28 research outputs found

    Novel dipolar 5,5,10,10-tetraphenyl-5,10-dihydroindeno[2,1-a]-indene derivatives for SM-OPV: A combined theoretical and experimental study

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    [[abstract]]In order to investigate the photo-physical, electrochemical, and optoelectronic properties of dipolar 5,5,10,10-tetraphenyl-5,10-dihydroindeno[2,1-a]-indene (TDI) derivatives, a facile synthesis has been developed to integrate arylamine (electron donor fragment, D) and aryl-2-methylenemalononitrile (electron acceptor fragment, A) into the TDI bridge. According to calculation results using the DFT/B3LYP/6-31G(d) method, the HOMO and LUMO energies of TDI derivatives are relevant to the extent of corresponding electron donating and accepting abilities, and influence the open-circuit voltage (Voc) and driving force (ΔE) in organic photovoltaics (OPV). The projected density of state (pDOS) analysis shows that the electron density distribution from the D fragment to TDI bridge in the HOMO is attributing to the electron-donating ability, whereas the electrons are mainly localized on A fragment in the LUMO. Calculations of the reorganization energy by the DFT/B3LYP/6-31G(d) method suggest these D-TDI-A derivatives are hole-transporting type materials. On the other hand, the calculated absorption spectra for these molecules in CH2Cl2 are simulated by using the TD-DFT/BH and HLYP/6-31G(d) method within the Polarizable Continuum Model (PCM) and provide the maximum absorption wavelength (λmax), which can be assigned to the HOMO to LUMO transition. HOMO is found to be the π orbital which is delocalized between the D fragment and the π-linker and LUMO is the π∗ orbital which is concentrated on the A fragment. The optical properties of D-TDI-A derivatives can be influenced by the D fragment and π-conjugated length. Calculated results of D-TDI-A derivatives also exhibited a large light harvesting efficiency related to the maximum absorption wavelength (RLHE)) and, according to these results, the D-TDI-A derivatives containing the Ab and Ad fragments would be useful electron donor materials for further development of new small molecular organic photovoltaic solar cell (SM-OPV) devices.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙

    Investigation of Photophysical Properties of mer-Tris(8-hydroxyquinolinato) Aluminum (III) and Its Derivatives: DFT and TD-DFT Calculations

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    100學年度研究獎補助論文[[abstract]]Optimized structures and photophysical properties of mer- and fac-Alq3 have been generated by using density functional theory (DFT) and time-dependent density functional theory (TD-DFT). Investigating the substitution effect in the Alq3 derivatives, the role of the electron-donating (CH3- and NH2-) and electron-withdrawing (F-, CN-, NO2- and phenyl-) groups with 2- to 7-substitution have been analyzed. According to the calculation results, the 4- and 5- substituted Alq3 exhibit an apparent spectral shift relative to the non-substituted Alq3. The HOMO, LUMO, Eg (the energy gap between LUMO and HOMO), View the MathML source (maximum absorption wavelength) and f (the relative oscillator strength) of mer-Alq3 with the 4- or 5-phenyl substitution on the quinoline ligand in the ground electronic state were calculated by using the DFT/B3LYP/6-31G(d) and TD-DFT methods. 5-phenyl substituted mer-Alq3 with an electron-donating substituent showed an increase in the π-delocalization as compared to the 4-phenyl substituted mer-Alq3 derivatives. Similarly, 4-phenyl substituted mer-Alq3 with electron-withdrawing substituents also exhibits increased π-delocalization in the pyridine ring as compared to the non-substituted Alq3. Replacing the CH group at the 4, 5 and 4,5 positions of the quinoline ligand of mer-Alq3 with the aza group (nitrogen atom) gives three Alq3 analogous: AlX3, Al(NQ)3 and Al(NX)3; the calculated energy gap Eg of these derivatives decreases in the order Al(NQ)3>Al(NX)3>AX3. Four quinoline with group III metals Mq3 complexes were investigated for the photophysical properties; the calculated energy gap Eg decreases in the order Tlq3>Inq3>Gaq3>Alq3. The photophysical properties of 4-hydroxy-8-methyl-1,5-naphthyridine (mND) chelated with group III metals (MmND3 complexes) were investigated also; their calculated Eg have the opposite order as those of Mq3 complexes.[[incitationindex]]SCI[[booktype]]紙

    Theoretical investigation of conformational stabilities and 13C NMR chemical shifts of a seven-membered ring thiosugar, (3R,4R,5R,7S)-7-(hydroxymethyl)thiepane-3,4,5-triol

