title: Icosahedral metallacarborane/carborane species derived from 1,1'-bis(o-carborane).
abstract: Examples of singly-metallated derivatives of 1,1'-bis(o-carborane) have been prepared and spectroscopically and structurally characterised. Metallation of [7-(1'-1',2'-closo-C2B10H11)-7,8-nido-C2B9H10](2-) with a {Ru(p-cymene)}(2+) fragment affords both the unisomerised species [1-(1'-1',2'-closo-C2B10H11)-3-(p-cymene)-3,1,2-closo-RuC2B9H10] (2) and the isomerised [8-(1'-1',2'-closo-C2B10H11)-2-(p-cymene)-2,1,8-closo-RuC2B9H10] (3), and 2 is easily transformed into 3 with mild heating. Metallation with a preformed {CoCp}(2+) fragment also affords a 3,1,2-MC2B9-1',2'-C2B10 product [1-(1'-1',2'-closo-C2B10H11)-3-Cp-3,1,2-closo-CoC2B9H10] (4), but if CoCl2/NaCp is used followed by oxidation the result is the 2,1,8-CoC2B9-1',2'-C2B10 species [8-(1'-1',2'-closo-C2B10H11)-2-Cp-2,1,8-closo-CoC2B9H10] (5). Compound 4 does not convert into 5 in refluxing toluene, but does do so if it is reduced and then reoxidised, perhaps highlighting the importance of the basicity of the metal fragment in the isomerisation of metallacarboranes. A computational study of 1,1'-bis(o-carborane) is in excellent agreement with a recently-determined precise crystallographic study and establishes that the {1',2'-closo-C2B10H11} fragment is electron-withdrawing compared to H.
authors.affiliation: Institute of Chemical Sciences, Heriot-Watt University, Edinburgh, UK EH14 4AS. a.j.welch@hw.ac.uk.
authors.forename: Gobika
authors.initials: G
authors.lastname: Thiripuranathar
authors.forename: Wing Y
authors.initials: WY
authors.lastname: Man
authors.forename: Cesar
authors.initials: C
authors.lastname: Palmero
authors.forename: Antony P Y
authors.initials: AP
authors.lastname: Chan
authors.forename: Bernhard T
authors.initials: BT
authors.lastname: Leube
authors.forename: David
authors.initials: D
authors.lastname: Ellis
authors.forename: David
authors.initials: D
authors.lastname: McKay
authors.forename: Stuart A
authors.initials: SA
authors.lastname: Macgregor
authors.forename: Laure
authors.initials: L
authors.lastname: Jourdan
authors.forename: Georgina M
authors.initials: GM
authors.lastname: Rosair
authors.forename: Alan J
authors.initials: AJ
authors.lastname: Welch