title: Synthesis, characterisation and molecular structure of Re(III) 2-oxacyclocarbenes stabilised by a benzoyldiazenido ligand.
abstract: A family of new Fischer-type rhenium(III) benzoyldiazenido-2-oxacyclocarbenes of formula [(ReCl2[eta1-N2C(O)Ph][=C(CH2)nCH(R)O](PPh3)2][n = 2, R = H (2), R = Me (3); n = 3, R = H (4), R = Me (5)] have been prepared by reaction of [ReCl2[eta2-N2C(Ph)O](PPh3)2] (1) with omega-alkynols, such as 3-butyn-1-ol, 4-pentyn-1-ol, 4-pentyn-2-ol, 5-hexyn-2-ol in refluxing THF. The correct formulation of the carbene derivatives 2-5 has been unambiguously determined in solution by NMR analysis and confirmed for compounds 2-4 by X-ray diffraction methods in the solid state. All complexes are octahedral with the benzoyldiazenido ligand, Re[N2C(O)Ph], adopting a "single bent" conformation. The coordination basal plane is completed by an oxacyclocarbene ligand and two chlorine atoms. Two triphenylphosphines in trans positions with respect to each other complete the octahedral geometry around rhenium. The reactivity of 1 towards different alkynes and alkenes including propargyl- and allylamine has been also studied. With propargyl amine, monosubstituted or bisubstituted complexes, [(ReCl2[eta1-N2C(O)Ph][eta1-NH2CH2C triple bond CH]n(PPh3)(3-n)][n= 1 (6); n = 2 (7)], have been isolated depending on the reaction conditions. In contrast, the reaction with allylamine gave only the disubstituted complex [(ReCl2[eta1-N2C(O)Ph][eta1-NH2CH2CH=CH2]2(PPh3)] (8). The molecular structure of the monosubstituted adduct has been confirmed by X-ray analysis in the solid state.
authors.affiliation: Laboratorio di Chimica Nucleare ed Inorganica, Dipartimento di Chimica, Università di Ferrara, Via L. Borsari 46, 44100, Ferrara, Italy.
authors.forename: Lorenza
authors.initials: L
authors.lastname: Marvelli
authors.forename: Nicoletta
authors.initials: N
authors.lastname: Mantovani
authors.forename: Andrea
authors.initials: A
authors.lastname: Marchi
authors.forename: Roberto
authors.initials: R
authors.lastname: Rossi
authors.forename: Michele
authors.initials: M
authors.lastname: Brugnati
authors.forename: Maurizio
authors.initials: M
authors.lastname: Peruzzini
authors.forename: Pierluigi
authors.initials: P
authors.lastname: Barbaro
authors.forename: Isaac
authors.initials: I
authors.lastname: de los Rios
authors.forename: Valerio
authors.initials: V
authors.lastname: Bertolasi