%0 Generic
%A Harvey, Benjamin G.
%A Mayne, Charles L.
%A Arif, Atta M.
%A Ernst, Richard D.
%D 2005
%T Structural and Spectroscopic Demonstration of Agostic C−C
Interactions in Electron-Deficient Metallacyclobutanes and
Related Cage Complexes: Possible Implications for Olefin
Polymerizations and Metatheses
%U https://acs.figshare.com/articles/dataset/Structural_and_Spectroscopic_Demonstration_of_Agostic_C_C_Interactions_in_Electron_Deficient_Metallacyclobutanes_and_Related_Cage_Complexes_Possible_Implications_for_Olefin_Polymerizations_and_Metatheses/3254038
%R 10.1021/ja052287b.s003
%2 https://acs.figshare.com/ndownloader/files/5089408
%K dienyl fragment
%K C 8 H 11 ligand
%K electron
%K PhC 2 SiMe 3
%K C 8 H 11
%K bond
%K C 5 H 5
%K allyl
%K interaction
%K PMe 3 coordinations
%K CH 2 group
%X The reaction of the half-open titanocene, Ti(C5H5)(c-C8H11)(PMe3) (c-C8H11 = cyclooctadienyl),
with two equivalents of PhC2SiMe3 leads to their incorporation and coupling to the dienyl fragment. One
alkyne inserts into a C−H bond of the central CH2 group of the c-C8H11 ligand's edge-bridge, while the
second undergoes a 5+2 coupling with the dienyl fragment, yielding coordinated σ-allyl and olefin fragments,
as demonstrated by X-ray diffraction. Together with the C5H5 and PMe3 coordinations, this leads to a 14-electron count. While the very electron-deficient titanium center passes up potential π coordination of the
allyl fragment, it instead engages in interactions with one or two C−C bonds, and perhaps a C−H bond,
as revealed from the structural and spectroscopic data. Similar interactions have been found in electron-deficient metallacyclobutane complexes of titanium and zirconium, but not in the 18-electron molybdenum
and tungsten analogues. These and other observations may have implications relating to metatheses and
polymerizations of olefins.
%I ACS Publications