الخلاصة:
Metal–metal bond in organometallic complexes have been investigated intensively since the fifties of the last century. Despite of the importance of such metal-metal interaction in biology and synthesis, the nature of these interactions still misunderstood and under investigation. The nature of the chemical metal-metal bonding in M2(CO)10(M = Mn, Re, Tc) dinuclear decacarbonyls complexes was investigated for the first time using the natural orbital chemical valence (NOCV) approach combined with the extended transition state (ETS) for energy decomposition analysis (EDA). The optimized geometries carried out at different levels of theory BP86, BLYP, BLYPD and BP86D, showed that the latter method, i.e., BP86D, led to the best agreement with X-ray experimental measurements. The ETS-NOCV/BP86D/TZP results revealed that the metal-metal interactions are mainly covalent with a contribution of 60.5%, 54.1% and 52.0% for Mn–Mn,Re–Re and Tc–Tc, respectively.
