Molecular Structure, Vibrational Spectra and Potential Energy Distribution of Colchicine Using ab Initio and Density Functional Theory

Abstract

This work deals with a theoretical study of the molecular structure of colchicine. The equilibrium geometry, harmonic vibrational frequencies, infrared intensities and Raman scattering activities were calculated by the ab initio Hartree-Fock method and the Density Functional B3LYP method employing 6-31G(d) as the basis set, and the vibrational studies were interpreted in terms of the potential energy distribution (P.E.D.). The internal coordinates were optimized repeatedly to maximize the P.E.D. contributions. A detailed interpretation of the infrared and Raman spectra of colchicine is reported. The scaled theoretical wave numbers are in perfect agreement with the experimental values. The FT-IR spectra of colchicine was recorded in solid phase, and the FT-Raman spectra of colchicine have been taken from the literature.

Anti‐Cancerous Brucine and Colchicine: Experimental and Theoretical Characterization

“…The carbonyl stretching C=O vibrations appear at 1665 cm −1 (IR), 1670 cm −1 (DFT) for brucine and 1723, 1618 (IR), 1716, 1620 cm −1 (DFT) for colchicine while C=C stretching modes were assigned at 1660 (Raman), 1658 (DFT) for brucine and at 1584, 1560, 1488 (IR), 1590 (Raman), 1583, 1572, 1489 (DFT) for Colchicine. The C−O modes were seen in the range 1250–1020 cm −1 (IR), and at 1250, 1193 cm −1 (Raman) for brucine and at 1086, 1050, 921 (IR), 1098, 1060, 926 (Raman) for colchicine . Most of the ring modes are also in agreement with theoretically predicted wave numbers.…”

Functionalized Fe3O4nanoparticles: influence of ligand addition sequence and pH during their continuous hydrothermal synthesis

“…S3 †). However for large pH and large molar ratio (100% and 50%), new bands (torsion s(HOCC)) 45 are observed (run{2/ DHCA/100%}, run{2/LDOPA/100%}, run{2/LDOPA/50%} and run{3/LDOPA/100%}) (Fig. S1 †).…”

All characteristic Raman markers of tyrosine and tyrosinate originate from phenol ring fundamental vibrations

“…[20] To analyze the structural features and accurately assign the Tyr and tyrosinate characteristic vibrations, modern quantum mechanical calculations generally based on the density functional theory were performed during the recent years. [9,[19][20][21][22][23][24][25] Among these calculations, one can distinguish those performed on the neutral (in vacuum) form of free Tyr, [21,22] as well as on its zwitterionic form. [9,19,23] The latter data are evidently more convenient for the interpretation of the aqueous phase experiments.…”