10.1021/ic990773s
The research focuses on the synthesis, spectroscopic characterization, crystal structure, and theoretical calculations of the dinuclear nickel(0) complex [Ni2(μ-CO)(CO)2(μ-dppa)2] (where dppa is bis(diphenylphosphino)amine). The complex was synthesized via two methods, yielding a stable microcrystalline yellow solid. The first method involved the reaction of Ni(CO)4 with the dppa ligand in benzene, while the second method used NiCl2·6H2O with dppa in methanol and sodium tetrahydroborate as a reducing agent with carbon monoxide. The synthesized complex was characterized using elemental analysis, infrared (IR) spectroscopy, proton and phosphorus-31 nuclear magnetic resonance (1H and 31P NMR), and cyclic voltammetry. The crystal structure was determined through X-ray diffraction, revealing a triclinic crystal system with a P1 space group and specific unit cell dimensions. Theoretical calculations using a semiempirical PM3 Hamiltonian were also conducted to predict bond orders and reactivity, supported by the Fukui function analysis. The complex was found to absorb carbon monoxide, leading to the formation of a mixture of nickel carbonyl compounds, and showed electrochemical behavior indicative of successive oxidation of the metal centers.