Thermochemical and structural properties of DMAN-"proton sponges"

• Tipo: Artigo em Revista Científica Internacional
• Data: 2012

Autores

Juan Z Davalos (Autor) Outra; Alexsandre F Lago (Autor) Outra; Costa, JCS (Autor) Outra; Luis M N B F Santos (Autor) FCUP; Javier Gonzalez (Autor) Outra

Revista

Título: Journal of Chemical Thermodynamics

Vol. 54

Páginas: 346-351

ISSN: 0021-9614

Editora: Elsevier

Indexação

ISI Web of Knowledge - 6 Citações

Scopus - 6 Citações

Classificação Científica

FOS: Ciências da engenharia e tecnologias > Engenharia mecânica

Outras Informações

ID Authenticus: P-002-4AP

DOI: 10.1016/j.jct.2012.05.013

Abstract (EN): We report a study on the energetics and structural properties of naphthalene-based proton sponges and their corresponding protonated cations. In particular, we have determined the experimental standard enthalpies of formation in the gas phase at T = 298.15 K, Delta fH(m)(o) m (g), for the neutral and protonated DMAN [1,8-bis (dimethylamino)-naphthalene], (221.0 +/- 7.3) and (729.0 +/- 11.1) kJ.mol(-1), respectively. A reliable experimental estimation of enthalpy associated with "strain'' effect and hydrogen bond intramolecular (included within "enhanced basicity'', EB) contributions to the basicity of DMAN, were deduced from isodesmic reactions, -(29.1 +/- 4.6) and (87.1 +/- 11.9) kJ.mol(-1), respectively. The gas-phase basicities (GB) of naphthalene-based proton sponges are compared with the corresponding aqueous basicities (pKa), covering a range of 149 kJ.mol(-1) in GB and 11.5 in pKa. Density functional calculations at the M05-2X/6-311++G(d,p) level of theory were used to check the consistency of the experimental results and also to estimate the unavailable GB values of the considered species.

Idioma: Inglês

Tipo (Avaliação Docente): Científica

Nº de páginas: 6