Half sandwich platinum group metal complexes containing tetradentate <i>N</i>-donor ligand bearing two pyrazolyl-pyridine units linked by an aromatic spacer

Reaction of the bis-bidentate ligand, 1,3-bis((3-(pyridin-2-yl)-1<i>H</i>-pyrazol-1-yl)methyl)benzene (<i>NN</i>∩<i>NN</i>), containing two chelating pyrazolyl-pyridine units connected by an aromatic spacer with platinum group metal complexes results in a series of cationic binuclear complexes, [(η⁶-arene)₂Ru₂(<i>NN</i>∩<i>NN</i>)Cl₂]²⁺ (arene = C₆H₆, <b>1</b>; p-iPrC₆H₄Me, <b>2</b>; C₆Me₆, <b>3</b>), [(η⁵-C₅Me₅)₂M₂(<i>NN</i>∩<i>NN</i>)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>). All these complexes have been isolated as their hexafluorophosphate salts and fully characterized by use of a combination of NMR spectroscopy, IR spectroscopy and mass spectrometry. The solid state structures of three complexes, [<b>2</b>][PF₆]₂, [<b>4</b>][PF₆]₂ and [<b>6</b>][PF₆]₂, has been determined by X-ray crystallographic studies.