• Bulletin of the Korean Chemical Society
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• v.33 no.4
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• pp.1264-1267
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• 2012

We rationally designed and synthesized metallopolymers with organic 1,4-benzenedicarboxylic acid (BDC) linkers with different lengths of oxyethylene side chains in order to examine the influence of side chains on the coordination characteristics. While in a previous report the BDC linkers with alkyl side chains were found to form three-dimensional (3D) isoreticular metal-organic framework (IRMOF) structures or one-dimensional (1D) coordination polymeric structures with short $-O(CH_2)_6CH_3$ or long $-O(CH_2)_9CH_3$ side chains, respectively, new BDC linkers with oxyethylene side chains of the same lengths, $-(OCH_2CH_2)_2CH_3$ and $-(OCH_2CH_2)_3CH_3$, form only 3D IRMOF structures. This result is attributed to the higher flexibility and smaller volume of oxyethylene side chains compared to alkyl side chains.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.08a
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• pp.92.1-92.1
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• 2013

Molecular electronics has been the subject of intese research for many years because of the fundamental interest in molecular charge transport and potential applications, such as (bio)nanosensors and molecular memory devices. Molecular electronics requires a method for making reliable eletrical contacts to singlemolecules. To date, several approaches have been reported: scanning-probe microscopy, mechanical break junctions, nano patterning, and direct deposition of electrode on a self-assembled monolayers. However, most methods are laborious and difficult for large-scale application and more importantly, cannot control the number of moleucles in the junction. Recently, DNA has been used as a template for metallic nanostructures (e.g., Ag, Pd, and Au nanowires) through DNA metallization process. Furthermore, oligodeoxynucleotides have been tethered to organic molecules by using conventional organic reactions. Collectively, these techniques should provide an efficient route toward reliable and reproducible molecular electronic devices with large-scale fabrication. Therefore, I will present a paradigm for the fabrication of moleuclar electronic devices by using micrometer-sized DNA-singe organic molecule and DNA triblock structures.

• Korean Journal of Pharmacognosy
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• v.7 no.3
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• pp.159-169
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• 1976

The present review records the known structures of more than 80 organic compounds containing halogens, which may be considered naturally occurring. The format of the review is based on the viewpoint of biochemists. Compounds containing one type of halogen atom have been placed in one of four major division, i.e., structures possessing fluorine, chlorine, bromine or iodine covalently bonded to carbon. Within each major division molecular structures are given along with the species from which the compounds have been isolated, The biological significance, if any, is also mentioned.

• Proceedings of the Korean Vacuum Society Conference
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• 2013.02a
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• pp.632-632
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• 2013

We generated single-crystal organic nanowire arrays using a direct printing method (liquidbridge- mediated nanotransfer molding) that enables the simultaneous synthesis, alignment and patterning of nanowires from molecular ink solutions. Using this method, single-crystal organic nanowires can easily be synthesized by self-assembly and crystallization of organic molecules within the nanoscale channels of molds, and these nanowires can then be directly transferred to specific positions on substrates to generate nanowire arrays by a direct printing process. The position of the nanowires on complex structures is easy to adjust, because the mold is movable on the substrates before the polar liquid layer, which acts as an adhesive lubricant, is dried. Repeated application of the direct printing process can be used to produce organic nanowire-integrated electronics with twoor three-dimensional complex structures on large-area flexible substrates. This efficient manufacturing method is used to fabricate all-organic nanowire field-effect transistors that are integrated into device arrays and inverters on flexible plastic substrates.

• 한국정보디스플레이학회:학술대회논문집
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• 2003.07a
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• pp.178-180
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• 2003

We performed semiempirical (AMl and ZINDO) and ab initio (HF and DFT) calculations, to investigate molecular structures and optical properties of DCM and its derivatives. DCM and its derivatives are used as a red fluorescent dopant of the organic electroluminescent host materials, $Alq_3$. We have studied the relationship between the molecular structure and the optical properties of these molecules for the improvement of EL efficiencies. Wavelength at the absorption maximum was found to be red-shifted when the molecule is substituted with both strong electron donating and withdrawing functional groups. A new red fluorescent dye was predicted by QSPR study based on calculations and experimental data.

