Rhenium chemistry

A particularly significant part of rhenium chemistry involves cluster compounds in which there is metal—metal bonding. This chemistry centers largely around the +3 oxidation state. 

Rhenium chemistry will not be discussed explicitly in this contribution. Various excellent reviews on the progress of organometallic rhenium chemistry have been published over recent years. [7] Rhenium is only mentioned when its comparison to new technetium compounds is interesting in the present context and the focus is on significant differences in the behaviour of the two homologs. 

However, problems are encountered in production of rhenium radionuclides and work is being done to increase the yields of the radionuclides to meet urgent demands for their use in therapy. Moreover, rhenium is not as reactive as technetium. This situation makes rhenium chemistry somewhat specific - optimum conditions in the preparation of rhenium complexes or in antibody labeling using bifunctional ligands must be identified. 

The last sequence in particular demonstrates the same sort of stepwise transformation observed in the rhenium chemistry described above. 

The rich and diversified rhenium chemistry developed with the PNX (X is O, S) phosphines motivated the authors to explore their use in the so-called 3+1 approach [58,59]. Different model complexes, 55-58, were synthesized by reacting [NBuJ [ReOClJ with H2PNO or with H2PNS in the presence of several monodentate thiols as coligands (Scheme 13) [58]. 

The complexes described here, which are very easy to prepare in a pure state, are useful starting materials for the preparation of most compounds of rhenium (V) and should be considered with perrhenic acid, potassium hexahalorhe-nate(IV) salts, rhenium(III) chloride, rhenium(V) chloride, and dirhenium decacarbonyl as basic source materials in rhenium chemistry. The procedure is a modification of that originally used by Freni and Valenti, although the nature of the compounds obtained was clarified only by subsequent studies. - ... 

There will be circumstances other than those I have described here in which "high oxidation state" organometallic chemistry of rhenium in a catalytic reaction will be viable, although it is becoming clear that the balance necessary to achieve this feat is more difficult to maintain as one moves to the right in the transition metal series, and that some of the d rhenium chemistry in fact may look like chemistry of dP osmium species. On this basis it would seem unlikely that the principles that have been used to prepare Re(VII) alkylidyne and alkylidene complexes (a hydrogen migration reactions) can be extended further (to technetium, or especially osmium or ruthenium), at least in a routine fashion. 

As observed in Table 1.8 most examples of compounds with electron configuration arise from rhenium chemistry. The most important group of... 

Progress in rhenium chemistry reported in 1991 is reviewed.549 There is much important material in a review of methyltrioxorhenium catalysed alkene metathesis, oxidation and aldehyde alkenation, a review of the insertion of activated alkynes into the metal-metal bond of dinuclear manganese and rhenium carbonyl complexes. i a review of the reactions of [Cp(CO)2Mn=CPh]+ towards electron rich alkynes and nitriles552 and a review of the discovery of tRe(CBu )(CHBu ) OCMe(CF3)2 2l and recent results covering the metathesis of alkenes. s... 

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