348 research outputs found
Definitive crystal structure of 1,1'-bis[1,2-dicarba-<i>clos</i>o-dodecaborane(11)]
In the title compound, C4H22B20, the two {1,2-closo-C2B10H11} cages are linked across a centre of inversion with a CβC distance of 1.5339β
(11)β
Γ
. By careful analysis of the structure, it is established that the non-linking cage C atom is equally disordered over cage vertices 2 and 3
Crystal structure of 1,1'-bis[1,7-dicarba-<i>closo</i>-dodecaborane(11)]
In the title compound, C4H22B20, the two {1,7-closo-C2B10H11} cages are linked across a centre of inversion, with CβC = 1.5401β
(16)β
Γ
. The position of the second non-linking cage C atom was established unambiguously by geometric and crystallographic methods and there is no evidence of C/B disorder
The exopolyhedral ligand orientation (ELO) in 3-(nitrato-ΞΊO)-3,3-bis(triphenylphosphane-ΞΊP)-3-rhoda-1,2-dicarba-closo-dodecaborane(11) dichloromethane 2.2-solvate
In the title compound, [Rh(C2H11B9)(NO3)(C18H15P)2]Β·2.2CH2Cl2, studied as a 2.2-solvate of what was assumed to be dichloromethane, the nitrate ligand liesciswith respect to both cage C atoms. Accordingly, the compound displays a pronounced preferred exopolyhedral ligand orientation (ELO) which is traced to both the greatertransinfluence of the cage B over the cage C atoms and the greatertransinfluence of the triphenylphosphane ligands over the nitrate ligand. The overall molecular architecture therefore agrees with that of a number of similar 3-L-3,3-Lβ²2-3,1,2-closo-MC2B9H11species in the literature.</jats:p
Reduction-induced facile isomerisation of metallacarboranes:synthesis and crystallographic characterisation of 4-Cp-4,1,2-closo-CoC<sub>2</sub>B<sub>9</sub>H<sub>11 </sub>
One-electron reduction of 3-Cp-3,1,2-closo-CoC2B9H11 followed by heating to reflux in DME (b.p. 85 Β°C) induces isomerisation to 4-Cp-4,1,2-closo-CoC2B9H11.</p
Steric <i>versus</i> electronic factors in metallacarborane isomerisation: nickelacarboranes with 3,1,2-, 4,1,2- and 2,1,8-NiC<sub>2</sub>B<sub>9</sub> architectures and pendant carborane groups, derived from 1,1β²-bis(o-carborane)
Nickelacarborane derivatives of 1,1β²-bis(o-carborane) allow comment on the factors important in the isomerisation of metallacarboranes.</p
Silver Effect in Regiodivergent Gold-Catalyzed Hydroaminations
We
report a silver-induced switching of regioselectivity in gold-catalyzed
reactions, and we provide mechanistic evidence to suggest a true βsilver
effectβ: that is, one that is implicated in the catalytic process
itself, via Ο-gold Ο-silver acetylides. These results
are of significance because they clearly show that the use of silver
as halide abstractors in gold-catalyzed reactions may result in βsilver
effectsβ when terminal alkyne substrates are involved
- β¦