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    [[abstract]]DFT/B3LYP/6-311++G(d,p) calculations have been performed to obtain optimized structures for fourteen conformers of (3R,4R,5R,7S)-7-(hydroxymethyl)thiepane-3,4,5-triol. These conformers are considered as the twist-chair (TC) and twist-boat (TB) conformations. Among all conformers, the TCS5 and TCS6 conformers appear to be the most energetically stable since they contain an intramolecular hydrogen bond between hydroxyl group at C(8) and S atom. Boltzmann weighting factor analysis provides valuable information on the population of the fourteen conformers, including both the TC and TB conformations. The analysis results demonstrate that the TCS2, TCS5, and TCS6 conformers provide a major population contribution with Boltzamann weighting factors larger than 7% as compared to other conformers. For these conformers of (3R,4R,5R,7S)-7-(hydroxymethyl)thiepane-3,4,5-triol, the GIAO/HF, GIAO/DFT/OPBE, GIAO/DFT/B3LYP and GIAO/DFT/mPW1PW91 calculations with the 6-311++G(d,p), 6-311+G(2d,p), cc-pVDZ and cc-pVTZ basis sets were used to obtain their 13C NMR chemical shifts. The calculated 13C NMR chemical shifts of the TCS2, TCS5, and TCS6 conformers show a close correlation with experimental data, within 2.4–3.0 ppm of MAE values. The experimental 13C NMR chemical shifts represent a combination of contributions from all the conformers. In our investigation, the calculated 13C NMR chemical shifts of the mixture of (3R,4R,5R,7S)-7-(hydroxymethyl)thiepane-3,4,5-triol conformers display a remarkable MAE and RMS improvement comparing to those for each individual conformer. The most appropriate calculation method and basis set to evaluate the theoretical 13C NMR chemical shifts for these conformers are OPBE/6-311+G(2d,p). Calculated results represent that the conformation of (3R,4R,5R,7S)-7-(hydroxymethyl)thiepane-3,4,5-triol can be determined by the intramolecular hydrogen bond which could be simulated by the 13C NMR chemical shift calculation.[[notice]]補正完畢[[incitationindex]]SCI[[booktype]]紙

    Substituted group and side chain effects for the porphyrin and zinc(II)–porphyrin derivatives: A DFT and TD-DFT study

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    [[abstract]]The DFT/B3LYP/LANL2DZ and TD-DFT calculations have been performed to generate the optimized structures, electronic and photo-physical properties for the porphyrin and zinc(II)–porphyrin (metalloporphyrin) derivatives. The substituted group and side chain effects for these derivatives are discussed in this study. According to the calculation results, the side chain moiety extends the π-delocalization length from the porphyrin core to the side chain moiety. The substituted group with a stronger electron-donating ability increases the energy level of highest occupied molecular orbital (EHOMO). The side chain moiety with a lower resonance energy decreases EHOMO, the energy level of the lowest unoccupied molecular orbital (ELUMO), and the energy gap (Eg) between HOMO and LUMO in the porphyrin and zinc(II)–porphyrin derivatives. The natural bonding orbital (NBO) analysis determines the possible electron transfer mechanism from the electron-donating to -withdrawing groups (the side chain moiety) in these porphyrin derivatives. The projected density of state (PDOS) analysis shows that the electron-donating group affects the electron density distribution in both HOMO and LUMO, and the side chain moiety influence the electron density distribution in LUMO. The calculated photo-physical properties (absorption wavelengths and the related oscillator strength, f) in dichloromethane environment for porphyrin and zinc(II)–porphyrin derivatives have been simulated by using the TD-DFT method within the Polarizable Continuum Model (PCM). The present of both of the substituted group and the side chain moiety in these derivatives results in a red shift and broadening of the range of the absorption peaks of the Q/Soret band as compared to porphin.[[incitationindex]]SCI[[booktype]]紙

    Photo-physical Properties of N-methyl-3,4-fulleropyrrolidine and Its Derivatives: A DFT and TD-DFT Investigation

