Ab Initio and DFT Study of the conformational Energy Hypersurface of cyclic Gly-Gly-Gly
The multidimensional conformational potential energy hypersurface (PEHS) of cyclic Gly-Gly-Gly (1,4,7triazonane-2,5,8-trione) was comprehensively investigated at the Hartree-Fock (RHF/6-31G(d)) level of theory. The equilibrium structures, their relative stability, and the transition state (TS) struc...
| Autores: | , , , |
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| Tipo de recurso: | artículo |
| Estado: | Versión publicada |
| Fecha de publicación: | 2009 |
| País: | Argentina |
| Institución: | Consejo Nacional de Investigaciones Científicas y Técnicas |
| Repositorio: | CONICET Digital (CONICET) |
| Idioma: | inglés |
| OAI Identifier: | oai:ri.conicet.gov.ar:11336/130369 |
| Acceso en línea: | http://hdl.handle.net/11336/130369 |
| Access Level: | acceso abierto |
| Palabra clave: | CYCLIC-TRIPEPTIDES CYCLIC-TRIGLYCINE CONFORMATIONAL STUDY AB INITIO DFT CALCULATIONS https://purl.org/becyt/ford/1.4 https://purl.org/becyt/ford/1 |
| Sumario: | The multidimensional conformational potential energy hypersurface (PEHS) of cyclic Gly-Gly-Gly (1,4,7triazonane-2,5,8-trione) was comprehensively investigated at the Hartree-Fock (RHF/6-31G(d)) level of theory. The equilibrium structures, their relative stability, and the transition state (TS) structures involved in the conformational interconversion pathways were analyzed. aug-cc-pVTZ//B3LYP/6-311++G** single point calculations predict a trans-cis-cis conformation as the energetically preferred form for this compound. However, all of the levels of theory employed here predicted that two forms, a trans-cis-cis and a cis-cis-cis (crown), of conformers contribute significantly to the equilibrium mixture at room temperature. The conformational interconversion between the global minimum and the symmetric cis-cis-cis crown form requires 12.49 kcal/mol at the RHF 6-31G(d) level of theory, whereas the conformational interconversion between the cis-cis-cis crown and cis-cis-cis boat form requires 18.70 kcal/mol. An exploratory topological analysis of the PEHS was also carried out. Our results allow us to form a concise idea about the internal intricacies of the PEHSs of these cyclic tripeptides, describing the conformations as well as the conformational interconversion processes in these hypersurfaces. |
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