Fluoroaluminate (AlF.sub.4) compounds

The present invention relates to fluoroaluminate compounds and methods for their preparation.
Many compounds of the general formula M.sup.+ AlF.sub.4.sup.- are known wherein the fluoroaluminate Al ion is six-coordinate and wherein M.sup.+ is a cation, for example, wherein M is potassium, thallium, rubidium, or NH.sub.4. Usually, such compounds are insoluble in nonaqueous media and have extended corner-shared fluoro-bridged network structures in the solid state.
Tetrahedrally coordinated AlF.sub.4.sup.- compounds have been proposed to exist in a hot melt form or in vapor phase, but upon cooling reassemble into six-coordinate forms. "Tetramethylammonium-fluoroaluminates, -gallates and indates", by P. Bukovec and J. Siftar, Monatsh. Chem. 1975, 106, 483-490, describes the "probable" synthesis of the material N(CH.sub.3).sub.4 AlF.sub.4 via dissolution of AlF.sub.3 in aqueous HF in the presence of tetramethylammonium fluoride. The material first isolated is N(CH.sub.3).sub.4 AlF.sub.4 H.sub.2 O which may be dehydrated at 120.degree. C. to give a material of the noted stoichiometry. Evidence for the anhydrous tetrafluoroaluminate as containing a tetrahedral AlF.sub.4.sup.- anion is based on the simplicity of the IR spectrum.
"Fluoroaluminates of some organic base cations" by A. K. Sengupta and K. Sen., Indian J. Chem., 1979, 17A, 107-108, describes a series of preparations of fluoroaluminate salts of organic cations prepared by dissolution of aluminum hydroxide in aqueous HF in the presence of the organic cation or base. In this case a series of compounds are prepared and their chemical analyses and thermal decomposition behavior reported. The authors claim that the products of thermal decomposition of their compounds are "a mixture of aluminum fluoride and oxide". The fact that oxide is present in the final materials indicates that the materials they have prepared are in all cases mixed fluoro/aquo/hydroxo aluminate species much like the N(CH.sub.3).sub.4 AlF.sub.4 H.sub.2 O material above.
The aqueous synthetic procedures taught in the above references are not likely to work well for many other compounds. An anhydrous process for preparation of fluoroaluminate compounds is desirable due to its versatility. Additionally, it is desirable to have compounds wherein the four-coordinate form of the AlF.sub.4.sup.- is retained. Such materials provide low temperature routes to new phases of AlF.sub.3, AlF.sub.3 being a well-documented catalyst for numerous fluorocarbon transformations of industrial importance. Additionally, the solubility of such AlF.sub.4.sup.- species in non-aqueous (organic) solvents provides a simple route for deposition onto high surface area supports for eventual conversion to well dispersed AlF.sub.3 catalyst phases. The present invention provides such four-coordinate compounds, their precursors, and anhydrous processes for their preparation.
SUMMARY OF THE INVENTION
The present invention comprises a compound of the formula I, M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is an organic cation or polycation other than NMe.sub.4.sup.+, NEt.sub.4.sup.+, N(n-Bu).sub.4.sup.+, guanidinium H.sup.+ or PyridineH.sup.+, and n is an integer from 1 to 3.
In particular the present invention comprises compounds of the above formula wherein M is selected from the group consisting of N(R.sub.2).sub.4, P(R.sub.2).sub.4, As(R.sub.2).sub.4, HN(R.sub.2).sub.3, H.sub.2 N(R.sub.2).sub.2, H.sub.3 N(R.sub.2), (R.sub.2).sub.3 P.dbd.N.dbd.P(R.sub.2).sub.3, S�N(R.sub.2).sub.2 !.sub.3, ##STR2## R is hydrogen, C.sub.1 -C.sub.10 linear or branched alkyl or aryl; R.sub.2 is C.sub.1 -C.sub.10 linear or branched alkyl or aryl;
n is 1; and
k is 1 to 10;
provided that M.sup.+n is other than NMe.sub.4.sup.+, NEt.sub.4.sup.+, N(n-Bu).sub.4.sup.+, guanidinium (H.sub.2 N.dbd.C(NH.sub.2).sub.2).sup.+ and pyridinium (C.sub.5 H.sub.6 N).sup.+.
The present invention further comprises compounds of formula I, M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is of the form ZH.sup.+, n is 1, and Z is a base capable of accepting n protons.
The present invention further comprises anhydrous PyH.sup.+ AlF.sub.4.sup.- wherein Py is pyridine and which when thermolyzed forms pure AlF.sub.3.
The present invention further comprises a polymer having a repeating unit of the formula (X) or formula (XI). ##STR3## wherein m is 0 or an integer equal to or greater than 1;
n is an integer greater than 1;
Q is NR, O, or S; and
R is H or C.sub.1 -C.sub.6 alkyl.
The present invention further comprises processes for the preparation of compounds of formula M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n and n are defined above. One such process comprises reacting Al(R).sub.3 with M.sup.+n (HF).sub.q F.sub.n.sup.- wherein M is an organic cation or polycation; n is an integer from 1 to 3; q is an integer of at least 1; and each R is independently C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.12 alkoxy, C.sub.1 -C.sub.12 enolate, aryl, or C.sub.1 -C.sub.12 alkamide.
A second process for the preparation of M.sup.+n (AlF.sub.4.sup.-).sub.n wherein n is an integer from 1 to 3, M is an organic cation of formula ZH.sub.n.sup.+n and Z is a base capable of accepting n protons, comprises reacting Al(R).sub.3 wherein each R is independently C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.12 alkoxy, C.sub.1 -C.sub.12 enolate, aryl, or C.sub.1 -C.sub.12 alkamide with a solution of HF and Z.
A third process for the preparation of M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is an organic cation or polycation, and n is an integer from 1 to 3 comprises reacting ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m with Y, wherein Z is a base capable of accepting m protons wherein m is an integer from 1 to 3, and Y is a proton-accepting base or a phosphorus ylid of formula R.sub.1 R.sub.2 R.sub.3 P.dbd.CR.sub.4 R.sub.5 wherein R.sub.1, R.sub.2 and R.sub.3 are each independently linear, branched or cyclic C.sub.1 -C.sub.10 alkyl or substituted C.sub.1 -C.sub.10 alkyl, C.sub.1 -C.sub.10 alkoxy, aryl, aryloxy, heterocyclic, substituted heterocyclic, or together two or more of R.sub.1, R.sub.2 or R.sub.3 may form a ring of 3 to 10 atoms; R.sub.4 and R.sub.5 are each independently hydrogen, linear, branched or cyclic C.sub.1 -C.sub.10 alkyl or substituted alkyl, C.sub.1 -C.sub.10 alkoxy, aryl, aryloxy, heterocyclic, substituted heterocyclic or R.sub.4 and R.sub.5 together may form a ring of 3 to 10 atoms.
A fourth process for the preparation of M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is an organic cation or polycation, and n is an integer from 1 to 3 comprises reacting ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m, wherein Z is a base capable of accepting m protons wherein m is an integer from 1 to 3, with M.sup.+n (X.sup.-).sub.n wherein M is an organic cation or polycation other than H.sup.+ and X is a stronger base than Z.
A fifth process for the preparation of M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is an organic cation or polycation, and n is an integer from 1 to 3 comprises reacting ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m, wherein Z is a base capable of accepting m protons wherein m is an integer from 1 to 3, with M.sup.+n (X.sup.-).sub.n wherein M.sup.+n is an organic cation or polycation other than H.sup.+ and X.sup.- is an anion which forms a compound ZH.sub.m.sup.+m (X.sup.-).sub.m easily separable from the M.sup.+n (AlF.sub.4.sup.-).sub.n product.

