• 제목/요약/키워드: supramolecular

검색결과 125건 처리시간 0.027초

Synthesis and Hydrogen-Bonded Supramolecular Assembly of trans-Dihydroxotin(IV) Tetrapyridylporphyrin Complexes

  • Jo, Hwa-Jin;Jung, Su-Hee;Kim, Hee-Joon
    • Bulletin of the Korean Chemical Society
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    • 제25권12호
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    • pp.1869-1873
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    • 2004
  • trans-Dihydroxo[5,10,15,20-tetrakis(n-pyridyl)porphyrinato]tin(IV) (n = 3 and 4) complexes have been synthesized and fully characterized. X-ray structural analysis of trans-dihydroxo[5,10,15,20-tetrakis(4-pyridyl)porphyrinato]tin(IV) reveals that the supramolecular hydrogen bondings between the hydroxotin(IV) porphyrins and lattice water molecules form a hydrogen-bonded two-dimensional network. The hydrogen bonding mode between the tin(IV) porphyrins and the water molecules closely resembles that of the hydrogenbonded outer-sphere intermediate in the acidolysis of dihydroxotin(IV) porphyrins.

One-step Synthesis of Supramolecular Rectangles Starting from ($\eta^5$-Pentamethylcyclopentadienyl)rhodium(III) Aqua Complex

  • 한원석;이순원
    • 한국결정학회:학술대회논문집
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    • 한국결정학회 2002년도 정기총회 및 추계학술연구발표회
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    • pp.27-27
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    • 2002
  • [Cp*Rh(H₂O)₃](OTf)₂ (1) reacts with a stoichiometric amount of A and B [ A = Me₃SiN₃, B = 4,4'-bipridyl, (2a), A = Me₃SiNCO, B = 4,4'-bipridyl (2b)] in acetone at room temperature for 3 h to give the supramolecular complexes [Cp*₄Rh₄(μ-A)₄(μ-B)₂] [A = Me₃SiN₃, B = 4,4'-bipridyl, (2a), A = Me₃SiNCO, B = 4,4'-bipridyl (2b)]. Complexes 2a and 2b have been structurally characterized by X-ray diffraction.

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Visualizing Halogen Bonds in a Two-dimensional Supramolecular System

  • 윤종건;손원준;정경훈;김호원;한승우;강세종
    • 한국진공학회:학술대회논문집
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    • 한국진공학회 2011년도 제40회 동계학술대회 초록집
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    • pp.38-38
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    • 2011
  • Covalently bonded halogen ligands possess unusual charge distributions, attracting both electrophilic and nucleophilic molecular ligands to form halogen bonds. In many biochemical systems, halogen bonds and hydrogen bonds coexist. The interplay between halogen and hydrogen bonds has been actively studied in various three-dimensional bulk molecular co-crystals. It was found that halogen bonds could be complementary to hydrogen bonds due to their similar bond strength and dissimilar directionality. In those ensemble-averaging approaches, however, it was not possible to extract local information such as individual bond configurations and nano-level domain structures, which is a crucial part of supramolecular studies. In this study, we directly visualize the individual molecular configuration of a brominated molecule and the role of halogen bonds on Au(111) using scanning tunneling microscopy. The precise arrangement of observed molecular structures was reproduced by first-principle studies and explained in the context of halogen and hydrogen bonds. We discuss the distances and the strengths of the observed halogen bonds and hydrogen bonds, which are consistent with previous bulk data.

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Supramolecular Micelle from Amphiphilic Mn(III)-porphyrin Derivatives as a Potential MRI Contrast Agent

  • Choi, Kwang-Mo;Lee, Do-Hyung;Jang, Woo-Dong
    • Bulletin of the Korean Chemical Society
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    • 제31권3호
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    • pp.639-644
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    • 2010
  • Amphiphilic porphyrin derivatives have been synthesized and characterized by $^1H$ NMR and MALDI-TOF-MS. All porphyrin derivatives showed very high solubility to aqueous medium as well as hydrophobic organic solvent. The UV-vis absorption of the porphyrin derivatives showed significant broadness and decrease of maximum intensity of absorption in aqueous solution. SEM experiment showed the formation of spherical micellar structure. The $T_1$ relaxation time of aqueous medium was drastically decreased in the presence of Mn(III)-porphyrin derivative, indicating that the supramolecular micelle has strong possibility to use as a $T_1$ contrast agent.

Ultrasonication-Induced Changes in Physicomechanical and Tribotechnical Properties of PTFE Composites

  • Argunova, Anastasiia G.;Petrova, Pavlina N.;Okhlopkova, Aitalina A.;Shadrinov, Nikolay V.;Gogoleva, Olga V.;Cho, Jin-Ho
    • 대한화학회지
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    • 제59권3호
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    • pp.233-237
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    • 2015
  • The effect of ultrasonication on PTFE and its composites with zeolite and fluoroplast F-4NTD-2 was studied. Ultrasonication was found to cause changes in the supramolecular structure, and consequently, the tensile strength, relative elongation, and mass wear rate. Changes in the topology of the materials following ultrasonication were investigated by scanning electron microscopy. The optimum enhancement of the desired properties was found in the PTFE composite containing 2% activated zeolite.