Rhodium silyl boryl hydride complexes: Comparison of bonding and the rates of elimination of borane, silane, and dihydrogen
Rhodium silyl boryl hydride complexes: Comparison of bonding and the rates of elimination of borane, silane, and dihydrogen
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DOI：
10.1002/anie.200460430
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发表时间：
2004-01-01
影响因子：
16.6
通讯作者：
Hartwig, JF
中科院分区：
文献类型：
--
作者：
Cook, KS;Incarvito, CD;Hartwig, JF
5474 2004 Wiley-VCH Verlag GmbH & Co. KGaA，魏因海姆DOI：10.1002/anie. 200460430 Angew. 2004，43，5474-5477和来自甲硅烷基的乙基共振，2a的1H NMR谱包含氢化物配体在d= 12.7ppm（1HRh-H = 42.0Hz）处的双峰。11B NMR谱包含在d= 40 ppm处的共振，这证实了硼基配体的存在。虽然通过NMR光谱以高产率形成2a，但我们不能从这些反应中分离结晶物质。然而，双（甲硅烷基）配合物1a和HBpin在环己烷中照射18小时允许以61%的产率分离结晶甲硅烷基硼基二氢化物2a。[Cp* RhH 2（SiMe 2 Ph）2]（1b）[21]与过量HBpin的反应在类似的光化学条件下以78%产率形成反式-[Cp* RhH 2（SiMe 2 Ph）（Bpin）]（2b）[Eq.①]。较长的反应时间不会导致2a或2b的第二硅烷被硼烷取代而形成[Cp* Rh（H）2（Bpin）2]（3）A2 pin 2与1的反应形成单一的主要产物，但是在该主要物质进行进一步反应之前1的转化是不完全的。我们以前制定的主要物种作为bisboryl 3，基于在NMR光谱中存在的广泛的共振信号的氢化物基团和频哪醇甲基基团的新的共振。[15]现在有了2a，从1和B2 pin 2产生的主要产物的光谱特征明显地来自2a。
5474 2004 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim DOI: 10.1002/anie. 200460430 Angew. Chem. Int. Ed. 2004, 43, 5474–5477 and ethyl resonances from the silyl group, the 1H NMR spectrum of 2a contained a doublet at d=¿ 12.7 ppm (1JRh-H= 42.0 Hz) for the hydride ligands. The 11B NMR spectrum contained a resonance at d= 40 ppm, which confirmed the presence of a boryl ligand. Though 2a formed in high yield by NMR spectroscopy, we were unable to isolate crystalline material from these reactions. However, irradiation of the bis (silyl) complex 1a and HBpin in cyclohexane for 18h allowed the isolation of crystalline silyl boryl dihydride 2a in 61% yield. Reaction of [Cp* RhH2 (SiMe2Ph) 2](1b)[21] with excess HBpin formed trans-[Cp* RhH2 (SiMe2Ph)(Bpin)](2b) under similar photochemical conditions in 78% yield [Eq.(1)]. Longer reaction times did not cause replacement of the second silane of 2a or 2b with borane to form [Cp* Rh (H) 2 (Bpin) 2](3).Reaction of B2pin2 with 1 formed a single major product, but the conversion of 1 was incomplete before this major species underwent further reaction. We previously formulated the major species as the bisboryl 3, based on the presence in the NMR spectra of a broad resonance signal for hydride groups and new resonances for pinacol methyl groups.[15] With 2a now in hand, the spectral features of the major product generated from 1 and B2pin2 clearly result from 2a.