Hydrido(hydrosilylene)tungsten complexes with strong interactions between the silylene and hydrido ligands.
Hydrido(hydrosilylene)tungsten complexes with strong interactions between the silylene and hydrido ligands.
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DOI：
10.1002/anie.200352383
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发表时间：
2004
影响因子：
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通讯作者：
Takahito Watanabe;H. Hashimoto;H. Tobita
中科院分区：
文献类型：
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作者：
Takahito Watanabe;H. Hashimoto;H. Tobita
213K=41kJ摩尔±1，用聚结点法测定)。这一结果表明，在室温下，1a中发生了快速的羰基交换。在红外光谱中，1a的νCO谱带(1928和1853 cm±1)比[Cp*(CO)2(H)W=SiPh2(Py)](1892和1806 cm±1)具有更高的能量[5]，这显然是由于1a中较强的对硅烯配体的回馈，导致对羰基配体的回馈较弱。νSiH带出现在2052 cm±1。在1589 cm±1处观察到一个微弱而广泛的吸收属于WH基团，其与硅烯配体的相互作用极大地降低了W±H键的强度。[14]通过X射线晶体结构分析(图1)确定了1b的固态结构(图1)。[15]选定的键长和键角列于表1。1b中的钨原子采用扭曲的四足钢琴凳结构，其中氢化物和硅烯配体占据相互的顺式位置。W±Si(1)的键长(2.3703(11))比已知的硅基钨配合物的键长(2.469-2.653)短。[16]这个长度甚至比不含环的硅基(硅烯)钨配合物[Cp*W(CO)2(=SiMe2)(SiMe3)](2.3850(12))，[7]更短，但略长于
213 K= 41 kJ molÀ1, determined by the coalescence-point method). This result indicates that rapid exchange of carbonyl groups occurs in 1a at room temperature. In the IR spectrum, the νCO bands for 1a (1928 and1853 cmÀ1) appear at higher energy than those of [Cp*(CO) 2 (H) W= SiPh2 (py)](1892 and 1806 cmÀ1).[5] This is apparently attributable to stronger back-donation to the silylene ligand in 1a, which leads to weaker back-donation to the carbonyl ligands. The νSiH band appears at 2052 cmÀ1. A weak and broad absorption observed at 1589 cmÀ1 can be assigned to the WH group, interaction of which with the silylene ligand dramatically reduces the strength of the WÀH bond.[14]The solid-state structure of 1b was determined by X-ray crystal structure analysis (Figure 1).[15] Selected bond lengths and angles are listed in Table 1. The tungsten atom in 1b adopts a distorted four-legged piano-stool structure, in which the hydrido and silylene ligands occupy the mutually cis positions. The WÀSi (1) bond length (2.3703 (11)) is shorter than those of known silyltungsten complexes (2.469–2.653).[16] This length is even shorter than that of the donorfree silyl (silylene) tungsten complex [Cp* W (CO) 2 (= SiMes2)(SiMe3)](2.3850 (12)),[7] but somewhat longer than that of