TDDFT investigation on methylviologen, 3,7-diazabenzophosphole, and helical helquat electrochromic systems

Photo-Responsive Carbon Capture over Metalloporphyrin-C60 Metal-Organic Frameworks via Charge-Transfer

Great efforts have been devoted to the study of photo-responsive adsorption, but its current methodology largely depends on the well-defined photochromic units and their photo-driven molecular deformation. Here, a methodology to fabricate nondeforming photo-responsive sorbents is successfully exploited. With C60-fullerene doping in metalloporphyrin metal-organic frameworks (PCN-M, M = Fe, Co, or Ni) and intensively interacting with the metalloporphyrin sites, effective charge-transfer can be achieved over the metalloporphyrin-C60 architectures once excited by the light at 350 to 780 nm. The electron density distribution and the resultant adsorption activity are thus changed by excited states, which are also stable enough to meet the timescale of microscopic adsorption equilibrium. The charge-transfer over Co(II)-porphyrin-C60 is proved to be more efficient than the Fe(II)- and Ni(II)-porphyrin-C60 sites, as well as than all the metalloporphyrin sites, so the CO2 adsorption capacity (CAC; at 0 °C and 1 bar) over the C60-doped PCN-Co can be largely improved from 2.05 mmol g-1 in the darkness to 2.69 mmol g-1 with light, increased by 31%, in contrast to photo-irresponsive CAC over all C60-undoped PCN-M sorbents and only the photo-loss CAC over C60.

The Contribution of Density Functional Theory to the Atomistic Knowledge of Electrochromic Processes

In this review, we provide a brief overview of the contribution that computational studies can offer to the elucidation of the electronic mechanisms responsible for the electrochromism phenomenon, through the use of the density functional theory (DFT) and its time-dependent formulation (TDDFT). Although computational studies on electrochromic systems are not as numerous as those for other physico-chemical processes, we will show their reliability and ability to predict structures, excitation energies, and redox potentials. The results confirm that these methods not only help in the interpretation of experimental data but can also be used for the rational design of molecules with interesting electrochromic properties to be initiated for synthesis and experimental characterization.

On the Electrochromic Properties of Borepins: A Computational Prediction

The spectroelectrochemical features of some recently synthesized borepins have been predicted herein using the methods based on density functional theory. The computed electronic spectra of neutral, radical anion, and dianion species clearly suggest that these molecules can be used as new electrochromic materials. The excellent agreement with the available structural and absorption experimental data for the neutral systems made us confident for the results obtained for charged species and suggests their potential use as electrochromic materials.

Time-Dependent Density Functional Computations of the Spectrochemical Properties of Dithiolodithiole and Thiophene Electrochromic Systems

The importance of organic electrochromic materials has grown considerably in recent decades due to their application in smart window, automotive, and aircraft technologies. Theoretical prediction of the optical properties should contribute to their better characterization and help the explanation of the experimental data. By using various exchange-correlation functionals, we show how density functional theory (DFT) and the related time-dependent formulation (TDDFT) are able to correctly reproduce the spectrochemical properties of dithiolodithiole and thiophene organic electrochromic systems.

Modeling electrochromic poly-dioxythiophene-containing materials through TDDFT

Here we report the first colormetric model using mPW1PBE/cc-PVDZ with CPCM to predict the chemical properties of three electrochromic polymers in which the largest UV-Vis absolute peak maximum difference when compared to experiment was 14 nm.