Mixtures o
f two scorpionate/cyclopentadiene regioisomers
![](http://pubs.acs.org/images/entities/sbd_2.gi<font color=)
f">bpzcpH (1-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethyl]-1,3-cyclopentadiene (
1a) and 2-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1,1-diphenylethyl]-1,3-cyclopentadiene (
1b)) and bpztcpH (1-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1-
tert-butylethyl]-1,3-cyclopentadiene (
2a) and 2-[2,2-bis(3,5-dimethylpyrazol-1-yl)-1-
tert-butylethyl]-1,3-cyclopentadiene (
2b))
![](http://pubs.acs.org/images/entities/sbd_2.gi<font color=)
f">were prepared by deprotonation o
f bis(3,5-dimethylpyrazol-1-yl)methane with Bu
nLi
followed by reaction with 6,6-diphenyl
fulvene or 6-
tert-butyl
fulvene and subsequent treatment with saturated aqueous ammonium chloride. Reactions o
f hybrid scorpionate/cyclopentadiene compounds with [M(CH
2SiMe
3)
3(THF)
3] (M = Sc, Y) a
fford the dialkyl comple
xes [M(CH
2SiMe
3)
2(bpzcp)] (M = Sc (
3), Y (
4)) and [M(CH
2SiMe
3)
2(bpztcp)] (M = Sc (
5), Y (
6)). The cationic alkyl comple
xes [M(CH
2SiMe
3)(bpzcp)]
+ (M = Sc (
7), Y (
8)) were also prepared by the reaction o
f comple
xes
3 and
4 with [CPh
3][B(C
6F
5)
4] in THF. The structures o
f these compounds were determined by spectroscopic methods, and the X-ray crystal structures o
f 2 and
3 were also established. The bis(alkyl) comple
xes
3 and
4 were
found to be active initiators
for the ring-opening polymerization o
f ε-caprolactone (up to 75% conversion o
f 200 equiv in 10 min) and yielded polymers with narrow molecular weight distributions.