• Korean Journal of Materials Research
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• v.19 no.9
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• pp.510-515
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• 2009

The compound of 2,6-Bis[(9-phenylcarbazolyl)ethenyl]naphthalene (BPCEN-1), 2-[6-{1-Cyano-2-(9-phenylcarbazoly)vinyl}naphthyl]-3-(9-phenylcarbazolyl)acrylonitrile (BPCEN-2), 2,6-Bis[{4-(1-naphthy l)phenylamino} styrenyl] naphthalene (BNPASN-1), 2-[6-{1-Cyano-2-(naphthylphenylaminophenyl) vinyl}naphthyl]-3-(naphthylphenylaminophenyl)acrylonitrile (BNPASN-2) was analyzed electrochemically and spectroscopically and can be obtained by bonding phenylcarbazolyl, naphthylphenylaminophenyl and -CN ligands to 2,7-naphthalene. The electrochemical and spectroscopic study resulted in the P-type (BPCEN-1, BNPASN-1) being changed to N-type (BPCEN-2, BNPASN-2) according to -CN bonding despite having the same structure. The value of band gap(Eg) was revealed to be small as HOMO had shifted higher and LUMO lower. The Eg value for naphthylphenylaminophenyl ligand was reduced because it has a smaller HOMO/LUMO value than that of phenylcarbazolyl from a structural perspective. The electrochemical HOMO/LUMO values for BPCEN-1, BPCEN-2, BNPASN-1, BNPASN-2 were measured to be 5.55eV / 2.83eV, 5.73eV / 3.06eV, 5.48eV / 2.78eV, and 5.53eV / 2.98eV, respectively. By -CN ligand, the UV max, Eg and PL max were shifted to longer wavelength in their spectra and the luminescence band could be also confirmed to be broad in the photoluminescence (PL) spectrum.

• Bulletin of the Korean Chemical Society
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• v.29 no.6
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• pp.1141-1148
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• 2008

Geometry optimizations and electronic structure calculations are reported for meso-tetraphenyl porphyrin (TPP) and a series of meso-substituted catecholic porphyrins (KP99150, KP99151, KP99152, KP99153, and KP99090) using density functional theory (DFT). The calculated B3LYP//RHF bond lengths are slightly longer than those of LSDA//RHF. The calculated electronic structures clearly show that TPP and meso-catecholic group contribute to π-electron conjugation along porphyrin ring for HOMO and LUMO, significantly reduced the HOMO-LUMO gap. The wavelength due to B3LYP energy gaps is favored with experimental value in Soret (B), and LSDA energy gaps are favored with experimental value in visible bands (Q). The electronic effect of the catecholic groups is to reduced energies of both the HOMOs and LUMOs. However, the distortion of porphyrin predominantly raises the energies of the HOMOs, so the net result is a large drop in HOMO and smaller drop in LUMO energies upon meso-substituted catecholic group of the porphyrin macrocycle as shown in KP99151 and KP99152 of Figure 5(a). These results are in reasonable agreement with normal-coordinate structural decomposition (NSD) results. The HOMO-LUMO gap is an important factor to consider in the development of photodynamic therapy (PDT).

• Journal of the Korean Chemical Society
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• v.40 no.4
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• pp.229-234
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• 1996

Carcinogenicities of Benzo[a]pyrene(BP) and its metabolites were investigated by PM3. The 4, 5, 5a, and 6 positions forming transbutadiene(TB) frame in BP have been proved to be carcinogenic region by LUMO. We have found that the carcinogenic region of BP-triol, ultimate cacinogen, is shifted from 4, 5, 5a, and 6 positions of precarcinogen to 10, 10a, 12c, and 12b ones. The appreximate charge transfer quantities turned out to have the largest value between HOMO of Guanine and LUMO of BP-triol corresponding to TB region on each other.

• Applied Biological Chemistry
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• v.38 no.1
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• pp.90-94
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• 1995

Post emergence herbicidal activities$(pI_{50})$ of X-substituted phenylvinylsulfone derivatives(S) in-vivo against rice(Oryza sativa L.), Barnyard grass(Echinochloa crus-galli) and Pickerelweed(Monochoria vaginalis Presl) were measured by the pot test under paddy conditions. The (S) showed herbicidal symptom rapidly with lower activity(average $pI_{50}=2.0$) as proherbicide, which was excellent tolerance to rice. The structure activity relationships(SAR) were analyzed using such a physicochemical parameters as hydrophobic$({\pi})$ and molecular orbital(MO) quantity by the multiple regression technique, and discussed with quantum pharmacology. The herbicidal activities were related to the hydrophobic$({\pi})$ effect of X-substituent and orbital(HOMO & LUMO) energy. In case of Pickerelweed, the effect was rationalized by parabolic function of ${\pi}$ constant, where the optimal value of ${\pi}$ was 1.10. An increase in hydrophobicity and negative orbital energy by the electron attracting X-substituent may contribute to the herbicidal activity. Based on results proposed from SAR analysis, the mode of herbicidal action could be assumed.

• Journal of the Korean Chemical Society
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• v.37 no.4
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• pp.431-441
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• 1993

The structure and reactivity of ${\pi}$-and metallacycle form in the bis(trimethylphosphine) palladium(0) complexes with acrylic acid, methacrylic acid, crotonic acid(A group) and 3-butenoic acid, 4-pentenoic acid(B group) have been investigated by Molecular Mechanics and Extended Huckel Molecular Orbital method. The calculation shows that A groups with large value of frontier electron density of HOMO and LUMO produce $\pi-complexes$ instead of metallacycle. But B groups with small value of frontier electron density of LUMO, especially 3-butenoic acid, form stable metallacycle. Moreover the methyl-substituted five-membered compared with the six-membered metallacycle is energetically stable conformation.

