Patent ID: 8048906

Claim:
A composition comprising a metal chelate having a structure: said composition having an enantiomeric excess of greater than 50% of an (R) isomer of said chelate at the 2 position, wherein n can range from 1 to 4, and wherein M can be selected from the group consisting of Gd(III), Fe(III), Mn(II), Mn(III), Cr(III), Cu(II), Dy(III), Ho(III), Er(III), Eu(III), Tb(II), Tb(III), Ce(III), Pr(III), Yb(III), Tm(III), Nd(III), and Tb(IV); and wherein said chelate is conjugated optionally through a linker to one or more TBMs, wherein said TBM is a peptide.