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A series of phosphoryl (P
O) contained compounds: triethylphosphate (
a), diethylphenylphosphate (
b), ethyldiphenylphosphate (
c) triarylphosphates (
d and
h–
m), triphenylphosphine oxide (
e), phenyl diphenylphosphinate (
f) and diphenyl phenylphosphonate (
g) have been prepared. Iron catalysts, which are generated
in situ by mixing the compounds with Fe(2-EHA)
3 and Al
iBu
3 in hexane, are tested for butadiene polymerization at 50
°C. Phosphates donated catalysts have been, unprecedently, found to conduct extremely high syndiotactically (pentad,
rrrr
=
46.1–94.5%) enriched 1,2-selective (1,2-structure content
=
56.2–94.3%) polymerization of butadiene. Introduction of electron withdrawing substituents on phenyl rings oftriphenylphosphate (
k–
m) remarkably promotes catalytic activity, while bulky substituent isopropyl at 2-position (
h) has beneficial influence on regioselectivity. Employment of
e,
f or
g as donor, results in a suppressed monomer conversion, accompanied by deteriorated 1,2-regioselectivity. The effects of polymerization conditions such as reaction temperature, types of cocatalysts and polymerization medium are also investigated by using catalyst system with tri(2,4-difluorophenyl)phosphate (
m) as donor. Highly tolerance to polymerization temperature up to 80
°C is observed for the first time in the iron-based catalyst.
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