title: Effect of Self-Association on the Phase Stability of Triphenylamine Derivatives.
abstract: The self-association equilibrium, i.e. formation of noncovalent dimers, in two triphenylamine derivatives, TPD (N,N'-bis(3-methylphenyl)-N,N'-diphenylbenzidine) and mMTDAB (1,3,5-tris[(3-methylphenyl)phenylamino]benzene), in solution was evaluated by (1)H NMR spectroscopy. The gas-phase energetics of the respective dimerization processes was explored by computational quantum chemistry. The results indicate that self-association is significantly more extensive in TPB than in TDAB. It is proposed that this fact helps to explain why TPB presents a stability higher than expected in the liquid phase, which is reflected in a lower melting temperature, a less volatile liquid, and possibly a higher tendency to form a glass. These results highlight the influence of self-association on the phase equilibria and thermodynamic properties of pure organic substances.
authors.affiliation: †CIQ, Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências da Universidade do Porto, P-4169-007 Porto, Portugal.
authors.forename: Carlos F R A C
authors.initials: CF
authors.lastname: Lima
authors.affiliation: †CIQ, Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências da Universidade do Porto, P-4169-007 Porto, Portugal.
authors.forename: José C S
authors.initials: JC
authors.lastname: Costa
authors.affiliation: §LAQV-REQUIMTE, Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências da Universidade do Porto, P-4169-007 Porto, Portugal.
authors.forename: André
authors.initials: A
authors.lastname: Melo
authors.forename: Hilário R
authors.initials: HR
authors.lastname: Tavares
authors.forename: Artur M S
authors.initials: AM
authors.lastname: Silva
authors.affiliation: †CIQ, Departamento de Quı́mica e Bioquı́mica, Faculdade de Ciências da Universidade do Porto, P-4169-007 Porto, Portugal.
authors.forename: Luís M N B F
authors.initials: LM
authors.lastname: Santos