Patent ID: 7767196

Claim:
A compound having the following structure: wherein M is a paramagnetic metal ion; only one of R 1 -R 3 comprises an adamantane compound, and R 4 -R 6 are the chelating groups CH 2 COO − , —CH 2 COO—, —CH 2 CONH—, —CH 2 COC—, —CH 2 OH, —CH 2 P(O)(OEt)(OH), —CH 2 P(O)(OEt)(Ph), CH 2 P(O)(OEt){CH 2 N(CH 2 Ph) 2 } or —CH 2 O—; X 1 -X 6 each comprise hydrogen, alkyl, aryl, alcohol, amine, amido, nitro, ether, ester, ketone, imino, aldehyde, alkoxy, carbonyl, halogen, sulfur containing moieties, phosphorous containing moieties, silicon containing moieties, or other blocking moieties, or together with an adjacent X group are alkyl or aryl groups; n=0-3; monosubstituted or trisubstituted adamantane modifications comprise hydrogen, alkyl, aryl, alcohol, amine, nitro, ether, ester, ketone, imino, aldehyde, alkoxy, carbonyl, halogen, sulfur containing moieties, phosphorous containing moieties, silicon containing moieties; and either one water molecules are directly coordinated with the paramagnetic metal ion.