Radicals in solution are crucial for many chemical processes. In this work, we unveil the photoreaction sequence leading to radical formation from tetrazolium salts, which are extensively used in enzyme assays and also exhibit a rich photochemistry. Upon UV irradiation, the tetrazolium ion turns into the tetrazolinyl radical via two intermediates on a nanosecond timescale. The solvent's polarity governs the rate of formation, but the reaction pathway towards the tetrazolinyl radical is identical for aqueous and alcoholic solutions, although the final photoproduct distribution differs. These observations provide new insight into the versatile reactivity of tetrazolium salts and ultrafast radical formation in the liquid phase.
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http://dx.doi.org/10.1002/cphc.201500628 | DOI Listing |
J Am Chem Soc
June 2023
Department of Chemistry, University of Nebraska, Lincoln, Nebraska 68588-0304, United States.
Open-shell organic molecules, including = 1/2 radicals, may provide enhanced properties for several emerging technologies; however, relatively few synthesized to date possess robust thermal stability and processability. We report the synthesis of = 1/2 biphenylene-fused tetrazolinyl radicals and . Both radicals possess near-perfect planar structures based on their X-ray structures and density-functional theory (DFT) computations.
View Article and Find Full Text PDFPhys Chem Chem Phys
February 2021
Department of Chemistry, The University of Hong Kong, Pokfulam Road, Hong Kong 11111, P. R. China.
Tetrazolium salts (TZs) are pervasively utilized as precursors in the dye industry, colorimetric probes in enzyme assays and for exploring nanomaterial toxicity, but its own toxicity is not investigated enough so far. Using femtosecond transient absorption spectroscopy, nanosecond pulse radiolysis (ns-PRL), western blotting and UV-vis absorption spectroscopy, here we characterized a neutral tetrazolinyl radical (with the same maximum absorption at 420 nm and different lifetimes of 5.0 and 9.
View Article and Find Full Text PDFChemphyschem
October 2015
Physikalische Chemie II, Ruhr-Universität Bochum, Universitätsstraße 150, 44801, Bochum, Germany.
Radicals in solution are crucial for many chemical processes. In this work, we unveil the photoreaction sequence leading to radical formation from tetrazolium salts, which are extensively used in enzyme assays and also exhibit a rich photochemistry. Upon UV irradiation, the tetrazolium ion turns into the tetrazolinyl radical via two intermediates on a nanosecond timescale.
View Article and Find Full Text PDFJ Biol Chem
October 1994
Molecular Dynamics Section, National Institute on Aging, Baltimore, Maryland 21224.
The autoxidation of hemoglobin as a function of oxygen pressure and the effect of added nitroblue tetrazolium have been studied. It has been shown that the enhanced autoxidation at intermediate oxygen pressures can only be partially explained by the outer-sphere reaction of oxygen with deoxygenated chains. An additional enhancement associated with the properties of partially oxygenated hemoglobins has been attributed to the mobility on the distal side of the heme which facilitates the nucleophilic displacement of bound oxygen by the distal histidine.
View Article and Find Full Text PDFActa Histochem
March 1994
Institut für Anatomie, Medizinische Fakultät (Charité), Humboldt-Universität Berlin, Germany.
Thin layer chromatography (TLC) was performed to analyze which products are formed when unstable tetrazolinyl radicals are generated during the reduction of tetrazolium salts under physiological conditions of biochemical and histochemical assays. It was found in aqueous media that irrespective the assay conditions, reduction of 2,3-di(4-nitrophenyl)-5-phenyl-2H-tetrazolium chloride (p-DNTTC) or 2,3-di(4-nitrophenyl)-5-t-butyl-2H-tetrazolium chloride (t-butyl-DNTC) always lead to production of formazan and never to generation of the corresponding 2(4-nitrophenyl)-5-phenyl- (respectively t-butyl-) tetrazoles by splitting off a nitrophenyl side chain from the tetrazolium ring as a cation. This reaction is known to occur in non-aqueous media (Neugebauer, 1973).
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