Photoisomerization of l,4-diphenyl-l,3-butadiene (DPB), l,6-diphenyl-l,3,5-hexatriene (DPH) and l,8-diphenyl-l,3,5,7-octatetraene (DPO) in polyvinyl alcohol) (PVA) films was studied unter daylight and direct irradiation. The most efficient photoisomerization occurs in the DPB molecule, the smallest among the compounds investigated. For the greatest, DPO, molecule no distinct isomerization was o...

1. The authors fail to distinguish adequately between photodegradation, in which bilirubin is degraded to substances of lower molecular weight, and photoisomerization, in which the pigment’s structure changes but no degradation occurs. Both processes contribute to the effects of phototherapy in humans, but their relative contributions are presently unknown. However, in the Gun rat animal model ...

Photoalignment of nematic liquid crystals is demonstrated using a di-π-methane rearrangement of a designed polymer. The alignment mechanism makes use of the strong coupling of the liquid crystal directors to dibenzobarrelene groups. The large structural changes that accompany photoisomerization effectively passivate segments of the polymer, allowing the remaining dibenzobarrelene groups to domi...

The effect on picosecond reaction dynamics due to complexation of a reactive molecule with cyclodextrins was examined, with the trans-cis photoisomerization of stilbene as an example. In the presence of a-cyclodextrin, a single, slow exponential decay of trans-stilbene fluorescence is observed, consistent with the formation of a single complex. In contrast, in the presence of 8-cyclodextrin, th...

The ability to dynamically control chirality remains a grand challenge in chemistry. Although many molecules possess chiral isomers, lacking their isolation, for instance during photoisomerization, results racemic mixtures with suppressed enantiospecific properties. Here, we present nanoporous solid which and enantioselective enrichment is induced by circularly polarized light (CPL). material b...

The total synthesis of hyacinthacine A2 is reported via a novel transannular hydroamination in which planar chirality of a 5-aza-trans-cyclooctene precursor is transferred to point chirality in the product. Key to the success of this strategy was the development of a method for establishing absolute planar chirality via stereocontrolled photoisomerization of a 5-aza-cis-cyclooctene. This was ac...

The intramolecular [2+2] photocyclization of a bis-stilbene macrocycle was studied. The reaction can be controlled by the insertion and removal of urea protecting groups. Upon UV-irradiation in both the solid state and DMSO solution, the free urea macrocycle undergoes a cis-trans photoisomerization that is followed by a [2+2] cycloaddition to afford a single product in high yield. The presence ...

The photophysical properties of tetraphenylethene (TPE) compounds may differ widely depending on the substitution pattern, for example, with regard to the fluorescence quantum yield ϕf and the propensity to exhibit aggregation-induced emission (AIE). We report combined electronic structure calculations and nonadiabatic dynamics simulations to study the excited-state decay mechanisms of two TPE ...

Stilbene-functionalized NHC accumulated vertical adsorption geometry on Au film, enabling reversible changes in surface potential following photoisomerization. Stronger interaction with Pt film quenched stilbene-NHC influence potential.