Structure, energetics and vibrational spectra of protonated chlortetracycline in the gas phase: An experimental and computational investigation
- 作者：Blake E. Ziegler ; Rick A. Marta ; Sabrina M. Martens ; Jonathan K. Martens ; Terry B. McMahon ; mcmahon@uwaterloo.ca
- 关键词：Tetracylcine ; IRMPD ; Gaseous ion structure ; Gaseous ion thermochemistry ; Electronic structure calculations
- 刊名：International Journal of Mass Spectrometry
- 出版年：2012
- 期刊代码：43_13873806
- 类别：ch
- 出版时间：15 April, 2012
- 卷：316-318
- 期：Complete
- 页码：117-125
- 文件大小：1867 K
摘要
Infrared Multiple Photon Dissociation (IRMPD) Spectroscopy has been used to generate gas phase vibrational spectra for six protonated tetracycline derivatives: chlortetracycline, meclocycline, minocycline, doxycycline, tetracycline, and metacycline. The IRMPD spectrum for protonated chlortetracycline is compared here to theoretical gas phase vibrational spectra obtained from geometry optimization and frequency electronic structure calculations using the B3LYP hybrid density functional method with the 6-311 + G(d,p) basis set. The most energetically favorable protonation sites, tautomer structures, and hydrogen bond orientations were determined. Protonation at the dimethyl amine functional group and an extensive hydrogen bonding network lead to the most energetically favourable structures. Calculated spectra directly resembled the IRMPD spectrum, supporting the conclusion that the probable gas phase structure of protonated chlortetracycline has been determined.