• Journal of the Korean Applied Science and Technology
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• v.22 no.4
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• pp.299-305
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• 2005

In this study, we designed color of tunable and high efficient organic materials using the quantum dynamics and the semi-empirical calculation, and applied this results to the fabrication of organic light-emitting diodes. Also we optimized the molecular structure of phosphorescent materials and the energy transfer from a host to a dye which makes organic light-emitting diodes improve. Using quantum dynamics method, the molecular structures of ligand only and the whole metal chelate were optimized, and these energy levels were calculated. From this test results, we could understand the emission mechanism of phosphors with various ligands as well as design the proper ligands reducing the T-T annihilation and the carrier lifetime. We also could design ligands with various colors using this test method.

• Proceedings of the Korean Vacuum Society Conference
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• 2008.08a
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• pp.230-230
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• 2008

• Proceedings of the Korean Vacuum Society Conference
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• 2012.02a
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• pp.563-563
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• 2012

We report a one-step fabrication of single-crystal organic nanowire arrays on substrates using a new direct printing method (liquid-bridge-mediated nanotransfer moulding, LB-nTM), which can simultaneously enable the synthesis, alignment and patterning of the nanowires using molecular ink solutions. Two- or three-dimensional complex structures of various single-crystal organic nanowires were directly fabricated over a large area with a successive process. The position of the nanowires can be aligned easily on complex structures because the mold is movable on substrates before drying the polar liquid layer, which acts as an adhesive lubricant. This efficient manufacturing method can produce a wide range of optoelectronic devices and integrated circuits with single-crystal organic nanowires.

• Proceedings of the Korean Vacuum Society Conference
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• 2011.02a
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• pp.26-26
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• 2011

Self-assembled monolayers (SAMs) prepared by sulfur-containing organic molecules on metal surfaces have drawn much attention for more than two decades because of their technological applications in wetting, chemical and biosensors, molecular recognition, nanolithography, and molecular electronics. In this talk, we will present self-assembly mechanism and two-dimensional (2D) structures of various organic thiol SAMs on Au(111), which are mainly demonstrated by molecular-scale scanning tunneling microscopy (STM) observation. In addition, we will provide some idea how to control 2D molecular arrangements of organic SAMs. For instance, the formation and surface structure of pentafluorobenzenethiols (PFBT) self-assembled monolayers (SAMs) on Au(111) formed from various experimental conditions were examined by means of STM. Although it is well known that PFBT molecules on metal surfaces do not form ordered SAMs, we clearly revealed for the first time that adsorption of PFBT on Au(111) at $75^{\circ}C$ for 2 h yields long-range, well-ordered self-assembled monolayers having a $(2{\times}5\sqrt{13})R30^{\circ}$ superlattice. Benzenethiols (BT) SAMs on gold usually have disordered phases, however, we have clearly demonstrated that the displacement of preadsorbed cyclohexanethiol self-assembled monolayers (SAMs) on Au(111) by BT molecules can be a successful approach to obtain BT SAMs with long-range ordered domains. Our results will provide new insight into controlling the structural order of BT or PFBT SAMs, which will be very useful in precisely tailoring the interface properties of metal surfaces in electronic devices.

• Journal of The Korean Association For Science Education
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• v.27 no.6
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• pp.477-487
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• 2007

Previous studies show that students have difficulties in understanding and using molecular visualization tools. This study focuses on the ways in which first year chemistry undergraduates use ball-and-stick molecular models to explain the concept of addition reaction and the difficulties that they face using the models. Video recordings of interviews with undergraduates manipulating ball-and-stick models to solve problems related to reaction mechanisms are analysed to determine if they are able to elucidate their understanding with use of models. The results showed that students have difficulties with viewing the ball-and-stick models from the proper perspective and understanding the relationship between the various structures that they have created using the models. They also find the use of ball-and-stick models tedious and prefer drawing molecular structures on paper to explain their ideas. Implications for the teaching using ball-and-stick molecular models are discussed.