Volume 78, Issue 7-8

By utilizing the well-known selective xanthine oxidase inhibitor topiroxostat, a new zinc(II) complex Zn(L) 2 (H 2 O) 2 ( 1 ) [HL = 4-(3-(pyridine-4-yl)-1 H -1,2,4-triazol-5-yl)picolinic acid] has been hydrothermally synthesized, involving in-situ ligand formation upon hydrolysis of topiroxostat. The complex has been structurally characterized by elemental analysis, IR spectroscopy, thermogravimetric analysis, powder X-ray diffraction, and single-crystal X-ray diffraction. X-ray structural analysis revealed that complex 1 is a N,O-chelating mononuclear Zn(II) complex. Complex 1  shows good thermal stability and exhibits photoluminescence in the solid state at room temperature. Moreover, complex 1 has been shown to be effective in the solvent-free ring-opening polymerization of ε -caprolactone without any co-catalyst or initiator.

This article focuses on the synthesis of nickel borides in different molten-salt systems (eutectic NaCl/KCl and borax) at elevated temperatures. The differences in the thermodynamic stability of different nickel borides and the formation of NiB in an eutectic halite-sylvine mixture at T  = 950 °C with different nickel-containing starting materials (NiO, Ni) has been elucidated. The results are compared to theoretical data calculated by the Calphad method. The results of the analysis shows that NiB 2 , if it exists, may only form a metastable phase.

The ternary silicide ErNi 4.04 Si 0.96 was synthesized by arc-melting of stoichiometric quantities of the elements, and its crystal structure has been determined using single-crystal X-ray diffraction data. The compound crystallizes in the CaCu 5 structure type: hexagonal space group P 6/ mmm , Pearson code hP 6, Z  = 1; a  = 4.874(3), c  = 3.959(2) Å, V  = 81.5(1) Å 3 ; R 1 = 0.0239, w R 2 = 0.0503, for 67 independent reflections with I  > 2 σ ( I ) and eight variables. The erbium and nickel atoms occupy the crystallographic positions 1 a and 2 c , respectively. The position 3 g is occupied by a mixture of Ni and Si atoms. The structure of this silicide represents a packing of bipyramidal units built from nickel and Ni/Si atoms.

The N-heterocyclic stannylene [Fe{( η 5 -C 5 H 4 )NC 6 H 3 -2,6- i Pr 2 } 2 Sn] ( 1 ) has been synthesised from SnCl 2 and the lithium amide [Fe{( η 5 -C 5 H 4 )NC 6 H 3 -2,6- i Pr 2 } 2 Li 2 ]. Compound 1 is inert towards H 2 , CO, CO 2 , and MeI under ambient conditions. Immediate hydrolysis and ammonolysis was observed with H 2 O and NH 3 , respectively. While oxidation reactions of 1 with chalcogens (O 2 , S 8 , Se 8 ) afforded only intractable material, the reaction with Ph 2 Se 2 cleanly furnished [Fe{( η 5 -C 5 H 4 )NC 6 H 3 -2,6- i Pr 2 } 2 Sn(SePh) 2 ] ( 2 ). Compounds 1 and 2 have been structurally characterised by single-crystal X-ray diffraction. Compound 2 exhibits an intramolecular CH⋯Se contact compatible with a weak hydrogen bond.

The solid solutions LaNiIn 1– x Sn x and CeNiIn 1– x Sn x were studied by means of X-ray powder diffraction and EDX analyses in the full concentration range for samples annealed at T = 870 K. The limited solubility of the fourth component in the starting compounds with equiatomic composition, and the limits and the unit cell parameters of the solid solutions have been determined. The crystal structure of CeNiIn 0.57 Sn 0.43 was refined from single-crystal X-ray diffraction data: ZrNiAl-type structure; hexagonal space group P 6 ‾ $\overline{6}$ 2 m , a = 0.74213(10), c = 0.40825(8) nm, R 1 = 0.0155, w R 2 = 0.0303, 282 independent hkl reflections and 15 refined parameters. The existence ranges within the solid solutions are discussed.

A coordination polymer Cu(3-CP) 3 (NO 3 ) ( 1 ) was synthesized from copper(II) sulfate and 3-cyanopyridine (3-CP) with in-situ reduction by hydroxylamine sulfate via the solvent evaporation method at room temperature, and structurally characterized by single-crystal X-ray diffraction and elemental analysis. Complex 1 exhibits a structure formed by cationic [Cu(3-CP) 3 ] n n + chains and NO 3 − anions with abundant supramolecular interactions. Solid-state photoluminescence experiments show that complex 1 exhibits a relatively strong blue-green emission, and its possible emission mechanism was investigated in detail based on theoretical calculations.

Selective oxidation of benzene to phenol is done in the liquid phase over copper-substituted LaFeO 3 perovskite oxides as catalyst using H 2 O 2 as oxidant under mild reaction conditions. Among the different copper-substituted perovskite catalysts synthesized by a novel solution combustion method, the LaFe 0.90 Cu 0.10 O 3 catalyst showed highest activity (∼56 % with 100 % selectivity of phenol) and also gives better activity than the corresponding catalyst made via incipient wetness impregnation of 10 at % Cu over combustion-synthesized LaFeO 3 . XRD analysis revealed formation of the perovskite phase as the predominant one. The greater activity of the combustion-made catalyst has been attributed to the occurrence of a peculiar poorly-defined structure having substitutional copper ion sites on top of the LaFeO 3 particle as observed in HRTEM analysis. Much less occurrence of this phase in the impregnated catalyst, where copper is primarily present as dispersed CuO crystallites, explains its comparatively lower activity in the oxidation reaction. The effect of catalyst recycling shows negligible change of activity for the combustion-made catalyst whereas the analogous impregnated catalyst shows considerable decrease in activity in recycling. This explained to be due to the essentially intact poorly-defined structure in the former and leaching of the finely dispersed CuO crystallites from the latter catalyst during cycling.

A metal-organic framework (MOF) {[Cd(EtOIPA)(bpp)(H 2 O)]·2H 2 O} n ( 1 ) has been synthesized under basic hydrothermal conditions by using of 5-ethoxyisophthalic acid (EtOIPAH 2 ) and 1,3-bis(4-pyridyl)propane (bpp) as reagents for cadmium nitrate. Compound 1 was characterized by elemental analysis, single-crystal X-ray diffraction and UV/Vis spectroscopy. In 1 , the bpp ligands extend the EtOIPA-Cd chains along the ab plane to form a 2-fold 3D interpenetrating network. Compound 1 emits blue phosphorescence at room temperature with a long lifetime of 4.2 ms.