BRIEF DESCRIPTION OF THE FIGURES
FIG. 1 depicts the powder X-ray diffraction pattern of M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is H-pyridine and n is 1.
FIG. 2 depicts the X-ray crystal structure of ZH.sup.+ AlF.sub.4.sup.- wherein Z is 1,8-bis(dimethylamino)naphthalene.
FIG. 3a depicts the structure of the tetrahedral AlF.sub.4.sup.- anion as obtained from the x-ray crystal structure of collidinium AlF.sub.4.
FIG. 3b depicts the structure of a chain of octahedral AlF.sub.6 units linked through corner and edge sharing of F as obtained from the x-ray crystal structure of collidinium AlF.sub.4.
FIG. 3c depicts the structure of collidinium cations as obtained from the x-ray crystal structure of collidinium AlF.sub.4.
FIG. 4a depicts the structure of the tetrahedral cation P(C.sub.6 H.sub.5).sub.4.sup.+ as obtained from the x-ray crystal structure of tetraphenylphosphonium AlF.sub.4.
FIG. 4b depicts the structure of the tetrahedral AlF.sub.4.sup.- anion as obtained from the x-ray crystal structure of tetraphenylphosphonium AlF.sub.4.
FIG. 5a depicts the structure of the tetrahedral As(C.sub.6 H.sub.5).sub.4.sup.+ cation as obtained from the x-ray crystal structure of tetraphenylarsonium AlF.sub.4.
FIG. 5b depicts the structure of the tetrahedral AlF.sub.4.sup.- anion as obtained from the x-ray crystal structure of tetraphenylarsonium AlF.sub.4.
FIG. 6 depicts the powder X-ray diffraction pattern of M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is the triphenylmethylphosphonium cation and n is 1.

DETAILED DESCRIPTION OF THE INVENTION
The present invention comprises compounds of formula I
M.sup.+n (AlF.sub.4.sup.-).sub.n I
wherein M.sup.+n is an organic cation or polycation other than NMe.sub.4.sup.+, NEt.sub.4.sup.+, N(n-Bu).sub.4.sup.+, guanidinium H.sup.+, or PyridineH.sup.+, and n is an integer from 1 to 3. In particular the present invention includes compounds of formula I wherein M is selected from the group consisting of N(R.sub.2).sub.4, P(R.sub.2).sub.4, As(R.sub.2).sub.4, HN(R.sub.2).sub.3, H.sub.2 N(R.sub.2).sub.2, H.sub.3 N(R.sub.2), (R.sub.2).sub.3 P.dbd.N.dbd.P(R.sub.2).sub.3, S�N(R.sub.2).sub.2 !.sub.3, ##STR4## R is hydrogen, C.sub.1 -C.sub.10 linear or branched alkyl or aryl; R.sub.2 is C.sub.1 -C.sub.10 linear or branched alkyl or aryl;
n is 1; and
k is 1 to 10;
provided that M.sup.+n is other than NMe.sub.4.sup.+, NEt.sub.4.sup.+, N(n-Bu).sub.4.sup.+, guanidinium (H.sub.2 N.dbd.C(NH.sub.2).sub.2).sup.+ and pyridinium (C.sub.5 H.sub.6 N).sup.+.
The present invention further comprises compounds of the formula I, M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is of the form ZH.sub.m.sup.+m, n is 1, m is an integer of 1 to 3, and Z is a base capable of accepting m protons.
The present invention further comprises PyH.sup.+ AlF.sub.4.sup.- wherein Py is pyridine and which when thermolyzed forms pure AlF.sub.3.
In the above recitations and the processes of the present invention, the term "alkyl" denotes straight chain or branched alkyl; e.g., methyl, ethyl, n-propyl, i-propyl, or the different butyl, pentyl, hexyl, etc. isomers. Cyclic alkyls include cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, etc. The abbreviation Me denotes methyl, Et denotes ethyl, and n-Bu denotes n-butyl.
"Alkenyl" denotes straight chain or branched alkenes; e.g., 1-propenyl, 2-propenyl, and the different butenyl, pentenyl, hexenyl, etc. isomers. "Dienyl" denotes polyenes having two double bonds such as 1,3-hexadiene and the like.
"Alkoxy" denotes methoxy, ethoxy, n-propyloxy, isopropyloxy and the different butoxy, pentoxy, hexyloxy, etc. isomers.
"Aryl" includes aromatic hydrocarbons such as benzene, substituted benzene, such as toluene, aniline, benzoic acid, halobenzene, nitrobenzene, etc., naphthalene, or substituted naphthalene.
"Heterocyclic" denotes 5- or 6-membered rings containing 1 to 3 nitrogen, oxygen, or sulfur atoms or combinations thereof such as furanyl, thiofuranyl, tetrahydrofuranyl, thiopheneyl, pyrrolyl, pyrazolyl, triazolyl, dithiolyl, oxathiolyl, oxazolyl, thiazolyl, dioxazolyl, oxathiazolyl, pyranyl, pyronyl, pyridinyl, pyrimindinyl, pyrazinyl, triazinyl, oxazinyl, oxathiazinyl, imidazolyl, etc. Preferred in the compounds and processes of the present invention are pyridinyl, furanyl, tetrahydrofuranyl, pyranyl, imidazolyl or thiopheneyl.
Substituted alkyl includes C.sub.1 -C.sub.10 alkyl having at least one substituent. Suitable substituents include hydrogen, C.sub.1 -C.sub.10 alkyl, C.sub.2 -C.sub.10 alkenyl, C.sub.2 -C.sub.10 alkynyl, or aryl.
Substituted heterocyclic includes heterocyclic as defined above having at least one substituent. Suitable substituents include hydrogen, C.sub.1 -C.sub.10 alkyl, C.sub.2 -C.sub.10 alkenyl, C.sub.2 -C.sub.10 alkynyl, or halogen.
"Polycation" denotes multiple singly charge atoms linked to form a cation having a net charge greater than one. It is not meant to indicate multiple charges on individual atoms making up the cation.
Preferred cations include trialkylammonium, tetraalkylammonium wherein alkyl is other than methyl, ethyl and butyl, tetraalkylphosphonium and mixed alkyl- and aryl-phosphonium where the P atom is bound to four different carbon atoms, and analogous arsonium compounds. Also preferred in addition to the above are pyrilium and substituted pyrilium, thiopyrilium and substituted thiopyrilium, and bis(triphenylphosphine)iminium cations, as well as polyvinylpyridinium and polyalkyleneammonium polycations.
Preferred compounds are: triphenylmethylphosphonium tetrafluoroaluminate, tetraethylphosphonium tetrafluoroaluminate, tetraphenylphosphonium tetrafluoroaluminate, tetraphenylarsonium tetrafluoroaluminate, tetrapropylammonium tetrafluoroaluminate or 1,8-bisdimethylaminonapthalenium tetrafluoroaluminate.
The present invention also comprises compounds of formula M.sup.+n (AlF.sub.4.sup.-).sub.n wherein M.sup.+n is of the form ZH.sub.n.sup.+n wherein n is 1 and wherein Z is a base capable of accepting n protons, preferably amine, pyridine or ylid. Preferred are such compounds wherein Z is pyridine, 1,8-bis(dimethylamino)naphthalene, 2,4,6-trimethylpyridine (collidine), or 2,6-dimethylpyridine (lutidine). Also preferred is anhydrous PyH.sup.+ AlF.sub.4.sup.- wherein Py is pyridine and which when thermolyzed at a temperature of from about 285.degree. C. to about 450.degree. C. forms pure AlF.sub.3. Pure is used herein to mean that the AlF.sub.3 is uncontaminated with Al.sub.2 O.sub.3 as detectable by X-ray diffraction.
