Azobenzene-Iron(III)porphyrin Hybrid Composite as a Light-Driven Molecular Spin Regulator: Some Promising Insights from DFT

Abstract

The photo-isomerization of azobenzene (AZB) provides the essential stimulation for the controlled regulation of spin-crossover in the iron­(III)­porphyrin complex. We have performed theoretical simulations to predict the strategic design of a modular material via attachment of azobenzene to the iron­(III) center. The light-induced isomerization of azobenzene triggers a cascade of electronic changes resulting from a low to a high-spin transition in the electronic configurations of Fe­(III) ions. In principle, the successive conformational changes in AZB exert considerable distortion on the iron coordination sphere, subsequently changing the crystal field splitting pattern. The light-induced rotatory motion of AZB is the necessary driving force to manipulate the spin state of the Fe­(III) ion. The density functional theory-based calculations on the 2D extended porphyrin array and its coupling to AZB molecules affirm considerable changes in the electronic properties of the system. The consequence of light-induced isomerization in azobenzene effectively modulates the electronic transport behavior of the system in the two different spin states. This was checked through the calculations of transmission, conductance, and IV characteristics. The comprehensive spectral simulations manifest a reasonable correlation to the predicted spin crossover in the system, with clear evidence provided by the transport properties.

Spintronics on Demand: Optically Tunable Kondo-Type Phenomena in Germanene-Azobenzene Single-Molecule Junctions

“…Our previous study provided valuable insights into the potential of light-responsive azobenzene (AZB) molecules as highly efficient molecular switches for manipulating the electronic structures of 2D surfaces. This research highlighted the significant electronic modifications triggered by the photoinduced conformational changes within AZB molecules when exposed to light.…”

“…The fundamental concept in spin-polarized transmission is that a molecule’s electronic structure can be affected by its conformation and can also impact the spin properties of the electrons. This distinct feature offers a valuable opportunity to study how the molecular structure influences spin-polarized electron transmission, as highlighted in our prior research endeavors . The on–off isomerization pattern induced by light irradiation in the AZB molecule, transitioning between trans and cis states, could potentially reversibly control spin polarization in the system.…”

Strong Be−N Interaction Induced Complementary Chemical Tuning to Design a Dual‐gated Single Molecule Junction

“…The advantages of single‐molecule electronic structure to manipulate the charge transport through these molecular junctions are well documented in our previous studies [69,70] . Here, we emphasized the comprehensive understanding of the gating effects of beryllium bonding (Be−N) interaction to tune the charge transport through a single‐molecule junction sandwiched between two metal electrodes.…”

“…The advantages of single-molecule electronic structure to manipulate the charge transport through these molecular junctions are well documented in our previous studies. [69,70] Here, we emphasized the comprehensive understanding of the gating effects of beryllium bonding (BeÀ N) interaction to tune the charge transport through a single-molecule junction sandwiched between two metal electrodes. On top of that, the chemical nature of the substituent groups at the para position of the pyridine molecule loaded the functionality of a secondary gate to further manipulate the electronic current through the molecular junction.…”

Functional Design of a Reconfigurable Molecular Nanomachine: A Promising Domain for Optically Propelled Molecular Motors

“…It is noteworthy that the rotational motion of the photoactive unit (motor) converts light energy input into mechanical work, while the overall system (machine) containing the molecular motor is designed to accomplish mechanical work done from the synchronized motion of the different modules. , Our previous work on molecular electronics − inspired us to explore the promising capabilities of light-driven organic molecular motors, which hold the potential to bring significant changes to the field of microelectronics in the foreseeable future. An important aspect of the proposed molecular machine is that the rotational motion of the submolecular component promotes periodic modulation of the bond length between the rotor and stator parts.…”