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Abstract

Three new coordination complexes [Zn(btec)0.5(L1)0.5(H2O)]n (1), [Ni(H2btec)(L1)(H2O)2]n (2), and {[Ni(btec)0.5(L2)(H2O)3]·2H2O}n (3) [H4btec = 1,2,4,5-benzenetetracarboxylic acid), L1 = N,N′-bis(3-pyridyl)adipamide, L2 = N,N′-bis(3-pyridyl)octanediamide] have been obtained under hydrothermal conditions. Single-crystal X-ray diffraction analysis has revealed that complex 1 has a layer structure based on [Zn(btec)0.5]n ribbons and the μ 2-bridging ligands L1. Complex 2 possesses a layered framework constructed by [Ni(H2btec)]n linear chains and [Ni(L1)]n wave-like chains. Complex 3 forms layers based on [Ni(L2)]n helical chains and μ 2-bridging L2 ligands, representing an interesting 4-fold interpenetrating 2D braided framework. The three different 2D frameworks exhibit 3,4-connected {4.62}2{42.62.82} topology for 1, 4-connected {44.62} topology for 2 and 3-connected {63} topology for 3. Their adjacent layers are further linked by hydrogen bonding interactions to generate 3D supramolecular structures. The differences in the nature of both the metal ions and the organic ligands lead to various coordination modes in the final structures. The photocatalytic activities and the fluorescence properties of complexes 13 were investigated.

Abstract

A detailed structural analysis has been carried out on the monohydrate of (E)-3-(2-hydroxy-5-methoxyphenyl)-1-(2-hydroxy-4-methoxyphenyl)prop-2-en-1-one, 1·H 2 O. The molecule, 1, shows a small deviation from planarity with an interplanar angle between the phenyl groups of 13.32(6)°. Classical O–H⋯O hydrogen bonds involving the water molecule play significant roles in determining the overall structure. The chalcone molecules in the structure are linked directly by C–H⋯O and off-set face-to-face π⋯π intermolecular interactions, as well as indirectly via interactions involving the water molecule in an elaborate spiralling hydrogen bonding scheme. The relative contributions of various intermolecular contacts were investigated using Hirshfeld surface analysis and the associated two dimensional fingerprint plots. Pairs of molecules were identified in the crystal structure using the Pixel method. The Pixel lattice energy calculations revealed that the dispersion and the Coulombic components were the major contributors to the packing stabilization. Comparisons were made between the structures of 1·H 2 O and hydroxylated (E)-3-(2-hydroxyphenyl)-1-phenyl-prop-2-en-1-one derivatives, in particular in regards to the participation of π interactions.

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Abstract

The rare earth oxoborates REB5O8(OH)2 (RE = Ho, Er, Tm) were synthesized in a Walker-type multianvil apparatus at a pressure of 2.5 GPa and a temperature of 673 K. Single-crystal X-ray diffraction data provided the basis for the structure solution and refinement. The compounds crystallize in the monoclinic space group C2 (no. 5) and are composed of a layer-like structure containing dreier and sechser rings of corner sharing [BO4]5− tetrahedra. The rare earth metal cations are coordinated between two adjacent sechser rings. Further characterization was performed utilizing IR spectroscopy.

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Abstract

Layer diffusion of 3,5-bis(4-pyridyl)-1H-1,2,4-triazole (BptH) in ethanol on an aqueous solution of cadmium sulfate leads to a novel three-dimensional cadmium sulfate-based inorganic-organic hybrid polymer (IOHP), CdSO4(H2O)(BptH)·1.5H2O (1). Its structure was determined by single-crystal X-ray diffraction (SCXRD), and further characterized by elemental analysis, powder X-ray diffraction (PXRD), infrared spectra (IR), and thermogravimetric (TG) analysis. IOHP 1 exhibits a novel 2-nodal 3,5-connected nanoporous structure formed by BptH ligands connecting 2D neutral inorganic cadmium sulfate layers. Water molecules reside in its nanoporous channels. The thermal stability and solid-state photoluminescence properties of the compound have also been investigated.

Abstract

A variety of 4-methoxysalicylates and related polyketide-type phenols are regioselectively prepared by formal [3+3] cyclocondensations of 1,3-bis(trimethylsilyloxy)-1,3-butadienes with 3-oxo-orthoesters. Cycloalkyl-substituted salicylates were prepared for the first time.

Abstract

The crystal and molecular structures of vardenafil (free, unprotonated base), vardenafil dihydrate and the hydrochloride salts, vardenafil monohydrochloride trihydrate and vardenafil dihydrochloride hexahydrate, were determined by single-crystal X-ray diffraction. The crystal structure of vardenafil monohydrochloride trihydrate is in good agreement with the published crystal structure obtained by powder diffraction using synchrotron radiation. This work shows that the crystal structure of anhydrous vardenafil free base is very similar to the crystal structure of sildenafil free base.

Abstract

Based on 2-(4-pyridyl)-terephthalate (H2pta) and oxalate ligands, two new lanthanide-containing coordination polymers (CPs), [Tb(pta)(C2O4)0.5(H2O)2)]·2H2O (1) and [Sm(pta)(C2O4)0.5(H2O)2)]·2H2O (2), have been synthesized under solvothermal conditions. The structures of both 1 and 2 have been determined by single-crystal X-ray diffraction. Infrared, elemental analysis, powder X-ray diffraction and thermogravimetric analysis data are also presented. The crystals of 1 and 2 exhibit isostructural layer-like networks, crystallizing in the triclinic space group P 1. The layers are further stabilized and associated into 3D architectures through hydrogen bonding. Remarkably, the CPs 1 and 2 exhibit excellent water stability and remarkable thermostability with thermal decomposition temperatures of more than 420 °C.

Abstract

Two new coordination polymers (CPs), [Zn(npba)2] (1) and [Cd(npba)2] (2), have been hydrothermally synthesized from Zn(NO3)2·6H2O/Cd(NO3)2·6H2O and 3-nitro-5-(pyridin-3-yl) benzoic acid (Hnpba). The products have been characterized by IR spectroscopy, elemental analysis, thermogravimetric analysis, and single-crystal X-ray diffraction. In CP 1, the four-coordinated Zn(II) centers are bridged by npba ligands to generate chains, which are connected through arene π–π stacking interactions to generate a layer structure. In CP 2, the six-coordinated Cd(II) centers are also bridged by npba ligands to form chains with similar connectivity. The photoluminescence properties of CPs 1 and 2 were studied.