Patent ID: 7012140

Claim:
A magnetic resonance contrast agent compound comprising: a tetraacyclododecane ligand having a general structural formula as follows: and comprising a macrocylic ring and wherein pendant arms R, R′, R″ and R′″ attached to a ring nitrogen have the general formula: —C′HR 1 R 2 and for three or more of said pendant arms a chirality of said carbon atoms C′ are identical for each of said three or more pendant arms, said R I are groups larger than hydrogen, and said R 2 is selected from the goup consisting of: an alcohol (—CH 2 OH); amides (—CONR 3 R 4 , where R 3 and R 4 are organic groups); a carboxyl(—COOH); phosphinates (—PO 2 HR 5 , where R 5 is an organic group); and a phosphonate (—PO(OH) 2 ); and wherein one or more of substituents R 6 is a group larger than a methyl group and is located on one or more ring carbons; and a paramagetic metal ion coordinated to said tetraazacyclododecane ligand.