Dangling chains/bonds

Table A9.1.2 also demonstrates that at each gelatin concentration, the number of bonds per gelatin molecule is relatively constant. This number, of course, is the number of bonds taking part in three-dimensional network formation. Not all the gelatin chains are bound in a true tetrafunctionally cross-linked network. Many dangling chain ends exist at these low concentrations, and the network must be very imperfect.

However, if the molecules of 5 had R alkyl chains longer than Me, the steric hindrance prevented 100% substitution and IR examinations indicated a 50% less derivatization. Moreover, XPS analysis showed that the surface is partly modified by substitution of hydrogen by halogen . In the case of 5 with X = I and to some extent X = Br, the formation of X radicals (besides 12) in a secondary reaction was reported . They participate in reactions analogous to equations 21 and 22b, but with X instead of 12, and attach to the Si surface improving the electronic passivation of the surface at defect sites, sterically inaccessible to 12. A possibility that surface dangling bonds may also appear in the charged states was discussed as well . 

A more complicated model has been used with success by Cutler and others, in which selenium and tellurium chains are broken with increasing temperature, giving rise to dangling bonds in equilibrium with valence alternation pairs this is described in Section 6. 

Organic Molecules Styrene [79], Vinylferrocene [95] Initial adsorption at dangling bond and chain reaction assembly of molecular wires along dimer row direction that are predicted to permit charge transport [96]. 

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