title: Structural determination of ruthenium-porphyrin complexes relevant to catalytic epoxidation of olefins.
abstract: A reproducible synthesis of a competent epoxidation catalyst, [Ru(VI)(TPP)(O)2)] (TPP = tetraphenylporphyrin dianion), starting from [Ru(II)(TPP)(CO)L] (L = none or CH3OH), is described. The molecular structure of the complex was determined by using ab initio X-ray powder diffraction (XRPD) methods, and its solution behavior was in detail investigated by NMR techniques such as PGSE (pulsed field gradient spin-echo) measurements. [Ru(IV)(TPP)(OH)]2O, a reported byproduct in the synthesis of [Ru(VI)(TPP)(O)2], was synthesized in a pure form by oxidation of [Ru(II)(TPP)(CO)L] or by a coproportionation reaction of [Ru(VI)(TPP)(O)2] and [Ru(II)(TPP)(CO)L], and its molecular structure was then determined by XRPD analysis. [Ru(VI)(TPP)(O)2] can be reduced by dimethyl sulfoxide or by carbon monoxide to yield [Ru(II)(TPP)(S-DMSO)2] or [Ru(II)(TPP)(CO)(H2O)], respectively. These two species were characterized by conventional single-crystal X-ray diffraction analysis.
authors.affiliation: Dipartimento di Chimica Inorganica, Metallorganica e Analitica, Università di Milano, and ISTM-CNR, Via Venezian 21, 20133 Milano, Italy.
authors.forename: Emma
authors.initials: E
authors.lastname: Gallo
authors.forename: Alessandro
authors.initials: A
authors.lastname: Caselli
authors.forename: Fabio
authors.initials: F
authors.lastname: Ragaini
authors.forename: Simone
authors.initials: S
authors.lastname: Fantauzzi
authors.forename: Norberto
authors.initials: N
authors.lastname: Masciocchi
authors.forename: Angelo
authors.initials: A
authors.lastname: Sironi
authors.forename: Sergio
authors.initials: S
authors.lastname: Cenini