J Phys Chem Lett
September 2024
We report an acid-mediated regulation of single-molecule junction conductance achieved using an electron-deficient unit, diazapentalene, functionalized with thiophene extending units and thiomethyl aurophilic terminal groups. This diazapentalene derivative exhibits a protonation reaction in the presence of trifluoroacetic acid, as characterized by UV-vis absorption spectroscopy, and the protonated species shows a voltage-dependent single-molecule conductance, which is not observed for the pristine molecules. Specifically, under a high bias voltage of 850 mV, we observe a conductance value for the protonated molecule larger than that for the deprotonated one by a factor of 4.
View Article and Find Full Text PDFElectrons moving through chiral molecules are selected according to their spin orientation and the helicity of the molecule, an effect known as chiral-induced spin selectivity (CISS). The underlying physical mechanism is not yet completely understood. To help elucidate this mechanism, a non-equilibrium Green's function method, combined with a Landauer approach and density functional theory, is applied to carbon helices contacted by gold electrodes, resulting in spin polarization of transmitted electrons.
View Article and Find Full Text PDFSignal transduction is essential for the survival of living organisms, because it allows them to respond to the changes in external environments. In artificial systems, signal transduction has been exploited for the highly sensitive detection of analytes. Herein, a remarkable signal transduction, upon ATP binding, in the multivalent fibrillar nanoaggregates of anthracene conjugated imidazolium receptors is reported.
View Article and Find Full Text PDFSynergy between a pair of weak non-covalent interactions can predispose a molecular self-assembly towards a specific pathway. We report assisted π-stacking, a synergy between aromatic π-stacking and n →π* interactions that exhibits an unprecedented strength and thermal stability. Natural bond orbital analysis reveals the non-additive nature of the interaction.
View Article and Find Full Text PDFWe calculated the ground and low-lying excited states of cyclopenta-fused polycyclic aromatic hydrocarbons (CP-PAHs) using exact diagonalization in full configuration interaction (CI) within the model Pariser-Parr-Pople Hamiltonian as well as a time-dependent density functional theory technique. The CP-PAHs include acenapthylene, isomers of pyracylene, cycloocta-pentalene, and three isomers of dicyclo-pentacyclo-octenes (DCPCO). We used the inherent symmetries of these systems to calculate the energy ordering of the lowest singlet (S) and lowest triplet excited (T) states with respect to the ground state (S).
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