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166 results on '"Lin, Ivan J. B."'

3. Probing C–H...X hydrogen bonds in amide-functionalized imidazolium salts under high pressure.

Author

Kwang Ming Lee, Jiang, Jyh-Chiang, Lu, Li-Chuan, Hsiao, Chia-Jung, Lee, Yi-Ting, Sheng Hsien Lin, Chang, Hai-Chou, and Lin, Ivan J. B.

Subjects
HYDROGEN bonding, HIGH pressure (Technology), IMIDAZOLES, INFRARED spectra, X-ray crystallography, AMIDES
Abstract

We have probed under high pressure the C–H hydrogen bonds formed by N,N′-disubstituted imidazolium ions having PF6- and Br- counterions. High-pressure infrared spectral profiles, x-ray crystallographic analysis, and ab initio calculations allow us to make a vibrational assignment of these compounds. The appearance of a signal for the free-NH unit (or weakly bonded N–H...F unit) in the infrared spectrum of the PF6- salt indicates that conventional N–H...O and N–H...N hydrogen bonds do not fully dominate the packing. It is likely that the charge-enhanced C2–H...F interactions, combined with other weak hydrogen bonds, disturb the formation of N–H hydrogen bonds in the PF6- salt. This finding is consistent with the pressure-dependent results, which reveal that the C2–H...F interaction is enhanced upon increasing the pressure. In contrast to the PF6- salt, the imidazolium C–H bonds of the Br- salt have low sensitivity to high pressure. This finding suggests that the hydrogen bonding patterns are determined by the relative hydrogen bond acceptor strengths of the Br- and PF6- ions. © 2004 American Institute of Physics. [ABSTRACT FROM AUTHOR]

Published
2004
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4. Charge-enhanced C–H[Single_Bond]O interactions of a self-assembled triple helical spine probed by high-pressure.

Author

Chang, Hai-Chou, Ming Lee, Kwang, Jiang, Jyh-Chiang, Lin, Ming-Shan, Chen, Jen-Shin, Lin, Ivan J. B., and Hsien Lin, Sheng

Subjects
HYDROCARBONS, HIGH pressure chemistry, DISPERSION (Chemistry)
Abstract

C-H—O interactions of a self-assembled triple helix based on the 1-acetamido-3(2-pyrazinyl)-imidazolium cation has been probed by high pressure. The infrared spectroscopic profiles and ab initio calculations allow us to make a vibrational assignment of this compound. The C-H bonds forming C-H—O interactions shorten as the pressure was elevated, while free C-H vibration modes show low sensitivity to high pressure. The pressure-dependent results can be attributed to the strengthening of C-H—O electrostatic-dispersion interactions upon increasing pressure. The appearance of the free-NH infrared absorption indicates that the conventional NH—O hydrogen bond does not dominate the inter-strand packing in the compound. It is proposed that the charge-enhanced C-H—O interactions, forming a helical hydrogen-bonding network, disturb the formation of inter-strand N-H—O hydrogen-bonding in order to form a maximum number of hydrogen bonds. Applying high-pressure seems not to change the C=O bond length in contrast to the trend of blue-shift in frequency of C-H vibrations. London dispersion energy is suggested to be required for understanding the pressure-dependent results, although more additional terms, such as the effect in the presence of charge, are needed for the correct explanation. This work demonstrates that high-pressure studies may have the potential to provide insight into the C-H—O structural properties of biological related systems. [ABSTRACT FROM AUTHOR]

Published
2002
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17. Polynuclear Silver(I) Triazole Complexes: Ion Conduction and Nanowire Formation in the Mesophase.

Author

Su, Padi Y. S., Hsu, S. J., Tseng, Jing C. W., Hsu, Hsiu ‐ Fu, Wang, Wen ‐ Jwu, and Lin, Ivan J. B.

Subjects
SILVER compounds, TRIAZOLES, NANOWIRES, MESOPHASES, METALLOMESOGENS, ELECTROLYTIC reduction
Abstract

Examples of polynuclear metallomesogens are few. Herein,1,2,4-triazole ligands were used to prepare mono- and polynuclear silver(I) triazole metallomesogens. Besides showing an SmA phase in the mesophase, two interesting properties were observed. First, higher ion conductivity is always found for the polynuclear complexes than for the mononuclear complexes with the same anion, an observation contrary to the knowledge that migration of a monomeric cation should be faster than that of a polymeric cation. Second, thermolysis of the polynuclear silver(I) triazole complexes in the assembled mesophase yielded Ag nanowires, in an excellent demonstration of the assembled nature of the polynuclear silver(I) ions in the thermolysis process. [ABSTRACT FROM AUTHOR]

Published
2016
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