Group rhenium complexes

Rhenium Halides and Halide Complexes. Rhenium reacts with chlorine at ca 600°C to produce rheniumpentachloride [39368-69-9], Re2Cl2Q, a volatile species that is dimeric via bridging hahde groups. Rhenium reacts with elemental bromine in a similar fashion, but the metal is unreactive toward iodine. The compounds ReCl, ReBr [36753-03-4], and Rel [59301-47-2] can be prepared by careful evaporation of a solution of HReO and HX. Substantiation in a modem laboratory would be desirable. Lower oxidation state hahdes (Re X ) are also prepared from the pentavalent or tetravalent compounds by thermal decomposition or chemical reduction. 

When alkenes are treated with certain catalysts (most often tungsten, molybdenum, or rhenium complexes), they are converted to other alkenes in a reaction in which the alkylidene groups (R RX=) have become interchanged by a process schematically illustrated by the equation ... 

The diamagnetic ylide complexes 34 have been obtained from the reaction of electron-deficient complexes [MoH(SR)3(PMePh2)] and alkynes (HC=CTol for the scheme), via the formal insertion of the latter into the Mo-P bond. The structural data show that 34 corresponds to two different resonance-stabilized ylides forms 34a (a-vinyl form) and 34b (carbene ylide form) (Scheme 17) [73]. Concerning the group 7 recent examples of cis ylide rhenium complexes 36 cis-Me-Re-Me) have been reported from the reaction of the corresponding trans cationic alkyne derivatives 35 with PR" via a nucleophilic attack of this phosphine at the alkyne carbon. 

Finally, (7 5-heterolyl)Mn(CO)3 complexes, the heterocymantrenes, have been prepared for the complete family of group 15 elements from N to Bi. As shown in Scheme 10, 2,5-dimethylarsacymantrene (71) is obtained directly from l-phenyl-2,5-dimethylarsole (25) in 50% yield by heating with Mn2(CO)10.26 The tetraphenylarsacymantrene (74) is obtained by pyrolysis of the corresponding cr-complex 72. Rhenium complex 75 is obtained by an analogous reaction. The 2,5-dimethylstibacymantrene (76)8 and 2,5-dimethylbismacymantrene (78)27 were obtained by similar routes. 

I. Recent review topics include carbon-rich acetylenic materials as molecular scaffolding, studies of luminescent di- and poly-ynyl-rhenium complexes containing Re(CO)3(bpy) groups and Group 4 diynyl tweezer complexes in the context of other tweezer and related molecules. ... 

Rapid development of this area followed the discovery of routes to these complexes, either by ready conversion of terminal alkynes to vinylidene complexes in reactions with manganese, rhenium, and the iron-group metal complexes (11-14) or by protonation or alkylation of some metal Recent work has demonstrated the importance of vinylidene complexes in the metabolism of some chlorinated hydrocarbons (DDT) using iron porphyrin-based enzymes (15). Interconversions of alkyne and vinylidene ligands occur readily on multimetal centers. Several reactions involving organometallic reagents may proceed via intermediate vinylidene complexes. 

Group 7 complexes, surface chemistry on oxides manganese, 12, 531 rhenium, 12, 531... 

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