Preparation and structural characterization of [CpRu(1,10-phenanthroline)(CH3CN)][X] and precursor complexes (X= PF6, BArF, TRISPHAT-N)

Overview & Synopsis

Cationic [Ru(η 5-C5H5)(CH3CN)3] + complex, tris(acetonitrile)(cyclopentadienyl)ruthenium(II), gives rise to a very rich organometallic chemistry. Combined with diimine ligands, and 1,10-phenanthroline in particular, this system efficiently catalyzes diazo decomposition processes to generate metal-carbenes which undergo a series of original transformations in the presence of Lewis basic substrates. Herein, syntheses and characterizations of [CpRu(Phen)(L)] complexes with (large) lipophilic non-coordinating (PF6 − and BArF −) and coordinating N-TRISPHAT − anions are reported. Complex [CpRu(η 6-naphthalene)][BArF] [1][BArF] is readily accessible, in high yield, by direct counterion exchange between [1][PF6] and sodium tetrakis[3,5-bis(trifluoromethyl)phenyl]borate (NaBArF) salts. Ligand exchange of [1][BArF] in acetonitrile generated stable [Ru(η 5-C5H5)(CH3CN)3][BArF] [2][BArF] complex in high yield. Then, the desired [CpRu(Phen)(CH3CN)] [3] complexes were obtained from either the [1] or [2] complex in the presence of the 1,10-phenanthroline as ligand. For characterization and comparison purposes, the anionic hemilabile ligand TRISPHAT-N (TTN) was introduced on the ruthenium center, from the complex [3][PF6], to quantitatively generate the desired complex [CpRu(Phen)(TTN)] [4] by displacement of the remaining acetonitrile ligand and of the PF6 − anion. Solid state structures of complexes [1][BArF], [2][BArF], [3][BArF], [3][PF6] and [4] were determined by X-ray diffraction studies and are discussed herein.