The compounds of formula I can be prepared as described below in rigorously pure and anhydrous form. Depending upon the choice of M.sup.+n, the compounds may be freely soluble in nonaqueous solvents, and the AlF.sub.4.sup.- anion may be four-coordinate with no bridging fluorides nor additional ligating groups.
The compounds of formula I are useful for the preparation of pure AlF.sub.3 in several of its crystalline phases such as alpha, beta, eta, theta, or kappa, without oxide or hydroxide contamination or incorporation. AlF.sub.3 results from the anhydrous thermal decomposition of compounds of formula I at temperatures ranging from about 285.degree. C. to about 450.degree. C. depending upon the exact composition of the organic cation or polycation. A. K. Sengupta and K. Sen (Indian J. Chem. 1979, 17A, 107-108) briefly describe the thermolysis of several fluoroaluminate salts of organic cations to "a mixture of aluminum fluoride and oxide", the oxide arising from water or hydroxide present in their "fluoroaluminate" materials. Bulk AlF.sub.3 is useful as a solid-state catalyst for chlorofluorocarbon isomerization and fluorination, and high surface area AlF.sub.3 dispersed onto carbon, organic, or inorganic supports may be a useful catalyst for these or other reactions. Embodiments of the latter are described by U.S. Pat. No. 5,171,798 issued Dec. 15, 1992 to McDaniel et al., wherein fluoroaluminum species generated on a support of alumina were subsequently treated with e.g., chromium to obtain active olefin polymerization catalysts. Routes to such high surface area AlF.sub.3 phases dispersed on inorganic supports are provided by the solubility of AlF.sub.4.sup.- species of the formula I type in non-aqueous solvents. Suitable non-aqueous solvents include solvents such as methanol, ethanol, pyridine, acetonitrile, acetone, tetrahydrofuran, dimethylsulfoxide, dimethylformamide, formamide, dichloromethane or chloroform. The AlF.sub.4.sup.- species are readily deposited onto high surface area supports and subsequent thermolysis converts the AlF.sub.4.sup.- species to well-dispersed AlF.sub.3 phases.
The present invention further comprises a polymer comprising repeating units having the formulae (X) or (XI) ##STR5## wherein m is 0 or an integer equal to or greater than 1; n is an integer greater than 1; Q is NR, O or S; and R is H or C.sub.1 -C.sub.6 alkyl. Preferred polymers are polyethylene containing pendant quaternary ammonium groups and polystyrene containing occasional incorporated polyvinyl pyridinium groups. The polymers of the present invention are prepared by anion exchange reactions known to those skilled in the art.
In a preferred example, a commercially available anion exchange resin in its halide (X.sup.- where X=Cl, Br, I) form may be packed in a vertical chromatography column using methanol solvent. A solution of collidineH.sup.+ AlF.sub.4.sup.- in methanol may be added to the top of the column and the solution drained through the column. As the AlF.sub.4.sup.- solution travels through the column it will displace the original halide ion (X.sup.-) from the anion exchange resin so that the column eluent will consist of collidineH.sup.+ X.sup.- while the column will become transformed to the desired AlF.sub.4.sup.- form. The progress of this transformation may be monitored by analyzing the effluent for halide ion (X.sup.-). When no further halide is present the exchange of AlF.sub.4.sup.- for X.sup.- on the resin is complete generating polymers of repeating units of formula (X) or (XI).
The utility of the AlF.sub.4.sup.- exchanged resin is in its ability to be transformed into the corresponding AlF.sub.3 phase upon mild thermal treatment (300.degree.-400.degree. C.) in an inert atmosphere (nitrogen, argon, helium or vacuum) to eliminate RF (where R is H or alkyl or aryl originating from the resin). The resulting composite material of AlF.sub.3 dispersed on an organic polymeric resin is useful as a high surface area form of the known fluorocarbon transformation catalyst AlF.sub.3.
The present invention further comprises the processes of Equations 1 to 5 useful for the preparation of compounds of formula I as shown in Scheme 1. ##EQU1##
In Equation 1 an aluminum source, Al(R).sub.3, wherein each R is independently C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.12 alkoxy, C.sub.1 -C.sub.12 enolate, aryl, or C.sub.1 -C.sub.12 alkamide is reacted with M.sup.+n (HF).sub.q F.sub.n.sup.- wherein M.sup.+n is an organic cation or polycation as defined in formula I, q is greater than or equal to 1, and n is an integer from 1 to 3. Such starting materials can be made according to the procedures of Colton, R., et al. Aust. J. Chem. 42, 1605-9, 1989. The reaction is conducted in a solvent which is unreactive with Al(R).sub.3 or which undergoes only coordination to Al(R).sub.3 such as ethers, tertiary amines, or nitrogen-containing heterocyclic compounds. Preferred is pyridine. The mole ratio of Al(R).sub.3 to q in M.sup.+n (HF).sub.q F.sub.n.sup.- is at least 1:3. The reaction is conducted at a temperature of from about -100.degree. C. to about 150.degree. C. depending upon the solvent employed. Preferably the reaction is conducted at a temperature of from about -40.degree. C. to 60.degree. C. Use of an inert atmosphere such as nitrogen or argon is required to exclude oxygen and water. The reaction is conducted at ambient pressure or under a vacuum. The preferred pressure is from about 0.01 to 5 atm (10.sup.3 to 5.times.10.sup.5 Pa). Agitation is optional but preferred. The desired product, M.sup.+n (AlF.sub.4.sup.-).sub.n can be isolated using routine procedures such as filtration or crystallization.
For the process of Equation 2, an aluminum source Al(R).sub.3, wherein each R is independently C.sub.1 -C.sub.12 alkyl, C.sub.1 -C.sub.12 alkoxy, C.sub.1 -C.sub.12 enolate, aryl or C.sub.1 -C.sub.12 alkamide, such as trimethylaluminum is mixed with reagent Z, under an inert atmosphere and anhydrous HF added. Z is a base capable of accepting n protons wherein n is an integer from 1 to 3. Such starting materials are commercially available or are prepared according to Colton above. Examples of suitable reagent Z include pyridine, triethylamine, substituted pyridines and substituted amines. The mole ratio of Al(R).sub.3 to HF employed is at least about 1:4. Suitable solvents include amines, phosphines, arsines, nitrogen containing heterocyclic compounds or Z as defined above. Preferred for use in this process are pyridine, substituted pyridine or trialkylamines. The reaction is conducted at a temperature of from about -100.degree. C. to about 150.degree. C., preferably at -40.degree. C. to 60.degree. C. depending upon the solvent used. Use of ambient pressure or a vacuum is employed, preferably from about 0.01 to 5 atm (10.sup.3 to 5.times.10.sup.5 Pa). An inert atmosphere such as nitrogen, argon, or helium is employed to maintain an environment free of oxygen, water or carbon dioxide. Agitation is optional but preferred. After stirring, the reaction mixture is left to stand at ambient temperature and the desired ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m product may precipitate out and can be isolated by filtration or other equivalent means.
ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m, prepared as in the process of Equation 2, can be employed in the process of Equation 3. The Equation 3 process comprises reacting ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m with Y, wherein Z is a base capable of accepting m protons wherein m is an integer from 1 to 3, and Y is a base capable of accepting n protons wherein n is an integer from 1 to 3 or a phosphorus ylid, and Y is more basic than Z. In Equation 3, Y is a proton-accepting base such as pyridine, amine, or a phosphorus ylid of formula R.sub.1 R.sub.2 R.sub.3 P.dbd.CR.sub.4 R.sub.5 wherein
R.sub.1, R.sub.2 and R.sub.3 are each independently linear, branched or cyclic C.sub.1 -C.sub.10 alkyl or substituted C.sub.1 -C.sub.10 alkyl, alkylene, C.sub.1 -C.sub.10 alkoxy, aryl, aryloxy, heterocyclic, substituted heterocyclic, or together two or more of R.sub.1, R.sub.2 or R.sub.3 may form a ring of 3 to 10 atoms;
R.sub.4 and R.sub.5 are each independently hydrogen, linear, branched or cyclic C.sub.1 -C.sub.10 alkyl or substituted C.sub.1 -C.sub.10 alkyl, alkylene, C.sub.1 -C.sub.10 alkoxy, aryl, aryloxy, heterocyclic, substituted heterocyclic or R.sub.4 and R.sub.5 together may form a ring of 3 to 10 atoms; and
Y is a stronger base than Z.
