First Application of fac-[^99mTc(OH₂)₃(CO)₃]⁺ in Bioorganometallic Chemistry: Design, Structure, and in Vitro Affinity of a 5-HT_1A Receptor Ligand Labeled with ^99mTc

Bioorganometallic chemistry comprises the combination of an organometallic transition metal complex and a targeting biomolecule. If ever such a combination should be applied, the synthesis has to be convenient, fast and requires one or two steps only. [^99mTc(OH₂)₃(CO)₃]⁺ 1 can be prepared in one step from [^99mTcO₄]^- in saline and bidentate aromatic amines are very efficient chelators for this organometallic precursor. Consequently, we have derivatized a 5-HT_1A (serotonergic) receptor ligand with high affinity and high selectivity for this subclass from the group of the arylpiperazines with a Schiff Base type chelator. In water, 1 radiolabels the receptor ligand in high yield and specific activity.