Cation effect on the structure of tetrahedral rhenium arsenide cyano clusters
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Cation effect on the structure of tetrahedral rhenium arsenide cyano clusters A. S. Pronin, A. I. Smolentsev, and Y. V. Mironov Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3 prosp. Akad. Lavrentieva, 630090 Novosibirsk, Russian Federation. Fax: +7 (383) 330 9489. E-mail: [email protected]; [email protected] New cyanometallate cluster complexes of the composition Na8[{Re4As1.5(AsO)2.5}(CN)12]• •20.5H2O (1) and Cs7K[{Re4As2(AsO)2}(CN)12]•12H2O (2) were synthesized by high-temperature reactions of ReI3 with As and MCN (M is Na or Cs) followed by the recrystallization of the soluble products from water. The crystal structures of the synthesized compounds were studied by X-ray diffraction. An increase in the ionic radius of the cation leads to an increase in the symmetry of the crystal lattice from monoclinic to tetragonal.
Key words: rhenium, arsenic, cyanide, crystal structure, tetrahedral cluster complexes.
Transition metal cluster complexes are a unique class of inorganic compounds exhibiting excellent physical and chemical properties due to their great structural diversity.1—4 Cluster compounds with inner-sphere chalcogenide ligands are the most typical examples of so-called high-valent clusters generally formed by Group 5—7 d-block metals. In particular, hundreds of rhenium chalcogenide compounds with cluster cores consisting of different numbers of metal atoms, from two to twelve, were synthesized and comprehensively characterized.5—9 Tetranuclear rhenium cluster complexes [{Re4Q4}(CN)12]4– (Q is S, Se, Te) bearing cubane cluster cores, which can be represented as two interpenetrating Re4 and Q4 tetrahedra, have been extensively studied in recent years.10—12 They are successfully used as building blocks for the synthesis of coordination polymers with d- and f-metal ions due to rigid geometry and the presence of bidentate terminal CN groups.12—14 The structural, physical, and chemical properties of cluster compounds strongly depend on the nature of ligands coordinated to metal atoms. The chalcogenide ions S2–, Se2–, and Te2– are the most commonly encountered inner-sphere ligands in the cluster cores {Re4X4}. However, we demonstrated that Group 15 elements and their oxygen-containing derivatives can also serve as μ3-bridging ligands. Thus, the following As-containing complexes were synthesized: K8[{Re4As2(AsO)2}(CN)12]•12H2O, K8[{Re4(AsO)4}(CN)12]•13H2O,15 K7[{Re4As3S}(CN)12]• •10H2O, K7[{Re4As3Se}(CN)12]•9.5H2O, K6[{Re4As2S2}(CN) 12]•3.5H 2O, 16 and K 7[{Re 4(AsO) 2.25As 0.75Te}(CN)12]•9H2O.17 As part of our continuing research, here we studied the reaction of ReI3 with As and excess MCN (M is Na or Cs) at 550 °C. Two new water-soluble highly charged tetrahedral clusters, Na8[{Re4As1.5(AsO)2.5}(CN)12]•20.5H2O (1) and Cs7K[{Re4As2(AsO)2}(CN)12]•
•12H2O (2), were isolated. The composition and structures of these compounds were determined by X-ray diffraction. Experimental Materials and methods. The compounds ReI3 (see Ref. 18) and Cs4[Fe(CN)6] (see Ref. 19) wer
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