• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2010년도 제3회 국제학회
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• pp.134-134
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• 2010

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2004년도 추계학술발표회 논문집
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• pp.274-275
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• 2004

The majority of dyes belong to the chromophoric class known as donor-acceptor systems, the essential structural feature of such systems being the presence of one or more electron donating groups conjugated to one or more electron withdrawing groups via an unsaturated bridge. The indigo molecule may be formally divided into two identical electron donor/acceptor subsystems, each containing an add number of pi electrons, two subsystems being joined by carbon-carbon double bond. Indigoid type dyes which show a strong colour change on protonation or dissociation have many potential functional applications, for example as analytical pH indicators, solvent polarity indicators, and in various imaging and reprographic systems.

• Bulletin of the Korean Chemical Society
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• 제35권6호
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• pp.1670-1674
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• 2014

Two red emitters, 2-(7-(4-(diphenylamino)styryl)-2-methyl-4H-chromen-4-ylidene)malonitrile (Red 1) and 2-(7-(julolidylvinyl)-2-methyl-4H-chromen-4-ylidene)malonitrile (Red 2) have been designed and synthesized for application as red-light emitters in organic light emitting diodes (OLEDs). In these red emitters, the julolidine and triphenyl moieties were introduced to the emitting core as electron donors, and the chrome-derived electron accepting groups such as 2-methyl-(4H-chromen-4-ylidene)malononitrile were connected to electron donating moieties by vinyl groups. To explore the electroluminescence properties of these materials, multilayered OLEDs using red materials (Red 1 and Red 2) as dopants in $Alq_3$ host were fabricated. In particular, a device using Red 1 as the dopant material showed maximum luminous efficiencies and power efficiencies of 0.82 cd/A and 0.33 lm/W at $20mA/cm^2$. Also, a device using Red 2 as a dopant material presented the CIEx,y coordinates of (0.67, 0.32) at 7.0 V.

• 한국진공학회:학술대회논문집
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• 한국진공학회 2011년도 제40회 동계학술대회 초록집
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• pp.336-336
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• 2011

Over the past decades, organic semiconductors have been investigated intensely for their potential in a wide range of optoelectronic device applications since the organic materials have advantages for very light, flexible and low cost device fabrications. In this study, we fabricated small-molecule organic solar cells (OSCs) based on chloro[subphthalocyaninato]boron(III) (SubPc) as an electron donor and $C_{60}$ as an electron acceptor material. Recently SubPc, a cone-shaped molecule with $14{\pi}$-electrons in its aromatic system, has attracted growing attention in small-molecule OSC applications as an electron-donating material for its greater open-circuit voltage (VOC), extinction coefficient and dielectric constant compared to conventional planar metal phthalocyanines. In spite of the power conversion efficiency (PCE) enhancement of small-molecule OSC using SubPc and $C_{60}$, however, the study on the interface between donor-acceptor heterojunction of this system is limited. In this work, SubPc thin films at various thicknesses were deposited by organic molecular beam deposition (OMBD) and the evolution of surface morphology was observed using atomic force microscopy (AFM) and field emission scanning electron microscopy (FE-SEM). We also investigated the influence of film thickness and surface morphology on the PCE of small-molecule OSC devices.

• EDISON SW 활용 경진대회 논문집
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• 제6회(2017년)
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• pp.128-131
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• 2017

We explore the inverse electron demand Diels-Alder reactions of tetrazines with various functional groups employing quantum calculations. In general, the rate of inverse electron demand Diels-Alder reaction depends on molecular orbital levels of electron donor and electron acceptor. Likewise, ${\pi}$ orbital of the dienophile and ${\pi}^*$ orbital of the diene is a key factor. In this work, we discuss the case where the energy of diene's ${\pi}^*$ molecular orbital is not the sole governing factor to determine the reaction rate, rather the rate shows strong correlation with the charge density of dienes.

• Bulletin of the Korean Chemical Society
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• 제27권9호
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• pp.1297-1304
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• 2006

A systematic study of the structure, energetics and spectral characteristics of substituted aminoketenes $R(NH_2)$C=C=O (R = H, $CH_3$, $NH_2$, OH, $OCH_3$, CH=$CH_2$, C$\equiv$CH, CN, CHO, NO, $NO_2$) which are highly reactive and transient intermediates in synthesis has been conducted by ab initio calculations at the MP2/6- 31G*//MP2/6-31G* level. Twenty four stable isomers of the eleven substituted aminoketenes having dihedral angles $\phi NH_2\sim120{^{\circ}}$ and $60^{\circ}$ have been identified and their optimized geometries and energies obtained. Electrostatic and steric effects on the molecular geometries have been analyzed. While the $\pi$-acceptor groups lead to planar conformations, the electron-donor groups give rise to non-planar conformations. Isodesmic substituent stabilization energies relative to alkenes have been calculated and correlation with group electronegativities established. Role of induction effect by the substituent groups and resonance effects in charge distribution in the molecules has been analyzed. An analysis of the asymmetric stretching frequencies and intensities of the C=C=O group shows that affect of non-$\pi$ acceptor substituents on the frequency is determined by the field effect (F) and resonance effect (R) parameters, the calculated intensities I (km/mol.) are correlated to group electronegativities $x$ of the substituents by the relationship I = 640.2–100.1 $x$ (r = 0.92). The $\pi$-acceptor substituents increase the intensity which may be explained in terms of their delocalizing effect on the negative charge at the $C_{\beta}$ atom.

