Ruthenium(II)–CO complexes of N-[(2-pyridyl)methyliden]-α(or β)-aminonaphthalene: Synthesis, spectral studies, crystal structure, redox properties and DFT calculation

The characterization and properties of trans-(X)-[RuX2(CO)2(α/β-NaiPy)] (1, 2) (α-NaiPy (a), β-NaiPy (b); X = Cl (1), I (2)) are described in this work. The structures are confirmed by single crystal X-ray diffraction studies. Reaction of these compounds with Me3NO in MeCN has isolated monocarbonyl trans-(X)-[RuX2(CO)(MeCN)(α/β-NaiPy)] (3, 4). The complexes show intense emission properties. Quantum yields of 1 and 2 (ϕ = 0.02–0.08) are higher than 3 and 4 (ϕ = 0.006–0.015). Voltammogram shows higher Ru(III)/Ru(II) (1.3–1.5 V) potential of 1 and 2 than that of 3 and 4 (0.8–0.9 V) that may be due to coordination of two π-acidic CO groups in former. The electronic spectra and redox properties of the complexes are compared with the results obtained by density functional theory (DFT) and time-dependent density functional theory (TD-DFT) using polarizable continuum model (CPCM).

Graphical abstracttrans-(X)-[RuX2(CO)2(α/β-NaiPy)] (1, 2) (X = Cl (1), I (2)) and trans-(X)-[RuX2(CO)(MeCN)(α/β-NaiPy)] (3, 4) are described. The structure of trans-(Cl)-[RuCl2(CO)2(β-NaiPy)] shows distorted octahedral geometry with trans-Cl and cis-CO groups. The complexes show intense emission properties. Cyclic voltammetry shows high potential Ru(III)/Ru(II) couple and ligand reductions. DFT and TD-DFT computations explain electronic transitions and redox properties.Figure optionsDownload full-size imageDownload as PowerPoint slide