Inorganic Chemistry, Vol.41, No.23, 5937-5939, 2002
Trans ruthenium(II) complexes with NH-bridged tetradentate symmetric and asymmetric polypyridyl ligands
NH-Bridged tetradentate ligands were synthesized to achieve stable trans Ru(II) bis(polypyridyl) complexes. The polypyridyl part of the ligand was either symmetric, as in N,N-bis(1,10-phenanthroline2-yl)amine (phen-NH-phen), or asymmetric, as in N-(1,10-phenanthroline-2-yl)-N-(6-yl-dipyridyl[2,3-a:2',3'-c]phenazine)amine (dppz-NH-phen). Protonation of phen-NH-phen with trifluoroacetic acid and the subsequent reaction with RuCl3 yield trans-[Ru(phen-NH-phen)Cl-2]. The chloro ligands in this compound can easily be replaced by stronger ligands, such as CH3CN and DMSO. In this way, complexes trans-[Ru(phen-NH-phen)(CH3CN)(DMSO)](PF6)(2) (1), trans-[Ru(phen-NH-phen)(DMSO)(2)](PF6)(2) (2), and trans-[Ru(phen-NH-phen)(CH3CN)(2)](PF6)(2) (3) were obtained. X-ray structures were determined for 1 and I Following a procedure similar to that used with phen-NH-phen, the complex trans-[Ru(dppz-NH-phen)(CH3CN)(2)](PF6)(2) (4) was obtained. To our knowledge, this is the first reported trans ruthenium(II) bis(polypyridyl) complex with two different polypyridyl ligands in the equatorial plane.