Patent Application
20200369697
The invention relates to molybdenum oxo alkylidene complexes, methods of making same and use thereof in metathesis reactions.
Imido alkylidene complexes of molybdenum and tungsten are frequently used as catalysts in metathesis reactions of olefins because an imido ligand was thought to be less likely than an oxo ligand to bridge between metals or to be attacked by an electrophile and removed, and thus to lose activity.
An approach to tungsten oxo alkylidenes allowed several examples that contain sterically demanding ligands to be prepared and their reactions explored (WO 2013/070725). Accordingly, a tungsten oxo alkylidene complex was the first high oxidation state complex to be prepared that would react with an olefin to give the new alkylidene expected from olefin metathesis. Contrary to this, isolable molybdenum oxo alkylidene complexes that are active for metathesis of olefins have remained elusive.
Two crystallographically characterized molybdenum oxo alkylidene thiolate complexes were prepared from Mo(IV) thiolate hydride complexes, phenylacetylene, and water, however, their olefin metathesis activities were not addressed (Fairhurst, S. A.; Hughes, D. L.; Marjani, K.; Richards, R. L. J. Chem. Soc., Dalton Trans. 1998, 1899-1904. Hughes, D. L.; Marjani, K.; Richards, R. L. J. Organomet. Chem. 1995, 505, 127-129).
Mo oxo alkylidene complex, Mo(O)(CHSiMe3)[NP(t-Bu)3]2, was prepared via a five-coordinate bistrimethylsilylmethyl intermediate (Varjas, C. J.; Powell, D. R.; Thomson, R. K. Organometallics 2015, 34, 4806-4809). However, the steric and electronic properties of the [NP(t-Bu)3]− ligand prevent facile initiation of olefin metathesis reactions, even upon “activating” Mo(O)(CHSiMe3)[NP(t-Bu)3]2 through addition of B(C6F5)3 which is known to bind to the oxo ligand, a process that has been proposed to accelerate reactions of tungsten-based oxo alkylidene complexes with olefins by at least two orders of magnitude.
Due to the growing importance of metathesis reactions not only at laboratory scale but in particular at industrial scale, there is an ongoing need for developing new catalysts and to test them for suitability in various types of metathesis reactions using various olefins to be metathesized. Thus, it was the object of the present invention to provide isolable molybdenum oxo alkylidene complexes that are active for metathesis of olefins.
This object has been achieved with isolable molybdenum oxo alkylidene complexes that are active for metathesis of olefins, which are prepared through addition of water to a molybdenum alkylidyne complex. The molybdenum oxo alkylidene complexes may be provided in grafted form onto an oxidic solid support.
According to a first aspect, the invention relates to a molybdenum oxo alkylidene compound of formula I
wherein:
According to a second aspect, the invention relates to a method of making a compound of formula I, the method comprising step (A):
with water;
According to a third aspect, the invention relates to a method of performing a metathesis reaction of an olefin using the compounds defined in the first aspect, the method comprising step (M):
According to a fourth aspect, the invention relates to compounds useful as intermediates in the synthesis of the compounds according to the invention or prepared according to the method of the invention, wherein the compound is selected from:
wherein RO is selected from (CF3)(CH3)2CO—, (CF3)2(CH3)CO— or (CF3)3CO—, preferably (CF3)2(CH3)CO—.
According to a fifth aspect, the invention relates to a method of making a molybdenum oxo alkylidene complex of formula Ib
wherein:
wherein:
The complexes known from the Background section, i.e. molybdenum oxo alkylidene thiolate complexes prepared from Mo(IV) thiolate hydride complexes, phenylacetylene, and water, as well as Mo oxo alkylidene complex, Mo(O)(CHSiMe3)[NP(t-Bu)3]2, do not belong to the present invention.
In the figures shows
According to a first aspect, the invention relates to a compound of formula I:
wherein:
In one embodiment, one of R1 and R2 is H and the other is an optionally substituted group selected from:
In one embodiment, one of R1 and R2 is —C(CH3)3.
In another embodiment, one of R1 and R2 is —C(CH3)2C6H5.
In yet another embodiment, one of R1 and R2 is optionally substituted phenyl.
The term “optionally substituted” encompasses one or more substituents selected from R; —N(R)2, —NRC(O)R, —NRC(O)OR, —NRC(O)N(R)2, —NRSO2R, —NRSO2N(R)2, —NROR; —OR, wherein R has the meaning as defined above.
In a preferred embodiment, one of R1 and R2 is optionally substituted phenyl bearing in ortho-position a O—R7 residue.
In another preferred embodiment, one of R1 and R2 is optionally substituted phenyl bearing in para-position a O—R7 residue.
In one embodiment, R7=C1-8 alkyl, optionally substituted.
Preferred R7 residues are methyl, ethyl, n-propyl, isopropyl, n-butyl, iso-butyl, t-butyl and cyclohexyl.
In a preferred embodiment, O—R7 is O-(ortho-CH3O—C6H4).
In another preferred embodiment, O—R7 is O-(para-CH3O—C6H4)
Preferred optional substituents in R7=C1-8 alkyl are one or more of halogen, cyano, C1-8 alkyl, C1-8 alkoxy or phenyl.
In one embodiment, substituted C1-8 alkyl is preferably fluorine-substituted C1-8 alkyl such as C(CH3)(CF3)2 or perfluoro C1-8 alkyl such as trifluoromethyl or C(CF3)3.
Other preferred optional substituents in R7=C1-8 alkyl may be selected from carboxylic esters C(O)OR8, wherein R8=C1-8 alkyl or phenyl.
Other preferred optional substituents in R7=C1-8 alkyl are derivatives of hydroxamic acids C(O)NHOR8, wherein R8=C1-8 alkyl or phenyl, or C(OR8)NOR8, wherein R8 independently from each other have the meaning of C1-8 alkyl or phenyl.
Other preferred optional substituents in R7=C1-8 alkyl are amides C(O)NHR8, wherein R8=C1-8 alkyl or phenyl, and amides C(O)N(R8)2, wherein R8 independently from each other have the meaning of C1-8 alkyl or phenyl.
In another preferred embodiment, R7=CHR8COOR8, CHR8C(O)NHOR8, or CHR8C(OR8)NOR8, CHR8C(O)NHR8, or CHR8C(O)N(R8)2, wherein R8 independently from each other have the meaning of C1-8 alkyl or phenyl.
In another embodiment, R7=C6-10 aryl such as phenyl, optionally substituted.
Preferred optional substituents in R7=C6-10 aryl such as phenyl are one or more of halogen, cyano, C1-8 alkyl, C1-8 alkoxy or phenyl.
Substituted phenyl is e.g. C6F5.
In a further embodiment, each of R3 and R4 is independently halogen, —N(R)2, or —OR, wherein R has the meaning as defined above.
In one embodiment, each of R3 and R4 is independently halogen.
The term “halogen” encompasses fluorine, chlorine, bromine and iodine.
In a preferred embodiment, each of R3 and R4 is chlorine.
