Synthesis and X-ray crystal structure of tetraethylammonium bis(1,1-dicyanoethene-2,2-diselenolato)oxotechnetate(V), [Et4N][TcO(Se2CC(CN)2)2]

[Tc(OH2)(CO)3(PPh3)2]+: A Synthon for Tc(I) Complexes and Its Reactions with Neutral Ligands

“…The formation of the aqua complex is easily verified by the appearance of a 99 Tc NMR resonance at −1232 ppm (ν 1/2 = approximately 5000 Hz), while the signal of [TcH(CO) 3 -(PPh 3 ) 2 ] at −2208 ppm disappears. The 99 Tc resonance of [Tc(OH 2 )(CO) 3 (PPh 3 ) 2 ] + is downfield-shifted by 100 ppm Scheme 1.…”

“…The formation of the aqua complex is easily verified by the appearance of a 99 Tc NMR resonance at −1232 ppm (ν 1/2 = approximately 5000 Hz), while the signal of [TcH(CO) 3 -(PPh 3 ) 2 ] at −2208 ppm disappears. The 99 Tc resonance of [Tc(OH 2 )(CO) 3 (PPh 3 ) 2 ] + is downfield-shifted by 100 ppm Scheme 1. Synthesis of [Tc(OH 2 )(CO) 3 (PPh 3 ) 2 ](X) Salts (X = BArF 24 − , BF with respect to neutral complexes with the same donor set and geometry around technetium, e.g., the [Tc{η 1 -O(CR)O}-(CO) 3 (PPh 3 ) 2 ] complexes (R = H, CF 3 ).…”

“…The 31 P NMR spectrum of [Tc(S 2 CPPh 3 )(CO) 2 (PPh 3 ) 2 ]-(BF 4 ) (7) shows a broad resonance at 18 ppm for the two axial PPh 3 ligands and a narrow resonance at 25 ppm for the S 2 CPPh 3 adduct. A drastic line broadening of 31 P signals for P atoms, which are directly bonded to the quadrupolar nucleus 99 Tc, is frequently found for complexes with low local symmetry. This is commonly explained by scalar couplings between the two nuclei, which in many cases make the 31 P signals practically invisible.…”

“…The complete consumption of 1b in such reactions and the formation of the solvent complexes can easily be checked by the absence of the characteristic splitting of the water band in the IR spectra of the products. The decarbonylation can be followed by the 99 Tc NMR resonances. For the two DMF complexes, they appear at −1245 ppm (4) and −736 ppm (5).…”

“…1−6 Modern approaches toward novel technetium radiopharmaceuticals also address bis(arene) compounds 7−9 and cyclopentadienyl complexes. 10−13 Particularly the latter group of compounds is frequently stabilized by the {Tc I -(CO) 3 } + core, which can be provided in aqueous solution as the [Tc(CO) 3 (OH 2 ) 3 ] + complex for 99 Tc as well for the clinically relevant gamma emitter 99m Tc. 14−19 The aqua ligands of this compound can be readily exchanged by biologically relevant ligands and give, thus, access to potential pharmaceuticals.…”