Theoretical study on the structures and electronic properties of oligo(p-phenylenevinylene) carboxylic acid and its derivatives: effects of spacer and anchor groups

Abstract

The structural parameters of oligo(p-phenylenevinylene)carboxylic acid (OPV 3 -COOH) and its derivatives were optimized using the density functionals B3LYP, M06, M06-HF, M06-2X and the MP2 method on 6-31G(d) basis set level. The results show that the structure from B3LYP calculation is more planar than from M06, M06-2X, M06-HF, and MP2, respectively. The structures of OPV 3 -COOH obtained from various methods were used to calculate the electronic properties by time-dependent density functional theory calculation with the TD-CAM-B3LYP/6-311G(d,p) including conductor polarizable continuum model solvation to compare with the experimental absorption bands of this molecule. The excitation energies from the coplanar structure using M06-2X/6-31G(d) (406 nm) are closer to the experimental absorption data (430 nm) than the data from geometries optimized by M06-HF/6-31G(d) (362 nm) and MP/6-31G(d) (382 nm). Therefore, in this study, the M06-2X/6-31G(d) method was selected to investigate the effects of spacers for the structures and the electronic properties of OPV 3 -COOH and some derivatives. Spacer groups such as thiophene, dithiophene and vinylenethiophene linking between chromophore and the cyanoacrylic acid (-CNCOOH) anchor group can increase the electron transfer and expand the p-conjugated system to shift the absorption band into the visible light region. The more extended electron transfer and the red-shift of the absorption band for OPV 3 -COOH and OPV 3 -CNCOOH derivatives are desirable for absorbing sunlight and good employing as photo-sensitizer in dyesensitized solar cell. Thiophene (OPV 3 -Th-CNCOOH), dithiophene (OPV 3 -diTh-CNCOOH) and vinylenethiophene (OPV 3 -viTh-CNCOOH) as spacer lead to the expansion of the p-conjugated system and to bathochromically shifted absorption spectra. Therefore, the modeling of side chain, spacer and anchor group in this study suggests new sensitizer compounds that enhance the efficiency of electron transfer and absorption of the sunlight for new synthetic materials.

Seven New Lobane Diterpenoids from the Soft Coral Lobophytum catalai

“…This deduction was further proven through a comparison of the chemical shifts with previously reported lobane-type diterpenoids [4][5][6][7]. The orientations of C-14 and C-17 were defined as 14R* and 17R* in the DP4 + calculations (Supplementary Materials, Figure S2) [17]. Finally, the absolute configurations of 1 were defined as 1R, 2R, 4S, 14R, and 17R in the TDDFT-ECD calculations (Figure 4).…”

Sarcocinerenoids A—J, Eight Rare Capnosane‐Type and Two New Cage‐Type Cembranoids with Promoting Angiogenesis Activity from the South China Sea Soft Coral Sarcophyton cinereum

“…The absolute configuration of 4 was validated by fitting the experimental ECD spectra with the calculated ECD, determined using the TDDFT/ECD method at the RB3LYP/DGDZVP level. [ 34 ] The ECD calculations were performed for 4 (3 S 4 R 7 S 11 S 12 R 15 S ) and 4 ’ (3 R 4 S 7 R 11 R 12 S 15 R ), respectively (Figure 5). And the results showed that the absolute configuration of 4 was 3 S 4 R 7 S 11 S 12 R 15 S .…”

Computational Thermo-chemical Study of Enthalpies of formation of β-Alkylthiophenes Using Ab Initio and DFT Calculations

“…Over the past years, theoretical calculations based on the ab initio and DFT calculations have been employed to investigate the different aspects related to the molecular and electronic structures of thiophene and its substituted derivatives. [20][21][22][23][24][25][26][27] Theoretical investigations carried out on a series of substituted thiophenes are, thereby, desirable for designing novel functional materials, and this is the main purpose of the current work. In the previous works, [28][29][30][31] we have studied a series of substituted pyrroles and thiophenes as potential monomers for the synthesis of conductive polymers and the corresponding oligomers with modified physical and electrical characteristics.…”