A new compound (1) formed by two antiparallelly disposed tetracyano thienoquinoidal units has been synthesized and studied by electrochemistry, UV/Vis-NIR, IR, EPR, and transient spectroscopy. Self-assembly of 1 on a Au(111)
surface has been investigated by scanning tunneling microscopy. Experiments have been rationalized by quantum chemical
calculations. 1 exhibits 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 1.
The realization of novel properties emerging upon electronic covalent coupling between chromophores (i.e., bichromophoric systems) is a critical issue for the development of photo- and electrically active systems.[1–3] In this regard, the
relative topology and orientation of the p-subchromophores, such as in A + B type p-systems in Figure 1, with 1D linear
conjugation, 2D parallel conjugation,[4] 3D orthogonal spiroconjugation[5] or 3D conjugation[6] are key factors. On the
other hand, studies of the distribution of the excess of charge in p-conjugated moieties in post-electron transfer events are
central issues in photophysics and photochemistry, in energy storage[7] and in organic electronics.[8] In addition to this
electronic provision, its embedment in different molecular forms is of relevance as these can define unique ways of shape
fitting in supramolecular and surface assemblies. Joint electronic and molecular shape designs thus allow to build
molecular-based synthons in a tailored manner towards new bulk and nano organized materials. (...)Funding for open access charge: Universidad de Málaga / CBUA. The authors thank the Spanish Ministry of Science, Innovation and Universities MCIU (projects CTQ2017-83531-R, RED2018-102815-T, MAT2017-85089-C2-1-R), Centro de Excelencia Severo Ochoa grants (SEV-2016-0686, SEV2015-0496 and FUNFUTURE CEX2019-000917-S) and the CAM (QUIMTRONIC-CM project Y2018/NMT-4783). We thank MINECO/FEDER of the Spanish Government (projects PGC2018-098533-B-100 and PID2019-109555GB-I00),
the Eusko Jaurlaritza (Basque Government, project PIBA19-0004) and the Junta de Andalucía, Spain (UMA18FEDERJA057). We also thank the Research Central Services (SCAI) of the University of Málaga and the Donostia International Physics Center (DIPC) Computer Center. We thank Dr. Juwon Oh and Prof. Donhgo Kim from the Spectroscopy Laboratory for Functional p-electronic Systems and Department of Chemistry, Yonsei University in Korea for the generous gift of the TRIR and UV/Vis transient absorption spectroscopy data
