Preparation and characterization of technetium-99m complexes with new diphosphines containing polyether groups

We report the synthesis and characterization of three new diphosphine ligands with polyether groups of general formula R(OCH2CH 2)nPPhCH2CH2PPh(CH 2CH2O)nR: 1 (R = Me, n = 3), 2 (R = Bu, n = 3) and 3 (R = Bu, n = 4). trans-[99mTcO2L2] + complexes were prepared by reaction between the diphosphine ligands and the 99mTc-gluconate precursor. The homologous rhenium complexes, trans-[ReO2L2]Cl (L = 1,2,3), were synthesized by ligand substitution reaction with [ReO2py4]Cl and oxorhenium (V) gluconate, and characterized by IR, ESMS and 1H, 13C{ 1H}, 31P{1H} NMR spectroscopy. All these data are consistent with the formation of diphosphine complexes chelated to the trans-ReO2 unit. The HPLC analyses of rhenium and 99mTc complexes display very similar profiles and retention times, consistent with the formation of the homologous complexes. Preliminary biodistribution studies with rats show significant differences between the behaviour of the three 99mTc complexes. Copyright © 2005 John Wiley & Sons, Ltd.