Substituted alkyl, heterocyclic, and substituted heterocyclic are as previously defined.
Examples of suitable Z include pyridine, 2,4,6-tri-methylpyridine, 1,8-bis(dimethylamino)naphthalene, 2,6-dimethylpyridine and the like. The mole ratio of Y to ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m employed is m, wherein m is an integer of 1 to 3 or greater. Suitable solvents include chlorocarbons, ethers, amines, nitrogen-containing heterocyclic compounds or Y as defined above. Preferred solvents are tetrahydrofuran and substituted pyridines. The reaction is conducted at a temperature of from about -100.degree. C. to about 150.degree. C., preferably from about -40.degree. C. to 60.degree. C. depending upon the solvent employed. Exclusion of water vapor, oxygen and carbon dioxide is required if they would react with Y or Z. Use of an inert atmosphere such as nitrogen, argon or helium is preferred. The reaction is conducted at ambient pressure or under vacuum, preferably from about 0.01 to 5 atm (10.sup.3 to 5.times.10.sup.5 Pa). Use of vigorous agitation is preferred.
It has been found that it is particularly advantageous to use bases as reagent Y in Equation 3 such that their conjugate acids YH.sup.+ are incapable of forming strong hydrogen bonds to the fluoroaluminate anion, as the resulting compounds YH.sup.+ AlF.sub.4.sup.- then tend to be freely soluble in organic solvents. Two particular examples are 1,8-bis(dimethylamino)naphthalene where the conjugate acid, even though possessing NH groups, is a very weak hydrogen-bonding participant; and (C.sub.2 H.sub.5).sub.3 P.dbd.CHCH.sub.3, where the conjugate acid has hydrogen only bonded to carbon and does not normally participate in hydrogen-bonding. Most ylid compounds of phosphorus, arsenic, sulfur, nitrogen, and other elements are suitable to serve as base Y in Equation 3 and likewise provide conjugate acid cations YH.sup.+ that form only weak hydrogen bonds to fluoroaluminate anions.
A further process for the preparation of M.sup.+n (AlF.sub.4.sup.-).sub.n is the reaction of Equation 4. ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m, prepared as in Equation 2, wherein Z is a base capable of accepting m protons wherein m is an integer of 1 to 3, is reacted in a simple ion metathesis with M.sup.+n (X.sup.-).sub.n wherein M.sup.+n is an organic cation or polycation as defined in formula I and X.sup.- is a stronger base than Z. Suitable cations for M.sup.+ include, for example, As(C.sub.6 H.sub.5).sub.4.sup.+, P(C.sub.6 H.sub.5).sub.4.sup.+, P(C.sub.6 H.sub.5).sub.3 CH.sub.3.sup.+, N(C.sub.2 H.sub.5).sub.4.sup.+ and the like. Suitable anions for X.sup.- include 2,6-dimethylphenolate, trimethylacetate, and the like. The mole ratio of M.sup.+n (X.sup.-).sub.n to ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m is preferably m:n. An excess of either can be used. The reaction is conducted in a solvent such as a halocarbon, ether, alcohol, ketone, amine, or heterocyclic nitrogen compound. Preferred solvents are tetrahydrofuran, methanol, acetone, dichloromethane, or pyridine. The temperature employed depends upon the solvent used and can range from about -100.degree. C. to about 150.degree. C., preferably -40.degree. C. to 60.degree. C. The pressure employed can be ambient or a vacuum used, and is preferably from about 0.01 to about 5 atm (10.sup.3 to 5.times.10.sup.5 Pa). Water vapor should be excluded so the reaction is conducted in an inert atmosphere such as nitrogen, argon, or helium. The desired product, M.sup.+n (AlF.sub.4.sup.-).sub.n is isolated by conventional means such as crystallization or filtration.
A further process for the preparation of M.sup.+n (AlF.sub.4.sup.-).sub.n is the reaction of Equation 5 comprising reacting ZH.sub.m.sup.+m (AlF.sub.4.sup.-).sub.m wherein Z is a base capable of accepting m protons wherein m is an integer of 1 to 3, with M.sup.+n (X.sup.-).sub.n wherein M.sup.+n is an organic cation or polycation as defined in formula I and X.sup.- is a halide or other anion, such as SCN.sup.-, N.sub.3.sup.-, OCN.sup.-, CF.sub.3 SO.sub.3.sup.-, ClO.sub.4.sup.-, NO.sub.3.sup.-, or SO.sub.4.sup.2-. The reaction conditions are substantially the same as those described for Equation 4 except that X.sup.- is not a stronger base than Z, but can be of comparable or lesser strength.
The following examples are representative of the present invention. The desired product, M.sup.+n (AlF.sub.4.sup.-).sub.n, is isolated by conventional means such as crystallization or filtration.
EXAMPLE 1
Preparation of H-pyridine.sup.+ AlF.sub.4.sup.-
Under an N.sub.2 atmosphere in a drybox, 0.216 g trimethylaluminum (CAUTION| This material is pyrophoric in air and reacts vigorously with many solvents, including alcohols, ethers, and pyridine) was dissolved in 20 mL dry pyridine in a plastic beaker. To this solution was added 0.37 g of HF-pyridine solution (separately determined to have the approximate composition HF(pyridine)0.135, equivalent weight 30.7). After the vigorous reaction had subsided the mixture was stirred for 1 hour. Additional pyridine (20 mL) was added and the mixture was transferred to a glass vessel. After standing 3 days at ambient temperature the mixture was filtered and the insolubles dried in vacuum at ambient temperature, yield 0.39 g. The resulting material contained excess solvent. Anal. Calcd. for H(pyridine).sub.1.3 AlF.sub.4 : C, 37.75%; H, 3.65%; N, 8.80%. Found (Galbraith): C, 37.77, 37.37%; H, 3.57, 3.67%; N, 8.47, 8.69%. The X-ray powder diffraction pattern of a typical sample is shown in FIG. 1. The corresponding data is in Table I.
