Reactions of a cyanosilane with an iron(II) centre.: Synthesis and crystal structure of the isocyanotriphenylborate complex trans-[FeH(CNBPh3)(Ph2PCH2CH2PPh2)2] and anodic deprotonation of the hydrogen isocyanide (CNH) analogue
被引:40
作者:
Almeida, SSPR
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机构:Inst Super Tecn, Ctr Quim Estrutural, P-1096 Lisbon, Portugal
Almeida, SSPR
da Silva, MFCG
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机构:Inst Super Tecn, Ctr Quim Estrutural, P-1096 Lisbon, Portugal
da Silva, MFCG
da Silva, JJRF
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机构:Inst Super Tecn, Ctr Quim Estrutural, P-1096 Lisbon, Portugal
da Silva, JJRF
Pombeiro, AJL
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机构:Inst Super Tecn, Ctr Quim Estrutural, P-1096 Lisbon, Portugal
Pombeiro, AJL
机构:
[1] Inst Super Tecn, Ctr Quim Estrutural, P-1096 Lisbon, Portugal
[2] Inst Super Engn Lisboa, P-1900 Lisbon, Portugal
[3] Univ Lusofona Humanidades & Tecnol, P-1700 Lisbon, Portugal
来源:
JOURNAL OF THE CHEMICAL SOCIETY-DALTON TRANSACTIONS
|
1999年
/
03期
关键词:
D O I:
10.1039/a807707j
中图分类号:
O61 [无机化学];
学科分类号:
070301 ;
081704 ;
摘要:
Treatment of a thf solution of trans-[FeH(Cl)(dppe)(2)] (dppe = Ph2PCH2CH2PPh2) with N=CSiMe3, in the presence of Na[BPh4], formed trans-[FeH(CNBPh3)(dppe)(2)] 1 whose crystal structure was determined, whereas the use of Tl[BF4] in an acidic medium, instead of Na[BPh4], yielded trans-[FeH(CNH)(dppe)(2)][BF4] 2. Complex 1 is also formed by BPh3 addition to trans-[FeH(CN)(dppe)(2)] 3 which can be obtained by reaction of trans-[FeH(Cl)(dppe)(2)] with [NBu4]CN in the presence of Tl[BF4]. Complexes 1 and 3 undergo single-electron reversible oxidations upon cyclic voltammetry in an aprotic medium, and the electrochemical P-L ligand parameter was estimated (-0.51 V) for the CNBPh3- ligand. Complex 2 undergoes anodically induced deprotonation to form the cyano-complex 3(+) following a mechanism that has been established by digital simulation of cyclic voltammetry and allowed an estimate of the rate and acid/base equilibrium constants for the CNH/CN- interconversion in the 2/3 and 2(+)/3(+) pairs, showing that the oxidation of 2 leads to enhancements of its acidity constant and of the rate of proton loss by factors of cn. 1.5 x 10(7) and 500, respectively.