Alun G. Jones

The chemistry of technetium I, II, III and IV

Abstract The synthesis, reactivity and molecular structure of technetium in the oxidation states (I), (II), (III) and (IV) are reviewed. The results show that the (III) state has a diverse chemistry and is quite accesible from TcO 4 − in aqueous solution. There is an emerging chemistry of technetium in the (I) state with π-acceptor ligands.

Carboxy, carboalkoxy and carbamile substituted isonitrile radionuclide complexes

A coordination complex comprising a radionuclide selected from the class consisting of radioactive isotopes of Tc, Ru, Co, Pt and Re and an isonitrile ligand of the formula: (CNX)R, where X is a lower alkyl group having 1 to 4 carbon atoms, wherein R is selected from the group consisting of COOR1 and CONR2 R3 where R1 can be H, a pharmaceutically acceptable cation, or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, R2, and R3 can be H, or a substituted or unsubstituted alkyl group having 1 to 4 carbon atoms, and R2 and R3 can be the same or different is disclosed. Kits that can be used to form these complexes are also disclosed.

The synthesis and characterization of [TcCl3(NPh)(Ph2PCH2CH2PPh2)] and [TcCl3(NPh)(PPh3)2]. The single crystal X-ray structure of [TcCl3(NPh)(Ph2PCH2CH2PPh2)]

Abstract The reaction of (Bu4N)[TcOCl4] in methanol with 1-acetyl-2-phenylhydrazine, followed by 1,2-bis(diphenylphosphino)ethane (DPPE) gives the green technetium(V) phenylimido complex [TcCl3(NPh)(DPPE)]. The IR spectrum of this complex shows a characteristic peak at 1110 cm-1 which is assigned to v(TcN) from the linearly coordinated phenylimido unit. The 1H NMR spectrum shows a pair of coupled multiplets at 3.1 and 3.6 ppm from the aliphatic protons plus a series of six multiplets between 6.5 and 8.1 ppm from the aromatic protons of the bidentate phosphine ligand and imido-phenyl groups. The positive mode fast atom bombardment mass spectrum displays a peak at 695 m/z which corresponds to the protonated patent molecule. Also, a peak at 658 m/z corresponds to the fragment generated from the loss of one chloride from the neutral patent molecule. The X-ray crystal structure shows a facial arrangement of chloride ligands, with a TcN bond length of 1.687 A and a TcNC bond angle of 175.7° indicative of sp hybridization of the linearly coordinated phenylimido unit. Crystal data for TcCl3P2NC32H29: monoclinic space group Pc (No. 7), a=11.177(2), b=10.912(2), c=14.056(2) A, β=108.34(1)°, V=1627.3(5) A3, with Dcalc=1.414 g cm−3 to give Z=2. Structure solution based on 3069 reflections converged at R=0.051, Rw=0.072, GOF=2.32. The analogous reaction with triphenylphosphine gives the previously reported Tc(V) phenylimido complex [TcCl3(NPh)(PPh3)2]. This Tc(V) phenylimido complex reacts with pyridine in methanol to give the mixed ligand complex [TcCl3(NPh)(PPh3)(NC5H5)]. The positive mode FAB mass spectrum of this complex shows fragments which correspond to the sodium adducts of the neutral molecule minus one chloride ligand, (Na)[TcCl2(NPh)(PPh3)(C5H5N)]+ at 624 m/z, and the molecule minus two chloride ligands, (Na)[TcCl(NPh)(PPh3)(C5H5N)]+ at 589 m/z. Also present in the mass spectrum are peaks which correspond to the fragments [TcCl3(PPh3)(C5H5N)]+ at 545 m/z and [TcCl2(PPh3)(C5H5N)]+ at 510 m/z. The IR spectrum of this complex shows an absorption at 1090 cm−1 which is assigned to v(TcN) from the linearly coordinated phenylimido unit.

Synthesis and characterization of tris(β-diketonato)technetium(III) and -(IV) complexes

Abstract The preparations and properties of tris(dipivaloylmethanato)technetium(III), tris(trifluoroacetylacetonato)technetium(III), and tris(hexafluoroacetonato)technetium(III) are described. The oxidation of the dipivaloyl derivative to tris(dipivaloyl)technetium(IV) hexafluorophosphate was shown to take place readily. Voltammetric studies and magnetic resonance results on the new complexes are reported. The large shifts observed for the complexes seem to be due to a contact interaction.

Reactions of the technetium(V) phenylimido complex [TcX3(NPh)(PPh3)2] with aromatic thiolate ligands (where X=Cl, Br)

Abstract The reaction of KTcO4 with triphenylphosphine and 1-acetyl-2-phenylhydrazine in methanol with HBr gives the Tc(V) phenylimido complex [TcBr3(NPh)(PPh3)2], analogous to the published reaction with HCl. The phenylimido complex reacts with unsubstituted thiophenol and a proton scavenger (R3N) in methanol to give the Tc(V) oxo complex (R3NH)[TcO(SPh)4] in excellent yield. The IR spectrum of this complex shows an absorption at 936 cm−1 associated with v(Tc=O). The Tc(V) complex [TcCl3(NPh)(PPh3)2] reacts with a four-fold excess of the sterically-hindered thiol 2,3,5,6-tetramethylbenzenethiol (TMBTH) and a proton sponge to give the Tc(V) complex [Tc(NPh)(TMBT)3(PPh3)]. The IR spectrum of this complex displays an absorption at 1100 cm−1 which is associated with v(TcN). The positive mode fast atom bombardment mass spectrum of this species displays an extensive fragmentation profile, including fragment of 947 m/z, which corresponds to the parent ion [Tc(NPh)(TMBT)3(PPh3)]+. The analogous reaction with a five-fold excess of 2,6-dimethylbenzenethiol (DMBTH) and a proton sponge gives the anionic Tc(V) complex (R3NH)[Tc(NPh)(SAr)4]. The IR spectrum of this complex displays an absorption at 1100 cm−1 which is associated with v(TcN). The positive mode fast atom bombardment mass spectrum of this anionic species displays an extensive fragmentation profile, including fragments of 998 m/z, which corresponds to {(R3NH)2[Tc(NPh)(DMBT)4]}+ and 868 m/z which corresponds to {(R3NH)[Tc(NPh)(DMBT)4]}+. The reaction of the Tc(V) complex [TcCl3(NPh)(PPh3)2] with the tetradentate phosphinetrithiol ligand [P(C6H4-o-SH)3], and a proton scavenger in methanol gives the neutral Tc(III) complex [Tc(PPh3)(PS3)]. The FAB(+) mass spectrum of this complex shows the parent ion of 716 m/z and the peak associated with the fragment generated by the loss of the triphenylphosphine of 454 m/z. The IR spectrum shows no absorptions in either the region associated with v(TcO) or v(TcN). The 1H NMR spectrum of the diamagnetic Tc(III) complex shows only narrow-line signals associated with the aryl protons.

Method for preparing radiopharmaceutical complexes

A method for preparing radiopharmaceutical complexes that are substantially free of the reaction materials used to produce the radiopharmaceutical complex is disclosed. The method involves admixing in a suitable first solvent in a container a target seeking ligand or salt or metal adduct thereof, a radionuclide label, and a reducing agent for said radionuclide, thereby forming said radiopharmaceutical complex; coating the interior walls of the container with said pharmaceutical complex; discarding the solvent containing by-products and unreacted starting reaction materials; and removing the radiopharmaceutical complex from said walls by dissolving it in a second solvent, thereby obtaining said radiopharmaceutical complex substantially free of by-products and unreacted starting materials.