TABLE I______________________________________Generator Settings 40 kV, 30 mACU alpha1, 2 wavelengths 1.540598, 1.544435 AngStep size, sample time 0.20 deg, 0.50 s, 25.00 s/degMonochromator used YesDivergence slit Automatic (specimen length: 12.5 mm)Analysis program number 1Peak angle range 2.000-60.000 degPeak position criterion Top of smoothed dataNumber of peaks in file 33 (Alpha1: 33, Amorphous: 0)______________________________________Peak Angle Width Peak Backg D spac I/ImaxNo. (deg) (deg) (cts) (cts) (Ang) (%)______________________________________1 2.272 0.24 22 27 38.8774 12 9.283 0.28 2343 99 9.5276 1003 10.258 0.14 1459 93 8.6240 624 15.422 0.20 64 82 5.7455 35 17.372 0.16 1129 87 5.1048 486 18.445 0.08 219 89 4.8103 97 18.715 0.14 262 89 4.7415 118 20.630 0.10 408 95 4.3055 179 22.357 0.18 353 99 3.9766 1510 23.872 0.20 645 103 3.7275 2811 25.650 0.06 339 107 3.4731 1412 26.057 0.14 581 109 3.4197 2513 27.780 0.08 289 113 3.2115 1214 29.455 0.12 161 118 3.0325 715 30.117 0.20 102 118 2.9673 416 31.105 0.10 231 122 2.8753 1017 34.410 0.06 112 129 2.6064 518 34.745 0.20 207 129 2.5820 919 35.878 0.48 48 129 2.5030 220 37.275 0.24 137 129 2.4124 621 38.048 0.08 159 129 2.3651 722 39.627 0.20 119 129 2.2744 523 41.950 0.16 98 129 2.1537 424 42.610 0.24 66 129 2.1219 325 44.735 0.12 135 143 2.0259 626 45.190 0.20 77 148 2.0065 327 46.768 0.10 27 148 1.9425 128 48.055 0.12 196 145 1.8934 829 51.140 0.24 56 148 1.7862 230 53.180 0.12 48 133 1.7224 231 53.658 0.24 45 133 1.7082 232 55.320 0.64 24 131 1.6607 133 57.472 0.24 25 1274 1.6035 1______________________________________
EXAMPLE 2
Preparation of BH.sup.+ AlF.sub.4.sup.-, B=1,8-bis(dimethylamino)naphthalene
H-pyridine.sup.+ AlF.sub.4.sup.- (0.19 g) prepared as in Example 1 and 1,8-bis(dimethylamino)naphthalene (0.21 g) were combined in a ca. 2 mL dry acetonitrile, under nitrogen in a drybox. The mixture was stirred and rapidly became a solution. Diethyl ether was then slowly added until precipitation began, at which time the mixture was filtered and the initial precipitate was discarded. More diethyl ether was added to the solution, eventually precipitating 0.19 g white solid, mp. 260.degree. C. Anal. Calcd. for C.sub.14 H.sub.19 N.sub.2 Al.sub.1 F.sub.4 : C, 52.83%; H, 6.02%; N, 8.80%; Al, 8.48%; F, 23.88%. Found (Galbraith): C, 52.61, 52.87%; H, 6.06, 5.78%; N, 8.74, 8.80%; Al, 8.73, 8.40%; F, 18.79, 18.70%. The fluorine analysis is poor owing perhaps to incomplete degradation of AlF.sub.4.sup.- during the analytical procedure. IR (Nujol) AlF.sub.4.sup.- at 790/cm. NMR (0.002M in CD.sub.3 CN): .sup.19 F, -194.2 ppm, 6 lines, J=38 Hz; .sup.27 Al, 49.2 ppm, binomial quintet, J=38 Hz. A single crystal, grown from CH.sub.2 Cl.sub.2 /toluene solution, was used for an X-ray structure determination. The resulting data are shown in Table II and FIG. 2.
The X-ray crystal analysis was as follows: ##STR6## CRYSTAL DATA
AlF.sub.4 N.sub.2 C.sub.14 H.sub.19, from CH.sub.2 Cl.sub.2 /toluene, colorless, square plate, .about.0.34.times.0.10.times.0.54 mm, triclinic, P1 (No. 2), a=8.081(1), b=8.307(1), c=12.375(1) .ANG., .alpha.=82.84(1), .beta.=76.16(1), .gamma.=79.13(1).degree., from 47 reflections, T=-100.degree. C., V=789.4 .ANG..sup.3, Z=2, FW=318.30, Dc=1.339 g/cc, .mu.(Mo)=1.58 cm.sup.-1.
DATA COLLECTION AND TREATMENT
Syntex R3 diffractometer, MoK.alpha. radiation, 7858 data collected, 5.0.degree..ltoreq.2.theta..ltoreq.55.0.degree., maximum h,k,l=10 10 31, data octants=+++, ++-, +-+, +--, -++, -+-, .omega. scan method, scan width=1.50.degree..omega., scan speed=3.90.degree.-11.70.degree./min., typical half-height peak width=0.70.degree..omega., 6.1% variation in azimuthal scan, no absorption correction, 1981 unique reflections with I.gtoreq.3.0 .sigma.(I).
SOLUTION AND REFINEMENT
Structure solved by direct methods (SHELXS), refinement by full-matrix least squares on F, scattering factors from Int. Tables for X-ray Crystallography, Vol. IV, including anomalous terms for Al, biweight .alpha. �.sigma..sup.2 (l)+0.0009I.sup.2 !.sup.-1/2, (excluded 2), refined anisotropic: all non-hydrogen atoms, isotropic: H, 293 parameters, data/parameter ratio=6.75, final R=0.051, Rw=0.048, error of fit=1.70, max .DELTA./.sigma.=0.12, largest residual density=0.27 e/.ANG..sup.3, near F1.
Results
The proposed crystal structure with an isolated, monomeric AlF.sub.4 anion was confirmed even though the anion was two-fold disordered around the Al(1)-F(1) axis. F(1) was fully occupied: the remainder of the fluorines were assigned occupancies of 0.5. F(1) was also unique in that it formed the closest contact with the proton, H(1). The distance, 2.77 .ANG., was too long to be considered a real hydrogen bond, the approach of the anion to the proton being hindered by the cluster of methyl groups. All of the hydrogen atoms were refined. Crystals of this compound were invariably twinned. The crystal selected for this study had a single set of diffraction spots when photographed but generally had broad omega scans and some split peaks. In addition, one low-angle peak had sufficient intensity to suggest that the cell should be doubled. The cell was doubled during the data collection but no other reflections with significant intensity were found. The intensity was probably diffuse scattering related to the disordered anion.
