Carbon-hydrogen stretching vibrations as a probe of the structure of unstable organometallic species

Time‐Resolved InfraredSpectroscopy in SupercriticalFluids

“…x2 more reactive than the corresponding alkane complex e.g., W(CO)5(Xe) W(CO)5(n-heptane). We have recently shown [7] that CpRe(CO)z(Xe) is surprisingly unreactive and is thermally more stable than all the reported organometallic alkane complexes except CpRe(CO)z(n-heptane). Furthermore CpRe(CO)z(Kr) is sufficiently stable to be detectable on the 100 ns timescale even in the presence of Xe.…”

“…We were able to o The FTIR spectrum of (CD3) Re(CO)5 in supercritical Xe (scXe) (25C, 1350psi) in the presence of CO (30psi); (b) TRIR spectrum obtained ItS following irradiation of this solution. The negative bands show depletion of parent and the positive bands at 1994, 1976 and 1960cmare assigned to (CD3)Re(CO)a(Xe) by comparison to the results in low temperature matrices[7].…”

Manganese Alkyls and Hydrides

“…From known v ls c _ H vs. r 0 (bond length) correlations, it was inferred that the C-H bond was lengthened and weakened, while the Mn-C bond was strengthened on substitution o f CO by N 2 . 120 Laser flash photolysis of MnMe(CO) 5 has been carried out in cyclohexane, isooctane, and THF under argon or CO with time-resolved IR and optical detection. 121 The second-order rate constant for the reassociation of CO with MnMe(CO) 4 (S) (93a(S)) was 2.1 x 10 6 M " 1 s " 1 in C 6 H 1 2 , and 1 .…”

“…This same process can be made much more efficient by treatment o f (96) with Me 3 NO followed by phosphine. Another example of the preference for substitution is the reaction of (95) (Scheme 17) with PPh 3 which effects only substitution to form(120)…”