A study on the synthesis and properties of substituted EHBG-Fe(III) complexes as potential MRI contrast agents

摘要

Mono- and disubstituted EHBG (HBED) ligands of different kind: forming hydrogen bonds (p-OMe, p- NHAc) and of high lipophilicity (3,4-Me_2, p-Ph) were obtained. The ligands were complexed with Fe(III). Complexes so obtained were studied for their stability in different pH environments; and r1 relaxivity, which turned out the highest for Fe-EHBG-NHAc, i.e. 0.95 mM~(-1) s~(-1) in aqueous solution and 1.34 mM~(-1) s~(-1) for Fe-EHBG-Me_2 in bovine serum. EPR signals were observed at g-factor of 4.27 indicative of Kramer's doublet transitions of a rhombically distorted high-spin paramagnetic center.