Minimum Energy Structure of Hydridotris(pyrazolyl)borato Iridium(V) Tetrahydride Is Not a C3v Capped Octahedron
详细信息 查看全文
- 作者：Charles Edwin Webster ; Daniel A. Singleton ; Michael J. Szymanski ; Michael B. Hall ; Cunyuan Zhao ; Guochen Jia ; and Zhenyang Lin
- 刊名：Journal of the American Chemical Society
- 出版年：2001
- 出版时间：October 10, 2001
- 年：2001
- 卷：123
- 期：40
- 页码：9822 - 9829
- 全文大小：128K
- 年卷期：v.123,no.40(October 10, 2001)
- ISSN：1520-5126
文摘
Recent synthesis and NMR spectroscopy of neutral Ir(V) complexes hydridotris(3,5-dimethylpyrazol-1-yl)borato tetrahydride (Tp*IrH4) and hydridotris(pyrazol-1-yl)borato tetrahydride (TpIrH4) have been interpretedas supporting face-capped octahedral structures (C3v) with each of three Ir-H bonds trans to an Ir-N bondand the fourth hydride capping the IrH3 face. Here, density functional geometry optimizations and coupledcluster calculations on hydridotris(pyrazol-1-yl)borato iridium tetrahydrogen find that a Cs edge-bridgedoctahedral tetrahydride structure and a C1 
2-dihydrogen, dihydride structure are local minima and find thatthe C3v structure is a local maximum (second-order saddle point). Several low energy transition states connectingthe local minima have been located, and these minima can be used to simulate the experimental NMR spectra.A comparison of the experimental infrared spectrum of Tp*IrH4 and the harmonic frequency calculations onthe Cs, C1, and C3v structures also supports the assignment of the Cs and C1 structures as the observed ones.
2-dihydrogen, dihydride structure are local minima and find thatthe C3v structure is a local maximum (second-order saddle point). Several low energy transition states connectingthe local minima have been located, and these minima can be used to simulate the experimental NMR spectra.A comparison of the experimental infrared spectrum of Tp*IrH4 and the harmonic frequency calculations onthe Cs, C1, and C3v structures also supports the assignment of the Cs and C1 structures as the observed ones.