Study of half sandwich platinum group metal complexes containing tetradentate N-donor ligand bearing two di-pyridylamine units linked by an aromatic spacer

A general approach for the preparation of dinuclear η5- and η6-cyclic hydrocarbon platinum group metal complexes, viz. [(η6-arene)2Ru2(NN∩NN)Cl2]2+ (arene = C6H6, 1; p-iPrC6H4Me, 2; C6Me6, 3), [(η5-C5Me5)2M2(NN∩NN)Cl2]2+ (M = Rh, 4; Ir, 5), [(η5-C5H5)2M2(NN∩NN)(PPh3)2]2+ (M = Ru, 6; Os, 7), [(η5-C5Me5)2Ru2(NN∩NN)(PPh3)2]2+ (8) and [(η5-C9H7)2Ru2(NN∩NN)(PPh3)2]2+ (9), bearing the bis-bidentate ligand 1,2-bis(di-2-pyridylaminomethyl)benzene (NN∩NN), which contains two chelating di-pyridylamine units connected by an aromatic spacer, is reported. The cationic dinuclear complexes have been isolated as their hexafluorophosphate or hexafluoroantimonate salts and characterized by use of a combination of NMR, IR and UV–vis spectroscopic methods and by mass spectrometry. The solid state structure of three derivatives, [2][SbF6]2, [3][PF6]2 and [4][PF6]2, has been determined by X-ray structure analysis.

Graphical abstractThe slight modified procedure of synthesis of the ligand {1,2-bis(di-2-pyridylamino methyl)-benzene} (NN∩NN) as well as the synthesis of new dinuclear η5- and η6-cyclic hydrocarbon platinum group metal complexes bearing the ligand (NN∩NN) is presented.Figure optionsDownload full-size imageDownload as PowerPoint slideResearch highlights► The ligand {1,2-bis(di-2-pyridylamino methyl)benzene} was used in this study. ► This ligand has shown different property with comparison to similar ligand for the formation of complexes. ► This ligand yielded only dinuclear compounds in spite of having provision to form mononuclear compounds.