Partial molar rotatory powers

Partial molar rotatory powers [37]. Due primarily to the work of Litman and Schellman [38], it now appears that a quadrant rule is most appropriate for a peptide chromophore, in which case the sign does not change with the -(-z and — z directions. As for distance dependence, there are two dominant terms, r and r , which are of opposite sign with the term relevant to the above discussion and dominating at distances greater than 3 A. A statement of has been written for the methyl moiety perturbing a peptide n-n transition [38]... 

The partial molar rotatory power approach requires simple compounds from which to solve for the values of the [P (fc)]. In this regard a particularly useful model of the peptide chromophore is contained in pyrrolid-2-one, the structure of which is given in Figure 19. The reason this structure is so useful is that it is essentially planar, as has... 

Considering these several different contributions, the partial molar rotatory powers may be written in general for a polymer as... 

In 1968, Minoura [183] described the reduction of polymethylvinylketone by lithium borneoxyaluminum hydride. The reduced copolymer was optically active and its dispersion was found to fit the simple Drude equation. The rotatory power of the polycar-binol increased with the f/-camphor-to-hydride molar ratio and its best value was obtained for a camphor-AlLiH4/polyketone ratio equal to 3. The reduction was partial (max. con-version=63%). The authors proposed to attribute the asymmetric induction to a classical transition state. 

---