Phenyl ring mobility

Tris(phenylquinoxaline) compounds containing two imine nitrogens on a phenyl ring, possess high EA (2.6-2.8 eV), high mobility (10-4 cm2/(V s) at 106 V/cm), and good thermal stability. Star-shaped TPQ (91) was investigated for application as an ETM in a PPV-based... 

The ft transition clearly originates from motions of the hydroxypropyl ether sequence, but the crosslink points are also involved. Whereas the motions involved in the low-temperature part of the ft transition are quite isolated motions of HPE units, when temperature increases a cooperativity appears directly with the mobility of the crosslinks and, indirectly, with the jr-flip motions of the DGEBA phenyl rings. 

V, O-Dimethy llythranidine (126) exists in mobile equilibrium in solution involving mainly two dynamic processes, namely, rotation about the carbon-carbon bond between the two phenyl rings and reversal of the piperidine ring. Tempera-... 

The molecular structure of decabenzylferrocene also helped to explain the rather low solubility of this compound in toluene or benzene, in sharp contrast with the previously found excellent solubility properties of other decabenzylmetallocenes and the pentabenzyl-Cp thallium and indium complexes in these solvents. The steric crowding of the benzyl groups in the ferrocene and their limited mobility leave little space for the solvent arene molecules to interact and subsequently to dissolve the molecule. This is quite similar to the situation encountered in the pentaphenylcyclopenta-dienyl derivatives with their closely packed phenyl rings (see Fig. 3). 

A study of the limits of rotational mobility of the aromatic ring relative to the piperidine unit and commensurate with opioid pharmacological responses has been commenced at NIH.(34) The importance of the torsion angle between these moieties has been a point of comment in the prodine series/35 36 By formally joining the 2 position of the phenyl ring of a 5-arylmorphan to the 6-position of the morphan moiety, a rigid congener would result (24). The NIH synthetic pathway to such a compound is outlined in Scheme 5.5. The key step is a photocyclization from 22 to the partially reduced dibenzofuran 23. 

Different alkoxy-substituted poly(p-phenylenevinylene)s (PPVs) have been examined to relate performance to the substitution on the phenyl ring (symmetric 40b, 40e or asymmetric 40a, 40c, 40d) and nature of side chain, either linear or branched.[233-235] The PPV polymers were soluble in common organic solvents and OTFTs were fabricated by spin-casting a 0.3 wt % solntion of PPV in chlorobenzene. Unsymmetrical alkoxy-substituted PPVs gave mobilities on the order of 10 cm V s, compared to 0.01 cm V s for symmetrically snbstimted polymers. 

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