Crystal structure and properties of the precursor [Ni(H<sub>2sub>O)<sub>6sub>](HTBA)<sub>2sub>路2袧<sub>2sub>袨 and the complexes M(HTBA)<sub>2sub>(H<sub>2sub>O)<sub>2sub> (M = Ni, Co, Fe)

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• 作者：Nicolay N. Golovnev ; Maxim S. Molokeev ; Sergey N. Vereshchagin ; Victor V. Atuchin ; Maxim Y. Sidorenko ; Michael S. Dmitrushkov
• 关键词：2-Thiobarbiturate complexes ; 3D elements ; Synthesis ; Structure ; IR spectra ; Thermal stability
• 刊名：Polyhedron
• 出版年：9 March, 2014
• 年：2014
• 卷：70
• 期：Complete
• 页码：71-76
• 全文大小：900 K

文摘

Four new compounds, the discrete complex [Ni(H<sub>2sub>O)<sub>6sub>](HTBA)<sub>2sub><sup>.sup>2袧<sub>2sub>袨 (<strong class="boldFont">1strong>) and the polymers Ni(H<sub>2sub>O)<sub>2sub>(HTBA-O,S)<sub>2sub> (<strong class="boldFont">2strong>), Co(H<sub>2sub>O)<sub>2sub>(HTBA-O,S)<sub>2sub> (<strong class="boldFont">3strong>) and Fe(H<sub>2sub>O)<sub>2sub>(HTBA-O,S)<sub>2sub> (<strong class="boldFont">4strong>) (H<sub>2sub>TBA = 2-thiobarbituric acid, C<sub>4sub>H<sub>4sub>N<sub>2sub>O<sub>2sub>S), have been synthesized and structurally characterized. The structure of <strong class="boldFont">1strong> has been solved by X-ray single-crystal diffraction analysis. The Ni(H<sub>2sub>O)<sub>6sub><sup>2+sup> cation has an almost ideal octahedral geometry, and there is no coordination of Ni(II) by HTBA<sup>鈭?/sup> in <strong class="boldFont">1strong>. Complexes <strong class="boldFont">2strong>-<strong class="boldFont">4strong> have been characterized by powder XRD, TG-DSC and FT-IR. In the isostructural polymers <strong class="boldFont">2strong>-<strong class="boldFont">4strong>, the metals are six-coordinated, and the octahedrons are connected by 渭<sub>2sub>-O,S bridging ligands. Each of the M(II) ions is surrounded by two water molecules, two O-coordinated HTBA<sup>鈭?/sup> ions and two S-coordinated HTBA<sup>鈭?/sup> ions, with all pairs being in trans-positions. Hydrogen bonding and 蟺-蟺 interactions play an important role for the construction of the supramolecular 3D structures of <strong class="boldFont">2strong>-<strong class="boldFont">4strong>. The formation of the complexes has been evidenced by infrared spectroscopy. The thermal decomposition of <strong class="boldFont">2strong>-<strong class="boldFont">4strong> under oxidative conditions has been divided into three major stages: dehydration, oxidative degradation of the organic moiety and transformation of the inorganic residue.