Study of the Electronic Effect to the Olefin Copolymerization and Geometrical Isomerism with respect to Methylpalladium(II) Complexes Bearing α-Amino-pyridine Lignads
Date Issued
2007
Date
2007
Author(s)
Yu, Kuo-Hsuan
DOI
zh-TW
Abstract
A series of α-aminopyridine ligands bearing different substituted group on the amine in the form of (C5H5N)CH(R1)NH(R2) (R1 = Me, R2 = p-N,N-dimethylaminophenyl(LH-a), p-methoxyphenyl(LH-b), p-methylphenyl(LH-c), phenyl(LH-d), p-fluoropheny(LH-e), p-chlorophenyl(LH-f), p-nitrophenyl(LH-g), o-methylphenyl(LH-h), 2,4,6-trimethylphenyl(LH-i), cyclohexyl(LH-k); R1 = H, R2 = 2,4,6-trimethylphenyl(LH-j)) were synthesized. Such derivatives are prepared to systematically investigate the ligand electronic effect to neutral organopalladium(II) complexes in the form of (LH)Pd(Me)Cl and the cationic derivatives in the form of [(LH)Pd(Me)(NCMe)]BF4. The prepared complexes were characterized by the NMR techniques and X-ray crystallography. 1H and 13C NMR chemical shifts and C≡N stretching frequencies of the neutral and cationic complexes were found to correlate strongly with the Hammett substituent constant (σp) of the substituent on the ligand. The square planar geometry of these species results in cis- and trans- isomers. The relative yields of the geometrical isomers exhibit significant correlation with the Hammett substituent constants (σp) of the substituent on the ligand. The electron-donating ligands appear to stabilize the isomers of cis form.
The cationic [Pd(LH)Me(MeCN)]BF4 complexes catalyze copolymerization of ethylene and norbornene with the activities of 5×103 ~ 9×104 g(COC)/mol Pd
Subjects
電子效應
胺基-吡
啶
鈀
共聚合
乙烯
降冰片烯
electronic effect
amino-pyridine
palladium
copolymerization
ethylene
norbornene
Type
thesis
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