Conformations and Binding Modes of 2,3,5,6-Tetra(2'-pyridyl)pyrazine

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• 作者：Clifford W. Padgett ; William T. Pennington ; and Timothy W. Hanks
• 刊名：Crystal Growth & Design
• 出版年：2005
• 出版时间：March 2005
• 年：2005
• 卷：5
• 期：2
• 页码：737 - 744
• 全文大小：412K
• 年卷期：v.5,no.2(March 2005)
• ISSN：1528-7505

文摘

The compound 2,3,5,6-tetra(2'-pyridyl)pyrazine (tppz) is a remarkably versatile electron donor thatdisplays a wide variety of binding modes. Quantum mechanical calculations on the 14 low energy conformations oftppz indicate a preference for four conformations in methanol and two others in either the gas phase or benzene.The prevalence of a species in solution and its predicted solubility, based on simple dipole moment considerations,provides an explanation for the isolation of different tppz polymorphs from the two solvents. Using a simple systemfor describing the tppz geometry, a review of previously reported crystal structures of complexes containing tppz asa ligand was conducted. The literature reveals a variety of tppz binding modes, including mono-, bi-, and tridentatecoordination to a variety of Lewis acids. In addition to small molecular complexes, tppz-containing macrocycles andone-, two-, and three-dimensional extended chain systems have been characterized. Upon the basis of the analysisof tppz coordination behavior, several new binding modes are proposed that could be used for the construction ofnovel tppz complexes and supramolecular systems.