Synthesis, molecular, spectroscopic and catalytic characterization of ruthenium(II) complexes with pyridine-2-carboxylic acid derivatives ligands

The ruthenium(II) complexes [RuH(CO)(6-OH-py-2-COO)(PPh3)2] (1) and [Ru(3-OH-py-2-COO)2(PPh3)2] (2) have been prepared in the reactions of [RuHCl(CO)(PPh3)3] and [RuCl2(PPh3)3] with 6-hydroxy- and 3-hydroxypyridine-2-carboxylic acids. The complexes have been characterized by IR, UV–Vis, NMR spectroscopy and X-ray crystallography. Based on the crystal structures, computational investigations were carried out in order to determine the electronic structures of the complexes. The electronic spectra were calculated with the use of time-dependent DFT methods, and correlated with the molecular orbitals of the complexes. The emission properties of the complexes have been examined and quantum efficiencies equal to 0.084 for the hydride carbonyl complex (1) and 0.046 for complex (2) have been determined. The catalytic activity in the reaction of the double bond migration in 4-allyloxybutan-1-ol for both the complexes was tested. Under properly selected reaction conditions, complex (1) selectively catalyzes double bond migration leading to 1-propenyloxyalcohol.

Graphical abstractThe ruthenium(II) complexes [RuH(CO)(6-OH-py-2-COO)(PPh3)2] (1) and [Ru(3-OH-py-2-COO)2(PPh3)2] (2) have been prepared in the reactions of [RuHCl(CO)(PPh3)3] and [RuCl2(PPh3)3] with 6-hydroxy- and 3-hydroxypyridine-2-carboxylic acids. The complexes have been characterized by IR, UV–Vis, NMR spectroscopy and X-ray crystallography. Based on the crystal structures, computational investigations were carried out in order to determine the electronic structures of the complexes. The electronic spectra were calculated with the use of time-dependent DFT methods, and correlated with the molecular orbitals of the complexes. The emission properties of the complexes have been examined and quantum efficiencies equal to 0.084 for the hydride carbonyl complex (1) and 0.046 for complex (2) have been determined. The catalytic activity in the reaction of the double bond migration in 4-allyloxybutan-1-ol for both the complexes was tested. Under properly selected reaction conditions, complex (1) selectively catalyzes double bond migration leading to 1-propenyloxyalcohol.Figure optionsDownload full-size imageDownload as PowerPoint slide