Reactions of the Rhenium(I) Fragment [{MeC(CH2PPh2)3}Re(CO)2]+. Synthesis and Characterization of a Stable Cationic .eta.2-H2 Complex of Rhenium

2-Oxacyclopentylidene, 2-Oxacyclohexylidene, and 2-Oxacycloheptylidene Rhenium Complexes by Reaction of ω-Alkynols with the [{MeC(CH2PPh2)3}Re(CO)2]+ Auxiliary

“…[19] We have now found that 2 in CH 2 Cl 2 reacts with 3-butyn-1-ol yielding the 2-various β-, γ-, and δ-alkynols with the kinetically inert organometallic support [{MeC(CH 2 PPh 2 ) 3 }Re(CO) 2 ] ϩ . [19] oxacyclopentylidene complex [(triphos)Re(CO) 2 {ϭCCH 2 -CH 2 CH 2 O}]BF 4 (3).…”

“…[19] We have now found that 2 in CH 2 Cl 2 reacts with 3-butyn-1-ol yielding the 2-various β-, γ-, and δ-alkynols with the kinetically inert organometallic support [{MeC(CH 2 PPh 2 ) 3 }Re(CO) 2 ] ϩ . [19] oxacyclopentylidene complex [(triphos)Re(CO) 2 {ϭCCH 2 -CH 2 CH 2 O}]BF 4 (3). The selective formation of this Fischer We were gratified to find that Fischer carbene complexes are selectively formed, via kinetic hydroxyvinylidene inter-carbene complex takes place already at Ϫ10°C, and proceeds with no detectable intermediate on the NMR timemediates, irrespective of the number of CH 2 spacers.…”

“…This may properly be computed using an AXXЈY spin system (A: carbonyl C atom, X and XЈ: P atoms trans to the CO ligands, Y: P atom trans to the carbene ligand; see Table 1). [19] [20] [22] The proton NMR spectrum correlates well with the spectra of various 2-oxacyclocarbene metal complexes containing three methylene groups in the ring. [4] A cyclic oxacarbene ligand in 3 is finally supported by the IR spectrum displaying a medium intensity ν(COC) band at 1194 cm Ϫ1 and two strong ν(CO) absorptions at wavenumbers (1962 and 1912 cm Ϫ1 ) that are typical of [(triphos)Re(CO) 2 {ϭCRRЈ}]Y carbene compounds.…”

“…In earlier work, [19] we have shown that [(trithe reaction of a unique metal fragment with different ω-alkynols could have provided additional information on the phos)Re(CO) 2 (2) which contains a mechanism of formation of 2-oxacarbene complexes as well as their chemistry, we decided to examine the reactions of weakly bound dihydrogen ligand. [19] We have now found that 2 in CH 2 Cl 2 reacts with 3-butyn-1-ol yielding the 2-various β-, γ-, and δ-alkynols with the kinetically inert organometallic support [{MeC(CH 2 PPh 2 ) 3 }Re(CO) 2 ] ϩ .…”

“…vided in the Experimental Section. The total and unam-A very low-energy barrier to rotation is typical of carbene biguous assignment of all the hydrogen and carbon reso-and vinylidene groups bonded to the [(triphos)Re(CO) 2 ] ϩ nances for all rhenium complexes was obtained by a combi-fragment, [19] [20] and it is also commonly encountered in carnation of 1D-and 2D-NMR spectroscopy including bene complexes with other transition metals.…”