Chiral Single-Molecule Potentiometers Based on Stapled ortho- Oligo(phenylene)ethynylenes

We report on the chemical design of chiral molecular junctions with stress-dependent conductance, whose helicity is maintained during the stretching of a single molecule junction due to the stapling of both ends of the inner helix. In the reported compounds, different conductive pathways are observed, with clearly different conductance values and plateau-length distributions, attributed to different conformations of the helical structures. The large chiro-optical responses and the potential use of these molecules as unimolecular spin filters have been theoretically proved using state-of-the-art Density Functional Theory (DFT) calculations, including a fully ab-initio estimation of the CISS-originating spin polarization which is done, for the first time, for a realistic molecular system
We thank the Spanish MICIN for the “María de Maeztu” Programme for Units of Excellence in R&D (grant No. CEX2018-000805-M). Financial support from MCIN/AEI/ 10.13039/501100011033 is acknowledged by L.A.Z. (grant PID2021-125604NB-I00), E. L. (PID2021-127964NB-C21), D. M. and J. M. C. (PID2020-113059GB-C21), A. M. (PID2021-127964NB-C22) and A. O. G. for her FPU contract (FPU16/02597). We also thank the Universidad Autónoma de Madrid and the Comunidad de Madrid (grants No. SI3/PJI/2021-00191, S2018/NMT-4321 through the Nanomag COST-CM Program and E.L. for Atracción de Talento grant 2019-T1/IND-16384). J. J. P. acknowledges financial support from Spanish MICINN (PID2019- 109539GB-C43) and the Generalitat Valenciana through Programa Prometeo/2021/01. This research was also funded by FEDER/Junta de Andalucía-Consejería de Economía y Conocimiento/P20 00162 and the Visiting Scholar Program in the University of Granada. IMDEA Nanociencia acknowleges support from the ’Severo Ochoa’ Programme for Center of Excelence in R&D (CEX2020-001039-S).