Crystal structure of AyV'-diphenylguanidinium acetate, C 1 3 H 1 4 N 3 + C 2 H 3 0 2 -

• Autor(a) principal: Beja, A. Matos
• Data de Publicação: 2000
• Outros Autores: Paixão, J. A., Silva, M. Ramos, Veiga, L. Alte da
• Tipo de documento: Artigo
• Idioma: eng
• Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
• Texto Completo: http://hdl.handle.net/10316/102791; https://doi.org/10.1515/ncrs-2000-0453

This work is part of a project to study the molecular conformations of diphenylguanidine (dpg) compounds and their optical and dielectric properties. Diphenylguanidine (dpg) is a flexible molecule which can assume different molecular conformations due to the low energy-barrier for rotation of the phenyl rings. In cationic form, stable conformers with the rings positioned syn-syn, anti-anti and syn-anti to the unsubstituted N atom have been observed both in solution and in several salts [1-3]. Two phases of monoclinic and orthorhombic symmetry are known, and in both two symmetry independent molecules are found in the asymmetric unit cell, always adopting syn-anti conformations [4, 5], Ab-initio and Monte Carlo molecular mechanics calculations [6,7] have shown that the equilibrium concentration of the three dpg+ conformers in solution depend to some extent on the counter ion. It was shown that the relative concentration of the anti-anti conformer increases from 7% to 30% in an chlorine acetate salin solution mimicking physiological conditions [7].