Abstract
The fac–mer isomerisation in [MX$_{3}$(CO)$_{3}$]$^{2−}$ (M = Re, $^{99}$Tc) is induced by a PNP pincer-type ligand in the presence of a halide scavenger. The adaptation to the aqueous and saline chemistry of $^{99m}$Tc yields mer-[$^{99m}$Tc(PNP)(CO)$_{3}$]$^{+}$.