The amide bridge in donor-acceptor systems: delocalization depends on push-pull stressElectronic supplementary information (ESI) available: DFT studies for computed structures 3a-i including frontier molecular orbitals, 1H and 13C NMR spectra for compounds 3a-i, crystal data for compounds 3b, 3f, 3h and 3i. CCDC 957820-957823. For ESI and crystallographic data in CIF or other electronic format see DOI: 10.1039/c3nj01176c

• Main Authors: Maldonado-Domínguez, Mauricio, Arcos-Ramos, Rafael, Romero, Margarita, Flores-Pérez, Blas, Farfán, Norberto, Santillan, Rosa, Lacroix, Pascal G, Malfant, Isabelle
• Format: Journal Article
• Published: 09.12.2013
• 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.