DFT study of cisplatin@carbon nanohorns complexes

• DFT investigation of carbon nanohorns inclusion complex with cisplatin is reported.
• Stable inclusion complex are formed that can be carried out through biological media.
• Calculated B3LYP 1H NMR and 15N NMR chemical shifts for cisplatin are reported.
• Very large changes in the chemical shits are observed due to complex formation.
• Experimental assignment of inclusion compound can be made using B3LYP results.

This paper reports a quantum chemical investigation of the inclusion complex formation between a carbon nanohorn structure and cisplatin molecule, using the density functional theory (DFT) with the B3LYP functional and 6–31G(d,p)/LanL2DZ standard basis sets. The inclusion of the drug in host molecules such as carbon nanohorns (CNHs), aims to reduce the toxicity and enhance the effectiveness of cisplatin. In this work we carried out a search for minimum energy structures on the potential energy surface (PES) for CNH–cisplatin interaction, and then calculated the stabilization energy, charge distribution and NMR spectra, which can be of great aid for the experimental identification of the inclusion compound. Our results indicate that the CNH and cisplatin can indeed form stable inclusion complex, with the calculated 1H NMR and 15N NMR chemical shifts for cisplatin atoms revealing very substantial changes due to complex formation (~ 20 ppm) that can be easily experimentally observed, which is helpful to the spectra assignment and the inclusion compound structural elucidation.

B3LYP/6-31G(d,p)/LanL2DZ PCM–Water 1H NMR spectra for free cisplatin and cisplatin@nanohorn inclusion compound (NH3 hydrogen atoms chemical shifts), showing the large shift due to the complex formation, that should be observed experimentally.Figure optionsDownload as PowerPoint slide