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• 作者：Mikhail Maliarik ; Jeffrey K. Nagle ; Andrey Ilyukhin ; Elena Murashova ; Já ; nos Mink ; Mikhail Skripkin ; Julius Glaser ; Margit Kovacs ; Attila Horvá ; th
• 刊名：Inorganic Chemistry
• 出版年：2007
• 出版时间：May 28, 2007
• 年：2007
• 卷：46
• 期：11
• 页码：4642 - 4653
• 全文大小：131K
• 年卷期：v.46,no.11(May 28, 2007)
• ISSN：1520-510X

文摘

The new crystalline compounds Tl₂Ni(CN)₄ and Tl₂Pd(CN)₄ were synthesized by several procedures. The structuresof the compounds were determined by single-crystal X-ray diffraction. The compounds are isostructural with thepreviously reported platinum analogue, Tl₂Pt(CN)₄. A new synthetic route to the latter compound is also suggested.In contrast to the usual infinite columnar stacking of [M(CN)₄]^2- ions with short intrachain M-M separations,characteristic of salts of tetracyanometalates of Ni^II, Pd^II, and Pt^II, the structure of the thallium compounds isnoncolumnar with the two Tl^I ions occupying axial vertices of a distorted pseudo-octahedron of the transition metal,[MTl₂C₄]. The Tl-M distances in the compounds are 3.0560(6), 3.1733(7), and 3.140(1) Å for Ni^II, Pd^II, and Pt^II,respectively. The short Tl-Ni distance in Tl₂Ni(CN)₄ is the first example of metal-metal bonding between these twometals. The strength of the metal-metal bonds in this series of compounds was assessed by means of vibrationalspectroscopy. Rigorous calculations, performed on the molecules in D_4h point group symmetry, provide force constantsfor the Tl-M stretching vibration constants of 146.2, 139.6, and 156.2 N/m for the Ni^II, Pd^II, and Pt^II compounds,respectively, showing the strongest metal-metal bonding in the case of the Tl-Pt compound. Amsterdam density-functional calculations for isolated Tl₂M(CN)₄ molecules give Tl-M geometry-optimized distances of 2.67, 2.80, and2.84 Å for M = Ni^II, Pd^II, and Pt^II, respectively. These distances are all substantially shorter than the experimentalvalues, most likely because of intermolecular Tl-N interactions in the solid compounds. Time-dependent density-functional theory calculations reveal a low-energy, allowed transition in all three compounds that involves excitationfrom an a_1g orbital of mixed Tl 6p_z-M nd_z² character to an a_2u orbital of dominant Tl 6p_z character.