• 대한화학회지
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• 제36권6호
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• pp.802-811
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• 1992

카르벤-올레핀-전이금속착물들[$(CO)_4M=CHX(CH_2=CH_2)$] (X: $OCH_3,\;NHCH_3,\;SCH_3$, M: C, Mo, W)의 형태에 대하여 확장된 Huckel 방법으로 계산하여 연구하였다. $d^6$ 전이금속 8면체 착물에서는 두 개의 인자 즉 금속에서 리간드로의 역제공과 리간드-리간드 상호작용이 안정한 형태를 결정해 준다는 사실이 밝혀졌지만 카르벤에 $\pi$-전자를 수용하는 리간드와 $\pi$-전자를 주는 기가 배위되어 있을 때 리간드-리간드 상호작용이 우세하므로 착물이 형태를 결정해 주는 주요한 인자라고 예측된다.

• Bulletin of the Korean Chemical Society
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• 제35권2호
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• pp.587-596
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• 2014

A new ${\pi}$-stacked donor-acceptor (D-A) system, [Ru(1-([2,2'-bipyridine]-6-yl-methyl)-3-(2-cyclohexa-2',5'-diene-1,4-dionyl)-1H-imidazole)(2,2':6',2"-terpyridine)]$[PF_6]_2$ (ImQ_T), has been synthesized and characterized. Similar to its precedent, [Ru(6-(2-cyclohexa-2',5'-diene-1,4-dione)-2,2':6',2"-terpyridine)(2,2':6',2"-terpyridine)]$[PF_6]_2$ (TQ_T), this system has a cofacial alignment of terpyridine (tpy) ligand and quinonyl (Q) group, which facilitates an electron transfer through ${\pi}$-stacked manifold. Despite the presence of lowest-energy charge transfer transition from the Ru-based-HOMO-to-Q-based-LUMO (MQCT) predicted by theoretical calculations by using time-dependent density functional theory (TD-DFT), the experimental steady-state absorption spectrum does not exhibit such a band. The selective excitation to the Ru-based occupied orbitals-to-tpy-based virtual orbital MLCT state was thus possible, from which charge separation (CS) reaction occurred. The photo-induced CS and thermal charge recombination (CR) reactions were probed by using ultrafast visible-pump/mid-IR-probe (TrIR) spectroscopic method. Analysis of decay kinetics of Q and $Q^-$ state CO stretching modes as well as aromatic C=C stretching mode of tpy ligand gave time constants of <1 ps for CS, 1-3 ps for CR, and 10-20 ps for vibrational cooling processes. The electron transfer pathway was revealed to be Ru-tpy-Q rather than Ru-bpy-imidazol-Q.

• 한국염색가공학회:학술대회논문집
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• 한국염색가공학회 2011년도 제44차 학술발표회
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• pp.63-63
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• 2011

The donor-${\pi}$-acceptor (D-${\pi}$-A) chromophoric dye system has received great attention in variety fields such as electroluminescent materials, sensors and optoelectronic devices. There are many research activities focused on the development for abovementioned application materials with the high-performance properties. In the previous work, we are reported that novel D-${\pi}$-A dye, 2-[4-(9H-carbazol-9-yl)benzylidene]-2,3-dihydroinden-1-one, is successfully attained and exhibited a positive fluorescence solvatochromism. In this work, the molecular structure and packing geometry of 2-[4-(9H-carbazol-9-yl)benzylidene]-2,3-dihydroinden-1-one was discussed by their conformational structure. Their single yellow prism crystal having approximate dimensions of $0.30{\times}0.10{\times}0.10$ mm was carried out with a Rigaku RAXIS RAPID imaging plate area detector with graphite monochromated $CuK_{\alpha}$ radiation. Their crystal structure were solved by using the CrystalStructure crystallographic software package.

• 대한화학회지
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• 제18권2호
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• pp.85-96
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• 1974

$C_6H_5YCH_2Cl$(Y=None, -$CH_2$-,-O-,-S-,-CO-,-$SO_2$-)에 대하여 EHT및 CNDO/2 MO계산을 행하고 이에 bond index 해석법을 적용하여, 분자내의 하전분포는 주로 원자가 비활성 전자의 이동에 기인되며, -O->-S->-$CH_2$-$SO_2$-의 순서로 ${\sigma}$-전자받게의 특성과 ${\pi}$-전자주게의 특성을 나타내며 -CO-는 ${\sigma}$-전자주게, ${\pi}$-전자받게로 작용함을 밝혔다. 또한 $C_6H_5YCH_2Cl$의 $S_N2$반응성이 현저한 용매효과가 없을 때 -O-${\thickapprox}$-CO->>-S-${\thickapprox}$None>-$CH_2$-의 순일 것으로 제안하였으며 실험 사실과 거의 일치함을 알았다. 이로부터 $S_N$형 반응에 크게 영향을 미치는 효과는 용매효과를 제안하였으며 실험 사실과 거의 일치함을 알았다. 이로 부터 SN형 반응에 크게 영향을 미치는 효과는 용매효과를 제외하면 반응중심의 양(+)하전 크기, C-Cl 결합에 대하여 ${\sigma}$-반결합성인 비점유궤도함수의 에너지 및 그 준위에서의 C-Cl간 반결합성이 경쟁적으로 작용할 것임을 밝혔다.