title: Cobalt analogues of Roussin's red salt esters: a density functional study.
abstract: Density functional theory calculations on the Co(2)(NO)(4)(SR)(2) compounds (R = CH(3), CF(3) and C(4)H(9)) predict butterfly and open isomeric structures with and without a direct Co-Co bond. The open Co(2)(NO)(4)(SR)(2) structures are favored over the butterfly isomers, in terms of relative energy. Furthermore the open structures are predicted to have approximately twice as large HOMO-LUMO gaps than the butterfly Co(2)(NO)(4)(SR)(2) isomers. For the related Co(2)(CO)(6)(SR)(2) species, competing open and butterfly structures with similar HOMO-LUMO gaps were predicted. This could explain why the Co(2)(NO)(4)(μ-SR)(2) compounds have already been synthesized and why no genuine Co(2)(CO)(6)(SR)(2) derivatives have yet been reported.
authors.affiliation: Faculty of Chemistry and Chemical Engineering, Babeş-Bolyai University, M. Kogălniceanu 1, RO-400084, Cluj Napoca, Romania.
authors.forename: Menyhárt B
authors.initials: MB
authors.lastname: Sárosi
authors.forename: R Bruce
authors.initials: RB
authors.lastname: King