Ab initio studies of NMR chemical shifts for calix[4]arene and its derivatives

Abstract

Ab initio calculations are performed for the calix[4]arene (1) and its derivatives (2 and 3), in this study. 1 H and 13 C NMR measured spectral data given in our previous work are used to elucidate the structures of the prepared calix[4]arenes (1-3). The molecular geometry and chemical shift are calculated by using ab initio calculations based on the Hartree-Fock (HF) and the density functional theory (DFT) in the ground state. The results obtained from both methods are in agreement with the experimental results. The results of molecular geometry and chemical shifts show that DFT approach is closer to the experimental data than HF method.

Investigation of Synthesis and some Properties of the Copper Complexes Containing Imidazole Ligand

“…[19] All the calculations were performed by using Gaussian 09.A1 program on ULAKBIM clusters and Gauss View 5.0.8 was used for visualization of the structure and simulated vibrational spectra. [20][21][22][23]…”

Complete 1H and 13C NMR signal assignments and chemical shift calculations of four 1,2,4-oxadiazole-based light-emitting liquid crystals

“…9). It is known that the chemical shifts of protons are more sensitive to solvent, conformations, and physico-chemical parameters [24][25][26][27][28][29][30][31]. It is well documented that GIAO calculations employed for predicting proton signals are, in general, less accurate compared to other nuclei.…”

“…[27]. This kind of approach was successfully applied for 1,2-oxathianes [28], aziridines [29], calix [4]arenes [30], and heterocyclic compounds [31]. In general, chemical shift calculations of these latter systems are more difficult to achieve because of the presence of hetero-aromaticity and tautomerisms, which are complicated to describe computationally.…”

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

“…Ab initio studies of NMR chemical shifts for calix [4]arene and its derivatives have been done by Kara et al [11]. Kurt et al [12] synthesized calix [4]arene derivate molecule and investigated the spectroscopic features with FT-IR, FT-Raman, dispersive Raman and NMR.…”

“…HF and DFT methods based on quantum mechanics are widely used to determine the molecular structure, thermodynamic properties, frontier molecular orbitals, molecular electrostatic potential, non-linear optical properties, fundamental vibrational modes and NMR spectra for small and large sized chemical molecules at low computational cost [21][22][23][24][25][26][27][28][29][30][31][32]. In our previous studies [11,33,34], we have also used these methods to investigate structural, vibrational and NMR properties of the calix [4]arenes, azocalix [4]arenes and dithiophosphonates.…”