-N(Cp H2p+1)--, and combination thereof, where and r and r' are independently integers of 0 to about 20, s is independently an integer of 1 to about 10 for each (Cs H2s O), t is an integer of 1 to about 6, and p is an integer of 0 to about 4; (b) a saturated, chiral or achiral, hydrocarbon terminal portion; and (c) a central core connecting said terminal portions.