Macrocyclic chelators and methods of use thereof

A chelator selected from the group consisting of:

• wherein:
• L1 is a linker selected from a substituted or unsubstituted alkyl, a substituted or unsubstituted heteroalkyl moiety, a substituted or unsubstituted aryl or heteroaryl, and a polyethylene glycol (PEG) moiety, wherein the alkyl, heteroalkyl, aryl, and heteroaryl are unsubstituted or substituted with one to three groups selected from alkyl, cycloalkyl, alkoxy, alkenyl, cycloalkenyl, alkynyl, cycloalkynyl, aryl, heterocyclyl, heteroaryl, halogen, hydroxy, amide, alkylthio, amino, alkylamino, aminoalkyl, hydroxyalkyl, hydroxyl, and carboxyl;
• R11 is a —NH2, —NCS, —NCO, —N3, alkynyl, cycloalkynyl, —C(O)R13, —COOR13, —CON(R13)2, maleimido, acyl halide, tetrazine, or trans-cyclooctene, or R11 comprises an antibody or antigen binding fragment thereof, scaffold protein, small molecule, or aptamer;
• and
• each R13 is independently hydrogen or alkyl.