Be. Bursten et al., IMPORTANCE OF STERIC REQUIREMENTS RELATIVE TO ELECTRONIC CONTRIBUTIONS IN BICYCLOALKYL-SUBSTITUTED TITANOCENE DICHLORIDES, Organometallics, 13(1), 1994, pp. 127-133
A group of bicycloalkyl-substituted titanocene dichlorides was examine
d by X-ray photoelectron spectroscopy in order to gauge if the rather
large steric requirements of these ligands exert greater or lesser imp
act on the binding energy of the titanium center relative to the elect
ronic effect of alkyl substitution. Simpler model systems were likewis
e evaluated. X-ray crystallographic data were available for many of th
e norbornyl-, bornyl-, and pinanyl-fused titanocenes. The solid-state
structure of 3 has been established by X-ray crystallographic analysis
: space group C2/c, a = 12.456(5), b = 6.695(3), c = 16.591(8) angstro
m; beta = 98.37(3)-degrees; Z = 4. The structure refined to R and R(w)
values of 0.067 and 0.079, respectively, with use of 1357 reflections
. This information and associated Fenske-Hall calculations revealed th
at, although heightened levels of ring slippage were in effect, the in
ductive contributions of substituents directly bonded to the Cp rings
dominate over the steric contributions of the space-demanding ligands
in controlling the electronic changes at the core titanium atom.