Induced - rearrangements in {M(CO)} complexes (M = Re, Tc) by a PNP ligand

The fac - mer rearrangements in [MX 3 (CO) 3 ] 2− (M = Re, 99 Tc) induced by a pincer-type ligand (PNP) and a "halide scavenger" are reported. The reactions of fac -[ 99m Tc(CO) 3 (OH 2 ) 3 ] + or [ 99m TcO 4 ] − in saline both yield mer -[ 99m Tc(PNP)(CO) 3 ] + , the first example of a mer -{ 99m Tc(CO) 3 } + type complex. In contrast, reactions with terpyridine (terpy) only gave the facial κ 2 -terpy complexes with Re and 99 Tc. 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 ] + .