TABLE II______________________________________Fractional Coordinates (X10000)and Isotropic Thermal ParametersATOM X Y Z BISO______________________________________Al(1) 3342.8(11) 2601.4(12) -1791.2(7) 3.1(1)'F(1) 3543(3) 2960(3) -553(2) 7.8(1)'F(2') 5040(8) 2716(12) -2673(5) 9.9(3)'F(2") 4929(9) 1435(10) -2592(6) 10.7(3)'F(3') 1658(8) 3708(9) -2083(4) 8.0(2)'F(3") 3303(14) 4424(6) -2490(5) 11.1(3)'F(4') 2895(11) 730(6) -1519(5) 9.5(3)'F(4") 1617(8) 1967(15) -1797(5) 11.1(4)'N(1) 685(3) 1749(3) 1764(2) 2.5(1)'N(2) 2896(3) 3451(3) 2033(2) 3.0(1)'C(1) 701(4) 2507(3) 3632(2) 2.9(1)'C(2) -153(3) 1845(3) 2948(2) 2.7(1)'C(3) -1658(4) 1258(4) 3389(3) 3.6(1)'C(4) -2423(5) 1314(4) 4540(3) 4.3(1)'C(5) -1621(5) 1876(4) 5215(3) 4.2(1)'C(6) -42(4) 2459(3) 4801(2) 3.5(1)'C(7) 822(5) 3008(4) 5518(3) 4.4(1)'C(8) 2309(6) 3604(4) 5118(3) 4.8(1)'C(9) 3014(5) 3752(4) 3966(3) 4.0(1)'C(10) 2228(4) 3227(3) 3244(2) 3.1(1)'C(11) 1549(5) 51(4) 1523(3) 4.1(1)'C(12) -489(4) 2437(5) 1009(3) 3.8(1)'C(13) 4765(4) 2773(6) 1683(3) 4.8(1)'C(14) 2492(6) 5191(5) 1603(3) 4.2(1)'H(1) 1966(50) 2654(48) 1695(31) 8.8(11)H(3) -2157(35) 780(34) 2909(23) 3.6(7)H(4) -3618(45) 868(41) 4811(27) 6.0(8)H(5) -2161(41) 1907(39) 6003(29) 5.4(8)H(7) 311(44) 2861(43) 6298(31) 6.3(9)H(8) 2776(41) 3998(39) 5551(28) 5.1(8)H(9) 3974(38) 4289(37) 3662(24) 4.0(7)H(11) 2133(37) 44(34) 798(26) 3.4(7)H(11') 645(38) -691(38) 1635(23) 4.3(7)H(11") 2436(46) -263(44) 1961(29) 5.8(9)H(12) 166(37) 2520(33) 297(25) 3.5(7)H(12') -1083(44) 3591(46) 1185(27) 5.7(9)H(12") -1400(42) 1808(38) 1040(24) 4.7(8)H(13) 5075(36) 2801(35) 861(28) 4.3(7)H(13') 4958(43) 1536(48) 2056(29) 5.9(9)H(13") 5354(42) 3399(40) 1957(27) 5.3(8)H(14) 2892(37) 5222(35) 817(27) 4.2(7)H(14') 3008(43) 5898(44) 1939(28) 5.8(9)H(14") 1199(49) 5607(41) 1826(27) 5.5(9)______________________________________
EXAMPLE 3
Preparation of CollidineH.sup.+ AlF.sub.4.sup.-
Inside a nitrogen filled glove box, 10 g of the material pyridineH.sup.+ AlF.sub.4.sup.- prepared as in Example 1 was slurried into 50 mL (excess) dry collidine (2,4,6-trimethylpyridine). This mixture was heated with stirring to 120.degree. C. at which point the white solid completely dissolved to give a pale yellow solution. Stirring was ceased and the solution allowed to slowly cool whereupon colorless needles of the desired compound crystallized from solution as a dense white mat. The solid was collected by filtration and washing with THF then suction dried. Yield=11.5 g (94%). IR (KBr) AlF.sub.4.sup.- at 783 cm.sup.-1 also AlF species at 687, 629, 603, 520 cm.sup.-1. .sup.27 Al 51.6 ppm, quintet, J=38 Hz. Solid state .sup.19 F MAS-NMR shows two resonances at -155 ppm (broad) and -187.8 ppm (sharp). A single crystal grown from the above solution in collidine was used for a single crystal structure determination. Crystal data: AlF.sub.4 NC.sub.8 H.sub.12 from hot collidine, colorless, needle, 0.05.times.0.05.times.0.70 mm, orthorhombic, Pbcn (#60), a=29.673(6), b=16.644(3), c=12.439(3) .ANG., T=-100.degree. C., V=6143.3 .ANG..sup.3, Z=24, FW=225.17, Dc=1.461 g/cc, .mu.(Mo)=2.10 cm.sup.-1. All non-hydrogen atoms refined anisotropic, 526 parameters, data/parameter ratio=6.46, final R=0.044, Rw=0.036, error of fit=1.24. Atomic coordinates are listed in Table III while the structure is depicted in FIG. 3. The structure showed both the tetrahedral AlF.sub.4.sup.- anions (FIG. 3a) and an infinite polymeric chain of octahedral AlF.sub.6 units linked through corner and edge sharing of F (FIG. 3b) and stabilized by hydrogen bonded collidinium cations (FIG. 3c).
TABLE III______________________________________Fractional Coordinates (X10000) andIsotropic Thermal ParametersATOM X Y Z BISO______________________________________Al(1) 5000 5000 0 1.2(1)'Al(2) 5000 5875(1) 2500 1.1(1)'Al(3) 5000 4137(1) 2500 1.2(1)'Al(4) 5000 10381(1) 2500 3.5(1)'Al(5) 2339 5875(1) -542(1) 3.2(1)'F(1) 4412 5006(1) -146(1) 1.6(1)'F(2) 4960(1) 5802(1) 1032(1) 1.4(1)'F(3) 4954(1) 4217(1) 1041(1) 1.5(1)'F(4) 4563(1) 6576(1) 2566(1) 1.8(1)'F(5) 4606(1) 5008(1) 2557(1) 1.3(1)'F(6) 4565(1) 3432(1) 2587(1) 1.7(1)'F(7) 5228(1) 9791(1) 1581(2) 6.5(1)'F(8) 4622(1) 10964(2) 1927(2) 6.0(1)'F(9) 2061(1) 5199(1) -1266(2) 4.1(1)'F(10) 1974(1) 6514(1) 2(2) 6.6(1)'F(11) 2680(1) 6402(1) -1325(2) 4.9(1)'F(12) 2644(11) 5430(2) 383(2) 6.9(1)'N(1) 3728(1) 4431(2) -1239(2) 1.7(1)'N(11) 3874(1) 7388(2) 1796(2) 2.1(1)'N(21) 4324(1) 2129(2) 3709(2) 2.0(1)'C(2) 3462(1) 4813(2) -1945(3) 1.9(1)'C(3) 3062(1) 4460(2) -2239(3) 2.2(1)'C(4) 2936(1) 3720(2) -1819(3) 2.2(1)'C(5) 3227(1) 3349(2) -1112(3) 2.2(1)'C(6) 3626(1) 3708(2) -816(3) 2.0(1)'C(7) 3610(2) 5610(3) -2367(5) 3.5(1)'C(8) 2492(2) 3359(3) -2124(4) 3.4(1)'C(9) 3962(1) 3342(2) -76(3) 2.7(1)'C(12) 3622(1) 7042(2) 1027(3) 2.1(1)'C(13) 3229(1) 7415(2) 739(3) 2.5(1)'C(14) 3090(1) 8118(2) 1239(3) 2.6(1)'C(15) 3370(1) 8446(2) 2009(3) 2.4(1)'C(16) 3767(1) 8078(2) 2286(3) 2.3(1)'C(17) 3793(2) 6279(3) 552(4) 3.1(1)'C(18) 2646(2) 8502(4) 950(5) 4.5(2)'C(19) 4083(2) 8392(4) 3117(5) 4.3(2)'C(22) 4577(1) 1876(2) 4542(3) 2.3(1)'C(23) 4440(1) 1199(2) 5083(3) 3.0(1)'C(24) 4051(1) 795(2) 4788(3) 2.6(1)'C(25) 3809(1) 1080(2) 3930(3) 2.6(1)'C(26) 3949(1) 1753(2) 3372(3) 2.3(1)'C(27) 4992(2) 2340(3) 4800(4) 4.0(1)'C(28) 3916(2) 43(3) 5373(4) 4.3(1)'C(29) 3721(2) 2083(3) 2408(5) 4.0(1)'H(1N) 3958(10) 4639(18) -1024(23) 1.5(7)H(3) 2892(10) 4704(18) -2726(23) 1.9(7)H(5) 3162(10) 2863(19) -760(24) 1.9(7)H(7) 3408(18) 5957(29) -2513(42) 8.0(16)H(7') 3733(16) 5540(28) -3034(40) 7.6(16)H(7") 3838(15) 5715(25) -2097(34) 5.3(12)H(8) 2271(14) 3644(26) -1878(34) 5.0(12)H(8') 2479(14) 2824(23) -1891(30) 4.5(11)H(8") 2446(13) 3411(24) -2885(33) 4.3(10)H(9) 4225(15) 3261(23) -450(32) 5.2(11)H(9') 3860(12) 2828(12) 166(27) 3.4(9)H(9") 4018(12) 3693(22) 550(29) 3.7(9)H(11N) 4093(11) 7169(18) 1975(25) 1.5(8)H(13) 3060(10) 7177(18) 206(24) 1.9(7)H(15) 3290(12) 8912(21) 2358(28) 3.7(9)H(17) 3980(16) 6385(28) 24(34) 6.3(14)H(17') 3562(12) 5949(22) 292(28) 3.4(9)H(17") 3942(12) 5963(22) 1063(30) 3.7(10)H(18) 2711(15) 8899(28) 521(38) 5.4(14)H(18') 2529(17) 8840(33) 1444(42) 7.9(17)H(18") 2430(23) 8122(39) 679(55) 12.6(24)H(19) 3941(21) 8447(36) 3720(48) 10.1(23)H(19') 4203(18) 8891(32) 2932(42) 8.1(16)H(19") 4283(22) 8057(36) 3211(51) 10.8(23)H(21N) 4426(12) 2570(22) 3345(27) 3.6(9)H(23) 4616(12) 1014(21) 5637(29) 3.5(9)H(25) 3563(10) 817(18) 3699(23) 1.4(6)H(27) 5154(23) 2510(43) 4200(55) 13.2(28)H(27') 5182(15) 2096(26) 5219(34) 5.5(13)H(27") 4911(21) 2763(36) 5031(48) 9.9(20)H(28) 4162(19) -374(32) 5226(39) 9.1(17)H(28') 3675(16) -226(28) 5081(33) 6.3(13)H(28") 3853(18) 148(33) 6073(41) 9.5(18)H(29) 3490(18) 2375(30) 2599(43) 7.8(16)H(29') 3594(14) 1703(25) 1928(33) 5.1(12)H(29") 3917(19) 2361(33) 1981(43) 9.2(18)______________________________________
