Phenyl ring, dimensions

The hard sphere exclusion distances for this system were chosen as follows nonbonded backbone carbons, 4.60 R (twice the C-H bond distance plus van der Waals radius for H) non-neighboring fluorines, 2.70 R (twice van der Waals radius for F) neighboring fluorines, 6.39 R (distance across phenyl ring using dimensions of Table I and van der Waals radius for Hof... 

In conclusion, from the study on the relationship between DAR antagonist activity and detailed molecular structure in certain analogs of butaclamol, it has been possible to confirm the existence of a lipophilic accessory binding site on the DAR, to define its probable dimensions, and to specify its locus with respect to the phenyl ring and the nitrogen atom primary binding sites. 

The motif in the smaller dashed cell shown in Figure 15 was used to construct a model for the PPP salt. Both the unit cell dimensions and the composition (C6H4)8(SbF6)3 were used without further adjustment and reproduced the experimental doping level (40% per phenyl ring) and the X-ray and neutron scattering (10). 

Figure 1.27. Intercalation model proposed for the structure of heavily doped PPP. Phenyl rings arc stacked parallel with a 3 39 A spacing close to the 3.35 A spacings measured in lamellar graphite. A lateral dimension of 5.75 A for the phenyl ring is in agreement with the data available from the known structure of the oligomers and the value of 4.75 A corresponds to ihe value for a graphite/AsF6 intercalation structure. (Reproduced from ref. 194 with kind permission, Copyright (1988) Chapman Hall, UK.)...

Representative examples are depicted in Fig. 5. The cholestane sfan probes (CSL), matching the dimension of most mesogenic units, are expected to reflect the orientational order and dynamics of the LCs. Likewise, deuterons, attached to a phenyl ring or alkyl chain segment, are employed to report on the molecular properties of these groups. It should be noted, however, that the technique is easily extended to other spin probes, propriate for dynamic NMR or ESR investigations. 

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