ch 2 m cooh ch 2 n nh 2 or ch 2 ch 2 o k ch 2 ch 2 nh 2 wherein m is 1 to about 11 n is 2 to about 12 and k is 1 to about 3 in another embodiment z 1 is co 2 h and z 2 z 3 z 4 and z 5 are each independently h x 1 and x 2 are each independently h me f cl br i so 3 h co 2 h conh 2 conme 2 cn or no 2 and x 3 and x 4 are each independently h me f cl br i so 3 h co 2 h cn ome nhch 2 r or nhso 2 r wherein r is ch 2 cooh ch 2 ch 2 ng 1 g 2 substituted 2 hydroxyphenyl or a five or six membered heterocyclic ring g 1 and g 2 are h me et ch 2 ch 2 oh or together are u2014 ch 2 4 u2014 u2014 ch 2 5 u2014 u2014 ch 2 ch 2 och 2 ch 2 u2014 or u2014 ch 2 ch 2 nhch 2 ch 2 u2014 in a preferred embodiment x 3 and x 4 are each independently nhch 2 r.