Hydridocopper complexes embedded in iron carbidocarbonyl clusters: synthesis, reactivity and structure of [Fe4C(CO)12CuCl]2-, [Fe4C(CO)12Cu(η2-BH4)]2-, [{Fe4C(CO)12Cu2(μ-H)}2]2- and [{Fe4C(CO)12Cu2(μ-OiPr)}2]2-

The reaction of [Fe4C(CO)12(CuCl)2]2- with NaBH4 yields sequentially [Fe4C(CO)12(CuCl)]2- (1) and [Fe4C(CO)12Cu(η2-BH4)]2- (2), depending on the Fe4Cu2:NaBH4 ratio. The reaction of [Fe4C(CO)12(CuNCMe)2] with NaBH4 yields [{Fe4C(CO)12Cu2( μ-H)}2]2- (3), which, upon precipitation with 2-propanol, forms [{Fe4C(CO)12Cu2( μ-OiPr)}2]2- (4). 1 and 2 are isostructural,with a CuX linearly bonded to the exposed carbide ligand of a butterfly [Fe4C(CO)12]2- unit. 3 and 4 are also very similar, with the four copper atoms of two Fe4Cu2 octahedra connected by bridging hydrides (in 3) and bridging alkoxides (in 4). However, 3 and 4 are not isoelectronic, and in agreement with the unsaturation of 3, its Cu-Cu distance is much shorter