Patent ID: 8110559

Claim:
A compound of Formula (I) wherein A is a capping group or R 1 is a polyalkylene oxide; L 1 and L′ 1 —NR 11 (CR 12 R 13 ) s , wherein R 11-13 are H and s is 5; L 2 and L′ 2 are independently selected bifunctional linkers of formula wherein Y 11-14 are O, a11, b11, and c11 are each 1, R 31-32 are each H, Ar is and L 11 is a bifunctional spacer of formula —[C(═O)] v (CR 22 R 23 ) t [C(═O)] v′ —, wherein v and v′ are zero, t is 1, and R 22-23 are H; Y 1 and Y′ 1 are independently O, or S; X and X′ are independently O or S; R 2 , R′ 2 , R 3 , R′ 3 are methyl; R 4 and R′ 4 are independently selected polynucleotides; (p) and (p′) are independently 1; (q) and (q′) are independently 1; and the capping group is C 1-6 alkyl.