نتایج جستجو برای: ir spectroscopy
تعداد نتایج: 230332 فیلتر نتایج به سال:
in this paper functionalized multiwall carbon nanotubes (fmwcnt) were modified using doxycycline, containing reactable nitrogen, which can attach chemically to functionalized mwcnt. the synthesized nano compounds were characterized by fourier transform infrared spectroscopy (ft-ir) and raman spectroscopy. these spectrums proved the existence of nitrogen atoms of amide functional groups. the mor...
Until now, ultrafast IR spectroscopy has been limited by the bandwidth of optical parametric amplifiers, typically 100-400 cm(-1). Here we present the first example of transient IR spectroscopy using a continuum laser source to probe the entire mid-IR region with ultrafast time resolution. The continuum source is based on focusing the fundamental, second harmonic, and third harmonic of 1 mJ, 2...
The dynamics of the hydrogen bond network of isotopically substituted liquid water are investigated with a new ultrafast nonlinear vibrational spectroscopy, three-dimensional infrared spectroscopy (3D-IR). The 3D-IR spectroscopy is sensitive to three-point frequency fluctuation correlation functions, and the measurements reveal heterogeneous structural relaxation dynamics. We interpret these re...
In many ways, mid-infrared spectroscopy would appear to be the ideal technology for on-line chemicals analysis. After all, IR spectroscopy is the only analytical method which provides both ambient temperature operation and the ability to directly monitor the vibrations of the functional groups which characterize molecular structure and govern the course of chemical reactions. In principle, IR a...
The electronic structures of monocationic tris[(5,10,15-pentafluorophenyl)-corrolato]iridium compounds, [Ir(tpfc)L2](+), where L = 4-cyanopyridine [1](+), pyridine [2](+), 4-methoxypyridine [3](+), or 4-(N,N'-dimethylamino)pyridine [4](+), have been probed by electron paramagnetic resonance (EPR) spectroscopy, Ir L3,2-edge X-ray absorption spectroscopy (XAS), UV/visible (UV-vis) spectroelectroc...
The tertiary interactions between amide-I vibrators on the separate helices of transmembrane helix dimers were probed by ultrafast 2D vibrational photon echo spectroscopy. The 2D IR approach proves to be a useful structural method for the study of membrane-bound structures. The 27-residue human erythrocyte protein Glycophorin A transmembrane peptide sequence: KKITLIIFG(79)VMAGVIGTILLISWG(94)IKK...
Transient two-dimensional infrared (2D IR) spectroscopy is used as a probe of protein unfolding dynamics in a direct comparison of fast unfolding experiments with molecular dynamics simulations. In the experiments, the unfolding of ubiquitin is initiated by a laser temperature jump, and protein structural evolution from nanoseconds to milliseconds is probed using amide I 2D IR spectroscopy. The...
in this paper, we report the synthesis and characterization of a new symmetric macroacyclic schiff base ligand (h2l) and related complexes with different metals. (h2l) was synthesized by the one pot condensation reaction of 2-[2-(2-formyl phenoxy)ethoxy]benzaldehyde and 2-aminobenzenethiol in a 1:2 molar ratio. the acyclic schiff base was characterized by ir, nmr spectroscopy and elemental anal...
The introduction of time-resolved Fourier transform infrared (FT-IR) spectroscopy to biochemistry opened the possibility of monitoring the catalytic mechanism of proteins along their reaction pathways. The infrared approach is very fruitful, particularly in the application to membrane proteins where NMR and X-ray crystallography are challenged by the size and protein hydrophobicity, as well as ...
Bone material is composed of an organic matrix of collagen fibers and apatite nanoparticles. Previously, vibrational spectroscopy techniques such as infrared (IR) and Raman spectroscopy have proved to be particularly useful for characterizing the two constituent organic and inorganic phases of bone. In this work, we tested the potential use of high intensity synchrotron-based far-IR radiation (...
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