Technetium, and Rhenium Complexes

The diamagnetic cation [(Me8Cg)2Mn] has been reported from the cyclic condensation of 2-butyne on diphenylmanganese 416). However, an attempt to reproduce this result led instead to the mixed arene cation 

The arene manganese tricarbonyl cations undergo a reversible reaction with amines giving neutral carboxamido derivatives 14)  

In contrast to the preceding carbonyl group reactions, cations [(CgHg)Mn(CO)3] and [(MegCg)Re(CO)3] reacted with primary amines with loss of the arene group to give derivatives of the type [(RNH2)3M(C0)3] 14). Arene replacement reactions have also been 

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Schiff bases provide useful mixed donor sets. The carbonyl function of the most frequently used ligands is derived from either 1,3-dicarbonyl compounds or salicylaldehyde. Favourable combinations involve O-, N- and S-donor atoms. A range of technetium and rhenium complexes exist with bi-, tri-, tetra- and pentadentate ligands. The geometry of these complexes depends on the number and type of coordinating atoms as well as on the chain length between the donor atoms in the SchifF-base ligands. 

Although these complicated features of the redox reactions of technetium are important topics, the present article is limited to the susbtitution kinetics of technetium complexes. Some redox kinetics of technetium complexes have been discussed by Koltunov and Gomonova [6], The redox potentials for analogous technetium and rhenium complexes, based on their differences, have been compiled by Deutsch et al. [7],... 

VII. In Vitro and In Vivo Reactivity of Technetium and Rhenium Complexes... 

Fig. 21. Comparison of half-lives. [Data from Table VII (equatorial ligand substitution, Table VIII (aqua substitution and related reactions) and Table IX (in vivo reactions of technetium and rhenium radiopharmaceuticals) of the complexes described in Section VII,A. Similar symbols denote similar technetium and rhenium complexes.]...

Pertechnetate forms a blue complex and perrhenate a brownish-yellow complex with K4[Fe(CN) ] in presence of bismuth amalgam. This permits the spectrophotometric determination of both elements in the same solution . The adsorption maxima of the technetium and rhenium complexes are at 680 and 420 nm, respectively. The molar extinction coefficients are 10,800 for technetium and 4,000 for rhenium. Metals forming color or precipitates with K4[Fe(CN) ] must first be removed. 

Abstract This review presents a comprehensive overview of the most significant developments in the chemistry of technetium and rhenium complexes anchored by heterofunc-tionalized phosphines and by hard and soft scorpionates. The main goal is to provide the reader with chemical,radiochemical and biological knowledge which is expected to enhance the application of these types of compounds in the development of target-specific radiopharmaceuticals. 

Eckelman WC, Meinken G, Richards P (1971) Tc-human serum albumin. J Nucl Med 12 707-710 Edwards D, Cheesman E Watson M, Maheu L, Nguyen S, Dimitre L, Nason T, Watson A, Walo-vitch R et al (1990) Synthesis and characterization of technetium and rhenium complexes of NdV -l,2-ethylenediylbis-L-cysteine. Neurohte and its metabolites. In Nicolini M, Bandoh G, Mazzi U (eds) Technetium and rhenium in chemistry and nuclear medicine 3. Cortina International, Verona, Italy, p 433... 

Fig. 2.2.6. Formyl peptide receptor-targeting peptide (fMLF)[(SAACQ-M(C0)3) ] conjugate useful for in vitro fluorescent microscopy (where M = Re) and in vivo single-photon emission computer tomography (SPECT) (where M = Tc) with isostructural technetium and rhenium complexes...

Seifert S, Syhre R, Gupta A, Spies H, Johannsen B (1999) Stability studies on 3+1 mixed-ligand technetium and rhenium complexes. In Nicolini M, Mazzi U (eds) Technetium, rhenium and other metals in chemistry and nudear medicine, vol 5. SGE Editoriali, Padova, p 687... 

Under the influence of water, cationic manganese compounds decompose immediately, as in organic donor solvents such as acetone and tetrahydrofuran. In contrast to isoelectronic compounds of the chromium group, diolefin technetium and rhenium complexes have cis structures. In aqueous solution, the cation [Re(CO)4 ( 2114)2] is stable the Re —C2H4 bond in [Re(CO)5 ( 2114)] is also stable. There is no exchange between free ethylene and the ethylene in the complex. 

Kunze, S., Zobi, R, Kurz, R, Spingler, B., Alberto, R. 2004. Vitamin B12 as a hgand for technetium and rhenium complexes. Angew Chem Int Ed Engl, 43, 5025-9. 

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