% of the conversion was measured. A sharply decreased yield (8%) was also observed with 10H-phenothiazine as an electron scavenger (Table 4)62,63. Based on these results, a plausible reaction mechanism for the Py-Td catalyzed the oxidation of sulfides is proposed. The excited Py-Td* experiences an oxidative quenching process by the transfer of electrons to O2. Through a redox reaction, the sulfides are oxidized by the holes in the valence band of the photosensitizer with the simultaneous regeneration of Py-Td and formation of sulfide radical cation, which is further oxidized by O2.− or 1O2 to afford the desired products.
To expand the applicability of this material, experiments were carried out in batch under natural sunlight irradiation as an alternative to the Xe lamp. Full conversion was achieved within 30 min in the presence of Py-Td. Using sunlight, along with superior performance, we were able to validate the efficiency of the Py-Td COF, thus implying its potential for low-environmental-impact transformations.
To explore the versatility of the Py-Td catalyst, a number of sulfide derivatives were evaluated. Various aryl sulfide substrates bearing chlorine, fluorine, methoxy, and methyl functionalities could be selectively oxidized with moderate to high conversions (Table 5). The applicability of Py-Td for sulfur mustard simulant oxidation was investigated. As one of the most broadly used and notorious chemical weapons, sulfur mustard can cause grievous skin blisters and irritation to the respiratory system or even death at high doses64. The selective oxidative detoxification of sulfur mustard to sulfoxide is a promising route. In this context, the capability of Py-Td in the oxidation of a sulfur mustard simulant 2-chloroethyl ethyl sulfide (CEES) was evaluated, affording full conversion within 1 h and thereby exhibiting great potential for rapidly and highly selectively detoxifying sulfur mustard (Table 5, entry 6).
aGeneral reaction conditions: Py-Td (5 mg), sulfide compound (1 mmol), acetonitrile (1 mL), Xe lamp (λ > 420 nm), O2, and RT.
b The selectivity was calculated based on the ratio of methyl phenyl sulfoxide and methyl phenyl sulfone in the products, which were determined by 1H NMR.
Catalytic Performance Evaluation in a Continuous Flow Reactor. A continuous flow experiment was conducted using Py-Td with the experimental setup described in
Incorporation of COFs into Fabrics and Textiles. Py-Td was integrated with protective fabrics to combine the self-detoxifying properties of the COF with the air permeation of textiles. To target this, nylon-66 fabric was chosen for its chemical resistance and mechanical strength. To increase the affinity between the substrate and the COF for potential application in process-intensive conditions, the fabric was first modified with poly-dopamine, followed by a bottom-up synthetic pathway, by submerging it hem into the system for COF synthesis. The SEM images indicate the successful deposition of the Py-Td COF crystals on it (
From the foregoing, it will be seen that aspects herein are well adapted to attain all the ends and objects hereinabove set forth together with other advantages which are obvious and which are inherent to the structure.
It will be understood that certain features and subcombinations are of utility and may be employed without reference to other features and subcombinations. This is contemplated by and is within the scope of the claims.
Since many possible aspects may be made without departing from the scope thereof, it is to be understood that all matter herein set forth or shown in the accompanying drawings is to be interpreted as illustrative and not in a limiting sense.
Various modifications and variations can be made to the compounds, compositions and methods described herein. Other aspects of the compounds, compositions and methods described herein will be apparent from consideration of the specification and practice of the compounds, compositions and methods disclosed herein. It is intended that the specification and examples be considered as exemplary.
This application claims priority upon U.S. provisional application Ser. No. 62/935,726 filed on Nov. 15, 2019. This application is hereby incorporated by reference in its entirety.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2020/060556 | 11/13/2020 | WO |
| Number | Date | Country | |
|---|---|---|---|
| 62935726 | Nov 2019 | US |
