Half-sandwich η6-arene ruthenium and Cp∗ rhodium/iridium compounds comprising with thioether ligands: Synthesis, spectral and molecular studies

•Half sandwich platinum group metal complexes with thioether ligands were isolated.•Variation of thioether moiety is shown that formation of mono/dinuclear complexes.•Only few compounds reported among the flexible thioethers with platinum group metals.

The reaction of [(η6-arene)Ru(μ-Cl)Cl]2 and [Cp∗M(μ-Cl)Cl]2 (M = Rh, Ir) with tetradentate N,N′-donor chelating ligand viz 3,6-bis(2-thiopyridyl)pyridazine(L1) leads to the formation of mononuclear compounds as general formula [(arene)MCl(L1)]+ {M = Ru, arene = C6H6 (1); p-iPrC6H4Me (2); C6Me6 (3); Cp∗, M = Rh (4); Cp∗, M = Ir (5)} where as 4,6-bis(2′-thiopyridyl)pyrimidine(L2) and 2,3-bis(2-thiopyridyl)pyrazine(L3) leads to the formation of dinuclear compounds as general formula [{(arene)MCl}2(L)]2+ {M = Ru, L = L2, arene = C6H6 (6); p-iPrC6H4Me (7); C6Me6 (8); Cp∗, M = Rh, (9); Cp∗, M = Ir, (10) and L = L3 C6H6 (11); p-iPrC6H4Me (12); C6Me6 (13), Cp∗, M = Rh, (14) Cp∗, M = Ir (15)}, respectively. The cationic complexes have been isolated as their PF6/SbF6 salts and characterized by FT-IR, UV–Vis, 1H NMR, Mass spectroscopic methods. X-ray crystallographic studies of some representative compounds revealed that typical piano-stool geometry around the metal center with a six-membered metallocycles in which thioether ligand acts as a N,N′-chelating ligand. Variation of bridging motifs of thioether ligands is revealed that formation of mono/dinuclear complexes. The L1 ligand yielded predominantly mononuclear compounds where as L2 and L3 yielded dinuclear compounds with trans and cis isomers, respectively.

Graphical abstractA series of arene ruthenium and Cp∗ rhodium/iridium compounds comprising with 3,6-bis(2-pyridylthio)pyridazine(L1)/4,6-bis(2-pyridylthio)pyrimidine(L2)/2,3-bis(2-pyridylthio)pyrazine(L3) as a thioether ligand have been synthesized and representative compounds have been determined by single crystal X-ray diffraction studies.Figure optionsDownload full-size imageDownload as PowerPoint slide