• Applied Chemistry for Engineering
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• v.27 no.5
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• pp.467-471
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• 2016

New electron deficient moiety, 6,7-difluoro-2,3-dihexylquinoxaline, was developed for the push-pull type copolymer for organic photovoltaics (OPVs). The PFDTQxF with lower HOMO energy level was synthesized using fluorene and 6,7-difluoro- 2,3-dihexylquinoxaline by Suzuki polymerization. The PFDTQxF thin film shows two absorption peaks at 368 and 493 nm. The HOMO and LUMO energy levels of PFDTQxF are calculated -5.55 and -3.91 eV, respectively. The device comprising PFDTQxF showed a $V_{OC}$ value of 0.47 V, a $J_{SC}$ value of $4.48mA/cm^2$, and a FF of 0.32, which yielded PCE of 0.78%, under the illumination of AM 1.5.

• Applied Biological Chemistry
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• v.48 no.1
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• pp.82-88
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• 2005

3D QSAR studies for the fungicidal activities against resistive phytophthora blight (RPC; 95CC7303) and sensitive phytophthora blight (Phytopthora capsici) (SPC; 95CC7105) by a series of new 2-alkoxyphenyl-3-phenylthioisoindoline-1-one derivatives (X: A=propynyl & B=2-chloropropenyl) were studied using comparative molecular field analyses (CoMFA) methodology. The CoMFA models were generated from the two different alignment, atom based fit (AF) alignment and field fit (FF) alignment. The atom based alignment exhibited a higher statistical results than that of field fit alignment. The best models, A3 and A7 using combination fields of H-bond field, standard field, LUMO and HOMO molecular orbital field as additional descriptors were selected to improve the statistic of the present CoMFA models. The statistical results of the two models showed the best predictability of the fungicidal activities based on the cross-validated value $q^2\;(r^2_{cv.}=RPC:\;0.625\;&\;SPC:\;0.834)$, non cross-validated value $(r^2_{ncv.}=RPC:\;0.894\;&\;SPC:\;0.915)$ and PRESS value (RPC: 0.105 & SPC: 0.103), respectively. Based on the findings, the predictive ability and fitness of the model for SPC was better than that of the model for RPC. The fugicidal activities exhibited a strong correlation with steric $(66.8{\sim}82.8%)$, electrostatic $(10.3{\sim}4.6%)$ and molecular orbital field (SPC: HOMO, 12.6% and RPC: LUMO, 22.9%) factors of the molecules. The novel selective character for fungicidal activity between two fungi depend on the positive charge of ortho, meta-positions on the N-phenyl ring and size of hydrophilicity of a substituents on the S-phenyl ring.

• Journal of the Korean Chemical Society
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• v.39 no.5
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• pp.329-337
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• 1995

Energetic oxetane derivatives which undergo cationic polymerizations have been investigated theoretically by using ab initio HF/3-21G calculations. We have examined structures, charges, and molecular electrostatic potentials. The ring structure of oxetane has changed significantly due to (1) the introduction of large substituents in the ring or (2) the addition of either proton or BF3. This structural change is attributed to electrostatic interactions and/or steric repulsions. The nucleophilicity and basicity of oxetane derivatives can be explained by the negative charge and the minimum electrostatic potential value of O atom. The reactivity in the polymerization can be rationalized by (1) the basicity of O atom and (2) the difference between HOMO energy of oxetanes and LUMO energy of activated oxetane polymeric chains. Our calculations predict that 3-azidomethyl-3-methyl oxetane (AMMO) is more basic than 3-nitratomethyl-3-methyl oxetane (NMMO), and AMMO is more reactive toward both AMMO and NMMO polymeric chains. Our results are in good agreement with previous experimental data.

• Journal of the Korean Chemical Society
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• v.48 no.2
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• pp.123-128
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• 2004

Quantum chemical quantities, enthalpy of formation(${\Delta}H_f$), HOMO and LUMO energy, and dipole moment(${\mu}_D$) were acquired by AM1, PM3, and ZINDO/1 methods for polyamines and imidazole derivatives. The investigation of the inhibitory activity on some Ni(II) complexes with polyamines and imidazole derivatives is performed by ZINDO/1 calculations. It was found that experimental inhibitory activity(IA) appeared when the value of net charge and enthalpy of formation were over 0.03 and -300 eV, respectively for Ni(II) complexes. These results showed that the Ni(II) complexes have exception on the following very unstable compounds: square pyramidal [Ni(dpt)(tn)])]$^{2+}$(dpt=3,3'-diaminodipropylamine)(tn=1,3-diaminopropane) and distorted tetrahedral [Ni(N-PropIm))$_2$(NCS))$_2$](N-PropIm=N-Propylimidazole).

• Proceeding of EDISON Challenge
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• 2013.04a
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• pp.77-88
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• 2013

The computational study on the fluoride ion binding with bis(bora)calix[4]arene has been performed using density functional theory and ONIOM model. The computed structure and fluorescent behavior of bis(bora)calix[4]arene was corresponded to experiment value. The binding energy for fluoride anion is computed to be 28.05kJ/mol in the chloroform solution. We also predicted that this sensing mechanism is only valid for fluoride ion in halogens. By analyzing molecular orbitals, binding with fluoride ion reduces energy differences between HOMO and LUMO, which leads to fluorescent sensing.