Self-inhibition of propagating carbenes in ROMP of 7-oxa-bicyclo[2.2,1]hept-2-ene-5,6-dicarboxylic acid dendritic diesters initiated with Ru(=CHPh)Cl2(PCy3)( 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene)

被引:33
作者
Buchowicz, W [1 ]
Holerca, MN [1 ]
Percec, V [1 ]
机构
[1] Univ Penn, Dept Chem, Roy & Diana Vagelos Labs, Philadelphia, PA 19104 USA
关键词
D O I
10.1021/ma0021500
中图分类号
O63 [高分子化学(高聚物)];
学科分类号
070305 ; 080501 ; 081704 ;
摘要
The kinetic study of the ring-opening metathesis polymerization (ROMP) of exo,exo-7-oxa-bicyclo[2.2.1 ]hept-2-ene-5,6-dicarboxylic acid diethyl ester (2), exo,exo-5,6-bis [[[3,5-bis(3,4(dodecyl-1-oxy)-benzyloxy)]benzyloxy] carbonyl]-7-oxabicyclo [2.2.1] hept-2-ene (3), exo,exo-5,6-bis [[[3,4-bis(3,4,5-(dodecyl-1-oxy)benzyloxy)]benzyloxy] carbonyl]-7-oxabicyclo[2.2.1]hept-2-ene (4), and exo,exo-5,6-bis[[[3,4,5-tris(3,4,5(dodecyl-1oxy)benzyloxy)]benzyloxy] carbonyl]-7-oxa-bicyclo [2.2.1]hept-2-ene (5) initiated with Ru(= CHPh)Cl-2(PCy3)L (L = 1,3-dimesityl-4,5-dihydroimidazol-2-ylidene (1) and with the novel catalyst Ru(= CH-C6H4-p-CF3)Cl-2(PCy3)L (1-CFs) revealed a competition between ROMP and a facile secondary metathesis reaction between the polymer backbone and the catalyst. Both 1 and 1-CF3 polymerize 2 with a rate of propagation much higher than the rate of initiation and therefore yield polymers with a broad molecular weight distribution. It was demonstrated that the propagation was self-inhibited, and the extent of the secondary metathesis was decreased by increasing the size of the monodendritic side groups of the monomer. Consequently, polymers with narrow molecular weight distribution, i.e., M-w/M-n = 1.05, were obtained from monomer 5 which bears the bulkiest dendritic side groups. These results have demonstrated that, during the ROMP of 5, backbiting and endbiting reactions are eliminated, and only the initiation, propagation, and secondary metathesis by free catalyst take place.
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页码:3842 / 3848
页数:7
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[31]   Controlling polymer shape through the self-assembly of dendritic side-groups [J].
Percec, V ;
Ahn, CH ;
Ungar, G ;
Yeardley, DJP ;
Möller, M ;
Sheiko, SS .
NATURE, 1998, 391 (6663) :161-164
[32]   Detecting the shape change of complex macromolecules during their synthesis with the aid of kinetics. A new lesson from biology [J].
Percec, V ;
Holerca, MN .
BIOMACROMOLECULES, 2000, 1 (01) :6-16
[33]   Visualizable cylindrical macromolecules with controlled stiffness from backbones containing libraries of self-assembling dendritic side groups [J].
Percec, V ;
Ahn, CH ;
Cho, WD ;
Jamieson, AM ;
Kim, J ;
Leman, T ;
Schmidt, M ;
Gerle, M ;
Möller, M ;
Prokhorova, SA ;
Sheiko, SS ;
Cheng, SZD ;
Zhang, A ;
Ungar, G ;
Yeardley, DJP .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1998, 120 (34) :8619-8631
[34]   Hierarchical control of internal superstructure, diameter, and stability of supramolecular and macromolecular columns generated from tapered monodendritic building blocks [J].
Percec, V ;
Schlueter, D ;
Ungar, G ;
Cheng, SZD ;
Zhang, A .
MACROMOLECULES, 1998, 31 (06) :1745-1762
[35]   Mechanistic investigations on the formation of supramolecular cylindrical shaped oligomers and polymers by living ring opening metathesis polymerization of a 7-oxanorbornene monomer substituted with two tapered monodendrons [J].
Percec, V ;
Schlueter, D .
MACROMOLECULES, 1997, 30 (19) :5783-5790
[36]   Self-encapsulation, acceleration and control in the radical polymerization of monodendritic monomers via self-assembly [J].
Percec, V ;
Ahn, CH ;
Barboiu, B .
JOURNAL OF THE AMERICAN CHEMICAL SOCIETY, 1997, 119 (52) :12978-12979
[37]   Tubular architectures from polymers with tapered side groups. Assembly of side groups via a rigid helical chain conformation and flexible helical chain conformation induced via assembly of side groups [J].
Percec, V ;
Schlueter, D ;
Ronda, JC ;
Johansson, G ;
Ungar, G ;
Zhou, JP .
MACROMOLECULES, 1996, 29 (05) :1464-1472
[38]  
REIF L, 1981, MAKROMOL CHEM-RAPID, V2, P183
[39]   KINETICS AND THERMODYNAMICS OF THE METATHESIS REACTION OF CYCLOOLEFINS .2. MOLECULAR-WEIGHT DISTRIBUTION [J].
REIF, L ;
HOCKER, H .
MACROMOLECULES, 1984, 17 (04) :952-956
[40]   ONE-POT SYNTHESIS OF CYCLIC AMIDINIUM TETRAFLUOROBORATES AND HEXAFLUOROPHOSPHATES - THE SIMPLEST MODELS OF N-5,N-10-METHENYLTETRAHYDROFOLATE COENZYME [J].
SABA, S ;
BRESCIA, AM ;
KALOUSTIAN, MK .
TETRAHEDRON LETTERS, 1991, 32 (38) :5031-5034