Ruthenium nitrosyl complexes [RuCl 3 (NO)(P–N)] bearing an oxazoline-derived P–N ligand (PHOX)

This work presents two complexes with general formula [RuCl 3 (NO)(PHOX)] (PHOX = 2-[2-(diphenylphosphino)phenyl]-4,4-dimethyl-2-oxazoline). Reaction of the PHOX ligand with [RuCl 3 (H 2 O) 2 (NO)] in refluxing methanol afforded fac -[RuCl 3 (NO)(PHOX)] ( 1 ), whereas exposure of a dichloromethane solution of complex 1 to ambient light gave mer,trans -[RuCl 3 (NO)(PHOX)] ( 2 ). On the other hand, reflux of complex 2 in methanol for 3 h resulted in thermal isomerization, to furnish complex 1 . 1 H and 31 P NMR, elemental analysis, vibrational spectroscopy, UV–Vis, cyclic voltammetry, and X-ray diffractometry (for complex 2 ) aided characterization of the complexes. This work also compares the chemical properties of complexes 1 and 2 with the properties of similar complexes bearing PMA ([ o -( N , N -dimethylamino)phenyl]diphenylphosphine, DPPE (1,2-bis(diphenylphosphino)ethane), and DPPP (1,3-bis(diphenylphosphino)propane); it also offers some insight into photo- and thermal isomerization mechanisms.