title: Synthesis and structure of two tetranuclear osmium carbonyl isotopomers: a crystallographic isotope effect.
abstract: A synthetic route to [Os4(mu-H)(mu-OH)(mu-CO)(CO)12] ( 1) has been devised through the activation of [Os4(CO)14] with Me3NO. The pyrolysis and photolysis of the reactant in the presence of a trace amount of water produces 1 in low yield. The solid-state structure of [Os4(mu-H)(mu-OH)(mu-CO)(CO)12 x H2O] (1 x H2O) reveals a butterfly Os4 skeleton with bridging H, OH and CO ligands as well as hydrogen-bonded molecules of water in the crystal lattice. A low-temperature 13C{1H} NMR spectroscopic study revealed a merry-go-round exchange of CO ligands around the Os3 plane containing the asymmetric bridging CO. The exposure of 1 x H2O to D2O yielded [Os4(mu-H)(mu-OD)(mu-CO)(CO)12]2. Although the solid-state, intramolecular structure of 2 closely matched that of 1 x H2O, the intermolecular structure did not: its crystal lattice contained no water of crystallization, a previously unreported crystallographic isotope effect.
authors.affiliation: Department of Chemistry, Simon Fraser University, Burnaby, British Columbia, CanadaV5A 1S6. jcanal@sfu.ca.
authors.forename: John P
authors.initials: JP
authors.lastname: Canal
authors.forename: Michael
authors.initials: M
authors.lastname: Jennings
authors.forename: Glenn P A
authors.initials: GP
authors.lastname: Yap
authors.forename: Roland K
authors.initials: RK
authors.lastname: Pomeroy