Estudo teórico da natureza da ligação M-NO do complexo tans-[M(NO)(OXA-AZA) L]N (M=Rh+2; L=CI-, H20 ou CN- e OXA-AZA = OXA-Azamacrocíclico)

Abstract

Our major interest in this work is to understand the nature of the M-NO bond in the trans-[M(NO)(oxa-aza)L]n (M= Rh+2; L=Cl‑, H2O or CN- ; oxa-aza = oxa-azamacrocyclic) complexes. Studies have been conducted through computational calculations at the level of DFT (Density Functional Theory). The complexes have been built and then optimized in all three oxidation states possible of the nitric oxide (NO): NO+, NO0 e NO-, using the B3LYP, BP86 and PBE1PBE approximation methods, combined with the LANL2DZ and SDD basis sets, generating six models of method/basis combination. The model BP86/SDD has shown to be the closest one to the experimental data, and thus chosen to deepen and describe the geometric, energetic and spectroscopic parameters. After the analysis of the different multiplicities for the complex, it has been observed that most have the least energy when adopted a hexacoordinated system of octahedral geometry and low spin rate. The UV-VIS calculations were performed for all systems and the composition analysis of each orbital and charge transfer shows that for NO- , the transfer is MLCT, for NO0, LMCT and MLCT prevail, whereas for NO+, LMCT and LLCT, observing the qualitative representation of each orbital. The study of charges NBO (too implemented within Gaussian) and AOMix has shown the existing donations and back donations in the complexes. Consequently, a larger interaction of the M-NO bond with the system formed by (H2O/NO0), via NBO, and (H2O/NO+) via AOMix, due to a large backdonation of metal (Rh+2) to NO.