First Row Transition Metal Complexes of 1-Methylcyclobutenedione, a Monosubstituted Squarate Ligand

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• 作者：Bert D. Alleyne ; Hazel-Ann Hosein ; Hema Jaggernauth ; Lincoln A. Hall ; Andrew J. P. White ; and David J. Williams
• 刊名：Inorganic Chemistry
• 出版年：1999
• 出版时间：May 17, 1999
• 年：1999
• 卷：38
• 期：10
• 页码：2416 - 2421
• 全文大小：101K
• 年卷期：v.38,no.10(May 17, 1999)
• ISSN：1520-510X

文摘

Reaction of 1-methylcyclobutenedione with M(NO₃)₂·xH₂O [M = Co (1) and Ni (2)] produces isomorphouspolymeric complexes of formula M(CH₃C₄O₃)(NO₃)(H₂O)₄·2H₂O that crystallize in the monoclinic space groupP2₁/m (No. 11) with, for 1, a = 6.409(5) Å, b = 14.717(10) Å, c = 7.259(6) Å, ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 114.73(4)ges/entities/deg.gif">, and Z = 2 (themetal atom being positioned on a center of symmetry). In both cases, adjacent metal centers are bridged ges/entities/mgr.gif">-1,3 bythe 1-methylcyclobutenedione ligand, which exhibits distinct multiple bond localization. The positive charges onthe polymer chains are in each case balanced by nitrate ions. The metal atoms are six-coordinate with trans-oriented 1-methylcyclobutenedione ligands, and with four aqua ligands completing the coordination sphere.Reduction of the crystallization temperature, however, resulted, with Co, in the formation of the monomericcomplex Co(CH₃C₄O₃)₂·4H₂O (4). Isomorphous Mn (3), Cu (5), and Zn (6) analogues have also been synthesized.These crystallize in the monoclinic space group P2₁/n (No. 14) with, for 3, a = 8.8258(8) Å, b = 16.1527(14)Å, c = 9.9084(8) Å, ges/gifchars/beta2.gif" BORDER=0 ALIGN="middle"> = 93.230(7)ges/entities/deg.gif">, and Z = 4. The central metal atom in each of these compounds is six-coordinate, being bound to two trans-oriented 1-methylcyclobutenedione ligands and four aqua ligands, the formercoordinating in a monodentate fashion via the oxygen atom trans to the methyl substituent. In both the polymericand monomeric complexes extensive three-dimensional hydrogen-bonded networks are formed in the solid state.