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Inorganica Chimica Acta 363 (2010) 2686–2691

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Inorganica Chimica Acta
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A new hexanuclear rhenium cluster complex with six terminal acetate ligands: Synthesis, structure, and properties of K4[Re6S8(CH3COO)6]Á8H2O
Konstantin A. Brylev a,*, Yuri V. Mironov a, Vladimir E. Fedorov a, Sung-Jin Kimb,**, Hans-Jürgen Pietzsch c, Holger Stephan c, Akitaka Ito d, Noboru Kitamura d
a

Nikolaev Institute of Inorganic Chemistry, Siberian Branch of the Russian Academy of Sciences, 3 Acad. Lavrentiev Prosp., 630090 Novosibirsk, Russia Department of Chemistry and Nano Science, Ewha Womans University, 11-1 Daehyun-dong, Seodaemun-gu, 120-750 Seoul, Republic of Korea Institut für Radiopharmazie,Forschungszentrum Dresden-Rossendorf, PF 510119, 01314 Dresden, Germany d Department of Chemistry, Graduate School of Science, Hokkaido University, 060-0810 Sapporo, Japan
b c

a r t i c l e

i n f o

a b s t r a c t
A room-temperature reaction between [Re6S8(OH)6]4À and acetic acid in an aqueous solution resulted in the substitution of all terminal hydroxo groups by acetate ligands, affordinga new hexanuclear anionic rhenium cluster complex [Re6S8(CH3COO)6]4À. The complex was isolated as a potassium salt with the composition of K4[Re6S8(CH3COO)6]Á8H2O (1) and characterized by X-ray single-crystal diffraction and elemental analyses, IR, 1H NMR, UV–Vis, and luminescence spectroscopies. Ó 2010 Elsevier B.V. All rights reserved.

Article history: Received 25 December 2009 Received inrevised form 14 April 2010 Accepted 25 April 2010 Available online 5 May 2010 Keywords: Synthesis Cluster compounds Rhenium Carboxylate ligands Luminescence

1. Introduction A large variety of bi-, tri-, and tetra-nuclear cluster complexes of transition metals (in particular, 4d and 5d metals of 6, 7, and 8 groups) with acetate ligands have been well-known for a long time [1–18]. Until recently,however, only few hexanuclear clusters with any carboxylate ligands have been reported, namely, molybdenum and tungsten acetate complexes [M6Cl8(CH3COO)6]2À (M = Mo, W) [19,20] were structurally characterized and formation of the molybdenum trifluoroacetato complexes [Mo6L8(CF3COO)6]2À (L = Cl, Br) [21,22] was confirmed by IR spectroscopy and mass spectrometry. Very recently, we reported thesynthesis and properties of the formate complex [Re6S8(HCOO)6]4À [23]. Nevertheless, no further example of any structurally characterized hexanuclear chalcogenide cluster complexes with six terminal carboxylate ligands has been hitherto known. In this contribution, we report the synthesis, crystal structure, and chemical/physical properties of the potassium salt of a new octahedral anionic rheniumcluster complex [Re6S8(CH3COO)6]4À.

2. Experimental 2.1. Materials and physical methods K4[Re6S8(OH)6]Á8H2O was synthesized as reported previously [24]. All other reagents were used as purchased. Elemental analysis was performed using a MICRO CORDER JM10 and Dionex DX-500. Energy dispersive X-ray spectroscopy (EDS) was performed on an EDAX equipped (JEOL EX-23000BU) JEOL JSM6700F field emissionscanning electron microscope. Infrared spectrum of KBr pellet sample was recorded on a Scimitar FTS 2000c spectrometer in the range of 400–4000 cmÀ1. 1H NMR spectroscopy was conducted by using a JEOL JME-EX270 spectrometer. UV–Vis spectra were recorded on a Hitachi U-3300 spectrophotometer. For emission measurements the solution and solid samples were excited by 355-nm laser pulses (6 ns duration, LOTISTII, LS-2137/3). The solution was deaerated by purging an Ar-gas stream over 20 min and then sealed. Corrected emission spectra were recorded on a multichannel photodetector (Hamamatsu Photonics, PMA-11). For emission decay measurement, the emission was analyzed by a streak-scope system (Hamamatsu Photonics, C4334 and C5094). The relative emission quantum yield (Uem) of K4[Re6S8(CH3COO)6]Á 8H2O...