Heteroleptic arene ruthenium complexes based on meso-substituted dipyrrins: synthesis, structure, reactivity, and electrochemical studies.

First examples of heteroleptic arene ruthenium complexes containing dipyrrin ligands with the general formulations [(eta(6)-arene)RuCl(L)] [(arene = C(6)H(6), C(10)H(14); L = 5-(4-cyanophenyl)-dipyrromethene, cydpm; 5-(4-nitrophenyl)-dipyrromethene, ndpm and 5-(4-benzyloxyphenyl)-dipyrromethene, bdpm] have been synthesized. The complexes [(eta(6)-C(10)H(14))RuCl(L)] (L = ndpm and cydpm) reacted with NaN(3) and NH(4)SCN to afford neutral mononuclear complexes [(eta(6)-C(10)H(14))Ru(N(3))(L)] and [(eta(6)-C(10)H(14))Ru(SCN)(L)]. Their reactions with EPh(3) (E = P, As) and exobidentate ditopic P-P and N-N donor ligands, namely, bis-(diphenylphosphino)methane (dppm) and 4,4'-bipyridine (bpy) in the presence of AgSO(3)CF(3) afforded cationic mono- and binuclear complexes [(eta(6)-C(10)H(14))Ru(L)(EPh(3))]SO(3)CF(3), {(eta(6)-C(10)H(14))Ru(L)}(2)(mu-dppm)(2), and {(eta(6)-C(10)H(14))Ru(L)}(2)(mu-bpy)(2), respectively. The reaction products have been characterized by analytical and spectral studies. Molecular structures of the representative complexes [(eta(6)-C(10)H(14))RuCl(cydpm)], [(eta(6)-C(6)H(6))RuCl(cydpm)], [(eta(6)-C(10)H(14))RuCl(ndpm)], [(eta(6)-C(10)H(14))Ru(N(3))(ndpm)], and [(eta(6)-C(10)H(14))Ru(PPh(3))(ndpm)]SO(3)CF(3) have been determined crystallographically. Redox behavior of the complexes has been investigated by electrochemical studies. Emission spectral studies at room temperature suggested that the complexes under study are non-emissive.