金属钨三键多核金属有机配合物高压拉曼及红外光谱研究

Raman and Infrared Spectral Studies of Tungsten Organometallic Carbyne Complex at High External Pressure

研究了金属钨三键多核金属有机配合物 [Cl(CO) 2 (DPPE)WCC6 H4CCC6 H4NC]2 ReCl(CO) 3(DPPE =bis(diphenylphosphino)ethane,(Ph) 2 PCH2 CH2 P(Ph) 2 )不同压力下的拉曼和红外光谱 (最高压力约 5 0kbar)。配合物在 3 0kbar存在一压力诱导二级相变。金属钨三键伸缩振动ν(WC)压力相关 (dν/dp)在低压相区 ( 0 5 9cm-1·(kbar) -1)与高压相区 ( 0 0 4cm-1·(kbar) -1)差别很大 (约 15倍 )。在高压下 ,从基团Cl(CO) 2 (DPPE)WC中的金属钨W向COπ 轨道的π 反馈明显增强 ,WC的键强度减弱 ,力常数减小和ν(WC)降低 ;此效应与压力缩短WC键 ,增大力常数和增加ν(WC)的效应互相竞争。

The Raman and infrared spectra of complex: [Cl(CO)(2), (DPPE)W equivalent to CC6H4C equivalent to CC6H4NC](2)Re Cl(CO)(3), (DPPE = bis(di-phenylphosphino) ethane, (Ph)(2)PCH2CH2P(Ph)(2)) were measured at high extemal pressure (up to about 50 kbar). The pressure induced phase transition was observed near 30 kbar. The pressure dependence dv/dp of v (W equivalent to C) at the low-pressure phase is a little high (0.59 cm(-1 .)(kbar)(-1)) and is very low (0.04 cm(-1.)(kbar)(-1)) at the high-pressure phase. It shows that the pi -backbonding from W to pi* -orbital of CO is strengthened at the high external pressure in fragment Cl(CO)(2) (DPPE) W equivalent to C; The bond intensity and the force constant of W equivalent to C and v(W equivalent to C) are decreasing;This effect compete with the normal increasing v(W equivalent to C) on compression.