Unexpected ligand substitutions in the cluster core {Re₆Se₈}: synthesis and structure of the novel cluster compound Cs₁₁(H₃O)[Re₆Se₄O₄Cl₆]₃·4H₂O

Abstract

The compound Cs11(H3O)[Re6Se4(O)4Cl6]3.4H2O containing a novel cluster core {Re6Se4(O)4} with ordered ligands, where the 4 positions of one face of a Se4(O)4 cube are occupied exclusively by Se atoms and 4 O atoms lie in the opposite face was synthesized via the interaction of solid Re6Se8Br2 with molten KOH.

Octahedral Hexahydroxo Rhenium Cluster Complexes [Re6Q8(OH)6]4–·(Q = S, Se): Synthesis, Structure, and Properties

“…This line is simulated by the Gaussian function with β 2 = 7.5 ± 0.1 kHz. [10] The ratio of the integral intensities of the two lines (I 2 /I 1 ) is R = 0.36 ± 0.02, which is very close to the composition of The most interesting feature of compound 4 is the oxidized state of the cluster core {Re 6 4-the electrochemi-cal potentials of a similar one-electron oxidation reaction are in decreasing order as S Ͼ Se Ͼ Te; thus for aqueous solutions E 1/2 are equal to 1.07, 0.82, and 0.53 V respectively for sulfur-, selenium-, and tellurium-containing complexes. [11] Thus, a selenium-containing cluster anion can be oxidized in aqueous solutions rather easily.…”

“…As seen from our experiments, the hexahydroxo complexes [Re 6 [6] In contrast to easy substitution of terminal OH groups, which is performed in solution, the substitution of inner µ 3 -Q ligands in the cluster core requires higher temperatures: for example, substitution of selenium with oxygen was carried out in molten KOH at 280°C. Finally, selenium-containing complexes can be converted easily in solution in oxidized form.…”

“…The structures of the cluster anions [Re 6 Q 8 (OH) 6 ] 4-, where Q = S (1) or Se (2) (Figure 1) 4-in 1. Displacement ellipsoids are drawn at the 50 % probability level.…”

“…[8] The structure of the oxidized cluster anion [Re 6 6 ]⋅8H 2 O. The wide-line 1 H NMR spectrum was recorded by sweeping the frequency in the neighborhood of 22.8 MHz using a home-made NMR spectrometer with signal accumulation.…”

“…A large number of articles have appeared within the last few years that have reported the preparation of molecular cluster complexes of the Re 6 Q 8 L 6 type (L = Cl, Br, I, or different organic ligands). [4] One way of preparing molecular cluster complexes is the excision reaction through interaction of polymeric solids such as Re 6 4 ]·12H 2 O, was described earlier. [7] Compounds 3 and 4 were obtained from aqueous solutions of compounds 1 and 2 by adding CsX and HX and further crystallization.…”