Facile self-assembly synthesis and characterization of diselenophosphinato octanuclear CuI clusters inscribed in a twelve-vertex selenium polyhedron

Abstract

The self-assembly synthesis and structural characterization of the first representatives of diselenophosphinato octanuclear CuI clusters inscribed in a twelve-vertex selenium polyhedron are reported herein. An extremely facile (room temp., THF, 1 h) reaction between [Cu(MeCN) 4](PF6) and ammonium diselenophosphinate, [NH 4][Se2P(CH2CH2Ph)2] (1), in a 4:3 molar ratio resulted in the self-assembly of copper(I) cluster [Cu 8{Se2P(CH2CH2Ph)2} 6](PF6)2 (2) containing an empty Cu8 cubic core. Meanwhile, when the reactants were allowed to react in the presence of appropriate anion sources, new anion-centered octanuclear copper(I) clusters self-assembled. Thus, the interaction of [Cu(MeCN)4](PF6) with diselenophosphinate 1 in the presence of [Cs4(P 2Se6)(H2O)4] as Se2- source under the same conditions gave neutral selenide-centered octanuclear copper cluster [Cu8(Se){Se2P(CH2CH 2Ph)2}6] (3). Three novel anion-centered Cu8 clusters of general formula [Cu8(X){Se 2P(CH2CH2Ph)2}6](PF 6) [X = H (4), Cl (5), or Br (6)] were synthesized in high yields by self-assembly reactions between Cu[(MeCN)4]PF6 and diselenophosphinate 1 in the presence of the corresponding anion sources (NaBH4 for H-, Bu4NCl for Cl-, and [Bu4N]Br forBr-) under exceptionally mild conditions (room temp., THF, 4 h). X-ray diffraction studies showed structures 3, 5, and 6 to consist of an anion-centered cubic Cu8 core capped by six diselenophosphinate ligands, whereas cluster 4 contains a tetracapped tetrahedral Cu8 cage with an interstitial hydride anion. In all the clusters, each of the six diselenophosphinate ligands exhibits a tetrametallic tetraconnective (μ2,μ2) coordination pattern. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.