Molecular shape, mobility

The correlation between mobility and sphericity has given rise to different speculations relating molecular shape and physical properties that could influence electron transport. However, it should be stressed that the liquid structure is important as well (Stephens, 1986). For example, although the electron mobility in liquid NP is several orders of magnitude larger than that in liquid... 

This stiffness also has an influence on the shape of the dendrimers, when different core building units are employed. The biphenyl core 9 leads to the dumbbell shaped molecule whose most stable conformers show a twist between 20° and 60° around the central biphenyl unit. 2, based on the tetrahedral core 4, with a diabolo-like molecular shape which resembles the shape of the core very well. Due to the large number of benzene rings around the central methane unit, the branches are hindered in their rotation (Scheme 4), lowering the internal mobility of the molecule compared to 15. 

The freedom to vary < ) and i so extensively—even if exaggerated here owing to the absence of other molecules—renders cellulose fragments such as an octamer, surprisingly flexible. Cellulose is generally considered to be a stiff molecule, but at least single-molecule simulations in vacuum at 400 K show it to have considerable internal mobility. The range of conformations that result from this mobility are quite apparent when the molecular shape is... 

Thus the mobility of an ion can be influenced by its pFa value the more it is ionised the greater its mobility and its molecular shape in solution. Since its degree of ionisation may have a bearing on its shape in solution, it can be seen that the behaviour of analytes in solution has the potential to be complex. For many drugs... 

Figure 14.7 shows the separation of all six components by CE. The cis isomer of GR50360A has a completely different molecular shape from the tram isomer, resulting in a smaller ionic radius and thus it runs earlier than the tram isomer. Otherwise the compounds elute in order of molecular size, the desfluorocompound being the first of the derivatives of GR50360A to elute. The presence of the isopropanol in the mobile phase slows down the EOF sufficiently for separation to develop. 

The influence of molecular shape on electrophoretic mobility is not a critical factor to consider in the experiment. The action of restriction enzymes on both covalent closed circular DNA and linear DNA results in the formation of linear fragments. 

The intrinsic pKas of the proteins depend on the local environment. They are further influenced by ionic strength, dielectric constant, and temperature. Mobility estimates should account for the effective mass-to-charge ratio and molecular shape contributions. The denaturation processes produce sets of... 

The value of p is a characteristic of a given macromolecule, and has been shown to depend on its molecular weight and molecular shape (through the frictional coefficient/), and on its net charge q. This simple equation correctly predicts that mobility increases with q, decreases with increasing/, and is equal to zero for uncharged particles. 

With the same goal of less conformational freedom and stronger inter-and intramolecular jt-overlap, a new fused compound, bis(dithienothiophene) (BDT, lla)[96-98] and its fused counterpart pentathienoacene (PTA, llb)[99] have been synthesized (Figure 3.1.4). PTA is attractive because it combines the molecular shape of pentacene with a thiophene monomer. The linear condensed thiophene backbone not only imparts extended Jt-conjugation, but is also more planar than BDT. OTFTs of 11a yielded high mobilities of 0.05 cm V s with a high on/off ratio of 10, ... 

Surface sorption Rate properties Diflusivity Ionic mobility Molecular size Molecular shape... 

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