EXAMPLE 4
Preparation of Tetraphenylphosphonium.sup.+ AlF.sub.4.sup.-
Inside a nitrogen filled glove box, 0.225 g collidine H.sup.+ AlF.sub.4.sup.- prepared as in Example 3 was dissolved into 5 mL dry methanol and rapidly mixed with a second solution of 0.42 g tetraphenylphosphonium bromide also in 5 mL methanol. After 30 seconds the clear solution became progressively cloudy and large needle-like crystals of the desired compound began to precipitate from solution. Yield 0.33 g (74%). The material was recrystallized from hot acetone or acetonitrile to give x-ray quality crystals. IR (KBr) AlF.sub.4.sup.- at 787 cm.sup.-1. NMR (CD.sub.3 CN): .sup.19 F, -194.6 ppm, 6 lines, J=38 Hz; Solid state .sup.19 F MAS-NMR shows a single sharp resonance at -190 ppm. A single crystal grown from acetonitrile was used for a single crystal structure determination. Crystal data: PAlF.sub.4 C.sub.24 H.sub.20 from acetonitrile, colorless, block, 0.26.times.0.26.times.0.50 mm, tetragonal, I.sub.4 (#82), a=12.209(3), c=7.050(2) .ANG., T=-65.degree. C., V=1050.9 .ANG..sup.3, Z=2, FW=442.38, Dc=1.398 g/cc, .mu.(Mo)=2.09 cm.sup.-1.
All non-hydrogen atoms refined anisotropic, 88 parameters, data/parameter ratio=7.03, final R=0.041, Rw=0.044, error of fit=1.95. Atomic coordinates are listed in Table IV while the structure is depicted in FIG. 4. The structure shows only the two expected tetrahedral ions--the anion AlF.sub.4.sup.- (FIG. 4b) and the cation P(C.sub.6 H.sub.5).sub.4.sup.+ (FIG. 4a).
TABLE IV______________________________________Fractional Coordinates (X10000) andIsotropic Thermal ParametersATOM X Y Z BISO______________________________________P(1) 0 0 0 2.3(1)'Al(1) 0 5000 2500 3.1(1)'F(1) 356(9) 4040(5) 1183(12) 21.7(4)'C(1) 978(2) 669(2) 1511(4) 2.6(1)'C(2) 2094(2) 458(2) 1376(4) 3.1(1)'C(3) 2807(3) 984(3) 2624(6) 4.0(1)'C(4) 2413(3) 1708(3) 3961(6) 4.3(1)'C(5) 1299(3) 1930(3) 4065(5) 4.3(1)'C(6) 583(2) 1390(3) 2855(4) 3.5(1)'H(2) 2324(22) -8(23) 477(37) 1.8(5)H(3) 3653(41) 747(36) 2457(90) 6.6(11)H(4) 2898(29) 2109(27) 4867(64) 4.6(8)H(5) 1017(32) 2384(37) 4849(90) 5.6(11)H(6) -218(29) 1484(30) 2771(62) 4.5(8)______________________________________
EXAMPLE 5
Preparation of Tetraphenylarsonium.sup.+ AlF.sub.4.sup.-
Inside a nitrogen filled glove box, 0.225 g collidineH.sup.+ AlF.sub.4.sup.- prepared as in Example 3 was dissolved in 5 mL dry methanol and rapidly mixed with a second solution of 0.42 g tetraphenylarsonium chloride also in 5 mL methanol. After 30 seconds the clear solution became progressively cloudy and large needle-like crystals of the desired compound began to precipitate from solution. Yield 0.43 g (88%). The material was recrystallized from hot acetone or acetonitrile to give x-ray quality crystals. IR (KBr) AlF.sub.4.sup.- at 788 cm.sup.-1, NMR (0.002M in CD.sub.3 CN); .sup.19 F, -194.6 ppm, 6 lines, J=38 Hz; Solid state .sup.19 F MAS-NMR shows a single sharp resonance at -190.1 ppm. A single crystal grown from acetone was used for a single crystal structure determination. Crystal data: AsAlF.sub.4 C.sub.24 H.sub.20 from acetone, colorless, block. 0.30.times.0.26.times.0.47 mm, tetragonal, I.sub.4 (#82), a=12.466(2), c=6.813(1) .ANG., T=-100.degree. C. V=1058.8 .ANG..sup.3, Z=2, FW=486.32, Dc=1.525 g/cc, .mu.(Mo)=16.82 cm.sup.-1.
All non-hydrogen atoms refined anisotropic, 88 parameters, data/parameter ration=7.78, final R=0.020, Rw=0.023, error of fit=1.24. Atomic coordinates are listed in Table V while the structure is depicted in FIG. 5. The structure shows only the two expected tetrahedral ions--the anion AlF.sub.4.sup.- (FIG. 5b) and the cation As(C.sub.6 H.sub.5).sub.4.sup.+ (FIG. 5a).
TABLE V______________________________________Fractional Coordinates (X10000) andIsotropic Thermal ParametersATOM X Y Z BISO______________________________________As(1) 0 0 0 1.5(1)'Al(1) 0 5000 2500 2.2(1)'F(1) 160(4) 3953(3) 1161(6) 12.4(2)'C(1) 1016(2) 713(2) 1645(3) 1.8(1)'C(2) 2102(2) 454(2) 1562(3) 2.2(1)'C(3) 2808(2) 972(2) 2826(4) 2.8(1)'C(4) 2439(2) 1737(2) 4123(4) 3.0(1)'C(5) 1358(2) 2010(2) 4174(4) 3.0(1)'C(6) 637(2) 1482(2) 2952(4) 2.5(1)'H(2) 2338(24) -21(23) 797(43) 2.2(5)H(3) 3595(28) 652(29) 2673(61) 3.5(7)H(4) 2871(24) 2138(22) 5247(66) 3.2(6)H(5) 1057(25) 2548(25) 4928(95) 3.9(6)H(6) -139(25) 1729(24) 2957(42) 2.4(6)______________________________________
EXAMPLE 6
Preparation of Tetraethylphosphonium.sup.+ AlF.sub.4.sup.-
A mixture of 0.45 g PEt.sub.4.sup.+ Br.sup.- in 10 ml dry THF was treated with 0.42 g of KN(SiMe.sub.3).sub.2 (Commercial, Aldrich) in a nitrogen atmosphere and was stirred 3 hours at room temperature. The resulting mixture was filtered, obtaining 0.24 g off-white solid which was discarded (theoretical yield of KBr, ca. 0.24 g). The solution was added to a suspension of 0.35 g pyridineH.sup.+ AlF.sub.4.sup.- in 10 ml dry pyridine in a nitrogen atmosphere and the mixture was stirred, soon becoming a pale yellow solution. After ca. 30 min the solution was evaporated to dryness and the residue recrystallized twice from CH.sub.2 Cl.sub.2, yield 0.12 g. IR (Nujol) 786 cm.sup.-1, .sup.1 H NMR (CD.sub.3 CN): 1.16 ppm, d (18 Hz) of t (8 Hz); 2.10 ppm, d (13 Hz) of q (8 Hz). .sup.19 F NMR (CD.sub.3 CN): -193 ppm, 6 lines, J=38 Hz, .sup.27 Al NMR (CD.sub.3 CN): quintet, J=38 Hz.
