Synthesis of cationic diiron complexes bridged by a base-stabilized gallium atom [Fp₂(μ-Ga·Do₂)]⁺X^- (Fp = (η-C₅H₅)Fe(CO)₂, Do₂ = 2,2′-bipyridine, N,N,N′,N′-tetramethylethylenediamine, 1,10-phenanthroline, (4-(dimethylamino)pyridine)₂

Addition of 2,2′-bipyridine (bpy) to an acetonitrile solution of Fp₂GaCl (1: Fp = CpFe(CO)₂; Cp = η-C₅H₅) afforded quantitatively a salt consisting of a diiron cation bridged by a Ga·bpy fragment [Fp₂(μ-Ga·bpy)]⁺ ([2a]⁺) and μ-GaCl₂ diiron anion [Fp₂(μ-GaCl₂)]^- ([3]^-). The reaction of 1 with Do₂ (Do₂ = N,N,N′,N′-tetramethylethylenediamine (tmeda), 1,10-phenanthroline (phen), and (4-(dimethylamino)pyridine)₂ (= dmap₂)) in the presence of 1 equiv of NaBPh₄ in acetonitrile afforded [Fp₂(μ-Ga·Do₂)]⁺BPh₄ ^- (Do₂ = tmeda (2b), phen (2c), and (dmap)₂ (2d)). Cation [2a-d]⁺ is the first example of a dinuclear complex bridged by a base-coordinated gallium atom Ga·Do₂ (Do = Lewis base). X-ray crystal structure analysis of [2a][3]·CH₃CN revealed that the Fe-Ga bond lengths (2.3969(16) and 2.4037(14) A) in [2a]⁺ are shorter than those of [3]^- (2.4234(13) and 2.4359(15) Å), but within the range previously observed for Fp-gallyl complexes (2.36-2.46 Å). The Ga - Cl bonds in [3]^- (2.3259(19) and 2.3537(19) A) are longer than those of known chlorogallyl complexes (2.18-2.29 Å).