Rhenium structural data

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. 

Reaction of the manganese and rhenium carbonyls, M2(CO)10, with Ru3(CO)12 or Os3(CO)12 in a 3 1 ratio yields the products [M(CO)5]2M (CO)4, with M = Re or Mn, M = Ru or Os. These are considered to be linear trinuclear metal systems. The only other trinuclear carbonyl derivative isolated is OsCo2(CO)n, obtained as one of a number of compounds from the reaction of Co2(CO)8 with H2Os(CO)4. No structural data are available for this compound (241). 

Scheme 47 Synthesis of the pentatetraenyhdene-rhenium(I) complexes 137 Tahle 3 Structural data of pentatetraenylidene complexes 132 and 134...

Mechanisms of formation of rhenium(I), -(III), -(IV), and -(V) complexes with bidentate Schiff bases have been discussed in relation to available structural data. This discussion includes a few qualitative comments on reactivities.The course of substitution at [ReBr ] " in aqueous hydrochloric acid, and at [ReClg] in hydrobromic acid, was monitored by periodic precipitation by Cs and identification of the solids produced. Species identified are shown in equations (2) and (3). These observations demonstrate the important role played by the effect... 

Table 7.11 Structural data for rhenium compounds containing the and Rcj cores.

The structures of the rhenium chalcogenide halides have not been studied. X-Ray powder data were collected, in order to prove the homogeneity of the compounds 140, 263, 264, 353). 

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