Ciguatoxin time–resolved absorption and resonance FT–IR and raman biospectroscopy and density functional theory (DFT) investigation of vibronic–mode coupling structure in vibrational spectra Analysis

Ciguatoxins are a class of toxic polycyclic polyethers found in fish that cause ciguatera.There are several different chemicals in this class."CTX" is often used as an abbreviation.Parameters such as FT -IR and Raman vibrational wavelengths and intensities for single crystal Ciguatoxin are calculated using density functional theory and were compared with empirical results.The investigation about vibrational spectrum of cycle dimers in crystal with carboxyl groups from each molecule of acid was shown that it leads to create Hydrogen bonds for adjacent molecules.The current study aimed to investigate the possibility of simulating the empirical values.Analysis of vibrational spectrum of Ciguatoxin is performed based on theoretical simulation and FT-IR empirical spectrum and Raman empirical spectrum using density functional theory in levels of HF/6-31G*, HF/6-31++G**, MP2/6-31G, MP2/6-31++G**, BLYP/6-31G, BLYP/6-31++G**, B3LYP/6-31G and B3LYP6-31-HEG**.Vibration modes of methylene, carboxyl acid and phenyl cycle are separately investigated.The obtained values confirm high accuracy and validity of results obtained from calculations.Molecular structure of Ciguatoxin [1-42].