Adolf, Ariane and Vogel, Ulf and Zabel, Manfred and Timoshkin, Alexey Y. and Scheer, Manfred (2008) N-Heterocyclic Carbenes in Lewis Acid/Base Stabilised Phosphanylboranes. European Journal of Inorganic Chemistry 2008 (22), pp. 3482-3492.
Download (347kB) - Repository staff only
The reactions of 2-borane-1,3,4,5-tetramethylimidazoline (BH3·NHCMe) with selected phosphane adducts of the Lewis acids B(C6F5)3 and Ga(C6F5)3 are studied. Among others, adducts (C6F5)3Ga·PH2Cp* (1a) and (C6F5)3B·PH2Cp* (2) are used as starting materials. When the (C6F5)3Ga-phosphane adducts 1a and (C6F5)3Ga·PPhH2 are treated with BH3·NHCMe, the Lewis acid/base stabilised phosphanylboranes (C6F5)3Ga·P(Cp*)HBH2·NHCMe (3a) and (C6F5)3Ga·P(Ph)HBH2·NHCMe (3b) are formed, respectively, by a hydrogen elimination reaction. In contrast, the reaction of BH3·NHCMe with the (C6F5)3B-phosphane adducts (C6F5)3B·PH2R [R = H, R = Cp* (2) and R = Ph] in CH2Cl2 at room temperature leads to the formation of a salt with the general formula [(C6F5)3BH][RPH2·BH2·NHCMe] (4a: R = H, 4b: R = Cp*, 4c: R = Ph). To synthesise the Lewis acid/base stabilised phosphanylborane with (C6F5)3B as a Lewis acid and 1,3,4,5-tetramethylimidazolylidene (NHCMe) as a Lewis base, a different synthetic pathway was applied: the replacement reaction of the Lewis base. At room temperature, NHCMe displaced the amine in (C6F5)3B·P(Ph)HBH2·NMe3 to yield (C6F5)3B·P(Ph)HBH2·NHCMe (5). All compounds were comprehensively characterised by spectroscopic methods. Compounds 1a, 1b, 2, 3a, 3b and 5 were additionally characterised by X-ray crystallographic analysis.
|Date:||4 July 2008|
|Institutions:||Chemistry and Pharmacy > Institut für Anorganische Chemie > Chair Prof. Dr. Manfred Scheer|
|Keywords:||Boron; Phosphorus; Gallium; Carbenes; Lewis acids; Lewis bases|
|Subjects:||500 Science > 540 Chemistry & allied sciences|
|Created at the University of Regensburg:||Unknown|
|Deposited On:||07 Jun 2010 12:24|
|Last Modified:||20 Jul 2011 22:29|