In its photosensory effect, the action of light depends on two variables,-intensity and time. If the intensity alone is varied, the photochemical effect is proportional to the logarithm of the intensity. If the time alone is varied, the effect is proportional to the time. Experiments here reported show that when both the intensity and the time are varied, the photochemical effect is equal to th...

Rhenium(I) N-heterocyclic carbene (NHC) complexes of the type fac-[Re(CO)3(NHC)L] with either azide or triazolate ancillary ligands L and pyridyl or pyrimidyl substituted imidazolyl units have been prepared and structurally characterised, and their photophysical and photochemical properties studied. All of the complexes exhibit phosphorescent emission from triplet metal-to-ligand (MCLT) excited...

Manuscript by Alyson Baergen and D. J. Donaldson focuses on formation of HONO, a key chemical species and/or reaction intermediate in atmospheric chemistry, during photolysis of urban grime. Given the fact that sources and formation of daytime HONO in urban setup are poorly understood, this study reveals potential chemical and photochemical reaction pathways and mechanisms to yield HONO. The kn...

The photochemistry of oriented rutile surfaces has been examined using the photoreduction of Ag+ to Ag metal from an aqueous solution onto the TiO2 surfaces. The photochemical reaction rates and quantum yields of rutile films were found to be a function of the orientation of the rutile surface. The (100) and (110) rutile orientations have lower photoreduction rates than the (101), (111), and (0...

We report a method to control the conformation of a weak polyampholyte (the protein β-casein) in Langmuir monolayers by light, even though the protein is not photosensitive. Our approach is to couple the monolayer state to a photochemical reaction excited in the liquid subphase. The conformational transition of the protein molecule is triggered through its sensitivity to a subphase bulk field (...

Sunlight is the ultimate driver of biosynthesis but photochemical steps late in biosynthetic pathways are very rare. They appear to play a role in the formation of certain furanocembranoids isolated from Caribbean corals. One of these compounds, intricarene, has been suspected to arise from an intramolecular 1,3-dipolar cycloaddition involving an oxidopyrylium. Here we show, by a combination of...

A cursory look to the literature shows that only about 1% of the published papers classed as organic syntheses by Chemical Abstracts involve a photochemical step. On the other hand, in photochemistry courses it is often stated that excitation by light multiplies by 3 the accessible reaction paths, because the chemistry of the excited singlet and triplet states are added to that of the ground st...

Asymmetric catalytic variants of sunlight-driven photochemical processes hold extraordinary potential for the sustainable preparation of chiral molecules. However, the involvement of short-lived electronically excited states inherent to any photochemical reaction makes it challenging for a chiral catalyst to dictate the stereochemistry of the products. Here, we report that readily available chi...

Photochemical processes enable spatial and temporal control of reactions, which can be implemented as an accurate external control approach in both polymer synthesis and materials applications. "Click" reactions have also been employed as efficient tools in the same field. Herein, we combined photochemical processes and thiol-Michael "click" reactions to achieve a "photo-click" reaction that ca...

The products of photoreactions of conjugated organic molecules may be allowed by selection rules but not observed in solution reactions because of unfavorable reaction geometries. We have used defect sites in self-assembled alkanethiolate monolayers on gold surfaces to direct geometrically unfavorable photochemical reactions between individual organic molecules. High conductivity and stochastic...