RuCp Complexes of Ambidentate 4,5-Diazafluorene Derivatives: From Linkage Isomers to Coordination-Driven Self-Assembly

The coordination chemistry of the {RuCp*}+ fragment was studied toward several 4,5-diazafluorene derivatives. The ambidentate nature of these 4,5-diazafluorene derivatives with multiple coordination sites allowed for the syntheses of different linkage isomers and self-assembled macrocycles. Both a tetramer (2) and a monomer (3) of [RuCp*L] (where L – = 4,5-diazafluorenide) were prepared with the L – ligand. The dimeric head-to-tail macrocycles [Cp*Ru(LpH)]2Cl2 (4) and [Cp*RuLp]2 (5) were obtained with the ditopic L p H and L p – ligands (where L p H = 9-(2-(diphenylphosphino)ethyl)-4,5-diazafluorene and L p – = 9-(2-(diphenylphosphino)ethyl)-4,5-diazafluorenide). The bulky arene-substituted L Mes H ligand (where L Mes H = 3,6-dimesityl-4,5-diazafluorene) was prepared, and its coordination to {RuCp*}+ gave [Cp*Ru(L Mes H)]Cl (13). The selective syntheses of different linkage isomers of [RuCp*(L Mes )] (14 and 15) (where L Mes – = 3,6-dimesityl-4,5-diazafluorenide) were also demonstrated.