Interconversion between Polymeric and Monomeric Forms of Oxovanadium(IV) Complexes with Tetradentate Schiff Base Ligands Derived from (R,R)-2,4-Pentanediamine

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• 作者：Ryuichi Kasahara ; Masanobu Tsuchimoto ; Shigeru Ohba ; Kiyohiko Nakajima ; Hiroyuki Ishida ; and Masaaki Kojima
• 刊名：Inorganic Chemistry
• 出版年：1996
• 出版时间：December 18, 1996
• 年：1996
• 卷：35
• 期：26
• 页码：7661 - 7665
• 全文大小：167K
• 年卷期：v.35,no.26(December 18, 1996)
• ISSN：1520-510X

文摘

New tetradentate Schiff base-oxovanadium(IV)complexes, [VO{3-Xsal-(R,R)-2,4-ptn}](H₂{3-Xsal(R,R)-2,4-ptn}:N,N'-di-3-Xsalicylidene-(R,R)-2,4-pentanediamine;X = EtO (ethoxy), MeO (methoxy), and H) were preparedand characterized. Only an orange polymeric form was obtained forthe 3-methoxy and nonsubstituted (X = H)complexes. Both orange polymeric (1) and greenmonomeric (2) crystals were obtained for the 3-ethoxysubstitutedcomplex. X-ray structure analyses of 1 and 2were carried out. Crystal data:[VO{3-EtOsal-(R,R)-2,4-ptn}]·H₂O(1),VO₆N₂C₂₃H₃₀,orthorhombic, P2₁2₁2₁,a = 13.764(4) Å, b = 21.544(4) Å,c = 7.682(5) Å, Z = 4;[VO{3-EtOsal-(R,R)-2,4-ptn}] (2),VO₅N₂C₂₃H₂₈,orthorhombic, P2₁2₁2₁,a = 10.393(2) Å, b = 22.278(2) Å,c = 9.886(2) Å, Z = 4. The orange crystals (1) havewater of crystallization, and the complexes take a polynuclearlinearchain structure (···V=O···V=O···) with asix-membered N-N chelate ring in a chair form. The greencrystals(2) have no water of crystallization, and the complexes takea mononuclear square-pyramidal structure with asix-membered N-N chelate ring in a flattened boat form. Uponheating at 170 C for 10 min, orange 1 turnedto green 2, which reverted to orange 1 bysuspension in water-acetonitrile. Mechanism of theinterconversionbetween the polymeric and monomeric forms is discussed on the basis oftheir crystal structures.