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Metallaboratranes: Bis- and Tris(methimazolyl)borane Complexes of Group 9 Metal Carbonyls and Thiocarbonyls

journal contribution
posted on 2023-06-08, 00:02 authored by Ian CrossleyIan Crossley, Anthony F Hill, Anthony C Willis
The iridium poly(methimazolyl)borane complexes [IrH(CE)(PPh3){3-B,S,S0-B(mt)2R}](IrfB)8 (mt=methimazolyl=2-mercapto-3-methylimidazol-1-yl; E=O, S; R=mt, H) are described in detail. For R = mt, these materials are elucidated as paradigms for the final mechanistic intermediate in metallaboratrane formation, a role illustrated through hydride abstraction to afford the cationic salts [Ir(CE)(PPh3){4-B(mt)3}]X(IrfB)8 (E=O, S; X=Cl, BF4). The rhodium poly(methimazolyl)borate complexes [Rh(CO)(PPh3){2-S,S0-HB(mt)2R}] (R=mt, H) are also reported. These compounds are obtained in preference to the respective borane complexes (analogous to iridium); however [Rh(CO)- (PPh3){2-S,S0-HB(mt)3}] is observed to undergo facile solution-phase conversion to [Rh(CO)(PPh3)- {4-B,S,S0,S00-B(mt)3}]Cl(RhfB)8 in chlorinated solvents. The ramifications of these results,with respect to metallaboratrane formation, are discussed, substantiating previous mechanistic conjecture. In an attempt to establish an alternative route to iridaboratranes, the first isolable tris(methimazolyl)borate complex of iridium, cis,cis-[IrHCl(PPh3)2{2-S,S0-HB(mt)3], is reported and shown not to evolve to the iridaboratrane [IrCl(PPh3){4-B(mt)3}](IrfB)8 under conditions that lead to the corresponding rhodaboratrane. Factors are discussed that may contribute to this fine balance between the formation of methimazolylborate and methimazolylborane complexes.

History

Publication status

  • Published

Journal

Organometallics

ISSN

0276-7333

Issue

2

Volume

29

Page range

326-336

Pages

11.0

Department affiliated with

  • Chemistry Publications

Full text available

  • No

Peer reviewed?

  • Yes

Legacy Posted Date

2012-02-06

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