Investigating the reactivity of neutral water-soluble Ru(ii)-PTA carbonyls towards the model imine ligands pyridine and 2,2'-bipyridine.

As a continuation of our strategy for preparing new Ru(ii) precursors to be exploited as building blocks in the construction of metal-mediated supramolecular assemblies with improved solubility in water, here we describe the reactivity of selected neutral Ru(ii)-PTA carbonyls (PTA = 1,3,5-triaza-7-phosphaadamantane) towards the model imine ligands pyridine (py) and 2,2'-bipyridine (bpy) and the preparation and characterization of several neutral and cationic water-soluble derivatives: trans , trans , trans -[RuCl 2 (CO)(py)(PTA) 2 ] (7), cis , cis , trans -[RuCl 2 (CO) 2 (py)(PTA)] (9), cis , trans -[Ru(bpy)Cl(CO)(PTA) 2 ]Cl (10), mer -[Ru(bpy)(CO)(PTA) 3 ](Cl) 2 (12), cis , trans -[Ru(bpy)(CO) 2 Cl(PTA)]Cl (13), cis , trans -[Ru(bpy)(CO) 2 (PTA) 2 ](NO 3 ) 2 (14NO 3 ). In addition, we found that light-induced isomerization in some bpy compounds could be induced. The following species, either side-products isolated in low yield or compounds obtained exclusively in solution, were also unambiguously identified: cis , cis , trans -[RuCl 2 (CO)(py)(PTA) 2 ] (8), trans -[RuCl 2 (bpy)(CO)(PTA)] (11), cis , cis -[Ru(bpy)Cl(CO)(PTA) 2 ]Cl (15) and cis , cis -[Ru(bpy)(CO) 2 Cl(PTA)]Cl (16). The X-ray structures of 7, 11·H 2 O, and 12·7H 2 O are also reported. All compounds are new and - with few exceptions - show a good solubility in water.