Synthesis, structure and dielectric properties of two Cr(III)-tetrazole complexes Cr2(2-TPY)4(HO)2 and Cr(2-TPY)2(H2O)Cl

Electron Density and Dielectric Properties of Highly Porous MOFs: Binding and Mobility of Guest Molecules in Cu3(BTC)2 and Zn3(BTC)2

Two isostructural highly porous metal-organic frameworks, the well-known {Cu₃(BTC)₂} _n (BTC = 1,3,5-benzenetricarboxylate), often appointed with the name HKUST-1, and {Zn₃(BTC)₂} _n, have been investigated as models for the buildup of dielectric properties, differentiating the role of chemi- and physisorbed guest molecules and that of specific intraframework and framework-guest linkages. For this purpose, electron charge density analysis, impedance spectroscopy, density functional theory simulations, and atomic partitioning of the polarizabilities have been exploited. These analyses at different degrees of pores filling enabled one to observe structural and electronic changes induced by guest molecules, especially when chemisorbed. The electrostatic potential inside the pores allows one to describe the absorption mechanism and to estimate the polarization of guests induced by the framework. The dielectric constant shows very diverse frequency dependence and magnitude of real and imaginary components as a consequence of (I) capture of guest molecules in the pores during synthesis, (II) MOF activation, and (III) water absorption from the atmosphere after activation. Comparison with calculated static-dielectric constant and atomic polarizabilities of the material has allowed for evaluating building blocks' contribution to the overall property, paving the way for reverse crystal engineering of these species.

One pot synthesis of two cobalt(iii) Schiff base complexes with chelating pyridyltetrazolate and exploration of their bio-relevant catalytic activities

Two new cobalt(iii) tetrazolato complexes [Co(L¹)(PTZ)(N₃)] (1) and [Co(L²)(PTZ)(N₃)] (2) {where H₂L¹ = 2((3-(methylamino)propylimino)methyl)-6-methoxyphenol, H₂L² = 2((3-(dimethylamino)propylimino)methyl)-6-ethoxyphenol and HPTZ = 5-(2-pyridyl)tetrazole}, have been synthesized via in situ 1,3-dipolar cycloaddition reaction of 2-cyanopyridine and sodium azide in the presence of cobalt(ii) nitrate hexahydrate and respective Schiff bases in the open atmosphere. The structures of both complexes have been confirmed by single crystal X-ray diffraction studies. Features of noncovalent interactions in the solid state of both complexes have been studied by means of DFT and MEP calculations and characterized using Bader's theory of “atoms in molecules” (AIM). These complexes act as biomimetic catalysts promoting the aerobic oxidation of 3,5-di-tert-butylcatechol (3,5-DTBC) to the corresponding o-benzoquinone at room temperature. The reaction follows Michaelis–Menten enzymatic reaction kinetics with turnover numbers of ∼0.030 s⁻¹ in an acetonitrile–methanol (2 : 1) mixture. Both complexes are also reactive towards aerobic oxidation of o-aminophenol in acetonitrile–methanol (2 : 1) with turnover numbers ∼0.095 s⁻¹.

Two cobalt(iii) tetrazolato complexes have been synthesized and characterized. Noncovalent interactions have been analysed by DFT and MEP calculations and characterized using Bader's theory of AIM. Both complexes catalyze the aerial oxidation of 3,5-DTBC and OAPH.

Guest dependent dielectric properties of nickel(ii)-based supramolecular networks

Nickel-based supramolecular compounds exhibit interesting guest dependent dielectric behaviour and high thermal stability. This study serves as a motivation to expand our research to create both high and low-κmaterials with a judicious selection of guest molecules.

(E)-1-(5-Bromo-2-hy-droxy-phen-yl)-3-[4-(dimethyl-amino)-phen-yl]prop-2-en-1-one

In the title compound, C₁₇H₁₆BrNO₂, the two benzene rings make a dihedral angle of 7.4 (3)°; the hy­droxy group links to the carbonyl group via an intra­molecular O—H⋯O hydrogen bond. In the crystal, weak C—H⋯O inter­actions link the mol­ecules into a supra­molecular chain running along the c axis.