Donor Atom Dependent Geometric Isomers in Mononuclear Oxo-Molybdenum(V) Complexes: Implications for Coordinated Endogenous Ligation in Molybdoenzymes
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- 作者：Carl J. Carrano ; Balwant S. Chohan ; Brian S. Hammes ; Brian W. Kail ; Victor N. Nemykin ; and Partha Basu
- 刊名：Inorganic Chemistry
- 出版年：2003
- 出版时间：September 22, 2003
- 年：2003
- 卷：42
- 期：19
- 页码：5999 - 6007
- 全文大小：160K
- 年卷期：v.42,no.19(September 22, 2003)
- ISSN：1520-510X
文摘
We have previously demonstrated that the complex [(L1O)MoOCl2], where L1OH = (2-hydroxy-3-tert-butyl-5-methylphenyl)bis(3,5-dimethylpyrazolyl)methane, exists as both cis and trans isomers (Kail, B.; Nemykin, V. N.;Davie, S. R.; Carrano, C. J.; Hammes, B. S.; Basu, P. Inorg. Chem. 2002, 41, 1281-1291). Here, the cis isomeris defined as the geometry with the heteroatom in the equatorial position, and the trans isomer is designated asthe geometry with the heteroatom positioned trans to the terminal oxo group. The trans isomer represents thethermodynamically more stable geometry as indicated by its spontaneous formation from the cis isomer. In thisreport, we show that for complexes of [(LO)MoOCl2], where LOH is the sterically less restrictive (2-hydroxyphenyl)bis(3,5-dimethylpyrazolyl)methane, only the trans isomer could be isolated, while in the corresponding thiolatecontaining ligand (2-dimethylethanethiol)bis(3,5-dimethylpyrazolyl)methane (L3SH) only the cis isomer could beobserved. In addition, we have isolated and structurally characterized the complex [(L1O)MoO(OPh)(Cl)], a rareexample of a species possessing both cis and trans phenolates. Using DFT calculations, we have investigated theorigins of the differences in stability between the cis and trans isomers in these complexes and suggest that theyare related to the trans influence of the oxo-group. Crystal data for [(LO)MoOCl2] (1) include that it crystallizes inthe triclinic space group P
with cell dimensions a = 8.9607 (12) Å, b = 10.596 (4) Å, c = 13.2998 (13) Å, 
=98.03 (2)
, 
= 103.21 (2), 
= 110.05(2), and Z = 2. [(L1O)MoO(OPh)Cl]·2CH2Cl2 (2·2CH2Cl2) crystallizes inthe triclinic space group P, with cell dimensions a = 12.2740 (5) Å, b = 13.0403 (5) Å, c = 13.6141 (6) Å, = 65.799 (2), = 64.487 (2), = 65.750 (2), and Z = 2. [(L3S)Mo(O)Cl2] (3) crystallizes in the orthorhombicspace group Pna21, with cell dimensions a = 13.2213 (13) Å, b = 8.817 (2) Å, c = 15.649 (4) Å, and Z = 4. Theimplications of these results on the function of mononuclear molybdoenzymes such as sulfite oxidase, and theDMSO reductase, are discussed.
with cell dimensions a = 8.9607 (12) Å, b = 10.596 (4) Å, c = 13.2998 (13) Å, =98.03 (2), = 103.21 (2), = 110.05(2), and Z = 2. [(L1O)MoO(OPh)Cl]·2CH2Cl2 (2·2CH2Cl2) crystallizes inthe triclinic space group P, with cell dimensions a = 12.2740 (5) Å, b = 13.0403 (5) Å, c = 13.6141 (6) Å, = 65.799 (2), = 64.487 (2), = 65.750 (2), and Z = 2. [(L3S)Mo(O)Cl2] (3) crystallizes in the orthorhombicspace group Pna21, with cell dimensions a = 13.2213 (13) Å, b = 8.817 (2) Å, c = 15.649 (4) Å, and Z = 4. Theimplications of these results on the function of mononuclear molybdoenzymes such as sulfite oxidase, and theDMSO reductase, are discussed.