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.

Synthesis and Crystal Structure Characterization of Thorium Trimesate Coordination Polymers

“…This study confirms the trend of thorium to limit the condensation process and to generate relatively small inorganic clusters, − whereas uranium or plutonium can lead to the production of giant polycondensed organization counting up to 38 metallic centers in molecular assemblies. ,− This limitation is explained well by a relative low Lewis acidity, compared to the other tetravalent actinides of this series.…”

Monomeric and Trimeric Thorium Chlorides Isolated from Acidic Aqueous Solution

“…Thermodynamic studies do not predict the Th 3 structural unit to exist in noncomplexing media over a pH range of 1–14 . Instead, only Th 4+ , [Th­(OH) x ] y+ , [Th 2 (OH) 2 ] 6+ , [Th 4 (OH) 8 ] 8+ , and [Th 6 (OH) 15 ] 9+ are proposed. , Monomers, dimers, tetramers, hexamers, octamers, and even a decamer are established in the solid-state for thorium. − ,,,,− ,− Thus, the isolation of 2 as a trimeric unit from aqueous solution illustrates the novelty of this complex. Of the previously reported trimers, Kadish et al established the persistence of the trimeric unit with a chelating porphyrin ligand in solution by NMR; Li and co-workers observed their Th MOF in aqueous solutions through hydrolytic stability measurements. , Other reports did not identify the trimer in solution.…”

“…It is the largest and least Lewis acidic of the tetravalent metal ions, yet exhibits fairly extensive hydrolysis and condensation chemistry, which has historically complicated interpretation of solution based studies and resulted in large discrepancies in thermodynamic literature . Over 1000 Th solid state structures have been reported in the Cambridge Structural Database and of those, approximately 50 arise from hydrolysis and condensation to include dimeric, − trimeric, − tetrameric, hexameric, − octameric, , and decameric units, with the hexameric [Th 6 (OH) 4 O 4 ] 12+ species being the most prevalent. Yet the [Rn]­5f 0 electron configuration of Th has limited the number of spectroscopic handles available to assess the correlation between these solid state structural units and those present in solution, although it promotes ease when performing electronic structure calculations.…”

Structural properties of ultra-small thorium and uranium dioxide nanoparticles embedded in a covalent organic framework

“…Recent developments in inorganic synthesis and increased understanding of environmental colloids have provided new opportunities to explore the chemistry of actinides at the nanoscale. [44][45][46][47][48][49][50][51][52][53] Molecular cluster chemistry of the tetravalent actinides, exemplied by a class of actinide oxo hydroxide clusters, [54][55][56][57][58][59][60][61][62][63][64][65][66] has provided valuable structural insight into the growth of bulk AnO 2 (An ¼ actinide) by the controlled hydrolysis of molecular precursors. Synthetic techniques for actinide nanoparticles have also been reported that include direct decomposition of actinide precursors into nanoparticles in aqueous solutions by irradiation, 2,8,67 sonolysis 68,69 or via hydrothermal approaches.…”