Along chain

In aqueous solutions we see enhanced mobility and conductivity of the hydrogen ions, which is caused by additional proton transfer along chains of water molecules linked by hydrogen bonds (see Section 7.2.4). Solutions with nonaqueous, proton-containing solvents (e.g., in ammonia) sometimes also exhibit enhanced hydrogen... 

Figure 2.8 Side views and projections along chain axis of two enantiomorphous hypothetical helices of isotactic polymer having unit height of 2 A and unit twist t = 144°, corresponding to intersection points of Figure 2.7a a, left-handed helix with s(5/3)l symmetry and t = —144° = 216° a, right-handed helix with s(5/2)l symmetry and t = 144°.27 (Reproduced with permission from Ref. 27. Copyright 1992 by the Societa Chimica Italiana.)...

Figure 2.19 Side view and projection along chain axis of conformation of chains in crystals of alternating e (hyIenc-c/.v-2-butene copolymer.119...

Figure 2.21 Side views and projections along chain axis of conformations of chains in syndiotactic121 and isotactic123 alternating styrene-CO copolymers.

Two radical sites in close proximity may be produced by migration of the sites along chains or by formation of the sites in close proximity through H or X abstraction on the second molecule by an H or X atom formed by C-X scission on the first molecule. H-links have been clearly demonstrated by 13C NMR in irradiated polydienes. 

Fig. 3.1-5. Crystal structure of [Ba2OJNa viewed along chains of trans edge sharing [Ba4/20] tetrahedra. Ba-Ba contacts outlined, Na light shading.

In 1975 Brown and Yamashita reported that a triple bond in any position of a straight chain hydrocarbon or acetylenic alcohol, when treated with a sufficiently strong base, could be isomerized exclusively to the free terminus of the chain. The "zipper reaction" thus provides a general solution to the problem of remote functionalization of a long hydrocarbon chain. Isomer-izations along chains of thirty carbon atoms have been achieved. 

This term reflects the structural motif of their arrangement. At the same time, the name also underlines the one-dimensionality of the charge-bearer (electron-bearer) shift in such crystals. Electron delocalization occurs in the framework not only for the one-molecule contour but also in an ensemble of many molecules. As a consequence, electrons shift along chains of organic ions. Collective conductivity arises. Naturally, this conductivity is large along the chain axes and insignificantly small in all other directions. 

The value of the exchange modes of the magnetic resonance has the same order of a magnitude as triplet excitations in the dimerized state [5], These modes exist in both U- and D-AFM states. Furthermore, these modes excite by a high frequency magnetic field polarized perpendicular to easy axis. Their intensities define by the DM interactions. The spin oscillations in these modes respect to a violation of 3D AFM order along chains as well as between chains. Therefore, one can expect an amplification of their intensities under motion of boundaries between coexisting SP- and AFM states. The next experiments are necessary to make situation clear. 

The question of whether proteins originate from random sequences of amino acids was addressed in many works. It was demonstrated that protein sequences are not completely random sequences [48]. In particular, the statistical distribution of hydrophobic residues along chains of functional proteins is nonrandom [49]. Furthermore, protein sequences derived from corresponding complete genomes display a distinct multifractal behavior characterized by the so-called generalized Renyi dimensions (instead of a single fractal dimension as in the case of self-similar processes) [50]. It should be kept in mind that sequence correlations in real proteins is a delicate issue which requires a careful analysis. 

A relation between the mean end-to-end distance of the entire chain (R2) and the mean end-to-end distance of a subchain b can be found from simple speculation. This relation includes temperature T, mean distance b between the nearest along chain particles, excluded volume parameter v and the number of particles on the chain N. When dimensional considerations are taken into account, the relation can be written in the form... 

Each of the photosystems ejects an electron from the excited chlorin complex to a quinone within a nanosecond, followed by electron transfer along chains leading out of the charge separation center within 100 ns. The high potential reaction of Tyr and Mn in PSII is quite rapid, beginning in the simulations on the same time scale as the quinone reduction reaction. However, it has been suggested that tyrosine oxidation may not be rate limited by tunneling, but by H+ transfer (Diner et al., 2001). 

FIGURE 5.8 Projections of short cellulose chains. Leftmost along chain axis. Left-center along ribbon edge. Right-center Maximal width view. Rightmost Ball and stick model in the same orientation as the space-fiUing model to its left. 

Figure 2.2 Orthorhombic crystalline structure of polyethylene perspective view of the unit cell and view along chain axis.

Molecular weight sensitive Break near middle of molecule Self-limiting Insensitive to chemistry Indiscriminate Random break along chain Complete degradation possible Dependent on chemistry... 

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