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

• Published in: New journal of chemistry 2014-01, Vol.38 (1), p.26-268
• Main Authors: Maldonado-Domínguez, Mauricio, Arcos-Ramos, Rafael, Romero, Margarita, Flores-Pérez, Blas, Farfán, Norberto, Santillan, Rosa, Lacroix, Pascal G, Malfant, Isabelle
• Format: Article
• Language: English
• Subjects: Chemical Sciences; Coordination chemistry
• ISSN: 1144-0546; 1369-9261
• DOI: 10.1039/c3nj01176c

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. Electron delocalization in amide-bridged push-pull systems gives access to electronic features of interest in materials science.