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Full-Text Articles in Physical Sciences and Mathematics
Interactions Between Temozolomide And Guanine And Its S And Se‐Substituted Analogues, Okuma Emile Kasende, Aristote Matondo, Jules Tshishimbi Muya, Steve Scheiner
Interactions Between Temozolomide And Guanine And Its S And Se‐Substituted Analogues, Okuma Emile Kasende, Aristote Matondo, Jules Tshishimbi Muya, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Temozolomide was paired with guanine, 6-selenoguanine, and 6-thioguanine, as well as the SH tautomer of the latter. The potential energy surface of each heterodimer was searched for all minima, using Dispersion-Corrected Density Functional Theory and MP2 methods. Among the dozens of minima, three categories were observed. Stacked geometries place the aromatic systems of the two molecules parallel to one another, while the two systems are roughly perpendicular to one another in a second category. Also found are coplanar structures held together by H-bonds. Dispersion proves to be a dominating attractive force for the stacked structures, less so for perpendicular, and …
Interactions Between Temozolomide And Quercetin, Okuma Emile Kasende, Vincent De Paul Nzuwah-Nziko, Steve Scheiner
Interactions Between Temozolomide And Quercetin, Okuma Emile Kasende, Vincent De Paul Nzuwah-Nziko, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Temozolomide and quercetin are both molecules with important pharmaceutical activity, whose effects can mutually enhance one another when clinically applied simultaneously. Quantum chemical calculations are used to examine how the two molecules might interact with one another. The most stabilizing force arises when the aromatic systems of the two molecules are arranged parallel to one another. These stacked configurations are reinforced by H-bonds, but geometries containing only H-bonds, without the aromatic stacking, are much less stable, even if the H-bonds are short and strong. Comparison between B3LYP and B3LYP-D binding energies allows an evaluation of dispersion energy, which is found …
H-Bonding And Stacking Interactions Between Chloroquine And Temozolomide, Okuma Emile Kasende, Vincent De Paul Nzuwah-Nziko, Steve Scheiner
H-Bonding And Stacking Interactions Between Chloroquine And Temozolomide, Okuma Emile Kasende, Vincent De Paul Nzuwah-Nziko, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
The interactions between temozolomide and chloroquine were examined via Dispersion-Corrected Density Functional Theory and MP2 methods. Chloroquine was considered in both its lowest energy structure and in a local minimum where its aromatic system and secondary amine group are free to interact directly with temozolomide. The accessibility of these two components to intermolecular interaction makes the lowest energy dimer of this local monomer minimum competitive in total energy with that involving chloroquine’s most stable monomer geometry. In either case, the most stable heterodimer places the aromatic ring systems of the two molecules parallel and directly above one another in a …
Hydrogen Bonded And Stacked Geometries Of The Temozolomide Dimer, Okuma Emile Kasende, Jules Tshishimbi Muya, Vincent De Paul Nzuwah-Nziko, Steve Scheiner
Hydrogen Bonded And Stacked Geometries Of The Temozolomide Dimer, Okuma Emile Kasende, Jules Tshishimbi Muya, Vincent De Paul Nzuwah-Nziko, Steve Scheiner
Chemistry and Biochemistry Faculty Publications
Dispersion-corrected Density Functional Theory (DFT) and MP2 quantum chemical methods are used to examine homodimers of temozolomide (TMZ). Of the twelve dimer configurations found to be minima, the antarafacial stacked dimer is the most favored, lower in energy than coplanar dimers which are stabilized by H-bonds. The comparison between B3LYP and B3LYP-D binding energies points to dispersion as a primary factor in stabilizing the stacked geometries. CO(π)→CO(π*)charge transfers between amide groups in the global minimum are identified by NBO, as well as a pair of weak CH∙∙N H-bonds. AIM analysis of the electron density provides an alternative description which includes …