In another embodiment, one of R3 and R4 is halogen and the other is —OR.
In still another embodiment, each of R3 and R4 is independently —OR.
In a preferred embodiment, —OR is —O-aryl, wherein aryl may be substituted.
A preferred aryl residue is phenyl. Said phenyl residue of —O-aryl may be substituted with one or more substituents selected from R; —N(R)2, —NRC(O)R, —NRC(O)OR, —NRC(O)N(R)2, —NRSO2R, —NRSO2N(R)2, —NROR; —OR, wherein R has the meaning as defined above.
In another preferred embodiment, said phenyl residue is substituted in 2- and 6-position with another aryl residue, respectively, which may optionally be substituted.
Preferred substituted phenyl residues are selected from the group: 2,6-(diphenyl)phenyl, 2,6-di(2,4,6-trimethylphenyl)phenyl, 2,6-di(2,4,6-triethylphenyl)phenyl, 2,6-di(2,4,6-triisopropylphenyl)phenyl, 2,6-di(2,4,6-tri-t-butylphenyl)phenyl, 2,6-di(2,4,6-triphenyl)phenyl, 2,6-di(3,5-di-t-butylphenyl)phenyl, 2,6-di(pentafluorophenyl)phenyl, 2,3,5,6-tetra(phenyl)phenyl, 4-bromo-2,3,5,6-tetra(phenyl)phenyl, 4-nitro-2,3,5,6-tetra(phenyl)phenyl, 4-amino-2,3,5,6-tetra(phenyl)phenyl, and 4-cyano-2,3,5,6-tetra(phenyl)phenyl.
Further preferred substituted phenyl residues are selected from the group: 2,6-di(2,6-dimethylphenyl)phenyl, 2,6-di(2,6-diethylphenyl)phenyl, 2,6-di(2,6-diisopropylphenyl)phenyl, 2,6-di(2,6-di-t-butylphenyl)phenyl, and 2,6-di(2,6-diphenyl)phenyl.
In another preferred embodiment, said phenyl residue is substituted in 2- and 6-position with another aryl residue, respectively, which may optionally be substituted, and in 3- and 5-position with an alkyl residue. The alkyl residue preferably is a C1-4 alkyl residue. In one embodiment, said alkyl residue is selected from methyl, ethyl, isopropyl, and t-butyl.
In one embodiment, substituted phenyl residues are selected from the group: 2,6-(diphenyl)-3,5-dimethyl-phenyl, 2,6-di(2,4,6-trimethylphenyl)-3,5-dimethyl-phenyl, 2,6-di(2,4,6-triethylphenyl)-3,5-methyl-phenyl, 2,6-di(2,4,6-triisopropylphenyl)-3,5-dimethylphenyl, 2,6-di(2,4,6-tri-t-butylphenyl)-3,5-dimethyl-phenyl, 2,6-di(2,4,6-triphenyl)-3,5-dimethyl-phenyl, 2,6-di(3,5-di-t-butylphenyl)-3,5-dimethyl-phenyl, and 2,6-di(pentafluorophenyl)-3,5-dimethyl-phenyl,
In another preferred embodiment, said phenyl residue is substituted in 2- and 6-position with another aryl residue, respectively, which may optionally be substituted, in 3- and 5-position with an alkyl residue, and in 4-position with a group selected from C1-4 alkyl, halogen, cyano, amino, nitro. In one embodiment, said alkyl residue is selected from methyl, ethyl, isopropyl, and t-butyl.
Exemplary compounds are 4-bromo-2,6-(diphenyl)phenyl-3,5-dimethyl-phenyl, 4-nitro-2,6-(diphenyl)-3,5-dimethyl-phenyl, 4-amino-2,6-(diphenyl)-3,5-dimethyl-phenyl, and 4-cyano-2,6-(tetraphenyl)-3,5-dimethyl-phenyl.
In another preferred embodiment, —OR is selected from (CF3)(CH3)2CO—, (CF3)2(CH3)CO—, or (CF3)3CO.
In another embodiment, one of R3 and R4 is halogen and the other is —N(R)2wherein R has the meaning as defined above.
In yet another embodiment each of R3 and R4 is independently —N(R)2.
In a preferred embodiment, —N(R)2 is selected from pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl and 2,5-diphenylpyrrol-1-yl.
In another embodiment, one of R3 and R4 is —N(R)2 and the other one is —OR, wherein R has the meaning as defined above.
According to the invention, R5 is a neutral ligand. Preferably, each R5 is independently a monodentate ligand, or two R5 are taken together with their intervening atoms to form an optionally substituted bidentate group.
In one embodiment, R5 is selected from an ether, a nitrile, a pyridine or a phosphine.
The ether may be an aliphatic ether such as diethyl ether (et2O) or dimethyl ethylene glycol (dme) or a cyclic ether such as tetrahydrofuran (THF).
The nitrile may be an alkyl nitrile such as methane nitrile, ethane nitrile or propane nitrile or an aromatic nitrile such as benzonitrile.
The pyridine may be substituted or unsubstituted pyridine.
In a preferred embodiment, R5 is a phosphine.
In one embodiment, the phosphine is of formula P(R6)3 wherein R6 is independently selected from C1-6 alkyl, C3-6 cycloalkyl, and phenyl.
Exemplary phosphines are trimethylphosphine (PMe3), triethylphosphine, triisopropylphosphine, tricyclohexylphosphine, dimethylphenylphosphine [PPhMe2] and diphenylmethylphosphine [PPh2Me].
Further according to the invention, one of R3 or R4 may be a covalent bond linking Mo to an oxidic solid support.
The oxidic solid support may be selected from an oxide of silicon, aluminum, titanium, vanadium, molybdenum, tungsten or a mixture of two or more thereof.
In a preferred embodiment, the oxidic solid support comprises or consists of an oxide of silicon.
In one embodiment, one of R3 or R4 is O—Si(O—)3, i.e. —O(Si≡).
In one embodiment, the compound of formula I is selected from:
In another embodiment, one of R3 or R4 in the compound of formula I is ArO and R5 is a phosphine such as trimethylphosphine, dimethylphenylphosphine or diphenylmethylphosphine or a nitrile such as acetonitrile or a pyridine such as pyridine as defined in the following Table 1:
In one embodiment, one of R3 and R4 in the compound of formula I is ArO and R5 is a phosphine such as trimethylphosphine, dimethylphenylphosphine or diphenylmethylphosphine or a nitrile such as acetonitrile or a pyridine such as pyridine as defined in Table 1, n is 1, and one of R3 and R4 is chlorine.
In another embodiment, one of R3 and R4 in the compound of formula I is ArO and R5 is a phosphine such as trimethylphosphine or dimethylphenylphosphine or a nitrile such as acetonitrile or a pyridine such as pyridine as defined in the Table 1, and one of R3 and R4 is —N(R)2selected from pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl and 2,5-diphenylpyrrol-1-yl.
