a valence bond analysis of olefin polymerization catalysts timothy k. firman and tom ziegler
Post on 19-Dec-2015
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TRANSCRIPT
-Conjugated Ligands in d0 Systems
X X
X X
X= CR2, SiR2, NR, PR, O, S
X groups are isolobally analogous
Several good catalysts of this type are known
Resonance StructuresA localized bonding picture of these ligandsrequires multiple resonance structures, e.g.:
HC
HN NH
M+
- HC
HN NH
M
HC
HN NH
M
Main group elements require an octet of electronsBond order to metal is variable, which may facilitate bond breaking during olefin insertion