Electronic Structures, Spectroscopy, and Electrochemistry of [M(diimine)(CN-BR3)4]2- (M = Fe, Ru; R = Ph, C6F5) Complexes.

Complexes with the formula [M(diimine)(CN-BR3)4]2-, where diimine = bipyridine (bpy), phenanthroline (phen), 3,5-trifluoromethylbipyridine (flpy), R = Ph, C6F5, and M = FeII, RuII, were synthesized and characterized by X-ray crystal structure analysis, UV-visible spectroscopy, IR spectroscopy, and voltammetry. Three highly soluble complexes, [FeII(bpy)(CN-B(C6F5)3)4]2-, [RuII(bpy)(CN-B(C6F5)3)4]2-, and [RuII(flpy)(CN-B(C6F5)3)4]2-, exhibit electrochemically reversible redox reactions, with large potential differences between the bpy0/- or flpy0/- and MIII/II couples of 3.27, 3.52, and 3.19 V, respectively. CASSCF+NEVPT2 calculations accurately reproduce the effects of borane coordination on the electronic structures and spectra of cyanometallates.

Synthesis and reactivity of two-coordinate Ni(I) alkyl and aryl complexes.

Reaction of [(IPr)Ni(µ-Cl)]2 (1-Cl; IPr = 1,3-bis(2,6-diisopropylphenyl)imidazolin-2-ylidene) with ClMg{CH(SiMe3)2}·Et2O affords (IPr)Ni{CH(SiMe3)2} (2), a two-coordinate Ni(I) alkyl complex. An analogous two-coordinate aryl derivative, (IPr)Ni(dmp) (dmp = 2,6-dimesitylphenyl), can be similarly prepared from Li(dmp) and 1-Cl. Reaction of 2 with alkyl bromides gives the three-coordinate Ni(II) alkyl halide complex (IPr)Ni{CH(SiMe3)2}Br. Evidence for a radical mechanism is presented to explain the reaction of 2 with alkyl halides.