Serkan Elçin

Synthesis and DFT calculation of a novel 5,17-di(2-antracenylazo)-25,27-di(ethoxycarbonylmethoxy)-26,28-dihydroxycalix[4]arene

In this study, 5,17-di(2-antracenylazo)-25,27-di(ethoxycarbonylmethoxy)-26,28-dihydroxycalix[4]arene has been synthesized from 2-aminoantracene and 25,27-dihydroxy-26,28-diethylacetate calix[4]arene. In order to identify the molecular structure and vibrational features of the prepared azocalix[4]arene, FT-IR and (1)H NMR spectral data have been used. FT-IR spectrum of the studied molecule is recorded in the region 4000-400 cm(-1). (1)H NMR spectrum is recorded for 0.1-0.2 M solutions in DMSO-d6 solution. The molecular geometry, infrared spectrum are calculated by the density functional method employing B3LYP level with different basis sets, including 6-31G(d) and LanL2DZ. The chemical shifts calculation for (1)H NMR of the title molecule is calculated by using by Gauge-Invariant Atomic Orbital method by utilizing the same basis sets. The total density of state, the partial density of state and the overlap population density of state diagram analysis are done via GaussSum 3.0 program. Frontier molecular orbital (HOMO-LUMO) and molecular electrostatic potential surface on the title molecule are carried out for various intramolecular interactions that are responsible for the stabilization of the molecule. The experimental results and theoretical calculations have been compared, and they are found to be in good agreement.

Synthesis and spectral characterization of azo dyes derived from calix[4]arene and their application in dyeing of fibers

In this study, the synthesis and characterization of two new upper rim functionalized azocalix[4]arene dyes have been obtained by coupling calix[4]arene with different diazo compounds of 3,5-dicarboxyaniline and 4-aminobenzene sulphon amide. The characterization of these dyes has been carried out by elemental analysis, FT-IR and 1H NMR spectra. The effect of varying dielectric constants of solvents on the absorption spectra of azocalix[4]arenes (1, 2, 3, 4) and commercial Isolan Gelb SGL (T) have been examined by UV–Vis spectrophotometer. These azocalix[4]arene dyes have also been used for dyeing textile fibers like cotton, wool, acetate, polyester and polyamide fibers. Their dyeing and fastness properties have also been discussed.

The synthesis and characterization of azocalix[4]arene based chemosensors and investigation of their properties

In the present study, azocalix[4]arenes were prepared by linking 4-methoxy, 4-methyl, 4-ethyl, 4-chloro, 4-bromo and 4-nitroaniline to calix[4]arene through a diazo-coupling reaction. A new family of azocalix[4]arene tetraester derivatives, (4a-f), have been prepared with the incorporation of ethyl ester units to azocalix[4]arene. Characterization of the synthesized azocalix[4]arenes was carried using elemental analyses, UV-vis, FT-IR and (1)H NMR spectroscopic techniques. The effect of varying pH levels and solvent types on the absorption ability of azocalix[n]arenes substituted with electron-donating and electron-withdrawing groups was examined. Thermal decomposition of azocalix[4]arene derivatives (4a-f) was investigated by means of thermogravimetry (TG), differential thermogravimetry (DTG) and differential thermal analysis (DTA) analyses. In conclusion of the examination of the extraction we found a selectivity characteristic of these compounds toward Ag(+), Hg(+) and Hg(2+) cations.

Synthesis and investigation of the properties of novel azocalix[4]arenes.

The azocalix[4]arenes molecules such as methylphenylazocalix[4]aren (MPcalix[4]) and methoxyphenylazocalix[4]aren (MOPcalix[4]) have been synthesized and characterized by experimental FT-IR and (1)H NMR spectral analyses. The fundamental vibrational transitions have been addressed by experimental FT-IR (4000-400 cm(-1)) technique and density functional theory (DFT) employing B3LYP level with the 6-31G(d) and 6-311G(d,p) basis sets. The (1)H NMR spectra of the studied compounds have been recorded in chloroform, and compared with computed data obtained by using gauge including atomic orbital (GIAO) method. Furthermore, thermodynamic properties (heat capacity, entropy, and enthalpy changes) and frontier molecular orbitals of the molecules in the ground state have been calculated by using the same method and basis sets. The non-linear optical properties such as the first order hyperpolarizability (β0), related properties (α0 and Δα) are also computed. Information about the charge density distribution of the molecules and its chemical reactivity has been studied by mapping molecular electrostatic potential surface (MEPs). The scaled vibrational frequency values have been compared with experimental FT-IR spectroscopic data. The correlations between the observed and calculated frequencies are in good agreement with each other as well as the correlation of NMR data. The linear polarizability and first hyperpolarizability of the studied molecules indicate that the compounds are a good candidate of nonlinear optical materials.

Synthesis and metal extraction studies of a novel chromogenic 5,17-bisazocalix(4)arenes

Three novel chromogenic cone azocalix[4]arenes 5a–c, which have cavity and the azo groups as metal-binding sites and as coloration sites were synthesized. They were studied by the liquid–liquid extraction of selected metal cations (Sr2+, Ag+, Hg+, Hg2+, Co2+, Ni2+, Cu2+, Zn2+, Cr3+, Al3+). Through examination of the extraction, a novel selectivity of these compounds toward Hg2+ cations has been determined. Besides, it has been also found that azocalix[4]arene 5c is highly sensitive to acid–base titration, which can be detected by the naked eye.

Thermal Behaviors of Bisazocalix[4]arene Derivatives

ABSTRACT In this article, calix[4]arene (4) was prepared by debutylation and hydrolyses reacting from 25,27-dibenzoyl-26,28-dihydroxy-5,11,17,23-tetra(tert-butyl)calix[4]arene (2). Azocalix[4]arenes (6a-c) were coupled by linking 4-methoxy, 4-ethyl, and 4-nitroaniline to calix[4]arene (4) through a diazo-coupling reaction. Thermal behavior characteristics and decomposition routes of 25,26,27,28-tetrahydroxy-11,23-di(tert-butyl)-5,17-(p-substitue phenyl)azocalix[4]arene (6a-c) were investigated in air atmosphere by means of thermogravimetry (TG), differential thermogravimetry (DTG), and differential thermal analysis (DTA) analyses. It was found that the decomposition of all compounds complete with two exothermic stages which corresponded to removal of substitute groups (methoxy-, ethyl-, nitro-) and second stage rest of structure decomposition.