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    [[abstract]]A series of N-methyl-3,4-fulleropyrrolidine (NMFP) derivatives were designed by selecting different π-conjugated linkers and electron-donating groups as D-π-A and D-A systems. The optimised structures and photo-physical properties of NMFP and its derivatives have been determined using density functional theory (DFT) and time-dependent density functional theory (TD-DFT) methods with the B3LYP functional and the 6-31G basis set. According to the computation analysis, both the π-conjugated linkers and the electron-donating groups can influence the electronic and photo-physical properties of the NMFP derivatives. Our calculated results demonstrated that the electron-donating groups, with significant electron-donating ability, had the tendency to increase the highest occupied molecular orbital (HOMO) energy. The π-conjugated linkers with lower resonance energy decreased the lowest occupied molecular orbital (LUMO) energy and caused a significant decrease in the energy gap (Eg) between the EHOMO and ELUMO. A Natural Bond Orbital (NBO) analysis examines the effect of the electron-donating group, π conjugated linker, and electron-withdrawing group for these NMFP derivatives. For the NMFP derivatives, a projected density of state (PDOS) analysis demonstrated that the electron density of HOMO and LUMO are concentrated on the electron-donating group and the π-conjugated linker, respectively. A TD-DFT/B3LYP calculation was performed to calculate the electronic absorption spectra of these NMFP derivatives. Both the electron-donating group and the π-conjugated linker contribute to the major absorption peaks, which are assigned as HOMO to LUMO transitions and are red-shifted relative to those of non-substituted NMFP.[[incitationindex]]SCI[[booktype]]電子

    Effects of Luteolin on Human Breast Cancer Using Gene Expression Array: Inferring Novel Genes

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    Taraxacum officinale (dandelion) is often used in traditional Chinese medicine for the treatment of cancer; however, the downstream regulatory genes and signaling pathways mediating its effects on breast cancer remain unclear. The present study aimed to explore the effects of luteolin, the main biologically active compound of T. officinale, on gene expression profiles in MDA-MB-231 and MCF-7 breast cancer cells. The results revealed that luteolin effectively inhibited the proliferation and motility of the MDA-MB-231 and MCF-7 cells. The mRNA expression profiles were determined using gene expression array analysis and analyzed using a bioinformatics approach. A total of 41 differentially expressed genes (DEGs) were found in the luteolin-treated MDA-MB-231 and MCF-7 cells. A Gene Ontology analysis revealed that the DEGs, including AP2B1, APP, GPNMB and DLST, mainly functioned as oncogenes. The human protein atlas database also found that AP2B1, APP, GPNMB and DLST were highly expressed in breast cancer and that AP2B1 (cut-off value, 75%) was significantly associated with survival rate (p = 0.044). In addition, a Kyoto Encyclopedia of Genes and Genomes pathway analysis revealed that the DEGs were involved in T-cell leukemia virus 1 infection and differentiation. On the whole, the findings of the present study provide a scientific basis that may be used to evaluate the potential benefits of luteolin in human breast cancer. Further studies are required, however, to fully elucidate the role of the related molecular pathways

    Passive Leg Raising Correlates with Future Exercise Capacity after Coronary Revascularization.

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    Hemodynamic properties affected by the passive leg raise test (PLRT) reflect cardiac pumping efficiency. In the present study, we aimed to further explore whether PLRT predicts exercise intolerance/capacity following coronary revascularization. Following coronary bypass/percutaneous coronary intervention, 120 inpatients underwent a PLRT and a cardiopulmonary exercise test (CPET) 2-12 days during post-surgery hospitalization and 3-5 weeks after hospital discharge. The PLRT included head-up, leg raise, and supine rest postures. The end point of the first CPET during admission was the supra-ventilatory anaerobic threshold, whereas that during the second CPET in the outpatient stage was maximal performance. Bio-reactance-based non-invasive cardiac output monitoring was employed during PLRT to measure real-time stroke volume and cardiac output. A correlation matrix showed that stroke volume during leg raise (SVLR) during the first PLRT was positively correlated (R = 0.653) with the anaerobic threshold during the first CPET. When exercise intolerance was defined as an anaerobic threshold < 3 metabolic equivalents, SVLR / body weight had an area under curve value of 0.822, with sensitivity of 0.954, specificity of 0.593, and cut-off value of 1504·10-3mL/kg (positive predictive value 0.72; negative predictive value 0.92). Additionally, cardiac output during leg raise (COLR) during the first PLRT was related to peak oxygen consumption during the second CPET (R = 0.678). When poor aerobic fitness was defined as peak oxygen consumption < 5 metabolic equivalents, COLR / body weight had an area under curve value of 0.814, with sensitivity of 0.781, specificity of 0.773, and a cut-off value of 68.3 mL/min/kg (positive predictive value 0.83; negative predictive value 0.71). Therefore, we conclude that PLRT during hospitalization has a good screening and predictive power for exercise intolerance/capacity in inpatients and early outpatients following coronary revascularization, which has clinical significance
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