Synthesis, Characterization, (31) P{H-1} Nmr, X-Ray Structure And Voltammetric Study Of 2-Mercaptothiazolines And Phosphines Ruthenium(Ii) Complexes

In this work, complexes containing mercaptothiazolines, and mono- and diphosphines with the general formula [Ru(N-S)(2)(P)(2)] or [Ru(N-S)(2) (P-P)] - N-S-: 1,3-thiazoline-2-thionate (tzt(--) - a) and benzo-1,3-thiazoline-2-thionate (bzoxt(-) - b), and P-2 = monophosphine: P{p-tol}(3) - 2; P-P = dppe - 3, dppp - 4, dppb - 5, dppf - 6 or DPEPhos - 7 were synthesized. The complexes were characterized by H-1 and P-31 NMR, vibrational spectroscopy, elemental analysis, and the molecular structures of 3a, 4a, 5a, 6a center dot CH2Cl2 and 7a were solved by X-ray diffraction. The Hirshfeld surface analysis and the 2D fingerprint plots were performed. The H-1 NMR spectra of the compounds revealed the signals of the ligands and the main feature is the absence of the NH signal of the protonated ligands TztH and BzoxtH supporting the coordination in their anionic forms, which is also evidenced by the vibrational spectroscopy and molar conductivity studies. The P-31{H-1} NMR spectra present only one singlet indicating the chemical equivalence of both phosphorus nuclei and in a region compatible with phosphorus cis-positioned for the P(p-tol)(3) and for the potentially trans-spanning dppf and DPEPhos, whereas for the other diphosphines (dppe, dppp and dppb) only the cis-configuration is expected. The molecular structure revealed the Ru center is sited on a distorted octahedral geometry mainly as a consequence of the formation of four-membered chelate rings involving the N-S(-)ligand. The coordination sphere is completed with two phosphorus atoms positioned in a cis-fashion while trans to the nitrogen atoms of the tzt(-) ligand, and the remaining sulfur donors (thiolate) of tzt(-) ligand positioned trans to each other. The cyclic voltammograms of the complexes presented one monoelectronic and reversible process attributed to the Ru3+/Ru2+ couple, and for the complexes with dppf an additional redox process is observed due to the Fe3+/Fe2+ couple. (C) 2021 Elsevier B.V. All rights reserved.