In another embodiment, the one of the respective residues R1 and R2 of the compounds defined in Table 1 is H and the other one is selected from C(CH3)3, —C(CH3)2C6H5, and preferably from optionally substituted phenyl, preferably bearing in o-position a —O—C1-6 alkyl residue or in p-position a —O—C1-6 alkyl residue.
In one embodiment, the compound of formula I is of structure
According to a second aspect, the invention relates to a method of making a compound of formula I as defined in the first aspect. The compound of formula I is prepared through addition of water to a molybdenum alkylidyne complex (molybdenum carbyne complex).
Accordingly, the method of making a compound of formula I comprises step (A):
with water;
Molybdenum alkylidyne complexes (molybdenum carbyne complexes) are known or may be prepared according to known methods (e.g. von Kugelgen, S; Bellone, D. E.; Cloke, R. R.; Perkins, W. S.; Fischer, F. R.; J. Am. Chem. Soc. 2016, 138, 6234-6239).
In a preferred embodiment, the carbyne complex of formula II is stabilized by a neutral ligand. Preferred neutral ligands are preferably ethers defined in connection with neutral ligand R5. A particularly preferred ether is dimethyl ethylene glycol (dme), wherein dme is a bidentate ligand.
Accordingly, in one embodiment, the compound of formula II encompasses compounds such as II(dme), II(et2O)1 or 2 and II(THF)1 or 2.
However, suitable neutral ligands may also be nitriles or phosphines as defined with respect to the compounds of formula I.
Further preferably, —OR is selected from (CF3)(CH3)2CO—, (CF3)2(CH3)CO—, (CF3)3CO—, preferably (CF3)2(CH3)CO—.
It is further preferred that in the compound of formula II none of R1 or R2 is hydrogen.
In one embodiment of the method according to the invention, if the compound of formula II is reacted with preferably one equivalent water in the presence of preferably one equivalent of ligand R5, water is added to the Mo-carbyne moiety, and a compound according to the invention of formula I is formed, wherein R3 and R4 are OR, respectively, and upon forming one equivalent ROH.
Accordingly, in one embodiment, the method of making a compound of formula I comprises step (A1):
in the presence of neutral ligand R5 with water to afford a compound of formula I (R5)n(OR)2Mo(O)(CR1R2), wherein n, R1, R2, R and R5 have the meaning as defined in the first aspect.
If the formed compound is reacted with a hydrogen halogenide HX, a further compound according to the invention of formula I (R5)nX2Mo(O)(CR1R2) is formed, wherein R3 and R4 are halogen X, respectively.
The compound formed in the reaction with hydrogen halogenide may subsequently be reacted according to following steps (B) or (C) with one equivalent or two equivalents of the respective anions RO− or N(R)2−, or with one equivalent of RO− and then with another equivalent N(R)2− or vice versa according to following step (D) to afford further compounds according to the invention:
In an alternative embodiment, if the compound of formula II is at first reacted with water in the absence of a ligand R5 but in the presence of an ether as solvent, the reaction may proceed differently compared to step (A1).
The inventors discovered that under these reaction conditions in the reaction with water in an ether as solvent at first a dimeric alkylidyne complex [(RO)2(Mo≡—(R1,R2)(—O—)2(RO)2(Mo≡—(R1,R2)]ether (ether=dme, et2O or THF) may be formed and may be isolated or spectroscopically identified in the reaction mixture as intermediate.
This dimeric alkylidyne complex may be subsequently subjected to a reaction with neutral ligand R5. The resulting product corresponds to the product obtained in the embodiment in which an alkylidyne complex is subjected to a reaction with water in the presence of a neutral ligand R5.
Accordingly, in one embodiment, the method of making a compound of formula I comprises step (A2):
The inventors have further discovered that known compounds of formula II may be easily converted to other carbyne complexes via a reaction with a suitable alkyne, i.e. by exchange of the carbyne moiety.
Accordingly, in one embodiment, the method further comprises prior to step (A) step (O):
wherein TAS has the meaning of a trialkylsilane. R1′ or R2′ have the meaning as defined for R1 or R2 but are not identical to R1 and R2.
The compound of formula II is preferably provided in the form of an adduct with an ether, wherein the obtained compound of formula IIa is also in the form of an adduct with the ether, preferably dme.
Starting from easily available carbyne complexes, the reaction according to step (O) provides for an easy access to other carbyne complexes. These other carbyne complexes may then be processed according to step (A), e.g. steps (A1) or (A2), and subsequently according to step (B) or (C) or (D) in order to afford a compound of formula I.
In a preferred embodiment, —OR in the compound of formula IIa is selected from (CF3)(CH3)2CO—, (CF3)2(CH3)CO—, (CF3)3CO—, preferably (CF3)2(CH3)CO—, and the ether is dme.
In a further preferred embodiment, —OR in the compound of formula IIa is selected from (CF3)(CH3)2CO—, (CF3)2(CH3)CO—, (CF3)3CO—, preferably (CF3)2(CH3)CO—, the ether is dme and R1′, R2′ is optionally substituted phenyl bearing in o-position a —O—C1-6 alkyl residue.
According to a fifth aspect, if the compound of formula I should be bound (grafted) to an oxidic solid support, i.e. one of R3 or R4 is a covalent bond linking Mo to an oxidic solid support, a method is provided comprising step (E):
This means that said reacting is performed under the proviso that none of R3 or R4 of the compound of formula I used in step (E) is a covalent bond linking Mo to an oxidic solid support.
This reaction is identical with a method of making a grafted molybdenum oxo alkylidene complex of formula Ib
wherein:
(E) reacting a compound of formula Ia
wherein:
Suitable reaction conditions are known in the art, e.g. from WO 2015/049047.
The catalyst according to this aspect is heterogeneous.
The term “solid support” encompasses any material that includes an oxide of silica, alumina, and zirconia or oxides such as TiO2, V2O5, MoO2, WO3, silicates, zeolites, or sulfates or phosphates of alkali metals or earth alkali metals
In a particularly preferred embodiment, said solid support comprises “silica” or consists of “silica”.
If silica is chosen as the solid support, the term “solid support” encompasses any material that includes silica such as silica as such or silica in combination with other materials. Accordingly, silica may be used in the form of a mixed oxide, e.g. a mixed oxide of silica and alumina or silica and zirconia or oxides such as TiO2, V2O5, MoO2, WO3, silicates, zeolites, or sulfates or phosphates of alkali metals or earth alkali metals.
The term “silica” encompasses compounds of formula SiO2 and further encompasses porous or non-porous silica.
The term “silica” further encompasses partially dehydroxylated and/or dehydrated silica. Dehydroxylation and/or dehydration may be performed using elevated temperature or elevated temperature and vacuum. Residual hydroxyl content may be determined by titration with MeMgCl.
Hydroxyl content may be freely selected depending on drying temperature and drying time. Accordingly, the silica used for the compounds according to the invention may be adjusted in a tailor-made manner to the required properties of the Mo-compound to be immobilized. In this regard it is noteworthy that depending on the number of mmol of hydroxyl groups per gram silica, the amount of Mo compound per gram of silica and ultimately the activity of the resulting catalyst may be adjusted depending upon needs.
