Degree of asymmetry

Figure 4.69 Relationships between % AE and number of reaction stages (a), % RME and % overall yield (b), degree of convergence and number of reaction stages (c), and degree of asymmetry and number of reaction stages (d) for 1 38 synthesis plans to 29 target molecules.

The ability of cobalt(II), nickel(II), and copper(II) to exhibit a greater tendency than Zn(II) towards bidentate coordination is further illustrated by structural comparisons within a series of bridging carbonate complexes (188). For example, of the complexes [TpPr 2]M 2(/x-C03) (M = Mn, Fe, Co, Ni, Cu, Zn), only the zinc derivative does not exhibit bidentate coordination at both metal centers (151,153). Furthermore, the carbonate ligand in the complexes [TpPr 2]M 2(/x-C03) (M = Mn, Fe, Co, Ni, Cu) also exhibits varying degrees of asymmetry that closely parallel the series of nitrate complexes described earlier (Fig. 47 and Table IX). 

Monodentate (monometallic monoconnective) phosphor-1,1-dithiolato ligands are rare. Bidentate (monometallic biconnective) form chelate rings and three sub-types can be distinguished according to the degree of asymmetry (Scheme 2). The most asymmetric type (anisobidentate) occurs when a covalent bond is associated with a secondary bond this takes place mostly in main-group metal complexes. The second type is rare and is the result of the association between a covalent and a dative coordinate bond. The symmetric bidentate bonding (isobidentate) is found mainly in transition metal complexes. 

We have interpreted the principal denaturation peaks in our data in terms of multiple sequential transitions, but in fact most of the peaks in the data base can be fitted almost as well by a model involving two independent transitions. For endotherm envelopes of this size and degree of asymmetry, the differences between the fits obtained from sequential and independent models are too small to allow a choice of one or the other based simply on goodness of fit. Our provisional preference for the sequential model is based on other considerations, one being the failure of a 3.5-unit... 

The chemical nature of the rubber determines which bonds are the weakest and are therefore more likely to be ruptured during mastication by the statistical concentration of mechanical energy about such bonds. An increase in the degree of asymmetry, an increase in the stiffness and the packing density of macromolecules facilitate mechanical scission resonance stability will influence the... 

The type of initiator sometimes exerts a noticeable influence on the degree of asymmetry obtainable in asymmetric polymerization. 

With application to dissolved proteins in mind, Oncley26 has computed frictional ratios for ellipsoids of revolution of varying degrees of asymmetry and hydration. The resulting contour diagram (Figure 2.1) shows the combinations of axial ratio and hydration which are compatible with given frictional ratios. The separate contributions of asymmetry and hydration cannot be determined unless other relevant information is available. 

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