Rhodium(III) in a cage of the 1,3-propanediamine-N,N,N′-triacetate chelate: X-ray structure, solution equilibria, computational study and biological behavior

New rhodium(II)-ED3AP-complex: Crystal structure, characterization and computational chemistry

Only one (trans(O5)-Na[Rh(ed3ap)]?3H2O) of possible two isomers was synthesized and characterized by single crystal X-ray analysis, IR, and UV-Vis spectroscopy. Computational analysis of both isomers was performed with three levels of theory (B3LYP/TZV, BP86/TZV, OPBE/TZV), which gave consistent results. The more stable isomer by total energy and ligand field stabilization energy (LFSE) was trans(O5) which appeared in synthesis. Calculation of excited state energies complied with UV-Vis spectra, especially with OPBE functional. The results of excited state energy pointed out the differences among isomers in means of a splitting pattern of 1T2g excited state term. Both isomers have a strongly delocalized structure according to the natural bonding orbital (NBO) analysis. The trans(O5) geometry has the stabilization of the whole system for roughly 87 kJ/mol and makes this isomer as the only one present in the reaction mixture.