Preferably, prior to step (E), silica is heated in a temperature range of from 150 to 1,000° C., preferably employing vacuum or a flow of dry air or inert gas such as nitrogen or argon.
In a further preferred embodiment, silica is subjected to a temperature in the range of from 300 to 800° C. under pressure ranging from 10−6 mbar to 1 bar or a flow of dry air or inert gas such as nitrogen or argon, preferably for a period ranging from 4 to 24 h. Temperature and pressure may be performed in ramps.
Preferably, hydroxyl content determined by means of titration with MeMgCI ranges from 0.05 mmol to 2.00 mmol per g silica, further preferred from 0.1 mmol to 2 mmol per g silica.
In one embodiment, silica is partially dehydroxylated and dehydrated at 700° C. (SiO2-(700)). However, other temperatures or temperature ranges may also be used depending on the requirements of the catalyst to be prepared and to be used as heterogeneous catalyst.
Thus, preferably, a silica is used in one embodiment of the method according to the invention which is partially dehydroxylated and dehydrated. Preferably, silica is dehydroxylated and dehydrated at elevated temperature, preferably at elevated temperature and in vacuo or a flow of dry air or inert gas such as nitrogen or argon.
If silica or silca comprised in a solid support is heated at relatively low temperatures, it is conceivable that the method according to the invention predominatly or exclusively may result in a structure of formula (≡SiO)2Mo(═O)(═CR1R2).
The term “relatively low temperatures” relates to a temperature range of from 150 to 300° C., preferably 180 to 250° C., more preferably 200° C. If silica or silica comprised in an oxidic solid support is heated at relatively high temperatures, the method according to the invention predominatly or exclusively results in structures of formula (≡SiO)Mo(═O)(═CR1R2)(R3 or R4). However it is conceivable that as by-product a compound of structure (≡SiO)Mo(═O)(—CHR1R2)(R3)(R4) may be formed.
The term “relative high temperatures” relates to a temperature range of 400 to 1,000° C., preferably 600 to 800° C., more preferably 700° C.
Thus, when selecting a medium temperature range, it is conceivable to generate a mixture of structures comprising or consisting both of (≡SiO)2Mo(═O)(═CR1R2) and (≡SiO)Mo(═O)(═CR1R2)(R3 or R4), and optionally (≡SiO)Mo(═O)(—CHR1R2)(R3)(R4).
The term “medium temperatures” preferably relates to a temperature range of from 200 to 600° C., more preferably 300 to 500° C.
In one embodiment, the method comprises at least step (0.1) or (0.2) or (0.3) prior to step (E):
Alternatively, the method comprises at least step (0.4):
In one embodiment, the grafted compound according to the invention may be prepared by contacting a solution or suspension of the molybdenum oxo alkylidene complex with a suspension of silica, preferably SiO2-(700), and stirring same at room temperature, e.g. for a period of from 2 to 24 h, preferably 6 to 18 h, whereby reaction (grafting) occurs.
Aromatics such as toluene or benzene, chlorinated hydrocarbons such as dichloromethane or chlorobenzene, or hydrocarbons such as heptane or octane or ethers such as tetrahydrofuran may be used as solvents. The proceeding of the reaction (grafting) may be frequently observed by fading of the color of the solution or suspension and a coloration of silica. The catalyst may be separated off, e.g. by filtration, and may be dried, preferably applying temperature and vacuum.
Accordingly, step (E) may be further characterized in that the reaction is carried out in an organic solvent.
Moreover, the method according to the invention according to step (E) may be further characterized in that the temperature employed in step (E) is from −80 to 150° C., preferably 0 to 80° C.
In another embodiment, the catalysts according to the invention are prepared by mixing the solid Mo oxo alkylidene complex of formula I with solid silica. In one embodiment of this method, ═CR1R2is selected from ═CHC(CH3)3 or ═CHC(CH3)2C6H5.
In a preferred embodiment of this method, ═CR1R2 is selected from ═CH(o-CH3O—C6H4) or ═CH(p-CH3O—C6H4)).
In another preferred embodiment of this method, R3 and R4 are independently —N(R)2, preferably pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl, or 2,5-diphenylpyrrol-1-yl, or —OR, wherein R is a six membered or 10 membered aryl ring, optionally substituted, or —OR is C1-4 alkyl such as (CF3)(CH3)2CO, (CF3)2(CH3)CO, (CF3)3CO, (C6H5)(CF3)2C0 or (CH3)3CO.
In a further preferred embodiment of this method, R in —OR is phenyl or annelated phenyl substituted with one or more of: C1-4 alkyl, C1-4 alkoxy, optionally substituted phenyl, optionally substituted phenoxy, halogen.
The term “halogen” refers to F, CI, Br, I.
In a further preferred embodiment of this method, ═CR1R2 is selected from ═CHC(CH3)3 or ═CHC(CH3)2C6H5 and R3═R4═—OR, wherein R is phenyl or annelated phenyl substituted with one or more of: C1-4 alkyl, C1-4 alkoxy, optionally substituted phenyl, optionally substituted phenoxy, halogen.
In a further preferred embodiment of this method, ═CR1R2 is selected from ═CHC(CH3)3 or ═CHC(CH3)2C6H5 and R3═—OR, wherein R is phenyl or annelated phenyl substituted with one or more of: C1-4 alkyl, C1-4 alkoxy, optionally substituted phenyl, optionally substituted phenoxy, halogen; and R4═—N(R)2, preferably pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl, or 2,5-diphenylpyrrol-1-yl.
Preferably, R in —OR is selected from 2,6-dimethylphenyl, 2,6-diisopropylphenyl, 2,6-ditertiobutylphenyl, 2,6-di-adamantylphenyl, 2,6-dimesitylphenyl, 2,6-di(trifluoromethyl)phenyl, 2,6-dichlorophenyl, 2,6-diphenylphenyl, 2,6-diphenoxyphenyl, pentafluorophenyl, 2-(trifluoromethyl)phenyl, 2,3,5,6-tetraphenylphenyl
Further preferred residues R in —OR are 4-fluoro-2,6-dimesitylphenyl or 2,6-di-tert.-butylphenyl, 4-bromo-2,6-di-tert.-butylphenyl or 4-methoxy-2,6-di-tert.-butylphenyl or 4-methyl-2,6-di-tert.-butylphenyl or 2,4,6-tri-tert.-butylphenyl or 2,3,5,6-tetraphenylphenyl or 4-bromo-2,3,5,6-tetraphenylphenyl or 2,6-di(4-bromophenyl)-3,5-diphenylphenyl or 4-bromo-2,6-di(4-bromophenyl)-3,5-diphenylphenyl.
In one embodiment of of this method, ═CR1R2 is selected from ═CHC(CH3)3 or ═CHC(CH3)2C6H5 and R3═R4═—N(R)2, preferably pyrrol-1-yl, 2,5-dimethylpyrrol-1-yl, or 2,5-diphenylpyrrol-1-yl.
