Chemistry with Red and Near Infrared Light

Opportunities are explored to initiate controlled chemistry by photolysis with long-wavelength visible and near infrared light. In one direction, bimolecular reactions are induced by exciting collisional pairs in a solid matrix to energy surfaces well below reactant dissociation limits. Ex...

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Main Author: Heinz Frei
Format: Article
Language:deu
Published: Swiss Chemical Society 1991-06-01
Series:CHIMIA
Online Access:https://www.chimia.ch/chimia/article/view/2031
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author Heinz Frei
author_facet Heinz Frei
author_sort Heinz Frei
collection DOAJ
description Opportunities are explored to initiate controlled chemistry by photolysis with long-wavelength visible and near infrared light. In one direction, bimolecular reactions are induced by exciting collisional pairs in a solid matrix to energy surfaces well below reactant dissociation limits. Examples discussed include product specific (including stereospecific) photo-oxidation of small alkenes and alkynes by NO2, and cycloaddition reactions of singlet SO and singlet O2. Conducting the chemistry in rare gas matrices allows us to elucidate elementary reaction steps by FT-IR spectroscopy of trapped intermediates, and to gain insight into the dynamics of transients by wavelength-dependent laser photochemistry. In the case of olefin epoxidations, stereochemical details of reaction paths are uncovered by chemical trapping of transient oxirane biradicals in their nascent conformation. State-specific reactions of singlet excited SO and singlet O2 with hydrocarbons illustrate how photons deep in the near infrared can be used for controlled chemical synthesis. In parallel work, excited state redox reactions in homogeneous and colloidal semiconductor solutions are explored that pertain to chemical storage of near infrared quanta and conversion into electrical energy. Examples are studies on chemical storage of singlet delta molecular oxygen (O2(1?), a metastable near infrared energy carrier, its excited state redox chemistry in aqueous solution, and direct reduction Of (O2(1?) at a semiconductor electrode. Using very sensitive time resolved optical techniques, new mechanistic insight is gained on singlet O2 reactions, and on photo-oxidation of halide at the semiconductor-solution interface.
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spelling doaj.art-f6a73cab24084d54b032a572f7931d4f2022-12-21T17:23:32ZdeuSwiss Chemical SocietyCHIMIA0009-42932673-24241991-06-01456Chemistry with Red and Near Infrared LightHeinz Frei Opportunities are explored to initiate controlled chemistry by photolysis with long-wavelength visible and near infrared light. In one direction, bimolecular reactions are induced by exciting collisional pairs in a solid matrix to energy surfaces well below reactant dissociation limits. Examples discussed include product specific (including stereospecific) photo-oxidation of small alkenes and alkynes by NO2, and cycloaddition reactions of singlet SO and singlet O2. Conducting the chemistry in rare gas matrices allows us to elucidate elementary reaction steps by FT-IR spectroscopy of trapped intermediates, and to gain insight into the dynamics of transients by wavelength-dependent laser photochemistry. In the case of olefin epoxidations, stereochemical details of reaction paths are uncovered by chemical trapping of transient oxirane biradicals in their nascent conformation. State-specific reactions of singlet excited SO and singlet O2 with hydrocarbons illustrate how photons deep in the near infrared can be used for controlled chemical synthesis. In parallel work, excited state redox reactions in homogeneous and colloidal semiconductor solutions are explored that pertain to chemical storage of near infrared quanta and conversion into electrical energy. Examples are studies on chemical storage of singlet delta molecular oxygen (O2(1?), a metastable near infrared energy carrier, its excited state redox chemistry in aqueous solution, and direct reduction Of (O2(1?) at a semiconductor electrode. Using very sensitive time resolved optical techniques, new mechanistic insight is gained on singlet O2 reactions, and on photo-oxidation of halide at the semiconductor-solution interface. https://www.chimia.ch/chimia/article/view/2031
spellingShingle Heinz Frei
Chemistry with Red and Near Infrared Light
CHIMIA
title Chemistry with Red and Near Infrared Light
title_full Chemistry with Red and Near Infrared Light
title_fullStr Chemistry with Red and Near Infrared Light
title_full_unstemmed Chemistry with Red and Near Infrared Light
title_short Chemistry with Red and Near Infrared Light
title_sort chemistry with red and near infrared light
url https://www.chimia.ch/chimia/article/view/2031
work_keys_str_mv AT heinzfrei chemistrywithredandnearinfraredlight