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중합촉매: 한 분자내 두 금속 또는 두 성분을 포함하는 뒷 전이금속 촉매
- Alternative Title
- SUJITH S.
- Author(s)
- Sujith S
- Alternative Author(s)
- SUJITH S.
- Advisor
- 이분열
- Department
- 일반대학원 분자과학기술학과
- Publisher
- The Graduate School, Ajou University
- Publication Year
- 2008-08
- Language
- eng
- Alternative Abstract
- 1. A highly active catalytic system for CO2/(propylene oxide) copolymerization was prepared based on the concept of a stystem containing a Lewis acidic metal center and quarternary ammonium salts units. The catalytic system showed high activity (TON >20000; TOF >20000 h-1) even at high temperature and high [epoxide]/[catalyst] ratio and selectively producing a very high molecular-weight copolymer (Mn, 300,000). The catalyst can be easily separated by filtration through a short pad of silica gel to obtain polymer containing negligible amounts of metal residue (1-2 ppm). The separated catalyst can be reused without significant loss in catalytic performance. 2. Bimetallic salicylaldimine-nickel complexes, bridge{[(2,6_(-i)Pr₂C_(6)H₂)-N=CH-(2- anthracenyl- C_(6)H₃-O)-κ²-N,O]Ni(η³-CH₂Ph)}₂ (bridge = ortho-C_(6)H₄, CH₂, ortho- C_(6)H₄(C_(6)H₄)₂,), are prepared. The bimetallic complexes show higher activities and higher polar monomer incorporations in the ethylene/2-(methoxycarbonyl)norbornene and ethylene/2-(acetoxymethyl)norbornene copolymerizations than the mononuclear complex, [(2,6-iPr₂C_(6)H₃)-N=CH-(2-anthracenyl-C_(6)H₃-O)- κ²-N,O]- Ni(η³-CH₂Ph). 3. Neutral η¹-benzylnickel carbene complexes, [Ni(η¹-CH₂C_(6)H_(5))(IiPr)(PMe3)(Cl)] (3) (IiPr = 1,3-bis-(2, 6-diisopropylphenyl)imidazol-2-ylidene) and [Ni(η¹- CH₂C_(6)H_(5))(SIiPr)(PMe3)(Cl)] (4) (SIiPr = 1,3-bis-(2, 6-diisopropylphenyl)imidazolin-2- ylidene), were prepared by the reaction between [Ni(η³- CH₂C_(6)H_(5))(PMe3)(Cl)] and an equivalent amount of the corresponding free N-heterocyclic carbene. The preparation of η³- benzylnickel carbene complexes, [Ni(η³-CH₂C_(6)H_(5))(IiPr)(Cl)] (5) and [Ni(η³- CH₂C_(6)H_(5))(SIiPr)(Cl)] (6) were carried out by the abstraction of PMe3 from 3 and 4 by the treatment of B(C_(6)F_(5))₃. The treatment of AgX on 5 and 6 produced the anion-exchanged complexes, [Ni(η³-CH₂C_(6)H_(5))(NHC)(X)] (7, NHC = IiPr, X = O₂CCF₃; 8, NHC = IiPr, X = O3SCF3; 9, NHC = SIiPr, X = O₂CCF₃; 10, NHC = SIiPr, X = O₃SCF₃). The solid state structures of 3 and 10 were determined by X-ray crystallography. The η³-benzyl complexes of IiPr (5, 7, and 8) alone, in the absence of any activators such as borate and MAO, showed good catalytic activity towards the vinyl-type norbornene polymerization. The catalyst was thermally robust and the activity increases as the temperature rises to 130 °C.
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- Graduate School of Ajou University > Department of Molecular Science and Technology > 3. Theses(Master)
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