title: Is bond stretch isomerism in mononuclear transition metal complexes a real issue? The misleading case of the MoCl5/tetrahydropyran reaction system.
abstract: Distinct batches of orange (1a-e) and green crystals (2a-e) were isolated from the reactions of MoCl5 with tetrahydropyran (thp), respectively at room temperature (in CH2Cl2) and at ca. 80 °C (in ClCH2CH2Cl). Crystals 2a-e are isomorphous to 1a-e and the IR spectra are almost superimposable. 1a-e were identified by X-ray studies as cis-MoCl4(thp)2, in agreement with previous findings. Careful refinement of the X-ray data of 2a-e by modeling one position as disordered between chlorine (minor component) and oxygen (major component) led to the conclusion that 2a-e consisted of a mixture of cis-MoCl4(thp)2 and mer-MoOCl3(thp)2, the latter being largely prevalent.
authors.affiliation: University of Bologna, Dipartimento di Chimica Industriale "Toso Montanari", Viale Risorgimento 4, I-40136 Bologna, Italy.
authors.forename: Francesco Paolo
authors.initials: FP
authors.lastname: Di Nicola
authors.forename: Massimiliano
authors.initials: M
authors.lastname: Lanzi
authors.forename: Fabio
authors.initials: F
authors.lastname: Marchetti
authors.forename: Guido
authors.initials: G
authors.lastname: Pampaloni
authors.forename: Stefano
authors.initials: S
authors.lastname: Zacchini