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, <i>viz</i>. [(η⁶-arene)₂Ru₂ (<i>NN</i>∩<i>NN</i>)Cl₂]²⁺ (arene = C₆H₆, <b>1</b>; p-ⁱ<i>P</i>rC₆H₄Me, <b>2</b>; C₆Me₆, <b>3</b>), [(^η5-C₅Me<ub>5</sub>)₂M₂(NN∩NN)Cl₂]²⁺ (M = Rh, <b>4</b>; Ir, <b>5</b>), [(η⁵-C₅H₅)₂M₂(<i>NN</i>∩<i>NN</i>)(PPh₃)₂]²⁺ (M = Ru, <b>6</b>; Os, <b>7</b>), [(η⁵-C₅Me₅)₂Ru₂(<i>NN</i>∩<i>NN</i>)(PPh₃)₂]²⁺ (<b>8</b>) and [(η⁵-C₉H₇)₂Ru₂(<i>NN</i>∩<i>NN</i>)(PPh₃)₂]²⁺ (<b>9</b>), bearing the bis-bidentate ligand 1,2-bis(di-2-pyridylaminomethyl)benzene (<i>NN</i>∩<i>NN</i>), 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, [<b>2</b>][SbF₆]₂, [<b>3</b>][PF₆]₂ and [<b>4</b>][PF₆]₂, has been determined by X-ray structure analysis.