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Abstract
Addition of the amine-boranes H3BNH2tBu, H 3BNHMe2 and H3BNH3 to the cationic ruthenium fragment [Ru(xantphos)(PPh3)(OH 2)H][BArF4] (2; xantphos=4,5- bis(diphenylphosphino)-9,9-dimethylxanthene; BArF4=[B{3,5- (CF3)2C6H3}4] -) affords the n1-B-H bound amine-borane complexes [Ru(xantphos)(PPh3)(H3BNH2tBu)H][BAr F4] (5), [Ru(xantphos)(PPh3)(H 3BNHMe2)H][BArF4] (6) and [Ru(xantphos)(PPh3)(H3BNH3)H][BAr F4] (7). The X-ray crystal structures of 5 and 7 have been determined with [BArF4] and [BPh4] anions, respectively. Treatment of 2 with H3BPHPh2 resulted in quite different behaviour, with cleavage of the B-P interaction taking place to generate the structurally characterised bis-secondary phosphine complex [Ru(xantphos)(PHPh2)2H][BPh4] (9). The xantphos complexes 2, 5 and 9 proved to be poor precursors for the catalytic dehydrogenation of H3BNHMe2. While the dppf species (dppf=1,1-bis(diphenylphosphino)ferrocene) [Ru(dppf)(PPh3)HCl] (3) and [Ru(dppf)(n6-C6H5PPh 2)H][BArF4] (4) showed better, but still moderate activity, the agostic-stabilised N-heterocyclic carbene derivative [Ru(dppf)(ICy)HCl] (12; ICy=1,3-dicyclohexylimidazol-2-ylidene) proved to be the most efficient catalyst with a turnover number of 76 h-1 at room temperature.
Original language | English |
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Pages (from-to) | 8704-8713 |
Number of pages | 10 |
Journal | Chemistry - A European Journal |
Volume | 17 |
Issue number | 31 |
DOIs | |
Publication status | Published - 25 Jul 2011 |
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Dive into the research topics of 'Ruthenium bidentate phosphine complexes for the coordination and catalytic dehydrogenation of amine- and phosphine-boranes'. Together they form a unique fingerprint.Projects
- 2 Finished
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SYNTHETIC APPLICATIONS OF CATALYTIC RUTHENIUM COMPLEXES
Williams, J. (PI) & Whittlesey, M. (CoI)
Engineering and Physical Sciences Research Council
1/10/07 → 30/09/11
Project: Research council
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500 MHZ NMR SPECTROMETER TO SUPPORT ORGANIC, BIO-ORGANIC AND INORGANIC CHEMISTRY
Whittlesey, M. (PI), Danson, M. (CoI), Frost, C. (CoI), Kohn, R. (CoI), Lowe, J. (CoI), Weller, A. (CoI) & Williams, J. (CoI)
Engineering and Physical Sciences Research Council
12/06/06 → 11/06/09
Project: Research council