Heteroleptic Arene Ruthenium Complexes Based on <i>meso-</i>Substituted Dipyrrins: Synthesis, Structure, Reactivity, and Electrochemical Studies

First examples of heteroleptic arene ruthenium complexes containing dipyrrin ligands with the general formulations [(η6-arene)RuCl(L)] [(arene = C6H6, C10H14; L = 5-(4-cyanophenyl)-dipyrromethene, cydpm; 5-(4-nitrophenyl)-dipyrromethene, ndpm and 5-(4-benzyloxyphenyl)-dipyrromethene, bdpm] have been synthesized. The complexes [(η6-C10H14)RuCl(L)] (L = ndpm and cydpm) reacted with NaN3 and NH4SCN to afford neutral mononuclear complexes [(η6-C10H14)Ru(N3)(L)] and [(η6-C10H14)Ru(SCN)(L)]. Their reactions with EPh3 (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 AgSO3CF3 afforded cationic mono- and binuclear complexes [(η6-C10H14)Ru(L)(EPh3)]SO3CF3, [{(η6-C10H14)Ru(L)}2(μ-dppm)](SO3CF3)2, and [{(η6-C10H14)Ru(L)}2(μ-bpy)](SO3CF3)2, respectively. The reaction products have been characterized by analytical and spectral studies. Molecular structures of the representative complexes [(η6-C10H14)RuCl(cydpm)], [(η6-C6H6)RuCl(cydpm)], [(η6-C10H14)RuCl(ndpm)], [(η6-C10H14)Ru(N3)(ndpm)], and [(η6-C10H14)Ru(PPh3)(ndpm)]SO3CF3 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.