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RISS 인기검색어
- 검색키워드
- 저자 : Kossowska, Dorota (검색결과 3 건)
- 무료
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Kossowska, Dorota,Park, Kwanghee,Park, Jun Young,Lim, Chaiho,Kwak, Kyungwon,Cho, Minhaeng American Chemical Society 2019 The journal of physical chemistry. B, Condensed ma Vol.123 No.29
<P>Developing infrared (IR) probes is of great interest in biomolecular imaging and spectroscopy. We report our attempt to improve the IR properties of alkyne-derivatized compounds. The vibrational properties of the alkyne (C≡C) stretch mode of aromatic silylacetylene <B>1</B> and aliphatic silylacetylene <B>2</B> were studied using Fourier transform infrared and femtosecond IR pump-probe spectroscopies. We find that the insertion of silicon at the position adjacent to the alkyne group, separating it from the compound’s main body, causes an approximately 10-fold increase in the dipole strength of the C≡C stretch mode and a lengthening of its vibrational lifetime from 5.6 ps for the acetylenic compound without a silicon atom acting like a thermal insulator to 50.6 and 50.4 ps for <B>1</B> and <B>2</B>, respectively. The enhanced dipole strength and the increased lifetime of <B>1</B> allowed us to measure the 2D IR spectra for long waiting times up to 450 ps, which suggests that the dynamic observation range of 2D IR spectroscopy with these IR probes can be extended into the subnanosecond range where protein skeletal movements occur.</P> [FIG OMISSION]</BR>
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Lee, Giseong,Kossowska, Dorota,Lim, Joonhyung,Kim, Soobin,Han, Hogyu,Kwak, Kyungwon,Cho, Minhaeng American Chemical Society 2018 The journal of physical chemistry. B, Condensed ma Vol.122 No.14
<P>Infrared (IR) probes based on terminally blocked β-cyanamidoalanine (AlaNHCN) <B>1</B> and <I>p</I>-cyanamidophenylalanine (PheNHCN) <B>2</B> were synthesized, and the vibrational properties of their CN stretch modes were studied using Fourier transform infrared (FTIR) and femtosecond IR pump-probe spectroscopies in combination with quantum chemical calculations. From FTIR studies, it is found that the transition dipole strengths of the cyanamide (NHCN) group in <B>1</B> and <B>2</B> are much larger than those of the nitrile (CN) group but comparable to those of the isonitrile (NC) and azido (N<SUB>3</SUB>) groups in their previously studied analogs. The CN stretch frequencies in <B>1</B> and <B>2</B> are red-shifted from those in their nitrile analogs but more blue-shifted from the NC and N<SUB>3</SUB> stretch frequencies in their isonitrile and azido analogs. The much larger transition dipole strength and the red-shifted frequency of the cyanamide relative to nitrile group originates from the n → π* interaction between the N atom’s nonbonding (n) and CN group’s antibonding (π*) orbitals of the NHCN group. Unlike aliphatic cyanamide <B>1</B>, aromatic cyanamide <B>2</B> shows a complicated line shape of the CN stretch spectra. Such a complicated line shape arises from the Fermi resonance between the CN stretch mode of the NHCN group and one of the overtones of the phenyl ring vibrations and can be substantially simplified by deuteration of the NHCN into NDCN group. From IR pump-probe experiments, the vibrational lifetimes of the CN stretch mode in <B>1</B> were determined to be 0.58 ± 0.04 ps in D<SUB>2</SUB>O and 0.89 ± 0.09 ps in H<SUB>2</SUB>O and those in <B>2</B> were determined to be 1.64 ± 0.13 ps in CH<SUB>3</SUB>OD/dimethyl sulfoxide and 0.30 ± 0.05 and 2.62 ± 0.26 ps in CH<SUB>3</SUB>OH. The short time component (0.30 ± 0.05 ps) observed for <B>2</B> in CH<SUB>3</SUB>OH is attributed to the vibrational relaxation through Fermi resonance. These vibrational lifetimes are close to those of the nitrile and azido groups but shorter than those of the isonitrile group. Consequently, cyanamide behaves like an apparent vibrational hybrid of nitrile and isonitrile in that cyanamide is similar to nitrile in vibrational frequency and lifetime but to isonitrile in transition dipole strength. It is believed that cyanamide has the potential to be a strongly absorbing IR reporter of the conformational and environmental structure and dynamics of biomolecules in comparison to nitrile, a weak absorber.</P> [FIG OMISSION]</BR>
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Maj, Michał,Ahn, Changwoo,Kossowska, Dorota,Park, Kwanghee,Kwak, Kyungwon,Han, Hogyu,Cho, Minhaeng The Royal Society of Chemistry 2015 Physical chemistry chemical physics Vol.17 No.17
<P>An infrared (IR) probe based on isonitrile (NC)-derivatized alanine <B>1</B> was synthesized and the vibrational properties of its NC stretching mode were investigated using FTIR and femtosecond IR pump–probe spectroscopy. It is found that the NC stretching mode is very sensitive to the hydrogen-bonding ability of solvent molecules. Moreover, its transition dipole strength is larger than that of nitrile (CN) in nitrile-derivatized IR probe <B>2</B>. The vibrational lifetime of the NC stretching mode is found to be 5.5 ± 0.2 ps in both D<SUB>2</SUB>O and DMF solvents, which is several times longer than that of the azido (N<SUB>3</SUB>) stretching mode in azido-derivatized IR probe <B>3</B>. Altogether these properties suggest that the NC group can be a very promising sensing moiety of IR probes for studying the solvation structure and dynamics of biomolecules.</P> <P>Graphic Abstract</P><P>An infrared (IR) probe based on isonitrile (NC)-derivatized alanine <B>1</B> was synthesized and the vibrational properties of its NC stretching mode were investigated using FTIR and femtosecond IR pump–probe spectroscopy. <IMG SRC='http://pubs.rsc.org/services/images/RSCpubs.ePlatform.Service.FreeContent.ImageService.svc/ImageService/image/GA?id=c5cp00454c'> </P>
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