| abstract |
A compound represented by the formula: n n n n n n n n n n n n wherein each R is independently selected from the group consisting of (i) substituted or unsubstituted alkyl with C=0 to 12 inclusive; n wherein X 1 , X 2 , X 3 and X 4 are each independently selected from the group consisting of alkyl, aryl, alkylaryl groups and hydrogen; n wherein R 1 , R 2 , R 3 , and R 4 are each independently selected from the group consisting of alkyl, aryl, alkylaryl groups and hydrogen; and wherein one of R 1 and R 2 and one of R 3 and R 4 may optionally be bridged by a polymethylene group to form a cycloalkyl; n wherein when C=0 in R, the combined group R 1 R 2 is the same as the combined group R 3 R 4 ; and n wherein when C=1 in R, each of R 1 , R 2 , R 3 , and R 4 are hydrogen. |