New mono and dinuclear arene ruthenium chloro complexes containing ester substituents

The dinuclear arene ruthenium complexes [RuCl2{C6H5(CH2)3OCO-p-C6H4-OC8H17}]2 (1) and [RuCl2{p-C6H4(CH2COOCH2CH3)2}]2 (2) have been obtained by dehydrogenation of the corresponding cyclohexadiene derivative with ruthenium chloride hydrate. The single-crystal X-ray structure analysis of 2 shows the arene ligands to be involved in slipped-parallel π–π stacking interactions with neighbouring molecules, thus forming infinite chains along the b-axis. The dinuclear complexes 1 and 2 react with two equivalents of triphenylphosphine (PPh3) to give in excellent yield the corresponding mononuclear phosphine complexes [RuCl2{C6H5(CH2)3OCO-p-C6H4-OC8H17}(PPh3)] (3) and [RuCl2{p-C6H4(CH2COOCH2CH3)2}(PPh3)] (4), respectively. The single-crystal X-ray structure analysis of 4 reveals the formation of a dimer through two C–H⋯Cl interactions in the solid state.