Organoplatinum complexes of the N,N-diisopropyl-diazabutadiene ligand: A structural and spectroscopic study

摘要

Organoplatinum complexes [Pt(R)(2)(iPr-DAB)], [PtCl(R)(iPr-DAB)] or [PtCl2(iPr-DAB)] (R = methyl or 2,4,6-trimethylphenyl = mesityl, iPr-DAB = N,N'-diisopropyl-1,4-diazabutadiene) have been investigated by a combination of multiple spectroscopy (NMR, UV/VIS), single crystal XRD and quantum chemical calculations. Excellent agreement of calculated and experimental structural data from XRD or NMR provide a good basis for the quantum mechanical calculations. DFT calculations reveal the contributions of the DAB ligand and the co-ligands to the electronic ground state. Methyl acts more or less purely as a alpha-donor, Cl or mesityl provide strong contributions (p or pi) to the highest occupied molecular orbital (HOMO) whereas the lowest unoccupied molecular orbital (LUMO) is mainly centred to the DAB ligand. The TD-DFT calculated electronic transitions were in excellent agreement with the experimental ones and allow reliable assignment of the absorption bands.