Related Experiment Video
Updated: Jun 25, 2025

Author Spotlight: Investigating Physiological Functions of Vitamin A Transporters Using HPLC-Based Vitamin A Profiling
Published on: December 27, 2024
Theoretical study on the structure, spectroscopic, and current-voltage behavior of 11-Cis and Trans retinal isomers
Amin Hamedian1, Mohammad Vakili2, Silvia A Brandán3
1Department of Chemistry, Faculty of Science, Ferdowsi University of Mashhad, Mashhad, 91775-1436, Iran.
Abstract:
In this study, the electronic transport properties of 11-Cis and Trans retinal, components of rhodopsin, were investigated as optical molecular switches using the nonequilibrium Green's function (NEGF) formalism combined with first-principles density functional theory (DFT). These isomers, which can be reversibly converted into each other, were examined in detail. The structural and spectroscopic properties, including infrared (IR), Raman, nuclear magnetic resonance (NMR), and ultraviolet (UV) spectra, were analyzed using the hybrid B3LYP/6-311 + + G** level of theory. Complete vibrational assignments were performed for both forms utilizing the scaled quantum mechanical force field (SQMFF) methodology. To evaluate the conductivity of these molecules, we utilized current-voltage (I-V) characteristics, transmission spectra, molecular projected self-consistent Hamiltonian (MPSH), HOMO-LUMO gap, and second-order interaction energies (E2). The trendline extrapolation of the current-voltage plots confirmed our findings. We investigated the effect of different electrodes (Ag, Au, Pt) and various connection sites (hollow, top, bridge) on conductivity. The Ag electrode with the hollow site exhibited the highest efficiency. Our results indicate that the Cis form has higher conductivity than the Trans form.
Related Concept Videos
Photoreceptors and Visual Pathways
Channel Rhodopsins
Rhodopsins belong to the family of cell surface proteins called G-protein coupled receptors,...
Stereoisomerism
Isomers are different chemical species that have the same chemical formula.
Transition metal complexes often exist as geometric isomers, in which the same atoms are connected through the same types of bonds but with differences in their orientation in space. Coordination complexes with two different ligands in the cis and trans positions from a ligand of interest form isomers. For example, the octahedral [Co(NH3)4Cl2]+ ion has two isomers (Figure 1) In the cis...
Stereoisomerism of Cyclic Compounds
The Retina
Photochemical Electrocyclic Reactions: Stereochemistry
Selection Rules: Photochemical Activation

