Binuclear Vanadium Carbonyls: The Limits of the 18-Electron Rule
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- 作者：Zhaohui Liu ; Qian-shu Li ; Yaoming Xie ; R. Bruce King ; Henry F. Schaefer III
- 刊名：Inorganic Chemistry
- 出版年：2007
- 出版时间：March 5, 2007
- 年：2007
- 卷：46
- 期：5
- 页码：1803 - 1816
- 全文大小：1155K
- 年卷期：v.46,no.5(March 5, 2007)
- ISSN：1520-510X
文摘
The fact that the stable mononuclear vanadium carbonyl V(CO)6 fails to satisfy the 18-electron rule has led to aninvestigation of the binuclear vanadium carbonyls V2(CO)n (n = 10-12) using methods from density functionaltheory. There are several important experimental studies of these homoleptic binuclear vanadium carbonyls. Theglobal minimum for V2(CO)12 is a singlet structure having two V(CO)6 units linked by a long V-V single bond (3.48Å by B3LYP or 3.33 Å by BP86) without any bridging CO groups. For V2(CO)11 the global minimum is a singletstructure V2(CO)10(
2-
-CO) with a four-electron 
-donor bridging CO group. For V2(CO)10 the global minimum isan unsymmetrical singlet (OC)4V
V(CO)6 structure with three semibridging CO groups and a V-V distance of2.54 Å (B3LYP) or 2.51 Å (BP86), suggesting a VV triple bond. The theoretical 
(CO) frequencies of this V2(CO)10 isomer agree approximately with those assigned by Ishikawa et al. (J. Am. Chem. Soc. 1987, 109, 6644)to a V2(CO)10 isomer produced in the photolysis of gas-phase V(CO)6. In contrast, the laboratory bridging (CO)frequency assigned to V2(CO)12 by Ford et al. (Inorg. Chem. 1976, 15, 1666) seems more likely to arise from thelowest-lying triplet isomer of V2(CO)11.
2--CO) with a four-electron -donor bridging CO group. For V2(CO)10 the global minimum isan unsymmetrical singlet (OC)4VV(CO)6 structure with three semibridging CO groups and a V-V distance of2.54 Å (B3LYP) or 2.51 Å (BP86), suggesting a VV triple bond. The theoretical (CO) frequencies of this V2(CO)10 isomer agree approximately with those assigned by Ishikawa et al. (J. Am. Chem. Soc. 1987, 109, 6644)to a V2(CO)10 isomer produced in the photolysis of gas-phase V(CO)6. In contrast, the laboratory bridging (CO)frequency assigned to V2(CO)12 by Ford et al. (Inorg. Chem. 1976, 15, 1666) seems more likely to arise from thelowest-lying triplet isomer of V2(CO)11.