[Cl-].[Cl-].[Cl-].[Al+3].FC1C([Mg]Br)=C(F)C(F)=C(F)C=1F.[Al:18]([C:41]1C(F)=C(F)C(F)=C(F)C=1F)([C:30]1C(F)=C(F)C(F)=C(F)C=1F)[C:19]1[C:28]([F:29])=[C:26]([F:27])[C:24]([F:25])=[C:22]([F:23])[C:20]=1[F:21].[Al](Cl)(C)C.C1([Li])C(F)=C(F)C(F)=C(F)C=1F>C(OCC)C>[Al:18]([C:19]1[C:28]([F:29])=[C:26]([F:27])[C:24]([F:25])=[C:22]([F:23])[C:20]=1[F:21])([CH3:30])[CH3:41]O(CH2CH3)2} from reaction of aluminum trichloride (AlCl3) and pentafluorophenylmagnesiumbromide (BrMgC6F5) in diethyl ether is also known. However, attempts at removing the coordinated ether resulted in explosion. The synthesis of base free Al(C6F5)3 was not possible until much later. The first disclosure of a method for making base free Al(C6F5)3 was provided by researchers in 1995. This was accomplished by reaction of Me2AlCl with C6F5Li in hexanes to initially form Me2AlC6F5 which is then heated to 180° C. in vacuo to liberate AlMe3 and generate crude Al(C6F5)3. Recrystallization of the crude reaction product from THF gave the adduct THF.Al(C6F5)3 in 64% yield. This procedure is dangerous to conduct as C6F5Li is thermally unstable and the produced Al(C6F5)3 is energetic and exploded on occasion. An alternative route for the synthesis of Al(C6F5)3 involves the exchange reaction between B(C6F5)3 and trimethylaluminum which is typically conducted in an aromatic hydrocarbon (i.e., toluene). This strategy purportedly gives rise to high yields of base free Al(C6F5)3 (stable in toluene) but involves the requisite use of pyrophoric Al(CH3)3 in addition to consuming valuable B(C6F5)3.
Wird geladen…
