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A three-dimensional terbium(III) coordination polymer of formula [Tb(bttb) 0.5 (2,5-pzdc) 0.5 ] n (1) [H 4 bttb = 1,2,4,5-tetrakis(4'-carboxyphenyl)benzene and H 2 -2,5-pzdc = 2,5-pyrazinedicarboxylic acid] was obtained under hydrothermal conditions. The bttb 4- tetraanion in 1 adopts the bridging and chelating-bridging pseudo-oxo coordination modes while the 2,5-pzdc 2- dianion exhibits a rather unusual bis-bidentate bridging pseudo-oxo coordination mode, both ligands being responsible for the stiffness of the resulting 3D structure. Solid-state photoluminescent measurements illustrate that 1 exhibits remarkable green luminescence emission, the most intense band occurring in the region of 550 nm ( 5 D 4 → 7 F 5 ) with lifetimes at the millisecond scale. Thermometric performances of 1 reveal a maximum relative sensitivity ( S m ) of 0.76% K -1 at 295 K (δ T = 0.05 K), constituting a Tb III ratiometric solid luminescent thermometer over the physiological temperature range. Variable-temperature static (dc) magnetic susceptibility measurements for 1 in the temperature range 2.0-300 K show the expected behavior for the depopulation of the splitted m J levels of the 7 F 7 ground state of the magnetically anisotropic terbium(III) ion plus a weak antiferromagnetic interaction through the carboxylate bridges. No significant out-of-phase magnetic susceptibility signals were observed for 1 in the temperature range 2.0-10.0 K, either in the absence or presence of a static dc magnetic field.

Herein, we describe the synthesis, crystal structure, and electronic properties of {[K 2 (dmso)(H 2 O) 5 ][Ni 2 (H 2 mpba) 3 ]·dmso·2H 2 O} n ( 1 ) and [Ni(H 2 O) 6 ][Ni 2 (H 2 mpba) 3 ]·3CH 3 OH·4H 2 O ( 2 ) [dmso = dimethyl sulfoxide; CH 3 OH = methanol; and H 4 mpba = 1,3-phenylenebis(oxamic acid)] bearing the [Ni 2 (H 2 mpba) 3 ] 2- helicate, hereafter referred to as {Ni II 2 }. SHAPE software calculations indicate that the coordination geometry of all the Ni II atoms in 1 and 2 is a distorted octahedron (O h ) whereas the coordination environments for K1 and K2 atoms in 1 are Snub disphenoid J84 (D 2d ) and distorted octahedron (O h ), respectively. The {Ni II 2 } helicate in 1 is connected by K + counter cations yielding a 2D coordination network with sql topology. In contrast to 1 , the electroneutrality of the triple-stranded [Ni 2 (H 2 mpba) 3 ] 2- dinuclear motif in 2 is achieved by a [Ni(H 2 O) 6 ] 2+ complex cation, where the three neighboring {Ni II 2 } units interact in a supramolecular fashion through four R 2 2 (10) homosynthons yielding a 2D array. Voltammetric measurements reveal that both compounds are redox active (with the Ni II /Ni I pair being mediated by OH - ions) but with differences in formal potentials that reflect changes in the energy levels of molecular orbitals. The Ni II ions from the helicate and the counter-ion (complex cation) in 2 can be reversibly reduced, resulting in the highest faradaic current intensities. The redox reactions in 1 also occur in an alkaline medium but at higher formal potentials. The connection of the helicate with the K + counter cation has an impact on the energy levels of the molecular orbitals; this experimental behavior was further supported by X-ray absorption near-edge spectroscopy (XANES) experiments and computational calculations.

Shrimp is one of the most traded fishery products in the world. The shrimp-farming water ionic composition is fundamental to the growth and survival of these specimens. Therefore, this study is aimed to develop a method for the simultaneous separation of Cl - , SO 4 2- , NO 3 - , NO 2 - , and HCO 3 - in this sample by capillary zone electrophoresis with UV indirect detection, without any prior sample treatment, besides dilution. The background electrolyte (BGE) was composed of CrO 4 2- (60 mmol L -1 ), cetyltrimethylammonium bromide (CTAB, 2.5 mmol L -1 ), acetonitrile (0.875% (v/v)), and methanol (2.625% (v/v)). The mixture design optimized the BGE composition. Acetonitrile and methanol changed the degree of solvation of the anions, which decreased the radius, a phenomenon proven by calculating the radius of anions in all the conditions of the mixture design. The optimized and validated method allowed the simultaneous determination of the five above-mentioned anions in 10 min.