Conformational Diversity of Thiosemicarbazonatovanadium(V) Complexes in the Solid State: From Polymorphism to Isostructurality

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• 作者：Mirta Rub膷i膰 ; Dalibor Mili膰 ; Gordana Pavlovi膰 ; Marina Cindri膰
• 刊名：Crystal Growth & Design
• 出版年：2011
• 出版时间：December 7, 2011
• 年：2011
• 卷：11
• 期：12
• 页码：5227-5240
• 全文大小：1325K
• 年卷期：v.11,no.12(December 7, 2011)
• ISSN：1528-7505

文摘

New alkoxooxovanadium(V) complexes, [VO(L)(OR)] (OR = OMe (<b>1b>), OEt (<b>2b>), OPr (<b>3b>)), were synthesized by the reaction of assorted vanadium precursors and 4-methoxysalicylaldehyde 4-phenylthiosemicarbazone (Hb>2b>L) in appropriate alcohols. Complexes <b>2b> and <b>3b> crystallized each in two polymorphic forms, which can be selectively prepared by using either a vanadium(IV) or a vanadium(V) precursor. The conformational flexibility of these complexes manifests itself in conformational polymorphism (<b>2ab> and <b>2bb>, <b>3ab>, and <b>3bb>), conformational isomorphism (<b>2bb>, <b>3ab>, and <b>3bb>), and conformational synmorphism (<b>3ab> and <b>3bb>). The largest conformational differences are found in the spatial arrangements of the coordinated alkoxo groups and the phenyl rings of the ligand. The isostructurality of complexes <b>2bb> and <b>3ab> reflects, on the other hand, their conformational similarity, with nearly the same pattern of intermolecular interactions dominating within their crystal architectures. However, unlike the case in <b>3ab>, the structure of <b>2bb> exhibits disorder in the stacking of molecular layers, which can be tentatively correlated with the crystallization rate. All compounds were thoroughly investigated by various solid-state methods, while the thermodynamic relation of polymorphs <b>2b> and <b>3b> was assessed via competitive slurry and thermal experiments.