• 대한화학회지
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• 제47권2호
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• pp.109-114
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• 2003

trans-$[CrX_2([15]aneN_4)]ClO_4 ([15]aneN_4=1,4,8,12-tetraazacyclopentadecane; X=F, Cl)$의 전자흡수 스펙트럼을 리간드장 이론으로 해석하였다. AOMX 프로그램을 사용하여 관측한 스핀허용 전이와 계산값을 최적화시켰다. 결정한 CFT 파라미터를 AOM, NSH 및 여러 가지 다른 파라미터와 관련시켜 구하고, 이를 화학적 견지에서 논의하였다. 리간드장 해석으로부터 이들 착물에서는 F 리간드가 강한${\sigma}-$ 및 ${\pi}-$주개인 반면에 Cl 원자는 Cr(III) 이온에 약한 ${\sigma}-$ 및 ${\pi}-$주개 성질이 있음을 확인할 수 있었다.

• Journal of Photoscience
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• 제7권1호
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• pp.21-26
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• 2000

The photoemission and excitation spectra of cis-[Cr(cyclam)F$_2$]ClO$_4$ (cyclam = 1,4,8,11-tetraazacy-clotetradecane) taken at 77 K are reported. The 298 K mid- and far-infrared spectra are also measured. The vibrational intervals of the electronic ground state are extracted from the far-infrared and emission spectra. The ten electronic bands due to spin-allowed and spin-forbidden transitions are assigned. The zero-phonon line In the excitation spectrum splits into two components by 169 cm$^{1}$, and the large $^2$E$_{g}$ splitting can be reproduced by the ligand field theory. According to the ligand field analysis, we can confirm that nitrogen atoms of the cyclam ligand have a strong c-donor character, and fluoride ligand also has strong $\sigma$- and $\pi$-donor properties toward chromium(III) ion.n.

• Journal of Photoscience
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• 제4권3호
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• pp.121-125
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• 1997

The 77 K emission and excitation, and room-temperature visible spectra of cis[Cr(cyclam)Br$_2$]Br (cyclam=1,4,8,11-tetraazacyclotetradecane) are reported. The mid- and far-infrared spectra at room-temperature are also measured. The vibrational intervals of the electronic ground state are extracted from the far-infrared and emission spectra. The ten electronic bands due to spin-allowed and spin-forbidden transitions are assigned. It is found that nitrogen atoms of the cyclam ligand have strong $\sigma$-donor characters, but bromide ligand has weak $\sigma$- and $\pi$-donor properties toward chromium(III) ion. The zerophonon line in the excitation spectrum splits into two components by 172 cm$^{2-}$, and the large $^2E_g$ splitting can be reproduced by the ligand field theory.

• 한국광과학회:학술대회논문집
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• 한국광과학회 2003년도 학술대회지
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• pp.22-22
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• 2003

• Bulletin of the Korean Chemical Society
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• 제15권2호
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• pp.145-150
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• 1994

The low temperature luminescence and excitation, room-temperature UV-visible and infrared spectra of [Cr(${\pm})chxn_3]Cl_3$ (chxn=trans-1,2-cyclohexanediamine) have been measured. It is found that the zero-phonon line in the excitation spectrum splits into two components by $47\;cm^{-1}$. The eight electronic transitions due to spin-allowed and spin-forbidden are assigned. As expected, nitrogen atoms of chxn ligand have strong ${\sigma}-donor $properties toward chromium(Ⅲ). The positions and splittings of sharp-line transitions are analyzed as a function of the Cartesian bite (${\alpha}$) and twist (${\beta}$) angles to predict the metal-ligand geometry.

• 대한화학회지
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• 제39권7호
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• pp.501-507
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• 1995

cis-$[Cr(cyclam)Cl_2]Cl$의 전자 구조를 77K의 방출 및 들뜬 상태 분광법을 비롯하여, 실온의 적외선과 가시선 분광법을 이용하여 연구하였다. 스핀-허용 및 스핀-금지에 해당하는 10개의 순수 전자전이의 성분을 배정하였다. 들뜬 상태 스펙트럼에서 0-0 띠는 $139\;cm^{-1}$로 분리되었으며, 이러한 갈라짐을 현대 리간드장 이론으로 재현할 수 있었다. 리간드장 해석의 결과에 의하면 cyclam의 N 원자는 Cr(III) 이온에 강한 ${\sigma}$-주개로 작용하는 반면에 Cl 리간드는 약한 ${\sigma}-$ 및 ${\pi}-$주개의 성질이 있음을 확인할 수 있었다.

• Interdisciplinary Bio Central
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• 제2권2호
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• pp.6.1-6.5
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• 2010

Fragment molecular orbital (FMO) method provides a novel tool for ab initio calculations of large biomolecules. This method overcomes the size limitation difficulties in conventional molecular orbital methods and has several advantages compared to classical force field approaches. While there are many features in this method, we here focus on explaining the issues related to protein-ligand binding: FMO method provides useful interaction-analysis tools such as IFIE, CAFI and FILM. FMO calculations can provide not only binding energies, which are well correlated with experimental binding affinity, but also QSAR descriptors. In addition, FMO-derived charges improve the descriptions of electrostatic properties and the correlations between docking scores and experimental binding affinities. These calculations can be performed by the ABINIT-MPX program and the calculation results can be visualized by its proper BioStation Viewer. The acceleration of FMO calculations on various computer facilities is ongoing, and we are also developing methods to deal with cytochrome P450, which belongs to the family of drug metabolic enzymes.

• Bulletin of the Korean Chemical Society
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• 제18권1호
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• pp.23-27
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• 1997

The luminescence and excitation spectra of [Cr(trans-diammac)](ClO4)3 (trans-diammac=trans-6, 3-dimethyl-l, 4, 8, 11-tetraazacyclotetradecane-6, 13-diamine) taken at 77 K are reported. The mid and far-infrared spectra at room-temperature are also measured between 4000 cm-1and 50 cm-1. In the excitation spectrum the 2Eg components are splitted by 102 cm-1. Using the observed electronic transitions, a ligand field analysis was performed to determine more detailed bonding properties of the coordinated atoms toward chromium(Ⅲ). According to the results, we can confirm that the six nitrogen atoms have a strong σ-donor character, and the trans-diammac secondary amine has a greater value of eσ than does the primary amine.

• 대한화학회지
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• 제58권6호
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• pp.681-685
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• 2014

• Bulletin of the Korean Chemical Society
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• 제32권1호
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• pp.296-298
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• 2011