Examples of compounds of the present invention include compounds containing structure (II) where -E is ???CHR1(???O???R5???R6), where R5 is an alkyl group containing from 1 to 20 carbon atoms; where R5 is an alkyl group containing from 2 to 20 carbon atoms; where R5 is an alkenyl group containing from 2 to 20 carbon atoms; and where R5 is an aryl group containing from 5 to 20 carbon atoms.