Ring asymmetric

The electron injection from the excited states of the dyes to the conduction band of the electrode is predominately affected by the oxidation potential of the dye molecules as well the distribution of the LUMO over the whole molecule. Tuning the redox potentials and the LUMO distribution by functionalizing the aromatic ring asymmetrically with different groups at different positions seems a promising way towards a better sensitizer. 

Figure 14 Plots of the integrated intensity of the ring asymmetric stretch of THF at 1064 cm-1 vs. mTHF obtained from the data in Figure 12. The errors are too small to be shown. (From Ref. 10.)...

Bringing the chiral centre closer to the carbene carbon atom would mean making the carbon atom adjacent to the ring nitrogen atoms on the imidazole ring asymmetric (see Figure 6.24). There are two options exocyclic or endocyclic. 

Accordingly, the synthesis of phthalide 44 began from methyl ketone 27 (Scheme 18). In order to avoid interference of the olefin moiety with haloge-nation of the aromatic ring, asymmetric dihydroxylation was conducted first. Treatment of alkene 27 with AD-mix a in tcrt-butanol/water (1 1) provided diol 27 in a pleasing 87% yield. Inspection of the and NMR spectra did not indicate the presence of a diastereomeric mixture. However, although alkene 27 is structurally well suited to the Sharpless mnemonic, we thought it... 

Saturated heterocycles and Flattened four-and five-membered rings Asymmetric synthesis ch41... 

CH) ring bending deformation (C—O—C) ring asymmetric stretching 1,150... 

CC out of plane bending ring asymmetric torsion CC ring in plane deformation CH out of plane deformation, CO bending Amide V... 

CO in plane bending ring asymmetric CH deformation CN stretching... 

Out of plane bending vibration of the p-disubstituted ring Non-coordinated bands Non-coordinated bands AI species modes of the benzene ring Asymmetric C-C stretch of central carbon atom... 

---