A new compound formed by two antiparallelly disposed tetracyano thienoquinoidal units has been synthesized and studied by electrochemistry and several spectroscopic techniques. Its self-assembly on a Au(111) surface has been investigated by scanning tunneling microscopy.
The observed self-assembly was rationalized by quantum chemical calculations showing a unique charge distribution in its anionic form, with a gradient of charge yielding a neat molecular in-plane electric dipole momentum, which transforms out-of-plane after surface deposition due to twisted → folded conformational change and to partial charge transfer from Au(111). Intermolecular van der Waals interactions and antiparallel trapezoidal shape fitting lead to the formation of an optimal dense on Au(111) two-dimensional assembly of this new compound.
A Trapezoidal Octacyanoquinoid Acceptor Forms Solution and Surface Products by Antiparallel Shape Fitting with Conformational Dipole Momentum Switch
Samara Medina Rivero, Javier Urieta-Mora, Agustín Molina-Ontoria, Cristina Martín-Fuentes, José I. Urgel, Maria Zubiria-Ulacia, Vega Lloveras, David Casanova, José I. Martínez, Jaume Veciana, David Écija, Nazario Martín, and Juan Casado
Angew. Chem. Int. Ed. 2021, 60, 1 – 7