L-CPL

Figure 9 Schematic representation of the shift between right- and left-handed helices of a poly isocyanate with bicycloketone chromophore pendants subjected to irradiation with r- or l-CPL or noncircularly polarized light (non-CPL).

Figure 16 CD spectra of a thin film (340 nm) of 41 on glass, as prepared (full line) and after sequential irradiation of l-CPL (dashed line) and r-CPL (dotted line) at 488 nm (7—160 mW cm 2). (Reproduced from Ref. 99 2002, Wiley-VCH.)...

Equation (7) is an interesting example of the versatility of the hypothesistesting technique that Barnett has exploited. Thus, suppose it is assumed that the important fluid properties which control the burn-out phenomenon are density pL, specific heat, CPL, and thermal conductivity kL of the liquid phase, together with density of the vapor phase pv and the latent heat L Then, for burn-out in a uniformly heated round tube we have... 

Loukas, A., Selzer, P.M. and Maizels, R.M. (1998) Characterisation of Tc-cpl-1, a cathepsin L-like cysteine protease from Toxocara canis infective larvae. Molecular and Biochemical Parasitology 92, 275—289. 

That chiral molecules can be produced in a CPL field, either from achiral precursors by photo-activated synthesis or by preferential chiral photodestruction of a racemic mixture, is now well demonstrated and has been reviewed. [46] In all cases currently known, however, such processes have proved very inefficient. For example, asymmetric photochemical ring-closures of achiral helicene precursors induced by CPL have produced only about 0.2% e.e. in the products. Likewise, the CPL-induced photolysis of racemic camphor produced about 20 % e.e., but only after 99% photodestruction, and photolysis of D.L-glutamic acid produced only 0.22 % e.e. after 52 % photodecomposition. [71]... 

Fig. 11.6 Conversion of one enantiomer to the other by CPL. The molecule 12-(9 H-thioxan-thene-9 -ylidene)-l 2H-benzo[a]xanthene exists in one of two chiral forms that can be intercon-...

From Table 4 it appears that photocyclization of l-(2-naphthyl)-2-(3-phenanthryl)-ethylene (2+3) with CPL leads to a higher optical yield (0.2 %) than that of 2-styryl-... 

Previous, unsuccessful attempts to demonstrate the principle of a molecular switch based on CPL irradiation include inherently dissymmetric fluorene derivative l,1161 atropisomeric bridged binaphthyls 2,1171 and l,l -binaphthylpyran 3J18 Inefficient photoracemization, low g-values, and insufficient sensitivity for detection were some of the problems encountered. 

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