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

•The methylphenylazocalix[4]aren and methoxyphenylazocalix[4]aren have been synthesized.•Spectroscopic features of the compounds have been examined by FT-IR, 1H and 13C NMR techniques and DFT method.•Thermodynamic features, nonlinear optical properties and frontier molecular orbitals have been calculated.

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 1H 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 1H 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.

Graphical abstractThe azocalix[4]arenes molecules such as methylphenylazocalix[4]aren (MPcalix[4] (a)) and methoxyphenylazocalix[4]aren (MOPcalix[4] (b)) have been synthesized and characterized by using the experimental techniques and the quantum chemical computational method such as DFT employing B3LYP level with the 6-31G(d) and 6-311G(d,p) basis sets.Figure optionsDownload full-size imageDownload as PowerPoint slide