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New Organometallic Technetium Complexes for Radiopharmaceutical Imaging

“…[Tc(CO) 6 ] + is available as well and can even be synthesized from water as recently published [42]. Most of the organometallic chemistry starts with [Tc 2 (CO) 10 )] and, for example, the important Tc(I) starting material [TcBr(CO) 5 ] can be produced directly by bromination [43].…”

Ligand exchange and complex formation kinetics studied by NMR exemplified on fac-[(CO)3M(H2O)]+ (M=Mn, Tc, Re)

“…The CO exchange was monitored by 99 Tc NMR (Fig. 9) [54]. Substitution of the NMR coupling silent 12 CO by one, two or three NMR coupling active 13 CO led to the successive appearance and disappearance of various multiplets.…”

“…The additional peaks at δ = −1050 and −1418 ppm are much broader and do not show any multiplet structure. From the assumption that each CO replacing a water molecule shifts the 99 Tc to lower frequency the signals were attributed to [(CO) 4 [54]. The broadening of the NMR signals of the quadrupolar 99 Tc is probably due to the reduction of symmetry on the Tc-centre, increasing therefore quadrupolar relaxation of 99 Tc [57].…”

“…12) 6 ] + disappears slowly within 2 days at room temperature [54]. Alberto [58] suggests that once one CO is replaced by a water molecule two other CO's are cleaved rapidly following Fig.…”

Labeling of Biomolecules for Medicinal Applications—Bioorganometallic Chemistry at Its Best

“…[8] The moderately fast exchange of 12 CO for 13 CO could be elegantly monitored by 99 Tc NMR spectroscopy through the subsequent appearance of a doublet, a triplet, and finally a quartet due to coupling to up to three 13 C nuclei, and an isotope shift Dd 1.05 per carbon mass unit was determined. When 1 is left to stand under CO pressure for two weeks, all water molecules are slowly exchanged for CO, and the homoleptic [Tc(CO) 6 ] carbonyl complex is formed in equilibrium with partially carbonylated [*] Prof. N. Metzler-Nolte…”