American Chemical Society
ja0689684_si_003.cif (52.88 kB)

Snapshots of an Alkylidyne for Nitride Triple-Bond Metathesis

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posted on 2007-02-28, 00:00 authored by Brad C. Bailey, Alison R. Fout, Hongjun Fan, John Tomaszewski, John C. Huffman, J. Brannon Gary, Marc J. A. Johnson, Daniel J. Mindiola
The transient titanium alkylidyne complex (PNP)Ti⋮CtBu (PNP = N[2-P(CHMe2)2-4-methylphenyl]2-), [2+2] cycloadds sterically bulky nitriles such as NCR to afford unique examples of kinetically stable azametallacyclobutadienes, (PNP)Ti(NCRCtBu) (R = tBu, 1; Ad, 2). Complexes 1 and 2 can further react with electrophiles such as ClSi(CH3)3 or Al(CH3)3 to extrude the alkyne RC⋮CtBu (R = tBu, 1; R = Ad, 2) and form neutral or zwitterionic titanium imide species, respectively. Imide formation for the latter species results from complete tBuC3- for N3- metathetical exchange. Isotopic labeling studies applying 15N enriched nitrile N⋮CAd clearly reveal the nitrogen atom transfer results from incomplete and complete metathesis of a titanium alkylidyne with a nitrile.