TRANSITION-METAL POLYHYDRIDE COMPLEXES .6. CPML6-NHN (N = 4-6) COMPLEXES

被引:25
作者
LIN, ZY [1 ]
HALL, MB [1 ]
机构
[1] TEXAS A&M UNIV SYST, DEPT CHEM, COLL STN, TX 77843 USA
关键词
D O I
10.1021/om00034a042
中图分类号
O61 [无机化学];
学科分类号
070301 ; 081704 ;
摘要
Ab initio calculations with effective core potentials have been used to study the relative stabilities of classical and nonclassical isomers of 18-electron polyhydride transition metal complexes, [CpML6-nHn]x+ (n = 4-6, x = 0-2, and L = PH3), where M = Nb, Ta, Mo, W, Tc, Re, Ru, Rh, Os, and Ir. These systematic calculations reveal that a diagonal line in the periodic table through Ru and Ir atoms divides the classical forms (left side of the line) and nonclassical forms (right side of the line). Most of these polyhydrides adopt classical isomers with a pseudo-pentagonal-bipyramidal geometry, where the Cp ring occupies one of the two axial positions. In this pseudo-pentagonal-bipyramidal structure, the Cp-M-H(e) (H(e): an equatorial hydrogen) angle is found to be about 110.0-degrees, significantly greater than the 90.0-degrees expected for a regular pentagonal bipyramid. This unexpected large deviation results from a pseudo-second-order Jahn-Teller (SOJT) distortion, which allows a stronger interaction between the equatorial hydrogens' el set of orbitals and metal d(xz) and d(yz) orbitals.
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页码:4046 / 4050
页数:5
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