The conjugated double bonds
and N, O, S atoms in the organic molecules help to form p-d bonds between the inhibitor and metal resulting from overlap of p-electrons to the 3d vacant orbital of metal atoms, which can enhance the adsorption of the inhibitors on the metal surface .
The deep red colour of lycopene and its antioxidant property is due to the presence of these 11 conjugated double bonds
and due because of this reason lycopene is used in food coloring.
Tung oil dries rapidly but it discolors rapidly due to the presence of the three conjugated double bonds
, and it is expensive.
The ability of carotenoids to quench singlet oxygen has been linked to the conjugated double bond
system, the maximum efficiency being shown by carotenoids with nine or more conjugated double bonds
(Foote et al., 1970).
Some of the earliest commercial anodic ED coatings were automotive primers based on natural oils with conjugated double bonds
(such as dehydrated castor oil and linseed oil) that were reacted with maleic anhydride.
This suggests that the conjugated double bonds
became longer in the order [N.sub.3.sup.-] > [SCN.sup.-] > [OH.sup.-].
Carotenoids are long carbon molecules with central conjugated double bonds
. Although lutein and zeaxanthin have the same number of double bonds, zeaxanthin has 11 conjugated double bonds
but lutein's eleventh double bond forms a more chemically reactive allylic hydroxyl end group.
Conjugated linoleic acids (CLA), a mixture of positional and geometric isomers of octadecadienoic acid with conjugated double bonds
, have a range of potent health effects, including suppression of carcinogenesis (Ip et al., 1999; Belury, 2002; Corl et al., 2003), antiobese effect (Park et al., 1997), modulation of the immune system (Cook et al., 1993), reduction in atherosclerosis (Nicolosi et al., 1997), diabetes (Houseknecht et al., 1998) and decreased body fat mass in humans (Blankson et al., 2000; Gaullier et al., 2005).
Similar oxygen-pressure-dependent behavior may be shown by other compounds containing many conjugated double bonds
[n.sub.x]= The number of conjugated double bonds
. A= The number of conjugated carbon atoms.
For tung oil, with mostly conjugated double bonds
from eleostearic acid (~ 77-82 percent eleostearic acid), the rate of autoxidation is much higher than that observed in linolenic acid, due to the conjugation.