New thorium(iv)-arsonates with a [Th8O13]6+ octanuclear core.

Abstract

Three new octanuclear Th(iv) arsonates, namely [Th(8)(O)(L)(6)(HL)(6)(H(2)O)(12)]·19.5H(2)O (1) (H(3)L = o-HO(3)S-C(6)H(4)-AsO(3)H(2)), [Th(8)(O)(L)(6)(HL)(6)(H(2)O)(10)]·17H(2)O (2) and [Th(8)(O)(L)(6)(HL)(6)(H(2)O)(5)]·0.5H(2)O (3), with o-sulfophenylarsonic acid as the bridging ligand, have been prepared under hydrothermal conditions. Each complex contains [Th(8)O(13)](6+) octanuclear cluster cores composed of two [Th(4)O(6)](4+) units bridged by a μ(2)-oxo anion. The structure of compound features a 0D highly symmetric polynuclear cluster encapsulating the octanuclear core of [Th(8)O(13)](6+) which is further decorated by six L(3-) and six HL(2-) ligands. Compound 2 features one-dimensional chains along the b-axis in which the neighboring clusters similar to are bridged by a pair of sulfophenylarsonate ligands via M-O-S-O-M bridges. Compound 3 with chiral P2(1)2(1)2(1) features two-dimensional cluster layers, in which each cluster connects with four neighbors via four M-O-S-O-M linkages. Compounds 2 and 3 display unusual broad green light emission bands at 523 nm (λ(ex) = 320 nm) and 517 nm (λ(ex) = 312 nm), respectively, which originate from the ligand-to-metal charge transfer (LMCT) transition.