Preparation of technetium-99m-humic complex by ligand exchange from hexakis (thiourea-S)technetium(III) complex

The preparation of technetium-99m-humic complex without presence of any metal reductant was studied. For the preparation of Tc-HA complex by ligand substitution hexakis(thiourea-S)technetium(III) complex was used as a precursor. Ligand exchanging reaction was studied with two different humate/thiourea concentration ratios. After mixing of [^99mTc(tu)₆]³⁺ complex with natrium humate under a nitrogen atmosphere a formation of technetium humate wasobserved. The determination of reaction products was performed by combination of gel and paper chromatography. Reaction yields are dependent on humate/thiourea concentration ratio and reaction time. Tc-HA complex was obtained with the highest yield of 62%. Reaction mixture also contains a technetium dioxide as a side product of exchanging reaction and other technetium species, which are also discussed. Oxidation state of technetium in prepared Tc-HA complex is apparently unchanged.     

Investigation of the complex formation of technetium with thiourea by spectrophotometry and electromigration

TcO ₄ ^– is reduced by thiourea /tu/ to Tc/III/ in 6N HCl. By capillar electrophoresis three different cations have been identified with electrophoretic mobilities of u=/4.3–4.8/x10^–4 u=/3.2–3.8/x10^–4, and u=/2.2–2.8/x10^–4 cm² v^–1s^–1. These species were assigned to complex cations [Tc/tu/₆]³⁺, [Tc/tu/₅Cl]²⁺, and [Tc/tu/₄Cl₂]⁺, respectively. [Tc/tu/₆]³⁺ was identified by spectrophotometry according to recently published data. [Tc/tu/₅Cl]²⁺ was isolated and chemically characterized. The formation of the monovalent cation [Tc/tu/₅Cl₂]⁺ was concluded from spectrophotometrical measurements.     

Preparation and characterization of bis(acetonitrile)bis(acetylacetonato)technetium(III)

A new chemical species of bis(acetonitrile)bis(acetylacetonato)technetium(III), [Tc(acac)₂(CH₃CN)₂]⁺, has been prepared by the reaction of tris(acetylacetonato)technetium(III) with acetonitrile in the presence of a strong acid, perchloric or hydrochloric acid. The reaction kinetics were followed by observing spectral change of Tc(acac)₃ in the UV-visible region. The complex has been characterized by combination of elemental analyses, IR and UV-visible spectrophotometry, ion-exchange chromatography, and paper electrophoresis. Applicability of this substance to synthesize mixed-ligand technetium(III) complexes was discussed based on the solubility of this complex and the ease of substitution of the acetonitrile ligand.     

Preparation and characterization of tris(1, 10-phenanthroline) technetium(III)

The [Tc(phen)₃] (PF₆)₃ complex has been synthesized by ligand substitution on [Tc(tu)₆]³⁺. The reaction proceeds quickly in aqueous solution. A pure compound is obtained with 40% yield. It was characterized by Tc elemental analysis, cerimetric titration, conductometry and electrophoresis. The corresponding spectroscopic properties (UV, Vis, IR and NMR) are also reported and discussed.     

Tricarbonyl complexes of rhenium(I) and technetium(I) with thiourea derivatives

fac-[M(CO)₃X₃]²⁻ complexes (M=Re, X=Br; M=Tc, X=Cl) react with thiourea derivatives under formation of stable rhenium(I) and technetium(I) complexes. The composition of the products can be controlled by the steric requirements of the ligands and their ability to form chelates.The products of reactions with tetramethylthiourea, Me₄tu (I), N,N-diethylthiocarbamoylbenzamidine, H₂Et₂tcb (II), and morpholinylthiocarbamoylbenzamidine, H₂morphtcb (III), have been studied by X-ray crystallography showing that the products belong to three different structural types. A mononuclear complex of the composition fac-[Re(CO)₃Br(Me₄tu)₂] has been isolated with tetramethylthiourea, whereas the thiocarbamoylbenzamidines deprotonate and act as N,S-chelating ligands. This results in the formation of a dimeric [Tc(CO)₃(HEt₂tcb-N,S)]₂ complex with a central, almost square Tc₂S₂ unit and a monomeric compound of the composition [Tc(CO)₃(Hmorphtcb-N,S)(H₂morphtcb-S)]. The latter compound contains a neutral, S-bonded morpholinylthiocarbamoylbenzamidine in the unusual imine form in addition to a chelate-bonded Hmorphtcb⁻ ligand.     

Studies on licand displacement of thiourea in technetium/III/-coordination compounds by chlorine and 1,2 bis/diphenylphosphino/-ethane /dppe/

Ligand displacement reaction between Tc/III/-thiourea complexes and the model ligand 1,2 bis/diphenylphosphino/ ethane /dppe/ were investigated. The results appear unfavourable to the purpose of synthesizing Tc/III/ dppe complexes.     

