Reduction pathways in lateral and diagonal (.eta.5-C5Me5)Re(CO)2Br2. Synthesis, structure, and reactivity of [(.eta.5-C5Me5)Re(CO)2Br-]

Synthesis and X-ray Structure of the Rhenium Methyl Complex trans-Cp*Re(CO)2(Me)I and a Study of the Products of Photolysis of the Rhenium Alkyl Methyl and Dimethyl Complexes Cp*Re(CO)2(Me)R (R = Ph, p-Tolyl, Me) under CO

“…For the trans isomer, the lower wavenumber band is the more intense, and this is consistent with similar relative intensities previously observed for related trans isomers of the type Cp*Re(CO) 2 X 2 or Cp*Re(CO) 2 XY. Examples are trans -Cp*Re(CO) 2 (Ph)I, trans -Cp*Re(CO) 2 R 2 (R = Me, Et), trans -Cp*Re(CO) 2 I 2 , trans -Cp*Re(CO) 2 {PO(OMe) 2 }I, and trans -Cp*Re(CO) 2 (Et)Br . This assignment is further supported by the determination of the X-ray crystal structure and the observation of a single 13 C resonance for the chemically equivalent carbonyl ligands.…”

Syntheses, Structures and Reactivities of [CpTc(CO)3X]+ and [CpRe(CO)3X]+

“…All CH 3 groups are displaced from these planes in a direction away from the rhenium atom with average deviations ranging from 0.05(2) A to 0.26(2) Å. This type of displacement appears to be general in pentamethyl-cyclopentadienyl metal complexes (average deviations ranging from 0.037 to 0.205 Å), [8,10,[17][18][19] with no observable significant statistical variation of the M-C(Cp*) bond lengths.…”

“…The M-C(CO) and C-O bonds lengths are in the expected ranges of 1.95-2.15 and 1.10-1.15 Å for metal carbonyl groups. [8,10,[17][18][19] The M-Cp* (centroid) distances range from 1.939(9) for 2a to 1.960(7) for 2, and might be viewed as almost identical and evidently insensitive to the differing arrangements of the carbonyl and halide basal ligands in the four structures. Examination of the individual M-C bond lengths to the Cp* ligand reveals, however, systematic differences in structures.…”

“…The [Cp*Re] 2+ moiety is apparently similar to the above- mentioned Ru and Rh cores but its d 4 electronic structure leads to a coordination number of 7. Some synthetic investigations with rhenium exist [7][8][9][10][11] but the chemistry of its technetium homologues is essentially unknown. In particular, the stability and reactivity in water or methanol is crucial in order to assess the versatility of this core for biological purposes.…”

Photochemical Reactions of [(η5‐C5R5)Re(CO)3] (R = Me or H) with Aryl Halides in Benzene: Stoichiometric Formation of Biphenyl

“…Sutton et al previously reported the synthesis of trans ‐ 2 by the reaction of [Cp*Re(CO) 2 (N 2 )] with HBr under scrupulously anhydrous conditions and demonstrated that the product readily reacts even in the presence of traces of water to give the corresponding dibromide products 1 13. Cowley and Richmond et al also described that this compound clearly begins to decompose after 6 h at room temperature even in a sealed tube 14. These results might provide a good explanation for the absence of product trans ‐ 2 when the separation was carried out by routine column chromatography in air.…”