• 제목/요약/키워드: chemical interaction

검색결과 2,122건 처리시간 0.024초

Studies of Inter/intramolecular Weak Interactions with CH… S; and S…arene Interaction in Symmetrical and Dissymmetrical Models

  • Dubey, Rashmi;Tewari, Ashish K.;Ravikumar, K.;Sridhar, B.
    • Bulletin of the Korean Chemical Society
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    • 제31권5호
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    • pp.1326-1330
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    • 2010
  • Evidences have proved the versatile role of sulfur atom in supramolecular chemistry. $^1$Presence of S atom in the molecule usually results in the specific structural properties of molecules. In the present study, $S{\cdots}arene$, $N{\cdots}arene$, $CH{\cdots}{\pi}$, $CH{\cdots}S$ and $CH{\cdots}N$ type of weak interactions stabilize the conformation and self assembly of symmetrical as well as dissymmetrical molecules.

Calculation of NMR Chemical Shift for a 3d$^1$ System in a Strong Crystal Field Environment of Tetrahedral Symmetry (1). Application of the Expansion Method for a Spherical Harmonics for Derivation of Overlap and the Dipole Moment Matrix Elements of $\mid$4p > Atomic Orbitals and Derivation of the Radial Integrals for the Hyperfine Interaction for $\mid$4p > Atomic Orbitals

  • Ahn, Sang-Woon;Kim, Dong-Hee;Choi, Chang-Jin
    • Bulletin of the Korean Chemical Society
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    • 제7권4호
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    • pp.299-304
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    • 1986
  • Master formulas for overlap integrals and the dipole moments involving |4p > atomic orbitals have been derived by the expansion method for spherical harmonics. The radial integrals for the hyperfine interaction have also been derived for |4p > atomic orbitals. The calculated values of the overlap integrals and dipole moment matrix elements by the expansion method for spherical harmonics for a hypothetical NO molecule are exactly in agreement with those of Mulliken's method. The radial integrals for the hyperfine interaction may be used to calculate the chemical shift for |4p > atomic orbitals.

Molecular Recognition : ${\alpha}$-Cyclodextrin and Aspirin Inclusion Complexation

  • Hee Sook Choi
    • Bulletin of the Korean Chemical Society
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    • 제13권5호
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    • pp.474-479
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    • 1992
  • Molecular interaction between ${\alpha}$-cyclodextrin and aspirin was studied by UV, $^2H$-NMR and $^2H$-NMR spectroscopy analyses for solution complex and by FT-IR analyses for solid complex. The inclusion structure provides a basic understanding of the aspirin and ${\alpha}$-cyclodextrin interaction.

Hydrophobic Interaction between Rhodamine 6G and Tetraphenylborate Anions

  • Lee, Beom-Gyu;Jung, Rae-Seok;Kim, Kang-Jin
    • Bulletin of the Korean Chemical Society
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    • 제10권2호
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    • pp.158-161
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    • 1989
  • The hydrophobic interaction occurring between rhodamine 6G and tetraphenylborate anions has been investigated with surfactants by absorption and fluorescence studies. In the order of tetraphenylborate, tetrakis(4-fluorophenyl)borate, and tetrakis[3,5-bis(trifluoromethyl)phenyl]borate the hydrophobicity is found to be increased.

The Effects of Intramolecular Interactions of Random Copolymers on the Phase Behavior of Polymer Mixtures

  • Kim, M. J.;J. E. Yoo;Park, H. K.;Kim, C. K.
    • Macromolecular Research
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    • 제10권2호
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    • pp.91-96
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    • 2002
  • To explore the effects of intramolecular interactions within the copolymer on the phase separation behavior of polymer blends, copolymers having two different types of intramolecular interactions, i.e., intramolecular repulsion and intramolecular attraction were prepared . In this study, poly(styrene-co-methylmethacrylate) (P(S-MMA)) having intramolecular repulsion caused by positive interaction between styrene and MMA and poly(styrene-co-ethyl-methacrylate) (P(S-EMA)) and poly(styrene-co-cyclohexylmethacrylate) (P(S-CHMA)) having intramolecular attraction caused by negative interaction between styrene and methacrylate were blended with tetramethyl poly-carbonate (TMPC). The phase behavior of blends was examined as a function of copolymer composition and blend composition. TMPC formed miscible blends with styrenic copolymers containing less than certain amount of methacrylate. The phase separation temperature of TMPC blends with copolymer such as P(S-MMA) and P(S-EMA), first increases with methacrylate content, goes through a maximum and then decreases just prior to the limiting content of methacrylate for miscibility, while that of TMPC blends with P(S-CHMA) always decreases. The calculated interaction energy for TMPC-P(S-EMA) pair is negative and monotonically increases with EMA content of the copolymer. Such behavior contradicted the general notion that systems with more favorable energetic interactions have higher LCST, The detailed inspection of the lattice-fluid theory related to the phase behavior was performed to explain such behavior.

Formamide, Acetamide 및 Propionamide계에 대한 리튬염의 상호작용에 관한 $^{13}C$ nmr 연구 ($^{13}C$nmr Studies on the Interaction of Lithium Salts to Formamide, Acetamide and Propionamide Systems)

  • 신대호;이조웅;최영상
    • 대한화학회지
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    • 제26권5호
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    • pp.291-295
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    • 1982
  • Li염이 아미드와 상호작용할 때 카르보닐기와 알킬기의 $^{13}C$chemical shift는 낮은 양쪽으로 이동하였으며, $Li^+$이온이 카르보닐기에 직접 결합함을 보였다. $^{13}C$ chemical shift의 크기는 아미드에 붙어있는 알킬기의 크기뿐만 아니라 음이온과의 상호작용에 의해서 지배됨을 알았다. 전하밀도가 큰 $Cl^-$이온이 $LiClO_4^-$이온보다 큰 음이온 효과를 나타냄을 보인다.

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