Preparation and properties of stable mono-, tris-, tetrakis- or hexakis(pentahalophenyl)thalliate(III) complexes

Reaction of TlR₂X, TlX₃ and [TlX₄^? with RLi ( R = C₆F₅ or C₆Cl₅) leads to derivatives containing anions of the types [TlR₄]^?, [TlR₂R′₂]^? or [TlR₆]^3?. Reactions of TlCl₃ with [TlR₄]^? lead to [(μ-Cl)(TlR₂Cl)₂]^? (R = C₆F₅) or [TlRCl₃]^? (R = C₆Cl₅) while addition of X^? (X = Br^? or SCN^?) to Tl(C₆Cl₅)₃ gives [Tl- (C₆Cl₅)₃X]^?. All the novel anions were isolated as salts of bulky cations (Me₄N, Bu₄N, PPN or Ph₃BzP).     

Homogeneous isotope exchange between thiourea and bis(thiourea)mercury(II) complex

The isotope exchange behavior of thiourea with bis(thiourea)mercury(II) complex has been studied. The concentrations of both the metal ion and the complex were varied. The results show that the complex is labile in the kinetic sense. An increase in concentration increases the rate of exchange. Increase in temperature also results in an increase of the rate of exchange.     

Ni(II) complex of bisthiophosphorylated thiourea prepared from the Betti base

Russian Journal of General Chemistry - The interaction between bisthiophosphorylated thiourea with nickel(II) nitrate in the presence of potassium tert-butylate has afforded NiL2 complex with...     

Vibrational spectroscopic force field studies of dimethyl sulfoxide and hexakis(dimethyl sulfoxide)scandium(III) iodide, and crystal and solution structure of the hexakis(dimethyl sulfoxide)scandium(III) ion

Hexakis(dimethyl sulfoxide)scandium(III) iodide, [Sc(OS(CH(3))(2))(6)]I(3) contains centrosymmetric hexasolvated scandium(III) ions with an Sc-O bond distance of 2.069(3) angstroms. EXAFS spectra yield a mean Sc-O bond distance of 2.09(1) angstroms for solvated scandium(III) ions in dimethyl sulfoxide solution, consistent with six-coordination. Raman and infrared absorption spectra have been recorded, also of the deuterated compound, and analysed by means of normal coordinate methods, together with spectra of dimethyl sulfoxide. The effects on the vibrational spectra of the weak intermolecular C-H...O interactions and of the dipole-dipole interactions in liquid dimethyl sulfoxide have been evaluated, in particular for the S-O stretching mode. The strong Raman band at 1043.6 cm(-1) and the intense IR absorption at 1062.6 cm(-1) have been assigned as the S-O stretching frequencies of the dominating species in liquid dimethyl sulfoxide, evaluated as centrosymmetric dimers with antiparallel polar S-O groups. The shifts of vibrational frequencies and force constants for coordinated dimethyl sulfoxide ligands in hexasolvated trivalent metal ion complexes are discussed. Hexasolvated scandium(iii) ions are found in dimethyl sulfoxide solution and in [Sc(OSMe(2))(6)]I(3). The iodide ion-dipole attraction shifts the methyl group C-H stretching frequency for (S-)C-H...I(-) more than for the intermolecular (S-)C-H...O interactions in liquid dimethyl sulfoxide.     

A new technetium(V)-2-thiohydantoin complex

Summary A new 2-thiohydantoin ^{99Tc v} complex was prepared by the direct reduction of TcO ₄ ^– with alkaline Na₂S₂O₄ in the presence of an excess of the ligand, and characterized by spectroscopy. Reversed phase HPLC on lichrosorb-Rp-18 showed the complex to be pure; electrophoresis measurements showed it to be neutral. The complex was H₂O soluble.     

Growth and characterization of tris thiourea chromium(III) sulphate

Single crystal of tris thiourea chromium(III) sulphate was grown by slow evaporation technique at 303?K. The structural properties of the grown crystals were characterized by FTIR spectroscopy, UV spectroscopy and powder X-ray diffraction analysis. FTIR and UV spectra provide information about the presence of functional groups. Thermal analysis confirms that the crystal is thermally stable up to 163.48?°C. The TG curve presented a two-step mass loss on heating the compound at 0?C1,200?°C.     

A proton magnetic resonance study of ligand exchange on hexakis(1,1,3,3-tetramethylurea) thulium(III)

A ¹H NMR study of the rate of exchange of 1,1,3,3-tetramethylurea (tmu) on [Tm(tmu)₆]³⁺ is found to be independent of [tmu] over a five-fold variation in CD₃CN solution, and to be characterized by k(298.2 K) = 145 ± 1 s⁻¹, ΔH^# = 29.3±0.3 kJ mol⁻¹, and ΔS^# = 105±1 J K⁻¹ mol⁻¹. These data are discussed in conjunction with data from related lanthanide and pseudo-lanthanide systems and the mechanistic implications are considered.