Multifunctional Uranyl Hybrid Materials: Structural Diversities as a Function of pH, Luminescence with Potential Nitrobenzene Sensing, and Photoelectric Behavior as p-type Semiconductors

Abstract

A series of uranyl-organic frameworks (UOFs), {[(UO2)2(H2TTHA)(H2O)]·4,4'-bipy·2H2O}n (1), {[(UO2)3(TTHA)(H2O)3]}n (2), and {[(UO2)5(TTHA) (HTTHA)(H2O)3]·H3O}n (3), have been obtained by the hydrothermal reaction of uranyl acetate with a flexible hexapodal ligand (1,3,5-triazine-2,4,6-triamine hexaacetic acid, H6TTHA). These compounds exhibited three distinct 3D self-assembly architectures as a function of pH by single-crystal structural analysis, although the used ligand was the same in each reaction. Surprisingly, all of the coordination modes of the H6TTHA ligand in this work are first discovered. Furthermore, the photoluminescent results showed that these compounds displayed high-sensitivity luminescent sensing functions for nitrobenzene. Additionally, the surface photovoltage spectroscopy and electric-field-induced surface photovoltage spectroscopy showed that compounds 1-3 could behave as p-type semiconductors.

Hydrothermal synthesis, crystal structure and properties of a two-dimensional uranyl coordination polymer based on a flexible zwitterionic ligand

“…BpmbÁ2HCl displays a broad emission peak around 478 nm, which belongs to atransition. In contrast, compound (1) exhibits the prototypical five-finger peaks [461 (m), 491 (m), 511 (s), 535 (m) and 560 (w) nm] of the uranyl species (Mei et al, 2015); these characteristic emissions generally correspond to the electronic and vibronic transitions S11-S00 and S10-S0v (v = 0-4) (Song et al, 2015;Liu et al, 2017). Emission spectra of (a) BpmbÁ2HCl ( ex = 300 nm) and (b) coordination polymer (1) ( ex = 340 nm).…”

Rational Design of a Uranyl Metal–Organic Framework for the Capture and Colorimetric Detection of Organic Dyes

“…[1] Uranyl-containing frameworks garner much attention in this regardo wing to their rich coordination chemistry and inherentl uminescence properties,t he latter having been explored for use in X-ray scintillation [2] and variousv isible and UV-light mediatedp rocesses, such as photocatalysis [3] and molecular sensing. [4] The crystal chemistry of uranyl-containing coordinationp olymers and frameworks is therefore well-developed, but despitethis, the rational design of three-dimensional MOFs remains ac hallenge because of the linearn ature of the uranyl cation. [5] The two axial oxo ligands(often) do not participate in additional bonding interactions and furtherl igand coordinationi sr estricted to the equatorialp lane.T his planar coordinationm ode gives rise to square, pentagonal, and hexago-nal bipyramidal building units that tend to assemble into 1and 2D dimensionals tructure types.…”

Multifunctional Inorganic‐Organic U‐MOF Materials with Nitrogen Heterocyclic Carboxylate: Synthesis, Structure and Properties

“…Up to now, some flexible and semirigid symmetrical polycarboxylic ligands have been introduced into syntheses of uranium(VI) MOF complexes with unusual topologies and interesting properties, for example, [UO 2 (L 2 )(MeOH)] (L=N,N'-di(5-bromosalicylidene)-o-phenylenediaminate ligand), [38] [UO 2 (salfen-tBu 2 )], [39] (UO 2 ) 2 (2,2'-bpy)-(CH 3 CO 2 )(O)(OH) (2,2'-bpy = 2,2-bipyridine), [40] (UO 2 ) 3 (H 2 O) 2 L 2 (L 2 = Hexakis [4-(carboxyphenyl) oxamethyl]-3-oxapentane). [41] Until now, a series of UOFs (uranium-organic frameworks) was synthesized, such as [UO 2 (H 2 O) 5 ][UO 2 (L)] 2 ⋅2H 2 O⋅3THF (L = all-cis-1,3,5-Cyclohexanetricarboxylic acid, THF = tetrahydrofuran), [42] [(CH 3 ) 2 NH 2 ][UO 2 (TATAB)]⋅2DMF⋅4H 2 O (H 3 TATAB = 4, 4', 4''-striazine-1, 3, 5-triyltri-p-aminobenzoate, DMF = N, N-Dimethylformamide), [43] [(UO 2 ) 5 (TTHA) (HTTHA)(H 2 O) 3 ]⋅H 3 O (H 6 TTHA = 1, 3, 5-triazine-2, 4, 6-triamine hexaacetic acid) [44] and so on.…”