Preferably, the heterogeneous catalysts are stored under an inert gas such as nitrogen or argon prior to the use.
The above disclosed reaction sequences are now exemplified:
The reaction between known carbyne complex 1 and C6H4(o-OMe)C≡CTMS (TMS=trimethyl silane) could be engineered to give 2 (Scheme 1). Addition of one equivalent of water to 3 in the presence of one equivalent of R5=PPhMe2 according to step (A1) led to 3(PPhMe2) in 34% yield .
A dimeric carbyne complex was obtained in high yield according to step (A2) when 2 reacts with one equivalent of water (in dme=dimethyl ethylene glycol) in the absence of any phosphine at −20° C. to give one equivalent of hexafluoro-t-butanol per Mo and the dimeric carbyne complex 4(dme) (Scheme 1 and Scheme 2).
Compound 4 (dme) is a dimeric hydroxy alkylidyne complex (
The subsequent reaction between 4(dme) and PPhMe2 in pentane gave 3(PPhMe2) in ˜30% yield, approximately the same yield as in the reaction between 2 and water in the presence of PPhMe2.
The reaction between 4(dme) and PMe3 gave 3(PMe3) (95% by proton NMR). Without being bound by theory, it is believed that in the reaction between 2 and water it seems to be important that only one molecule of water attacks each metal to give 4(dme) before more water reacts with 4(dme). Therefore all water in solution is consumed before a complex mixture of hydrolysis products (e.g., through loss of another hexafluoro-t-butoxide) can be formed. The yield of 3(PMe3) is highest when approx. five and up to 10 equivalents of PMe3 per Mo are added to 4(dme).
Addition of HCl to 3(PMe3) yields 5 (Scheme 3) in 95% yield.
Compound 6 could then be prepared in 58% yield through addition of LiOHIPT to 5. An X-ray study revealed 6 to have the structure shown in
According to a third aspect, the invention relates to a method of performing a metathesis reaction of an olefin using the compounds defined in the first aspect or prepared in the method according to the second aspect.
The method comprises step (M):
In one embodiment, the method is performed in the presence of a Lewis acid.
In one embodiment, the Lewis acid is B(C6F5)3.
The compound of formula I catalyzes the commonly known metathesis reactions of olefins such as homocoupling (homo-metathesis; HCM)), cross-metathesis (CM), ring opening metathesis (ROM), ring opening polymerization metathesis (ROMP), and acyclic diene metathesis (ADM ET).
Exemplary metathesis activity of complex 6 is listed in Table 3. 6 catalyzes at room temperature ring opening polymerization (ROMP) of cyclooctene, homocoupling of 1-decene, or ROMP of 5,6-dicarbomethoxynorbornadiene (DCMNBD) and 5,6-dicarbomethoxynorbornene (DCMNBE). If two equivalents of B(C6F5)3 are added along with the olefin, reaction is accelerated.
1-decene forms 9-octadecene. Both E and Z 9-octadecene are formed from 1-decene, in part through isomerization of Z to E with time.
Cyclooctene, dicarbomethoxynorbornadiene (DCMNBD), and rac-dicarbomethoxynorbornene (DCMNBE) are polymerized readily at room temperature.
a Open vial.
bZ/E ratio.
ccis, syndiotactic.
dcis, syndiotactic, alt.
It is important to note that poly(DCMNBD) is >97% cis,syndiotactic, while poly(DCMNBE) is >97% cis, syndiotactic, alt (a cis, syndiotactic structure and a backbone that contains alternating enantiomers). These polymers are essentially identical to analogous polymers made from monoaryloxide pyrrolide Mo or W catalysts that have been reported in the literature. In at least one case, the boron-activated initiator has been shown to produce a more highly structured polymer than in the absence of the Lewis acid. In this vein it should be noted that the poly(DCMNBD) formed in the absence of B(C6F5)3 is less regular than that formed in the presence of B(C6F5)3 (Table 3).
According to a fourth aspect, the invention relates to compounds useful as intermediates in the synthesis of the compounds according to the invention or prepared according to the method of the invention.
In one embodiment, the compound of formula IIa is of structure
wherein RO is selected from (CF3)(CH3)2CO—, (CF3)2(CH3)CO— or (CF3)3CO—.
In a preferred embodiment, the compound of formula IIa is of structure
In another embodiment, the intermediate formed in the reaction according to step (A2) is of structure
wherein RO is selected from (CF3)(CH3)2CO—, (CF3)2(CH3)CO— or (CF3)3CO—.
In a preferred embodiment, the intermediate is of structure
Conclusively, the present disclosure shows that molybdenum oxo alkylidene complexes can be prepared in a controlled fashion from an alkylidyne complex and water. Said molybdenum oxo alkylidene complexes may also be grafted on an oxidic solid support.
The molybdenum oxo alkylidene complexes according to the invention are highly active for metathesis reactions.
Further embodiments of this invention have been published in J. Am. Chem. Soc. 2018, 140, 13609-13613 by F. Zhai et al.
Accordingly, the para-methoxy-benzylidene carbyne complex in the following scheme may be reacted with water and THF to the respective dimeric carbyne complex:
Alternatively, the carbyne complex may be reacted with water in the presence of triethylphosphine to the respective alkylidene complex:
The formed alkylidene complex may be converted with LiOHMT (lithium 2,6-di(2,4,6-trimethylphenyl)phenoxylate) to Mo(═O)(OHMT)2(═CH(p-CH3O—C6H4)):
All air- and moisture-sensitive materials were manipulated in a nitrogen-filled Vacuum Atmospheres glovebox or on a dual-manifold Schlenk line. All glassware were oven dried prior to use. Dichloromethane, et2O, 1,2-dimethoxyethane, and toluene were degassed, passed through activated alumina columns, and stored over 4 Å Linde-type molecular sieves prior to use. Pentane was washed with H2SO4, followed by water and saturated aqueous NaHCO3, and dried over CaCl2 pellets for at least 2 weeks prior to use in the solvent purification system. Deuterated solvents were dried over 4 Å Linde-type molecular sieves prior to use. 1H NMR spectra were obtained on 400 or 500 MHz spectrometers and 13C NMR spectra on 101, 125 or 151 MHz machines. Chemical shifts for 1H and 13C spectra are reported as parts per million relative to tetramethylsilane and referenced to the residual 1H or 13C resonances of the deuterated solvent (1H δ: benzene 7.16, chloroform 7.26, methylene chloride 5.32; 13C δ: benzene 128.06, chloroform 77.16, methylene chloride 53.84).
