Electron-transfer reactions of technetium complexes. 1. Rate of the self-exchange reaction of the technetium(I)/technetium(II) couple [Tc(DMPE)3]+/2+, where DMPE = 1,2-bis(dimethylphosphino)ethane

Abstract

Br), prepared anaerobically in perchloric acid at 0.10 M ionic strength, was saturated with alkali-scrubbed nitric oxide. A solution of chromium(ll) perchlorate was then slowly added while the solution was efficiently stirred and continuously saturated with NO. After addition of Cr2+ was complete, the NO was removed with a vigorous stream of argon. Samples were taken for the analysis of the cobalt(II) produced by the thiocyanate method57 in 1:1 aqueous acetone. This measurement was made by incorporating an appropriate reagent blank, which was critical given the small concentrations involved, and was based on a molar absorptivity of 1.84 X 103 M"1 cm"1 at 623 nm. These measurements provided the values of [Co2+]" necessary for the calculation of the data according to eq 8. Product Analysis. The inorganic products, Cr(H20)63+ and (H20)5CrN02+, were readily recognized by their elution times from a column of Sephadex SP C-25 ion-exchange resin. Their identities were confirmed and yields determined on the basis of their known UV-visible spectra and, in the case of (H20)5CrN02+, analysis for total chromium.The organic products, with the exception of CH2Q, were identified and determined by gas chromatography. The experiments with CrCH2CH32+and CrCH(CH3)22+ used as blanks solutions of the same organochromium complex, which had been allowed to undergo acidolysis to give (57) Kitson, R. F. Anal. Chem. 1950, 22, 664. Cr(H20)63+ and RH. No sodium nitrite was added to the blanks. The purity of CrCH2OCH32+, which undergoes acidolysis very slowly, was checked by gas chromatography of the eluent during purification on the ion-exchange resin. This analysis showed that no methanol (a product of the reaction with HN02) was present in the original stock solution ofCrCH2OCH32+. The compounds sought were compared with the known materials calibrated in concurrent experiments. All of the experiments used a 10% FFAP column.

Three-component spectroelectrochemical sensor module for the detection of pertechnetate (TcO4-)

“…Previous studies have shown that non-aqueous [Tc(dmpe) 3 ] + is part of a redox couple with well-defined, reversible electrochemistry. It can be reversibly converted to the higher oxidation state [Tc(dmpe) 3 ] 2 + according to the process below, with a formal reduction potential of 0.05 V vs. Ag/AgCl: ( Doyle et al 1986, Chatterjee et al 2011b …”

99mTc Labeling of Highly Potent Small Peptides

“…If pentane-2,4-dione is used as a ligand, the red Tc(III) complex, [Tc(acac) 3 ], results (48), while the Nsubstituted pyridinone ligands form very stable trisligand Tc(IV) complexes [Tc(L) 3 ] + (L ) N-substituted pyridinonate) (49). If the ligand contains P donors, Tc(IV), Tc(III), and Tc(I) complexes are isolated depending on the number of P donors and coligands in the complex (50)(51)(52). Isonitrile ligands form colorless Tc(I) complexes, [(Tc(CNR) 6 ] + , almost quantitatively (53).…”

A Kinetic Study of the Reduction of Np(VI) and Pu(VI) in Carbonate Media by Tris[1,2-bis(dimethylphosphino)ethane] Complexes of Tc(I) and Re(I)

“…Moreover, the fe 22 values for the self-exchange reactions of the TC(DMPE)3 +/2+ and Re(DMPE)3 +/2+ are well established from both the measured rates of cross reactions [3,4] and calculations based on structural data [4], Thus, the Marcus formulation can be used to calculate the fen values for the Np(VI)/(V) and Pu(VI)/(V) self-exchange reactions from values of the Brought to you by | New York University Bobst Library Technical Services Authenticated Download Date | 7/18/15 11:16 PM equilibrium constants (Table 1), the measured rate constants for the cross reactions (k 12 ), and the selfexchange rates of M(DMPE)3 +/2 + . When the self-exchange rate constant for the Tc(DMPE)3 +/2+ couple and the measured rate (k l2 ) for the cross-reaction are used, the values for fcn are 0.69 and 3.0 M _1 s _1 for Np(VI)/(V) and Pu(VI)/(V) respectively; whereas, when the k 12 for the Re(DMPE)3 +/2+ couple is used, the ku values are 0.64 and 8.9 M _1 s _1 , respectively.…”

“…The extension of these studies to actinide redox reactions in basic carbonate solutions attains additional relevance by the need for a greater understanding of actinide chemistry under environmental conditions. Previous kinetic studies involving actinide complexes have included investigations of electron exchange and oxo-group transfer reactions, and the in- [3,4] have recently been determined. These M(II)/(I) couples provide useful electron transfer partners since the M(I) form is colorless while the M(II) form has a relatively intense band in the visible region which can be readily monitored.…”