Visible-light irradiation

Figure 3 Optical rotation change of F-3 in a PMMA film upon iterative irradiate visible light (> 470 nm) and UV light (366 nm).

Photosensitive azobenzene units were further incorporated into the polyisocyanide 17 by random living copolymerization of the corresponding monomers [64]. The helical polyisocyanide 18 (30 mer) contains 33% azobenzene units as pendants and caused a slight decrease in the UV-visible and CD intensities (8%) upon UV-irradiation. Visible light irradiation effected the reverse photochromic process (Fig. 5). 

Asymmetric synethesis of dipeptides. The chromium amino-carbcnc 1, pcntacar-bonyl [(R-l-aza-2,2-dimcthy]-3-oxa-5-phenylcyclopentyl)(methyl)carbcne]chromium(0), derived from (R)-alaninc, undergoes carbonylative coupling with amino esters under irradiation (visible light) at 0° to form (S,S)-dipcptidcs with high diastereoselectivity. 

Dentures require accurate fit, reasonable chewing efficiency, and lifelike appearance (189). The chewing efficiency of artificial dentures is one-sixth that of natural dentition (190). AcryHc resins are generally used as powder/Hquid formulations for denture base, bone cement, and related appHcations. Polymerization is achieved thermally using initiators photochemicaHy using photoactive chemicals and either uv or visible light irradiation and at ambient temperatures using initiator/activator systems. 

A review of what has come to be called molecular electronics (Mirkin and Ratner 1992) includes many striking discoveries, such as a device based on azoben .ene (Liu et al. 1990) that undergoes a stereochemical transition, trans-to-cis, when irradiated with ultraviolet light, but reverts to trans when irradiated with visible light. The investigators in Japan found that L-B films of their molecules can be used for a... 

The visual limit of detection, when irradiating with UV light, is 250 ng per chromatogram zone the zones are only detectable in visible light when the amounts are 4 to 5 times greater [2]. 

Fig. 11. Schematic representation of ion-transport mediated by alternative irradiation of u.v. and visible light. (Cited from Ref. 64))...

A recent study of the interaction of sodium with furan in an argon matrix at 4 °K32 has shown that the irradiation of the matrix with visible light (X = 550 run) induces the reaction... 

P vs I Relationships. In our investigation we em-ployed a technique widely used by plant physiologists, namely, the study of rate of photosynthesis (P) as a function of irradiance (I). The results of one experiment in which phytoplankton were kept under the four experimental treatment conditions for 24 hours arc shown in Fig. 4. It is clear from this figure that phytoplankton exposed to visible light alone (i.e., when UV was excluded) had the highest photosynthctic rates, and these rates were maintained over a higher range of irradiance levels. On the other hand, the lowest carbon fixation rates occurred when the phytoplankton were exposed to ambient and enhanced levels of UV. 

H NMR data has been reported for the ethylzinc complex, Zn(TPP—NMe)Et, formed from the reaction of free-base N-methyl porphyrin H(TPP—NMe) with ZnEti. The ethyl proton chemical shifts are observed upheld, evidence that the ethyl group is coordinated to zinc near the center of the porphyrin. The complex is stable under N2 in the dark, but decomposed by a radical mechanism in visible light.The complex reacted with hindered phenols (HOAr) when irradiated with visible light to give ethane and the aryloxo complexes Zn(TPP—NMe)OAr. The reaction of Zn(TPP—NMe)Et, a secondary amine (HNEt2) and CO2 gave zinc carbamate complexes, for example Zn(TPP—NMclOiCNEti."" ... 

Anoxic Hydrogen Production over CdS-based Composite Photocatalysts under Visible Light Irradiation (X, 420nm)... 

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