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

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.

Theoretical calculations of a compound formed by Fe(+3) and tris(catechol)

Phenolic compounds generally have special smell, easily soluble in water, organic solvents (alcohols, esters, chloroform, ethyl acetate), in aqueous solutions of bases, colorless or colorful, crystalline and amorphous materials. Phenols form colorful complexes when they form compounds with heavy metals. In this study, the structural properties of a compound formed by catechol and Fe(+3) are investigated theoretically. The electronic and thermodynamic properties of the complex were also investigated in gas phase and organic solvents at B3LYP/6-31+G(d,p) and B3LYP/6-311++G(d,p) basis set. The formation of Fe-tris(catechol) complex compound is exothermic, and it is difficult to obtain the complex as the temperature increases. The observed and calculated FT-IR and geometric parameters spectra are in good agreement with empirical.

Ab initio/DFT calculations of butyl ammonium salt of O,O'-dibornyl dithiophosphate

O,O'-dibornyl dithiophosphete has been synthesized by the reaction of P2S5 and borneol in toluene. Fourier Transform Infrared spectra (FT-IR) of the title compound are measured. The molecular geometry, vibrational frequencies, infrared intensities and NMR spectrum of the title compound in the ground state have been calculated by using the density functional theory (DFT) and ab initio Hartree-Fock (HF) methods with the basis set of 6-31G(d). The computed bond lengths and bond angles show the good agreement with the experimental data. Moreover, the vibrational frequencies are calculated and the scaled values have been compared with experimental FT-IR spectra. Assignments of the vibrational modes are made on the basis of total energy distribution (TED) calculated with scaled quantum mechanical (SQM) method. The observed and calculated FT-IR and NMR spectra are in good agreement with each other.

Synthesis, crystal structure and ab initio/DFT calculations of a derivative of dithiophosphonates

The compound 2 has been synthesized from the reaction of 2,4-Bis(4-methoxyphenyl)-1,3,2,4-dithiadiphosphetane-2,4-disulfide and (R)-1-[3,5-Bis(trifloromethyl)phenyl]ethanol in toluene. The obtained crude dithiophosphonic acid 1 has been treated with the excess of N(C2H5)3 to give rise to 2, [(+HN(C2H5)3][O-CH3CH-C6H3(CF3)2)(CH3OC6H4)PS2(-)]. The compound 2 has been characterized by using the spectroscopic methods such as IR, (1)H, (13)C, (31)P NMR and structural analysing method such as X-ray crystallography. It crystallizes in the orthorhombic system, whose space group is P212121. It consists of a dithiophosphonate bridged methoxyphenyl and bis(triflorophenylethyl) groups and a triethylammonium moiety linked by N-H⋯S and C-H⋯F hydrogen bonds. In the crystal structure, the C17H14F6O2PS2 molecule is elongated along the b-axis and stacked along the a-axis. The triethylammonium, N(CH2CH3)3, molecule fill in the cavities between the C17H14F6O2PS2 molecule. Moreover, ab initio methods based on Hartree-Fock (HF) and Density Functional Theory (DFT) calculations with the basis set of 6-31G(d) are also carried out to determine the molecular structural properties and to calculate FT-IR and NMR spectrum of the compound 2. The experimental results and theoretical calculations have been compared, and they are found to be in good agreement.

Synthesis, FT-IR, FT-Raman, dispersive Raman and NMR spectroscopic study of a host molecule which potential applications in sensor devices

The solid phase FT-IR, FT-Raman and dispersive Raman spectra of the host molecule which potential applications in sensor devices have been recorded in the region 400-4000 and 50-3500cm(-1), respectively. The spectra were interpreted in terms of fundamentals modes, combination and overtone bands. The structure of the molecule was optimized and the structural characteristics were determined by density functional theory (DFT) using B3LYP method with 6-31G(d) basis set. The vibrational frequencies were calculated for the studied molecule by DFT method, and compared with the experimental frequencies, which yield good agreement between observed and calculated frequencies. Finally the calculation results were applied to simulate infrared and Raman spectra of the compound. Obtained these spectra also showed good agreement with observed spectra. The dipole moment, linear polarizability and first hyperpolarizability values were also computed. The linear polarizability and first hyperpolarizability of the studied molecule indicate that the compound is a good candidate of nonlinear optical materials.