Crystal and molecular structure of W₂(OBu^t)₆ and electronic structure calculations on various conformers of W₂(OMe)₆

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• 作者：Malcolm H. Chisholm ; Judith C. Gallucci and Carl B. Hollandsworth
• 关键词：Tungsten ; Alkoxide ; Metal– ; metal bonds ; Density functional theory
• 刊名：Polyhedron
• 出版年：2006
• 期刊代码：87_02775387
• 类别：ch
• 出版时间：6 March 2006
• 卷：25
• 期：4
• 页码：827-833
• 文件大小：429 K

摘要

The structure of W₂(OBu^t)₆ was determined via a single crystal X-ray diffraction study. In the space group C2/c, there are 1.5 W₂(OBu^t)₆ molecules in the asymmetric unit, with one half molecule located on a crystallographic inversion center and one full molecule in a general position. The WW bond distances are 2.328(1) and 2.335(1) and the average W–O distances are 1.89(1) . The alkoxide alkyl groups are found oriented in the “one distal, two proximal” arrangement with respect to the W–W vector, giving on average, W–W–O angles of 99(1)° for the distal alkoxide and 110(1)° for the proximal. This arrangement is common to other W₂(OR)₆ compounds. Computational studies employing density functional theory on several conformers of the model compound W₂(OMe)₆ were undertaken. The results for the total bonding energies for each conformer indicate that this “one distal, two proximal” arrangement is only slightly more stable than the all-distal, D_3d and the alkoxide-eclipsed D_3h structures in the gas phase. This small difference in conformer energy suggests that the proximality preference is likely due to steric effects that are important in the solid state.