PMe3, PPhMe2, B(C6F5)3 was purchased from Strem chemicals. HCl (1.00 M solution in ether) was purchased from Aldrich. Cyclooctene and 1-decene were purchased from Alfa Aesar, distilled over CaH2 and stored over 4 Å Linde-type molecular sieves prior to use. The syntheses of Mo(CEt)[OCMe(CF3)2]3(dme)1 (1), ((2-methoxyphenyl)ethynyl)trimethylsilane,2 2,3-dicarbomethoxynorbornadiene3 (DCMNBD), rac-endo,exo-5,6-dicarbomethoxynorbornene4 (rac-DCMNBE) and 2,6-bis(2,4,6-triisopropylphenyl)phenol5 (HOHIPT) were prepared as reported. LiOHIPT was prepared by addition of one equivalent of n-butyllithium to a cold pentane solution of HOHIPT5, and the solid was collected on a glass frit, washed with pentane, and dried in vacuo. 1 Gdula, R. L. and Johnson, M. J. A. J. Am. Chem. Soc. 2006, 128, 9614-9615.2 Huang, Q. and Larock, R. C. J. Org. Chem. 2003, 68, 980-988.3 Tabor, D. C.; White, F. H.; Collier, L. W.; Evans, S. A. J. Org Chem. 1983, 48, 1638.4 Flook, M.; Ng, V.; and Schrock, R. J. Am. Chem. Soc., 2011, 133, 1784-1786.5 Koh, M. J.; Nguyen, T. T.; Lam, J.; Torker, S.; Hyvl, J.; Schrock, R. R.; Hoveyda, A. H. Nature 2017, 542, 80-85.
A solution of Mo(CEt)[OCMe(CF3)2]3(dme)1 (1) (5.00 g, 6.49 mmol, 1 eq.) and ((2-methoxyphenyl)ethynyl)trimethylsilane2 (1.46 g, 7.14 mmol, 1.1 eq.) in 20 mL of toluene was stirred at 30° C. under vacuum (0.2 Torr) until all volatiles were removed. Toluene (20 mL) was added and procedure was repeated 3 more times (total 4 times). The residue was dissolved in 20 mL of dichloromethane and filtered through Celite. The resulting dark red solution was kept at −20° C. overnight to produce large red crystals of Mo[C(2-(MeO)C6H4)][OCMe(CF3)2]3(dme) (2) (3.6 g, 65%): 1H NMR (500 MHz; C6D6) δ 7.27 (d, J=7.7 Hz, 1H), 6.68 (t, J=7.8 Hz, 1H), 6.61 (t, J=7.6 Hz, 1H), 6.22 (d, J=8.3 Hz, 1H), 3.32 (s, 6H), 3.10 (s, 4H), 3.08 (s, 3H), 1.88 (s, 9H); 19F NMR (282 MHz; C6D6) δ −76.9; 2-12-17; 13C NMR (151 MHz; C6D6) δ 292.2, 159.8, 133.6, 133.3, 130.9, 124.8 (q, JCF=290 Hz), 120.1, 110.8, 84.03 (m, JCF=28 Hz), 71.7, 63.7, 53.9, 18.3. Anal. Calcd for C24H26F18MoO6 (848.40 g/mol): C, 33.98%; H, 3.09%. Found: C, 33.91%; H, 2.80%.
Water (10 μL, 10 mg, 0.556 mmol, 1 eq.) was added to the solution of Mo[C(2-(MeO)C6H4)][OCMe(CF3)2]3(dme) (2) (471 mg, 0.556 mmol, 1eq.) and PPhMe2 (76.7 mg, 0.556 mmol, 1 eq.) in 20 mL of ether at −78° C. using micro syringe. The resulting solution was stirred in the same cooling bath for 16 hours and the mixture was allowed to warm up slowly. All volatiles were removed in vacuo and the residue was crystallized in pentane at −20° C. to give Mo(O)[CH(2-(MeO)C6H4)][OCMe(CF3)2]2 (PPhMe2) (3(PPhMe2)) (140 mg, 34%) as orange crystals: 1H NMR (400 MHz; C6D6) δ 13.24 (d, JPH=7.2 Hz, JCH=140 Hz, 1H), 6.90-6.76 (m, 5H), 6.61-6.56 (m, 2H), 6.09-6.06 (m, 1H), 5.87-5.85 (m, 1H), 3.32 (s, 3H), 2.20 (s, 3H), 1.24 (s, 3H), 1.20 (d, JPH=9.4 Hz, 3H), 1.10 (d, JPH=9.9 Hz, 3H); 19F NMR (376 MHz; C6D6) δ −76.74 (q, J=9.4 Hz, 3F), −76.93 (m, 6F), −77.4 (q, J=9.4 Hz, 3F); 31P NMR (162 MHz; C6D6) δ 4.5; 13C NMR (101 MHz; C6D6) δ 280.6 (dd, J=21 Hz, J=11 Hz), 160.45, 134.1, 133.7, 132.61, 132.55, 132.46, 129.77, 129.68, 128.19, 127.3, 126.6, 124.4, 123.8, 122.4, 121.3, 109.1, 82.20-80.2 (m), 55.2, 18.2, 17.9, 13.2 (d, JCP=25 Hz), 10.2 (d, JCP=23 Hz). Anal. Calcd for C24H25F12MoO4P (732.37 g/mol): C, 39.36%; H, 3.44%. Found: C, 39.37%; H, 3.29%. Crystals of 3(PPhMe2) suitable for X-ray data collection were obtained through crystallization from pentane at −20° C.
A solution of water (106 μL, 0.106 g, 5.89 mmol, 1 eq.) in 2 mL of DME was added to the cold solution of Mo[C(2-(MeO)C6H4)][OCMe(CF3)2]3(dme) (2) (5.00 g, 5.89 mmol, 1 eq.) in 150 mL of dichloromethane at −20° C. The resulting solution was stirred at RT for 10 minutes, during this time red dark solution became orange suspension. All volatiles were removed in vacuo and the residue was washed by pentane and filtered off to produce {Mo[CH(2-(MeO)C6H4)][OCMe(CF3)2]2(μ—OH)}2(dme) (4(dme)) (3.76 g, 98%) as an orange powder: 1H NMR (400 MHz; CD2Cl2) δ 9.30 (s, 2H), 7.10 (ddd, J=8.6, 7.3, 1.5 Hz, 2H), 7.01 (dd, J=7.7, 1.6 Hz, 2H), 6.89 (td, J=7.5, 0.7 Hz, 2H), 6.52 (d, J=8.4 Hz, 2H), 3.72 (s, 4H), 3.36 (s, 6H), 3.14 (s, 6H), 1.90 (s, 12H); 19F NMR (376 MHz; CD2Cl2) δ −77.2 (m, 12F), −77.9 (m, 12F); 13C NMR (101 MHz; CD2Cl2) δ 290.2, 166.1, 132.2, 131.3, 129.2, 124.1 (q, JCF =289 Hz), 124.0 (q, JCF=289 Hz), 83.0 (m, JCF=28 Hz), 73.4, 60.0, 55.6, 19.4. Anal. Calcd for C36H38F24Mo2O10 (1278.57 g/mol): C, 33.82%; H, 3.00%. Found: C, 33.72%; H, 2.68%. Crystals of 4(dme) suitable for X-ray data collection were obtained through crystallization from dichloromethane at −20° C.
