Halogenation effects of pheniramines on the complexation with β-cyclodextrin

Exploring the inclusion interaction of estradiol with β-CD and HP-β-CD with the help of molecular dynamics simulation as well as multi-spectroscopic approaches

The inclusion behaviors of estradiol with β-CD and HP-β-CD were characterized using molecular dynamics simulation combined with multi-spectroscopic approaches. The findings revealed that estradiol enclosed into the cavity of β-CD and HP-β-CD and produced the estradiol-β-CD and estradiol-HP-β-CD complexes with the stoichiometry of 1:1. The association constants of the estradiol-β-CD and estradiol-HP-β-CD complexes were 3.14 × 10⁴ and 3.22 × 10⁴ M^-1 at 298 K, respectively, which declined with rising temperature. The analysis results of thermodynamic parameters confirmed that the dominate interaction forces were the hydrophobic and hydrogen-bonding interactions for stabilizing the estradiol-β-CD complex, and were the hydrogen bonding interaction and van der Waals forces for stabilizing the estradiol-HP-β-CD complex. Moreover, it was confirmed from the results of molecular modeling that estradiol inserted into the hydrophobic cavity of β-CD and HP-β-CD and form a stable estradiol-CD complexes. And, it is also observed that the phenyl moiety in estradiol is almost parallel to the central axis of β-CD and HP-β-CD, and the phenyl moiety was located on wider rim of β-CD and HP-β-CD.

FTIR and Raman spectra, electronic spectra and normal coordinate analysis of N,N-dimethyl-3-phenyl-3-pyridin-2-yl-propan-1-amine by DFT method

The Fourier transform infrared (FT-IR) and FT-Raman spectra of N,N-dimethyl-3-phenyl-3-pyridin-2-yl-propan-1-amine have been recorded in the range 4000-500cm(-1) and 4000-50cm(-1) respectively. The complete vibrational assignment and analysis of the fundamental modes of the compound were carried out using the observed FT-IR and FT Raman data. The vibrational frequencies experimentally determined, was compared with the theoretical frequencies computed by DFT gradient calculations (B3LYP method) employing the 6-31+G(d,p) basis set for the optimized geometry of the compound. The geometry and normal modes of vibration obtained from the DFT method are in good agreement with the experimental data. The assignments of the vibrational spectra have been carried out with the help of Normal Coordinate Analysis (NCA) following the Scaled Quantum Mechanical Force Field Methodology (SQMFF). The calculated infrared and Raman spectra of the title compounds were also stimulated utilizing the scaled force fields and the computed dipole derivatives for IR intensities and polarizability derivatives for Raman intensities. The change in electron density (ED) in the σ(*) and π(*) antibonding orbitals and stabilization energies E(2) have been calculated by Natural Bond Orbital (NBO) analysis to give clear evidence of stabilization originating in the hyper conjugation of hydrogen-bonded interaction. The electronic spectrum determined by TD-DFT method is compared with the observed electronic spectrum.