Radioactive transition metal-imido hetero-diphosphine complexes, their preparation and radiopharmaceutical compositions thereof

摘要

The present invention provides radioactive metal heterocomplexes of formula (I): [(Me-N-R)L₁L₂]+Z. (I), wherein Me, R, L¹ L² and Z^- have the meanings indicated in the description. The complexes include a trivalent radioactive metal-imido group, typically a technetium- or rhenium-imido group, strongly stabilized by the presence of an ancillary tridentate hetero-diphosphine ligand L¹, which allows the formation of substitution-inert [(Me-N-R)L¹] moieties. Such moieties are fixed in an intermediate [(Me-N-R)Y₂L¹)]⁺ compound which contains two labile, cispositioned, Y ligands, where Y is preferably an halide group. The latter are easily replaced by a bidentate ligand L² to give the final [(Me-N-R)L¹L²]⁺Z^-heterocomplexes. The complexes of the invention are useful for the preparation of radiopharmaceuticals: in fact, a bioactive fragment which confers biological target-seeking properties can be introduced either on the L² framework or the imido R group.