Optical properties of nanostructured antiviral and anticancer drugs

We present a computational study on the optical absorption properties of some systems of interest in the field of drug delivery. In particular we considered as drug molecules favipiravir (T705, an antiviral molecule) and 5-fluorouracil (5FU, an anticancer molecule) and, on the other hand, pure fullerenes (C24, B12N12, Ga12N12) and doped fullerenes (C23B, CB11N12) are considered as nanocarriers. Some combined configurations between the drug molecules and the carrier nanostructures have been then studied. The optical absorption properties of the above mentioned drug molecules and their carrier nanostructures in the free and bound states are obtained by a TD-DFT method, in gas phase and in aqueous solution. We perform a detailed analysis of the modifications arising in the absorption spectra that take place in some linked configurations between the drug molecules and the carrier nanostructures. These changes could be of importance as an optical fingerprint of the realized drug/carrier link.

Computational insights into bis-N,N-dimethylaniline based D-π-A photosensitizers bearing divergent-type of π-linkers for DSSCs

In this study, theoretically designed D-π-A derivatives containing different π-subunits as linkers were investigated to enlighten their potential applicability in photovoltaic applications. For this aim, we first focused on clarifying the effect of tailored π-linker scaffolds on the frontier orbital energies of the investigated photosensitizers. In the concomitant step, global descriptors, TiO₂ adsorption, maximum absorbance wavelength, light-harvesting efficiency (LHE), energy conversion efficiency (η), short circuit current density (J_SC), open circuit photovoltage (V_OC), fill factor (FF), and reorganization energy (λ_e, λ_h, λ_T) values, electron density differentiation maps (EDDM), transition density matrices (TDM), fragmental contributions on electron-hole overlap were investigated in detail. Based on the trend of the calculated properties, 2,3-dimethylthieno [3,4-b]pyrazine (D-Ɛ₃-δ_n-A; n = 1-3) and 5-isobutyl-10,11-dimethyl-10,11-dihydro-5H-pyrrolo [3,4-e]thieno [2',3':4,5]pyrrolo [3,2-g]thieno [3,2-b]indole (D-Ɛ₆-δ_n-A; n = 1-3) bearing molecules were identified as the best-suited and improved dye candidates for DSSC applications. Following the prediction of photovoltaic properties for the pristine dye molecules, our consecutive efforts have contributed to a similar calculation protocol comprising DFT and subsequent TD-DFT computations for the D-Ɛ_n-δ_n-A@Ti₅O₁₀ clusters to elucidate the interaction of the investigated photosensitizers with the semiconductor layer (TiO₂).

Double Hybrid Density Functionals for the Electronic Excitation Energies of Linear Cyanines

The lowest bright electronic excitations of seven model linear cyanines (CN3-CN15) using 28 double-hybrid (DH) density functionals are benchmarked against accurate and recent CC3 results. Some of these DH functionals are recently designed specifically for excited electronic state calculations. In addition, CIS, CIS(D), SCS-CIS(D), and SOS-CIS(D) were also tested. Four different basis sets were used for the vertical electronic excitation calculations: cc-pVDZ, aug-cc-pVDZ, cc-pVTZ, and aug-cc-pVTZ basis. Augmented basis sets (e.g. aug-cc-pVDZ and aug-cc-pVTZ) are found to be required for accurate and consistent results using DH functionals. The DH functionals tested in this work are classified into four main groups: global double-hybrids (GDH), range-separated double-hybrids (RSDH), spin-component and spin-opposite scaling global double-hybrids (SCS/SOS-GDH), and spin-component and spin-opposite scaling range-separated double-hybrids (SCS/SOS-RSDH). Within these groups, the SCS/SOS-RSDH group of functionals is found to provide the lowest mean absolute error (MAE) values (in the range 0.020-0.148 eV) in comparison with the GDH group (0.195-0.441 eV), the RSDH group (0.186-0.511 eV), and the SCS/SOS-GDH group (0.079-0.461 eV). Of all the DH functionals and ab initio methods investigated in the present contribution, the following functionals are found to be the most accurate and consistent: SCS-ωB2GPPLYP (MAE = 0.036 eV), SOS-ωB2GPPLYP (MAE = 0.020 eV), SOS-ωB88PP86 (MAE = 0.035 eV), and SOS-ωPBEPP86 (MAE = 0.037 eV). In general, the ab initio methods tested here show mediocre performance as compared to many DH functionals.