C. H. anal. Calcd. C: 38.41, H: 8.06%. Found C: 37.83, 38.27; H: 8.11, 8.15%.
The reaction between P(C.sub.2 H.sub.5).sub.4.sup.+ Br.sup.- and KN(Si(CH.sub.3).sub.3).sub.2 in THF is well known to form KBr, the amine HN(Si(CH.sub.3).sub.3).sub.2, and the ylid (C.sub.2 H.sub.5).sub.3 P.dbd.CHCH.sub.3, and the ylid was not isolated for this Example.
In a related preparation, 0.55 g P(C.sub.2 H.sub.5).sub.4.sup.+ Br.sup.- and 0.48 g KN(Si(CH.sub.3).sub.3).sub.2 were stirred in 15 ml dry THF for 30 min, the mixture was filtered, and the solution added to 0.47 g pyridineH.sup.+ AlF.sub.4.sup.- in 10 ml pyridine, all in a nitrogen atmosphere. After stirring for several minutes the mixture became a solution which was evaporated; the residue was recrystallized from CH.sub.2 Cl.sub.2 /ether, yield 0.41 g (68%). IR, .sup.1 H and .sup.19 F NMR as above.
EXAMPLE 7
Preparation of Triphenylmethylphosphonium.sup.+ AlF.sub.4.sup.-
Inside a nitrogen filled glove box, 0.225 g collidineH.sup.+ AlF.sub.4.sup.- prepared as in Example 3 was dissolved into 5 mL dry methanol and rapidly mixed with a second solution of 0.36 g triphenylmethylphosphonium bromide also in 5 mL methanol. The clear solution was evaporated to dryness and the white powder was extracted into acetone leaving behind collidinium bromide which was removed by filtration. The clear acetone solution was evaporated to dryness forming colorless needle-shaped crystals of the desired material. Yield 0.23 g (61%). Thermal analysis of the crystals showed a single, sharp, weight loss event centered at 495.degree. C. and a weight change corresponding exactly to the transformation to AlF.sub.3. X-ray powder diffraction data are listed in Table VI and depicted in FIG. 6.
TABLE VI______________________________________Generator settings 40 kV, 30 mACU alphal, 2 wavelengths 1.540598, 1.544435 AngStep size, sample time 0.020 deg, 0.50 s, 25.00 s/degMonochromator used YesDivergence slit Automatic (specimen length: 12.5 mm)Peak angle range 2.000-60.000 degPeak position criterion Centroid second derivativeNumber of peaks in file 24 (Alphal: 21, Amorphous: 0)______________________________________Peak Angle Width Peak Backg D spac I/Imax TypeNo. (deg) (deg) (cts) (cts) (Ang) (%) A1 A2______________________________________1 5.290 1.92 10 6 16.7059 0 X X2 10.145 0.16 961 27 8.7194 44 X X3 14.408 0.12 1332 40 6.1479 61 X X4 20.417 0.10 2200 95 4.3498 100 X X5 20.532 0.10 1406 95 4.3257 64 X X6 22.930 0.18 529 99 3.8786 24 X X7 25.105 0.10 250 103 3.5472 11 X X8 29.117 0.08 130 111 3.0669 6 X X9 32.635 0.08 350 97 2.7417 16 X10 32.728 0.08 454 97 2.7364 21 X X11 32.865 0.04 182 97 2.7298 8 X12 34.145 0.06 144 95 2.6238 7 X13 34.268 0.06 76 93 2.6212 3 X14 36.230 0.40 30 89 2.4795 1 X X15 37.475 0.12 42 91 2.3999 2 X X16 38.952 0.20 24 89 2.3122 1 X X17 41.688 0.06 151 84 2.1666 7 X X18 43.118 0.06 59 86 2.0980 3 X X19 45.548 0.24 21 84 1.9916 1 X X20 46.967 0.24 81 82 1.9347 4 X X21 49.315 0.24 64 78 1.8479 3 X X22 52.803 0.14 88 75 1.7338 4 X X23 53.993 0.10 177 68 1.6969 8 X24 54.143 0.06 102 68 1.6968 5 X______________________________________
EXAMPLE 8
Preparation of Tetraethylammonium.sup.+ AlF.sub.4.sup.-
Inside a nitrogen filled glove box, 0.90 g collidineH.sup.+ AlF.sub.4.sup.- prepared as in Example 3 was dissolved in 10 mL warm methanol and then mixed with a second solution containing 0.66 g tetraethylammonium chloride dissolved in 10 mL methanol. After stirring for 15 mins the clear solution was evaporated to dryness and the white solid was placed in a horizontal tube furnace. The solid was heated to 300.degree. C. in flowing nitrogen (50 cc/min) at 10.degree. C. min and then held at 300.degree. C. for 30 mins before cooling in nitrogen. The sample was then returned to the glove box and the solid was extracted into dry acetonitrile. The clear acetonitrile was evaporated to dryness leaving hygroscopic, clear, blocky crystals of the desired material. Yield 0.46 g (49%). Thermal analysis of these crystals shows a single, sharp, weight loss event centered at 400.degree. C. and a weight change corresponding exactly to the transformation to AlF.sub.3. X-ray powder diffraction data are listed in Table VII and depicted in FIG. 7. .sup.19 F NMR (0.002M in CD.sub.3 CN): .sup.19 F, -194.6 ppm, 6 lines, J=38 Hz.
TABLE VII______________________________________Generator settings 40 kV, 30 mACU alpha1, 2 wavelengths 1.540598, 1.544435 AngStep size, sample time 0.020 deg, 0.50 s, 25.00 s/degMonochromator used YesDivergence slit Automatic (specimen length: 12.5 mm)Peak angle range 2.000-60.000 degPeak position criterion Centroid second derivativeNumber of peaks in file 11 (Alpha1: 11, Amorphous: 0)______________________________________Peak Angle Width Peak Backg D spac I/Imax TypeNo. (deg) (deg) (cts) (cts) (Ang) (%) A1 A2______________________________________1 7.715 1.92 10 11 11.4595 1 X X2 16.077 0.06 1076 33 5.5129 97 X X3 16.225 0.06 1076 33 5.4631 97 X X4 16.332 0.06 1116 35 5.4274 100 X X5 16.460 0.04 595 35 5.3856 54 X X6 22.982 0.24 272 62 3.8698 24 X X7 26.995 0.12 69 82 3.3030 6 X X8 28.100 0.24 102 82 3.1756 9 X X9 32.585 0.96 10 89 2.7480 1 X X10 36.285 0.56 30 75 2.4759 3 X X11 49.553 0.96 10 66 1.8396 1 X X______________________________________

Number	Name	Date
4034068	Aramaki	Jul 1977
4540841	Miale	Sep 1985
5171798	McDaniel et al.	Dec 1992
5254416	Kubota	Oct 1993
5393509	Corbin	Feb 1995

	Number	Date	Country
Parent	242480	May 1994
Parent	978590	Nov 1992

Fluoroaluminate (AlF.sub.4) compounds

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