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The amide bridge in donor–acceptor systems: delocalization depends on push–pull stress

2013; Royal Society of Chemistry; Volume: 38; Issue: 1 Linguagem: Inglês

10.1039/c3nj01176c

1369-9261

Mauricio Maldonado‐Domínguez, Rafael Arcos‐Ramos, Margarita Romero, Blas Flores-Pérez, Norberto Farfán, Rosa Santillán, Pascal G. Lacroix, Isabelle Malfant,

Molecular spectroscopy and chirality

Transmission of electronic information through amide bonds may be, under appropriate conditions, effectively achieved. In this work, a family of explicitly designed donor–(amide bridge)–acceptor architectures was synthesized. NMR studies and UV-vis absorption solvatochromism support that cross-conjugation leads to measurable polarization across push–pull, amide-bridged molecules. Computational analysis of structural parameters and frontier molecular orbitals shows the contribution of an additional, dienoid amide canonical structure to intramolecular electron delocalization, as the electron donor–acceptor strength of the substituents increases. Within the context of nonlinear optics and molecular materials, computational comparison between amide-bridged molecules and those containing typical linkers shows that there is a compromise between nonlinear optical response, ease of synthesis and chemical inertness, making the systems studied herein interesting alternatives for such applications.