Design of Tetrathiafulvalene-Based Phosphazenes Combining a Good Electron-Donor Capacity and Possible Inclusion Adduct Formation (Part II)

Abstract

Physical properties of intercalated porous material can be modulated by intercalation of small molecules, as this was demonstrated through the iodine (I2) intercalation into tris(o-phenylenedioxy)cyclotriphosphazene (TPP) crystals. This work describes in depth theoretical considerations of TPP derivatives. The core ring [(NP)3] substitution by [(CO)3], [(CNH)3], and [(CS)3], as well as the side group modification in size and composition (containing tetrathiafulvalene-like fragments), is well described from the most important aspects as their geometry optimization, their highest occupied molecular orbital (HOMO)−lowest unoccupied molecular orbital (LUMO) consideration together with ionization potentials (IP), and their charged forms. On the basis of PBE0/6-31G(d,p) calculations, the neutral forms of the [(CO)3], [(CNH)3], and [(CS)3] containing derivatives are predicted in a distorted caplike conformation. In the first two series, planar (or nearly planar) conformations are predicted upon oxidation, while IP and HOMO energy calculation revealed an electron-donor strength better or comparable to that of the known tetrathiafulvalene (TTF)-like superconductors. Within the [(NP)3] based derivatives, the results show that the geometry of the central part may be influenced by the structure of the side fragment. Among the most interesting results, a number of derivatives are predicted to show a good electron-donor strength compared to the commonly used TTF-like donors. More interestingly, a larger number of [(NP)3] containing derivatives, especially the O/“NH”-substituted series, are found to combine the good electron-donor capacity and the “paddle wheel” molecular shape, making them good candidates for organic superconductors with the ease of modulating their conducting properties by intercalation of suitable acceptors.

First principles investigation on the key factors of broad absorption spectra and electronic properties for oligothiophene and its derivatives for solar cells

“…For example, the C 4 -S a is 1.758 Å at the B3LYP/6-31G(d) level, whereas the result of the PBE0 method is in the identical value (1.740 Å ) in comparison with the experimental data (1.740 Å ) [44]. This observation was consistent with our previous study [45] and the report by Jacquemin et al [46], in which the PBE0 was proven to be a method of choice for systems bearing sulfur atoms. Thus the PBE0/6-31G(d) method was used for all the geometry optimizations in the rest of our study.…”

Design of donors with broad absorption regions and suitable frontier molecular orbitals to match typical acceptors via substitution on oligo(thienylenevinylene) toward solar cells

“…[39] The PBE0 was proven to be a method of choice for systems bearing sulfur atoms. [40] The HOMO–LUMO gap of 1 has been calculated as representation at the PBE0 level with 6‐31G(d) and 6‐31+G(d,p) basis set, respectively. The difference between the values obtained at the PBE0/6‐31G(d) (2.57 eV) and the PBE0/6‐31+G(d,p) (2.52 eV) levels for the HOMO–LUMO gap of 1 is pretty small (0.05 eV).…”

Theoretical studies of the effect of electron-withdrawing dicyanovinyl group on the electronic and charge-transport properties of fluorene-thiophene oligomers

“…To investigate the effect of different functionals on the molecular geometry, four density functionals including the B3LYP [20,31,37,38], PBE1PBE (also called PBE0) [39][40][41][42], B3PW91 [43], and BP86 [44] methods were used with the 6-31G* basis set in the geometry optimization of the ground state (S 0 ) in case of FT. The selected bond lengths, bond angles, and corresponding experimental values are listed in Table S1, together with the sketch of relative errors of functional effects for bond lengths.…”