Organic photochemistry, comparison

Some general ideas about the reaction mechanisms involved can be obtained from a comparison of plasma products with the products of other reactions. Often similarities are found between plasma chemistry and photochemistry, pyrolysis, radiochemistry or mass spectroscopy. If the reaction products are identical, it is reasonable to assume that the reaction mechanism will be the same or at least the final steps in a sequence of elementary processes. Occasionally, the products indicate mechanisms which have no known analogues in other fields of organic chemistry. ... 

To learn more about the factors governing the photochemical behaviour of organic systems coordinated to transition metals systematic studies appear necessary, e.g. the comparison of olefin photochemistry with that of olefin metal complexes (e.g. see 428>). 

Topics which have formed the subjects of reviews this year include excited state chemistry within zeolites, photoredox reactions in organic synthesis, selectivity control in one-electron reduction, the photochemistry of fullerenes, photochemical P-450 oxygenation of cyclohexene with water sensitized by dihydroxy-coordinated (tetraphenylporphyrinato)antimony(V) hexafluorophosphate, bio-mimetic radical polycyclisations of isoprenoid polyalkenes initiated by photo-induced electron transfer, photoinduced electron transfer involving C o/CjoJ comparisons between the photoinduced electron transfer reactions of 50 and aromatic carbonyl compounds, recent advances in the chemistry of pyrrolidino-fullerenes, ° photoinduced electron transfer in donor-linked fullerenes," supra-molecular model systems,and within dendrimer architecture,photoinduced electron transfer reactions of homoquinones, amines, and azo compounds, photoinduced reactions of five-membered monoheterocyclic compounds of the indigo group, photochemical and polymerisation reactions in solid Qo, photo- and redox-active [2]rotaxanes and [2]catenanes, ° reactions of sulfides and sulfenic acid derivatives with 02( Ag), photoprocesses of sulfoxides and related compounds, semiconductor photocatalysts,chemical fixation and photoreduction of carbon dioxide by metal phthalocyanines, and multiporphyrins as photosynthetic models. 

In theory, the photostability of luminescent lanthanide complexes should be superior to the photostabihty of purely organic chromophores since excited lanthanide ions do not undergo photochemistry, and the energy transfer from the antenna chromophore to the lanthanide ion deactivates any organic excited states that would give rise to destructive photochemistry. Direct comparison of the photostability of NIR luminescent lanthanide complexes and organic fluorophores has not yet been carried out. 

---