Coupling of photoactive transition metal complexes to a functional polymer matrix**

Abstract

Conductive polymers represent a promising alternative to semiconducting oxide electrodes typically used in dye-sensitized cathodes as they more easily allow a tuning of the physicochemical properties. This can then also be very beneficial for using them in light-driven catalysis. In this computational study, we address the coupling of Ru-based photosensitizers to a polymer matrix by combining two different first-principles electronic structure approaches. We use a periodic density functional theory code to properly account for the delocalized nature of the electronic states in the polymer. These ground state investigations are complemented by time-dependent density functional theory simulations to assess the Franck-Condon photophysics of the present photoactive hybrid material based on a molecular model system. Our results are consistent with recent experimental observations and allow to elucidate the light-driven redox chemical processes -eventually leading to charge separation -in the present functional hybrid systems with potential application as photocathode materials.

Exploring π–π interactions and electron transport in complexes involving a hexacationic host and PAH guest: a promising avenue for molecular devices

“…41,42 Simultaneously, we noted consistency in prior literature where the computed HOMO-LUMO energy gap value, obtained through the PBE0 functional, exhibited favorable alignment with experimental findings. 43 So, we have incorporated this functional in our work and opted for the basis set def2-TZVP to balance the dependable interaction energy and computational cost of our host-guest complexes, which comprise a substantial number of atoms. We also noticed from the preceding literature that this basis set elucidates the noncovalent interactions.…”

Polymerization of Primary Amines with Sulfur Monochloride to Yield Red Polymers with a Conjugated SN Backbone

“…63 Methyl groups were added to the backbone at the nitrogen atoms to model the octyl groups in polymer I and the minimum-energy geometry (Figures 9 and S34−S36) was found using periodic DFT from the Vienna Ab initio Software Package (VASP 6.3). 64 The following calculation parameters were used: a PBE0 functional, 65 a 2x2x4 k-point mesh, and 1.3 times the default cutoffs from the potential files. As the crystal structure was not known, further calculations were performed on an oligomer with 12 repeat units with end groups of −NH using a molecular density functional theory package (Q-Chem 5.3), 66 with common calculation parameters of a B3LYP5 67 functional with a D3 correction and 6−31G(d,p) basis set.…”

Prediction of Strong Solvatochromism in a Molecular Photocatalyst**

“…[1] Recent years have witnessed an increased understanding of the mechanisms operative in photochemical molecular devices which combine a photosensitizer and a catalyst connected by an electron relay. [2][3][4][5][6][7][8][9] The operation of such molecular devices requires the presence of solvents, and as many molecular complexes are insoluble in aqueous media, often organic solvents are used. [4] Although it is known that the activity of photocatalysts is influenced by the properties of the solvent, [5] it is fair to say that a systematic understanding of this influence is still lacking.…”

“…The efficient direct conversion of sunlight into valuable chemicals is challenging but has the potential to significantly contribute to a carbon‐emission‐free energy economy [1] . Recent years have witnessed an increased understanding of the mechanisms operative in photochemical molecular devices which combine a photosensitizer and a catalyst connected by an electron relay [2–9] . The operation of such molecular devices requires the presence of solvents, and as many molecular complexes are insoluble in aqueous media, often organic solvents are used [4] .…”