PMe3 (3.0 mL, 29.40 mmol, 10 eq.) was added to suspension of {Mo[CH(2-(MeO)C6H4)][OCMe(CF3)2]2(μ—OH)}2(dme) (4(dme)) (3.76 g, 2.94 mmol, 1 eq.) in 100 mL of mixture pentane/toluene (4:1, v/v) at RT for 1.5 hours. During this time the starting material dissolved and crude product precipitated as a yellow powder. Crude product (1.3 g) was filtered off and the solution was kept at −20° C. for 1 hour to produce 1.5 g of pure product 3(PMe3) as orange crystals. The mother liquor was used to recrystallize crude product, which gives additionally 1.1 g of Mo(O)[CH(2-(MeO)C6H4)][OCMe(CF3)2]2(PMe3) (3(PMe3)) (total 2.6 g, 66%): 1H NMR (400 MHz; C6D6) δ 13.42 (d, JPH=7.3 Hz, JCH=142 Hz, 1H), 6.71-6.67 (m, 2H), 6.34-6.30 (m, 1H), 6.15-6.12 (m, 1H), 3.53 (s, 3H), 2.19 (s, 3H), 1.28 (s, 3H), 0.71 (d, JPH=9.9 Hz, 9H); 19F NMR (376 MHz; C6D6) δ −76.81 (q, J=9.4 Hz, 3F), −76.93 (q, J=9.4 Hz, 3F), −77.3 (q, J=9.4 Hz, 3F), −77.5 (q, J=9.4 Hz, 3F); 31P NMR (162 MHz; C6D6) δ −2.7. 13C NMR (101 MHz; C6D6): δ 278.5 (dd, J=22 Hz, J=12 Hz), 160.6, 132.80, 132.61, 127.52, 127.33, 126.9, 126.6, 124.7, 124.4, 124.0, 123.8, 122.5, 121.8, 109.3, 80.6 (m), 55.5, 18.2, 17.9, 13.1 (d, JCO=28 Hz). Anal. Calcd for C19H23F12MoO4P (670.30 g/mol): C, 34.05%; H, 3.46%. Found: C, 34.01%; H, 3.21%.
HCl (8.15 mL, 1.00 M solution in ether, 8.15 mmol, 2.1 eq.) was added to solution of Mo(O)[CH(2-(MeO)C6H4)][OCMe(CF3)2]2(PMe3) (3(PMe3)) (2.6 g, 3.88 mmol, 1 eq.) in 30 mL of ether at −96° C. (dichloromethane/liquid N2 cooling bath) under nitrogen. A yellow precipitate formed immediately. The cooling bath was removed and the resulting suspension was stirred at RT for 30 minutes to produce orange precipitate. The product was filtered off, washed with 20 mL of ether and dried in vacuo to produce Mo(O)[CH(2-(MeO)C6H4)]Cl2(PMe3) (5) (1.4 g, 95%) as an orange powder. 5 decomposes in the solution at RT during few hours and has to be kept as a solid at −20° C.: 1H NMR (500 MHz; CD2Cl2) δ 14.52 (d, JPH=5.7 Hz, JCH=143 Hz, 1H), 7.28 (t, J=7.9 Hz, 1H), 7.11 (t, J=7.4 Hz, 1H), 7.03 (d, J=8.3 Hz, 1H), 6.81 (d, J=7.6 Hz, 1H), 4.04 (s, 3H), 1.44 (d, JPH=10.8 Hz, 9H); 31P NMR (162 MHz; C6D6) δ 4.7; 13C NMR (151 MHz; CD2Cl2) δ 288.5 (m), 161.6, 135.0, 132.45, 124.2, 122.6, 111.1, 58.0, 14.58 (d, JCP=30 Hz). Anal. Calcd for C11H17Cl2MoO2P (379.09 g/mol): C, 34.85%; H, 4.52%. Found: C, 34.85%; H, 4.33%.
LiOHIPT (665 mg, 1.32 mmol, 1 eq.) was added to solution of Mo(O)[CH(2-(MeO)C6H4)]Cl2(PMe3) (5) (500 mg, 1.32 mmol, 1 eq.) at RT. The resulting solution was stirred at RT for 3 hours. All volatiles were removed in vacuo, the residue was stirred in 20 mL of pentane for 10 minutes and filtered through Celite. The resulting dark red solution was kept at −20° C. for 24 hours to produce red crystals of Mo(O)[CH(2-(MeO)C6H4)](OHIPT)Cl(PMe3) (6) (610 mg, 58%): 1H NMR (500 MHz; C6D6) δ 13.34 (d, JPH=6.9 Hz, JCH=142 Hz, 1H), 7.31 (s, 2H), 7.27 (d, J=7.4 Hz, 2H), 7.13 (s, 2H), 6.99 (t, J=7.4 Hz, 1H), 6.71-6.66 (m, 2H), 6.37-6.35 (m, 1H), 6.24-6.22 (m, 1H), 3.59-3.42 (m, 4H), 2.94 (dquintet, J=13.8, 6.9 Hz, 2H), 2.82 (s, 3H), 1.60 (d, J=6.8 Hz, 6H), 1.36 (d, J=6.9 Hz, 12H), 1.29 (d, J=6.8 Hz, 6H), 1.20 (d, J=6.8 Hz, 6H), 1.17 (d, J=6.8 Hz, 6H), 0.58 (d, JPH=10.0 Hz, 9H); 31P NMR (162 MHz; C6D6) δ −0.03; 13C NMR (101 MHz; C6D6) δ 273.15 (m), 161.5, 160.0, 148.7, 148.32, 148.13, 146.9, 137.6, 133.55, 133.48, 132.3, 131.9, 131.1, 130.5, 122.3, 121.52, 121.39, 121.0, 120.8, 120.5, 118.2, 109.3, 56.4, 34.9, 31.2, 30.9, 26.6, 26.2, 24.77, 24.62, 24.3, 23.1, 14.0 (d, JCP=27 Hz). Anal. Calcd for Mo(O)[CH(2-(MeO)C6H4)](OHIPT)Cl(PMe3)*0.5(n-C5H12), C49.5H72ClMoO3P (877.50 g/mol): C, 67.75%; H, 8.27%. Found: C, 67.85%; H, 8.34%. Crystals of 6 suitable for X-ray data collection were obtained through crystallization from pentane at −20° C.
Cyclooctene (3.1 μL, 2.6 mg, 23.8 μmol, 20 eq.) was added to solution of Mo(O)[CH(2-MeO)C6H4](OHIPT)(Cl)(PMe3) (1 mg, 1.2 μmol, 1 eq.) and B(C6F5)3 (1.2 mg, 2.4 μmol, 2 eq.) in 0.1 mL of C6D6at RT using micro syringe. The solution was stirred at RT for 18 hours, diluted with 0.5 mL of C6D6 and analyzed by proton NMR. Conversion to polycyclooctene is >99%. Conversion was estimated by integration olefin proton resonance of cyclooctene (m, 5.69-5.61 ppm) and polycyclooctene (m, 5.51-5.45 ppm). The same reaction in the absence of B(C6F5)3 gives <1% conversion to polycyclooctene.
