Cyclic configurations

The new photographs, like the old ones, are incompatible with a cyclic configuration. 

The effective cyclic configuration interaction is required for an enhancement of the delocalization-polarization processes via different radical centers. The requirement is satisfied when any pair of the configuration interactions simultaneously contributes to stabilization or to accumulation of electron density in the overlap region. The condition is given by the overlap integrals, S, between the configurations QG, and involved in the proposed delocalization-polarization processes (Fig. 5). Therefore, an effective cyclic configuration interaction needs... 

Doyne T., Pepinsky R. Watanabe T. Cyclic configuration of the aspartate ion in the crystal structures of zinc, cobaltous and niekelous aspartate trihydrate. Acta Cryst. 1957 10 438. 

Figure4.31 A simplified design scheme ofthe AlkyClean process, using three reactors in a cyclic configuration. At any given time, two reactors are used for alkylation, while the catalyst in the third reactor is regenerated.

Several interesting cyclic configurations are observed. The very short carboxylic acid hydrogen bond C-OH... 0 = C of 1.475 A occurs in L-glutamic acid B-form, as part of a trimer system. Cyclic trimers involving the components of three-center bonds are also observed in the A-form of glutamic acid. In this pattern,... 

The water dimer is the most important H-bonded system. The major attractive contribution to the interaction energy of the water dimer is the electrostatic effect. It dominates over other attractive terms, such as the induction and dispersion energies, and it is the most anisotropic. To discuss the properties of the fundamental components in the water dimer case we chose to demonstrate the angular dependence of various terms in the dimer geometry derived from the cyclic configuration of a trimer (see Fig 6). 

Table 3.53 Frequencies (cm ) and intensities (D A amu ) calculated for the ammonia dimer in its cyclic configuration .

Figures 3a, b, c, and d illustrate the hexahydrate configurations analyzed in this work. In the Th symmetry the water molecule is arranged with the hydrogen atoms pointing symmetrically outwards with respect to the ion, the main geometrical parameters are listed in Table 5. For Li and Na we have calculated the hexahydrate in the S6 symmetry, which consists of the ion inserted between two parallel planes of water trimers, with the main distances and angles indicated in Table 6. The geometries of the water molecules in each of these trimers can be compared to those in the pure water trimer. Table 3. The water molecules in the S6 hexahydrate remain in cyclic configurations...

Notice also that although the methods, compute-nonbonded-strain and compute-torsional-strain were inherited by cyclic-aliphatic, more sophisticated versions of these methods were supplied to cyclic-aliphatic. This would have been unnecessary if the original versions of these methods supported fully all cyclic configurations (i.e., a robust method given at any ring configuration). We have found that the ability to incrementally improve methods accelerates model development. 

Figure 7. Illustrations of gelation according to the classical Flory-Stockmayer model and the percolation model. In the classical model, cyclic configurations are avoided, so the unphysical situation M R4 results. As illustrated by the 29Si NMR spectrum of an acid-catalyzed TEOS sol (36), cyclic species are quite prominent sol components. (Reproduced with permission from reference 36. Copyright 1988.)...

The somatostatin analog depreotide consists of ten amino acids containing the key ssts-hinding amino acid residues - Tyr-(D-Trp)-Lys-Val - protected in a cyclic configuration, increasing in vivo stability. Depreotide binds with high affinity to sst-positive tumors and their metastases (Vallabhajosula et al. 1996). 

Using only one of these cyclic configurations, for purposes of illustration an approximate structure of a diallyl o-phthalate prepolymer near the gel point is given in Fig. 5. 

Cyclic systems, such as 2-chloro-A -pyrrolin, react considerably slower, because elimination can not readily occur in the cyclic configuration. 

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