Patent ID: 7943594

Claim:
A compound represented by formula I: wherein, n is 3, or 4; R represents independently for each occurrence H, alkyl, aryl, —CH 2 -aryl, —C(O)-alkyl, —C(O)-aryl, or —Si(alkyl) 3 ; R 1 and R 2 are independently H, —CH 2 -aryl, —C(O)-alkyl, —C(O)-aryl, —Si(alkyl) 3 ; or R 1 and R 2 taken together are C(CH 3 ) 2 , P(O)OH, or P(O)OR 5 ; R 3 is amino, —N 3 , or —NH 3 X; R 4 represents independently for each occurrence alkyl, aryl, —CH 2 -aryl, —C(O)-alkyl, —C(O)-aryl, —Si(alkyl) 3 , or —P(O)(OR 5 ) 2 ; R 5 represents independently for each occurrence H, Li + , Na + , Rb + , Cs + , aryl, or an optionally substituted alkyl group; and X is a halogen, alkyl carboxylate, or aryl carboxylate.