Design And Synthesis Of A Bombesin Peptide-Conjugated Tripodal Phosphino Dithioether Ligand Topology For The Stabilization Of The Fac-[M(Co)(3)](+) Core (M=(99) Tc-M Or Re)

A new tumor-seeking tridentate topology consisting of a phosphino dithioether ((HOCH2)(2)PCH2CH2S(CH2)(n)CH2SR; PS2) ligand framework for the production of kinetically inert and in vivo stable facial [Tc-99m(CO)(3)(PS2)](+) or [Re(CO)(3)(PS2)](+) is described. The X-ray crystal structure of fac-Re(CO)(3)(PS2)PF6 is reported. The bioconjugation strategies for incorporating bombesin (BBN) peptides on to the PS2 tripodal framework and, thereby, de novo designing of GRP receptor-seeking Tc(PS2-BBN)(CO)(3) are developed.