Raman and Infrared Spectroscopy, DFT Calculations, and Vibrational Assignment of the Anticancer Agent Picoplatin: Performance of Long-Range Corrected/Hybrid Functionals for a Platinum(II) Complex

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• 作者：Magdalena Malik ; Rafa艂 Wysoki艅ski ; Wiktor Zierkiewicz ; Katarzyna Helios ; Danuta Michalska
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：August 28, 2014
• 年：2014
• 卷：118
• 期：34
• 页码：6922-6934
• 全文大小：387K
• ISSN：1520-5215

文摘

Picoplatin, cis-[PtCl₂(NH₃)(2-picoline)], is a new promising anticancer agent undergoing clinical trials, which reveals high efficacy against many tumors and greatly reduced toxicity, in comparison to cisplatin. In this work, we present for the first time the Fourier-transform Raman and infrared spectra of picoplatin, in the region of 3500鈥?0 cm^鈥?. The comprehensive theoretical studies on the molecular structure, the nature of Pt鈥搇igand bonding, vibrational frequencies, and intensities were performed by employing different DFT methods, including hybrid (PBE0, mPW1PW, and B3LYP) and long-range-corrected hybrid density functionals (LC-蠅PBE, CAM-B3LYP). Various effective core potentials (ECP) and basis sets have been used. In the prediction of the molecular structure of picoplatin, the best results have been obtained by LC-蠅PBE, followed by PBE0, mPW1PW, and CAM-B3LYP density functionals, while the least accurate is B3LYP. The use of the LanL2TZ(f) ECP/basis set for Pt, in conjunction with all tested DFT methods, improves the calculated geometry of the title complex. The PBE0, mPW1PW, and CAM-B3LYP methods have shown the best performance in the calculations of the frequencies of Pt鈥搇igand vibrations. A clear-cut assignment of all the bands in the IR and Raman spectra have been made on the basis of the calculated potential energy distribution (PED). The nature of the 鈥渧ibrational signatures鈥?of picoplatin have been determined. These results are indispensable for further investigation on drug鈥搕arget interactions using vibrational spectroscopy.