Bismuth Coordination Chemistry with Allyl, Alkoxide, Aryloxide, and Tetraphenylborate Ligands and the {[2,6-(Me2NCH2)2C6H3]2Bi}+ Cation

A series of bis(aryl) bismuth compounds containing (N,C,N)-pincer ligands, [2,6-(Me2NCH2)2C6H3]- (Ar(prime)), have been synthesized and structurally characterized to compare the coordination chemistry of Bi3+ with similarly-sized lanthanide ions, Ln3+. Treatment of Ar(prime)2BiCl, 1, with ClMg(CH2CH=CH2) affords the allyl complex Ar(prime)2Bi(η--CH2CH=CH2), 2, in which only one carbon coordinates to bismuth. Complex 1 reacts with KOtBu and KOC6H3Me2-2,6 to yield the alkoxide Ar(prime)2Bi(OtBu), 3, and aryloxide Ar(prime)2Bi(OC6H3-Me2-2,6), 4, respectively, but the analogous reaction with the sterically crowded KOC6H3-tBu2-2,6 forms [Ar(prime)2Bi][OC6H3tBu2-2,6], 6, in which the aryloxide ligand acts as an outer sphere anion. Chloride is removed from 1 by NaBPh4 to form [Ar(prime)2Bi][BPh4], 5, which crystallizes from THF in an unsolvated form with tetraphenylborate as an outer sphere counteranion.