1-decene (112.6 μL, 83.4 mg, 594.2 μmol, 100 eq.) was added to the mixture of Mo(O)[CH(2-MeO)C6H4](OHIPT)(Cl)(PMe3) (5 mg, 5.9 μmol, 1 eq.) and B(C6F5)3 (6.1 mg, 11.9 μmol, 2 eq.) at RT using micro syringe. The resulting mixture was stirred at RT in open vial. Aliquots were taken, diluted with 0.6 mL of CDCl3 and analyzed by 1H NMR. Conversion was estimated by integration olefin proton resonance of 1-decene (m, 5.86-5.78) and 9-octadecene (m, 5.39-5.32). The Z/E ratio was estimated by integration olefin proton resonance of E-9-octadecene (m, 5.39-5.37) and Z-9-octadecene (m, 5.37-5.32).
Solution of Mo(O)[CH(2-MeO)C6H4](OHIPT)(Cl)(PMe3) (5 mg, 5.9 μmol, 1 eq.) in 0.5 mL of toluene was added to the solution of DCMNBD3 (124 mg, 594.2 μmol, 100 eq.) and B(C6F5)3 (6.1 mg, 11.9 μmol, 2 eq.) in 1.5 mL of toluene at RT. White poly(DCMNBD) started to precipitate immediately. The reaction mixture was stirred for 1 hour and poured into 100 mL of methanol. The polymer was filtered off, washed with methanol and dried in vacuo to give white poly(DCMNBD) (115 mg, 93%). 1H NMR (400 MHz; CDCl3): δ 5.37-5.31 (m, 2H), 4.02-3.97 (m, 2H), 3.73 (s, 6H), 2.57-2.50 (m, 1H), 1.49-1.43 (m, 1H). 13C NMR (101 MHz; CDCl3): δ 165.5, 142.4, 131.6, 52.1, 44.6, 38.1. Data corresponds to cis-syndiotactic poly(DCMNBD).6 6 Flook, M.; Jiang, A.; Schrock, R.; Muller, P.; and Hoveyda A. J. Am. Chem. Soc., 2009, 131, 7962-7963.
Solution of Mo(O)[CH(2-MeO)C6H4](OHIPT)(Cl)(PMe3) (5 mg, 5.9 μmol, 1 eq.) in 0.5 mL of toluene was added to the solution of rac-DCMNBE4 (125 mg, 594.2 μmol, 100 eq.) and B(C6F5)3 (6.1 mg, 11.9 μmol, 2 eq.) in 1.5 mL of toluene at RT. White poly(rac-DCMNBE) started to precipitate after a few minutes. The reaction mixture was stirred for 1 hour and poured into 100 mL of methanol. The polymer was filtered off, washed with methanol and dried in vacuo to give white poly(rac-DCMNBE) (120 mg, 96%). 1H NMR (400 MHz; CDCl3): δ 5.37-5.31 (m, 1H), 5.25-5.20 (m, 1H), 3.66 (s, 3H), 3.61 (s, 3H), 3.36-3.26 (m, 2H), 3.13-2.95 (m, 2H), 2.10-2.07 (m, 1H), 1.40-1.32 (m, 1H). 13C NMR (101 MHz; CDCl3): δ 174.2, 172.9, 133.0, 130.8, 52.7, 52.3, 52.1, 51.8, 42.1, 40.6, 39.1. Data corresponds to cis-syndio, alt poly(rac-DCMNBE).4
Low-temperature diffraction data were collected on a Bruker-AXS X8 Kappa Duo diffractometer coupled to a SMART Apex2 CCD detector or a Bruker-AXS D8 Venture Duo diffractometer coupled to a Bruker-AXS Photon II CPAD detector with Mo Kα radiation (λ=0.71073 Å) from an 1 μS micro-source, performing ϕ- and ω-scans. The structures were solved by direct methods using SHELXT7 and refined against F2 on all data by full-matrix least squares with SHELXL-20148 following established refinement strategies9. All non-hydrogen atoms were refined anisotropically. Except where specified for alkylidene hydrogen atoms, all hydrogen atoms were included into the model at geometrically calculated positions and refined using a riding model. The isotropic displacement parameters of all hydrogen atoms were fixed to 1.2 times the U value of the atoms they are linked to (1.5 times for methyl groups). 7 Sheldrick, G. M. Acta Cryst. 2015, A71, 3-8.8 Sheldrick, G. M., Acta Cryst. 2015, C71, 3-8.9 Milder, P. Crystallography Reviews 2009, 15, 57-83.
Compound Mo(O)[CH(2-(MeO)C6H4)][OCMe(CF3)2]2(PPhMe2) (3(PPhMe2)) crystallizes in the triclinic centrosymmetric space group P
Compound {Mo[CH(2-(MeO)C6H4)][OCMe(CF3)2]2(μ—OH)}2(dme) (4(dme)) crystallizes in the monoclinic centrosymmetric space group P21/n with one molecule of {Mo[CH(2-(MeO)C6H4)][OCMe(CF3)2]2(μ—OH)}2(dme) (4(dme)) per asymmetric unit. The hydrogen atoms on the bridging hydroxides was located in the difference map and refined semi-freely with the help of a distance restraint.
The structure exhibited one disordered alkoxide group, which was modeled over two positions, and a disordered bridging dimethoxyethane ligand, which was modeled over three positions. All disorders were refined with the help of similarity restraints on 1,2- and 1,3-distances as well as similarity and rigid bond restraints for anisotropic displacement parameters; additionally, the anisotropic displacement parameters of all three positions of one atom involved in the three-part disorder were constrained to be equal.
Compound Mo(O)[CH (2-(MeO)C6H4)](OHIPT)Cl(PMe3) (6) crystallizes in the monoclinic centrosymmetric space group P21/c with two molecules of Mo(O)[CH(2-(MeO)C6H4)](OHIPT)Cl(PMe3) (6) and two molecules of pentane per asymmetric unit. The structure was refined as a two-component pseudo-merohedral twin with a freely-refined twin ratio of 79:21. The alkylidene hydrogen was located in the difference map and refined semi-freely with the help of a distance restraint. Both pentane molecules were disordered over two positions and were refined with the help of similarity restraints on 1,2- and 1,3-distances as well as similarity and rigid bond restraints for anisotropic displacement parameters.
This patent application claims priority to U.S. Provisional Patent Application No. 62/628,804, entitled “MOLYBDENUM OXO ALKYLIDENE COMPOUNDS, METHODS OF MAKING THE SAME AND USE THEREOF IN METATHESIS REACTIONS,” filed Feb. 9, 2018, which is incorporated herein by reference in its entirety.
This invention was made with government support under Grant No. R01-GM059426 awarded by the National Institutes of Health, and Grant No. CHE-0946721 awarded by the National Science Foundation. The government has certain rights in the invention.
| Filing Document | Filing Date | Country | Kind |
|---|---|---|---|
| PCT/US2019/017348 | 2/8/2019 | WO | 00 |
| Number | Date | Country | |
|---|---|---|---|
| 62628804 | Feb 2018 | US |
