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FT-IR and Raman spectra of methyl(5-[2-thienylcarbonyl]-1H-benzimidazol-2-yl (nocodazole) are experimentally examined in the region of 4000-400 cm. The optimized geometric parameters, conformational equilibria, normal mode frequencies, and corresponding vibrational assignments of nocodazole (CHNOS) calculated by means of the B3LYP hybrid density functional theory (DFT) method using the 6-31++G( d,p) basis set. Vibrational assignments are made based on the total energy distribution (TED) and the thermodynamic functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of nocodazole are calculated. Calculations are employed for four energetically possible conformers of nocodazole (N1, N2, N3, and N4) in the gas phase. A comparison between the experimental and theoretical results indicates that the B3LYP method is able to provide satisfactory results for predicting vibrational wavenumbers if calculated values are scaled properly and the structural parameters. [ABSTRACT FROM AUTHOR]

FT-IR and FT-Raman spectra of 1-cyclopropylpiperazine (1cppp) are experimentally examined in the range 4000-200 cm. The optimized geometric parameters, conformational equilibria, normal mode frequencies and corresponding vibrational assignments of 1cppp CHN are theoretically examined by means of B3LYP hybrid density functional theory (DFT) with the 6-31++G( d,p) basis set. Based on the potential energy distribution (PED) reliable vibrational assignments are made and the thermodynamics functions, highest occupied and lowest unoccupied molecular orbitals (HOMO and LUMO) of 1cppp are predicted. Calculations are performed for four different conformations in two point groups of 1cppp in the gas phase. A comparison between the experimental and theoretical results indicates that the B3LYP method is able to provide satisfactory results for the prediction of vibrational frequencies, structural parameters, and assignments. Furthermore, the C (equatorial-equatorial) point group is found as the most stable conformer of 1cppp. [ABSTRACT FROM AUTHOR]

Abstract: FT-IR and 1H, 13C, DEPT, HETCOR, COSY, and NOESY NMR spectra of 2-(1-cyclohexenyl)ethylamine (CyHEA) have been reported for the first time. The vibrational frequencies and 1H, 13C NMR chemical shifts of CyHEA (C8H15N) have been calculated by means of the Hartree–Fock (HF), Becke–Lee–Yang–Parr (BLYP) and Becke-3–Lee–Yang–Parr (B3LYP) density functional methods with 6-31G(d) and 6-31G(d,p) basis sets, respectively. The comparison between the experimental and the theoretical results indicates that density functional B3LYP method is superior to the scaled HF and BLYP approach for vibrational frequencies and predicting NMR properties. [Copyright &y& Elsevier]

Abstract: An efficient route was developed for the synthesis of novel 3-(2-morpholinyl-4-phenylthiazol-5-oyl)coumarin (MPTC). FT-IR spectrum of MPTC was recorded and analyzed. The crystal structure data are also described. The vibrational wavenumbers were computed theoretically using the Gaussian03 package of programs using HF/6-31G(d) and B3LYP/6-31G(d) levels of theory. The data obtained from vibrational wave number calculations are used to assign vibrational bands observed in the infrared spectra of MPTC. The first hyperpolarizability, infrared absorption band intensities and intensities of raman active bands are reported. The calculated first hyperpolarizability is comparable with the values reported for compounds of similar structure. The structural parameters of MPTC obtained from XRD studies are in agreement with the calculated values. The unit cell parameters of crystals of MPTC are: a =8.6017(10)Å, b =9.9735(5)Å, c =13.3870(13)Å, α =111.123(6)°, β =90.102(9)°, γ =110.246(6)°, and Z =2,1.397Mg/m3. [Copyright &y& Elsevier]