异多核金属三键(W≡C)有机化合物的红外和拉曼光谱研究

Infrared and Raman Spectra Studies on Isomultinuclear Organometallic Carbyne Compounds

五种 (Ⅰ ,Ⅱ ,Ⅲ ,Ⅳ ,Ⅴ )异多核金属钨三键W≡C金属有机化合物的红外和拉曼光谱研究表明 ,由于N和P原子为强的σ 给予体和弱的π 接受体 ,在金属原子上分别引入含N或P的功能基团 (TMEDA或DPPE)将降低金属三键 (W≡C)的键强度 ,W≡C伸缩振动νW≡C 波数下降。化合物Ⅲ的压力调制红外和拉曼光谱显示 ,在 2 0kbar压力附近存在一压力诱导相变。低压相区高的压力灵敏度dv/dp(0 75cm-1·kbar-1)和高压相区很低的压力灵敏度 (0 0 8cm-1·kbar-1)指出 ,对W≡C键存在两种压力效应 ,一种是正常的 ,W≡C键强度随压力增加而增强 ,伸缩振动 νW≡C 波数增加 ;另一种是随着压力增加 ,从W到COπ 轨道反馈增加 ,导致W≡C键强度减弱 ,伸缩振动νW≡C 波数下降。

The infrared and Raman spectra of five isomult in uclear organometallic carbyne compounds were studied.The results show that the i ntroduction of N atom from TMEDA or P atom from DPPE to W atom (both N and P are strong σ-donor and weak π-acceptor) will decrease the bonding intensity of W≡C. The pressure tunning IR and Raman spectra of compound Ⅲ indicate the pres ence of pressure-induced phase-transition near 20 kbar in it. There are two ef fects on the ν (W≡C) of this compound with increasing pressure:th e normal increasing the ν (W≡C) wavenumber due to the shorting W ≡C bond and increasing the W-CO π backbonding to decrease the ν (W ≡C) wavenumber.