Loading of a Phenanthroline-Based Platinum(II) Complex onto the Surface of a Carbon Nanotube via π–π Stacking

Abstract

The stacking of the metal complex [(5,6-dimethyl-1,10-phenanthroline)(1S,2S-diaminocyclohexane)platinum(II)] 2+ (56MESS) onto the surface of two different fullerenes, a carbon nanotube, and a C 60 -buckyball was examined. The metal complex forms a supramolecular complex with multi-walled carbon nanotubes (CNTs) but not with C 60 -buckyballs. Binding of 56MESS to the CNTs is highly efficient (90 %) but can be further stabilized by the addition of the surfactant, pluronic F-127, resulting in a loading efficiency of 95 %. Molecular modelling shows that binding of 56MESS to the CNTs is supported by the large surface area of fullerene, whereas the more pronounced curvature and lack of a flat surface on the buckyballs affect the ability of 56MESS to form bonds to its surface. The loading of 56MESS onto the CNTs is via π-π stacking from the metal complex phenanthroline ligand and C-H···π bonding from the diaminocyclohexane ligand. 56MESS has 13 critical bonding points with the CNTs, eight of which are π-π stacking bonds, but the metal complex forms only seven bonds with the buckyballs. In addition, the loading of 56MESS onto the CNT results in a charge transfer of -0.111 eV. However, charge transfer is almost negligible for binding to the buckyball.The anticancer metal complex [(1,10-phenanthroline)(1S,2S-diaminocyclohexane)platinum (II)] 2+ forms a supramolecular complex with multi-walled carbon nanotubes through π-π stacking.

Theoretical Investigation of the Binding of Nucleobases to Cucurbiturils by Dispersion Corrected DFT Approaches

“…The elegance of NCI-RDG analysis lies in its ability to provide the interaction in real space, thereby enabling a graphical visualization of the regions where noncovalent interactions occur, which facilitates understanding of the nature of interaction in different types of systems. , The nature of bonding could be best described by the phenomenon of charge accumulation or depletion in a plane perpendicular to that of the interaction. The second eigenvalue (λ 2 ) contains interesting information.…”

“…From Figure c, one may notice that the relatively large contributions from the electrostatic interactions are reflected in the increase of “splattered” green regions. It has been proposed that the presence of alternative electron donating or withdrawing groups and mutual existence of hydrogen bond along with other noncovalent interactions can lead to encircling the van der Waal interactions . Considering other nucleobases, one can see the existence of functional with the alternate hydrogen bonds in guanine, and this helps in “splattering” of charges, which helps in stabilizing the guanine@CB7 inclusion complex.…”