Researchers from Indian Institute of Chemical Technology Report on Findings in Biological Pigments (Investigation of supramolecular stoichiometry and dynamic for inclusion complex of water soluble porphyrin with cucurbituril by fluorescence ...)
By a News Reporter-Staff News Editor at Life Science Weekly -- Current study results on Biological Factors have been published. According to news reporting from Andhra Pradesh, India, by NewsRx journalists, research stated, "Detection and identification of supramolecular binding stoichiometry are trivial by traditional spectroscopic methods such as, UV-vis spectroscopy, fluorescence spectroscopy and NMR spectroscopy for polytopic system like meso-substituted porphyrin where multiple identical binding sites are present. We use fluorescence correlation spectroscopy (FCS) to understand the interaction and supramolecular binding stoichiometry of inclusion (host-guest) complexes between cucurbiturils (CB) as host and water soluble 5,10,15,20 meso-tetrakis (N-methyl4-pyridyl)-21,23H-porphyrin tetratosylate (TMPyP) as guest."
The news correspondents obtained a quote from the research from the Indian Institute of Chemical Technology, "Tuning of binding stoichiometry is achieved in FCS titration for these systems by changing concentration of CB from nano-molar (nM) to milli-molar (mM) keeping TMPyP concentration fixed at similar to 3 nM. Stepwise formation of 1:1, 2:1, 3:1 and finally 4:1 (CB:TMPyP) complexes are determined. Inclusion dynamic at each step of complex formation was analyzed by monitoring the diffusion properties and the molecular brightness of free TMPyP as well as respective complexes of different order of complexities. Global target analysis of correlation curves for each step yields association equilibrium constant (K) and dissociation rate constant (k(-)) unveiling the complexation dynamics of the systems in each step. Observed results reveal that the value of association rate constant (k(+)) remains more or less same on going from 1:1 to 4:1 complexes while k(-) successively increases on going from 1:1 to 4:1 complexes. Hence, k(-) is found to be determining factor for evaluating K value in each step of inclusion complex formation for the studied host-guest system."
According to the news reporters, the research concluded: "Formation of higher order complexes is found to be anti-cooperative in nature for the present host-guest system."
For more information on this research see: Investigation of supramolecular stoichiometry and dynamic for inclusion complex of water soluble porphyrin with cucurbituril by fluorescence correlation spectroscopy. Journal of Photochemistry and Photobiology A-Chemistry, 2014;284():27-35. Journal of Photochemistry and Photobiology A-Chemistry can be contacted at: Elsevier Science Sa, PO Box 564, 1001 Lausanne, Switzerland (see also Biological Factors).
Our news journalists report that additional information may be obtained by contacting P. Suthari, CSIR, Indian Inst Chem Technol, Dept. of Inorgan & Phys Chem, Hyderabad 50007, Andhra Pradesh, India. Additional authors for this research include P.H. Kumar, S. Doddi and P.R. Bangal.
Keywords for this news article include: Asia, India, Porphyrins, Andhra Pradesh, Nanotechnology, Supramolecular, Biological Factors, Biological Pigments, Emerging Technologies
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