Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization
The Me2Si-bridged ansa-Cp/amido half-metallocene, [Me2Si(η5-Me4C5)(NtBu)]TiCl2, termed a “constrained-geometry catalyst (CGC)”, is a representative homogeneous Ziegler catalyst. CGC derivatives with the [1,2]azasilinane framework, in which the amide alkyl substituent is joined by the Si-bridge, were...
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MDPI AG
2017-02-01
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| Series: | Molecules |
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| Online Access: | http://www.mdpi.com/1420-3049/22/2/258 |
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| author | Seul Lee Seung Soo Park Jin Gu Kim Chung Sol Kim Bun Yeoul Lee |
| author_facet | Seul Lee Seung Soo Park Jin Gu Kim Chung Sol Kim Bun Yeoul Lee |
| author_sort | Seul Lee |
| collection | DOAJ |
| description | The Me2Si-bridged ansa-Cp/amido half-metallocene, [Me2Si(η5-Me4C5)(NtBu)]TiCl2, termed a “constrained-geometry catalyst (CGC)”, is a representative homogeneous Ziegler catalyst. CGC derivatives with the [1,2]azasilinane framework, in which the amide alkyl substituent is joined by the Si-bridge, were prepared, and the catalytic performances of these species was studied. Me4C5HSi(Me)(CH2CH=CH2)-NH(C(R)(R’)CH=CH2) (R, R’ = H or methyl; Me4C5H = tetramethylcyclopentadienyl) was susceptible to ring closure metathesis (RCM) when treated with Schrock’s Mo-catalyst to afford -Si(Me4C5H)(Me)CH2CH=CHC(R)(R’)NH- containing a six-membered ring framework. Using the precursors and the products of RCM, various CGC derivatives, i.e., [-Si(η5-Me4C5)(Me)CH2CH=CHC(R)(H)N-]TiMe2 (13, R = H; 15, R = Me), [-Si(η5-Me4C5)(Me)CH2CH2CH2CH2N]TiMe2 (14), [(η5-Me4C5)Si(Me)(CH2CH=CH2)NCH2CH=CH2]TiMe2 (16), [(η5-Me4C5)Si (Me)(CH=CH2)NCH2CH=CH2]TiMe2 (17), and [(η5-Me4C5)Si(Me)(CH2CH3)NCH2CH2CH3]TiMe2 (18), were prepared. The catalytic activity of the newly prepared complexes was lower than that of CGC when activated with [Ph3C][B(C6F5)4]/iBu3Al. However, the catalytic activity of these species was improved by using tetrabutylaluminoxane ([iBu2Al]2O) instead of iBu3Al and the activity of 14/[Ph3C][B(C6F5)4]/[iBu2Al]2O was comparable to that of CGC/[Ph3C][B(C6F5)4]/iBu3Al (4.7 and 5.0 × 106 g/mol-Ti, respectively). Advantageously, the newly prepared complexes produced higher molecular weight poly(ethylene-co-1-octene)s than CGC. |
| first_indexed | 2024-12-23T23:07:01Z |
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| last_indexed | 2024-12-23T23:07:01Z |
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| spelling | doaj.art-2e93324167bc4bd3835326d1731bd4192022-12-21T17:26:46ZengMDPI AGMolecules1420-30492017-02-0122225810.3390/molecules22020258molecules22020258Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene CopolymerizationSeul Lee0Seung Soo Park1Jin Gu Kim2Chung Sol Kim3Bun Yeoul Lee4Department of Molecular Science and Technology, Ajou University, Suwon 443-749, KoreaDepartment of Molecular Science and Technology, Ajou University, Suwon 443-749, KoreaDepartment of Molecular Science and Technology, Ajou University, Suwon 443-749, KoreaDepartment of Molecular Science and Technology, Ajou University, Suwon 443-749, KoreaDepartment of Molecular Science and Technology, Ajou University, Suwon 443-749, KoreaThe Me2Si-bridged ansa-Cp/amido half-metallocene, [Me2Si(η5-Me4C5)(NtBu)]TiCl2, termed a “constrained-geometry catalyst (CGC)”, is a representative homogeneous Ziegler catalyst. CGC derivatives with the [1,2]azasilinane framework, in which the amide alkyl substituent is joined by the Si-bridge, were prepared, and the catalytic performances of these species was studied. Me4C5HSi(Me)(CH2CH=CH2)-NH(C(R)(R’)CH=CH2) (R, R’ = H or methyl; Me4C5H = tetramethylcyclopentadienyl) was susceptible to ring closure metathesis (RCM) when treated with Schrock’s Mo-catalyst to afford -Si(Me4C5H)(Me)CH2CH=CHC(R)(R’)NH- containing a six-membered ring framework. Using the precursors and the products of RCM, various CGC derivatives, i.e., [-Si(η5-Me4C5)(Me)CH2CH=CHC(R)(H)N-]TiMe2 (13, R = H; 15, R = Me), [-Si(η5-Me4C5)(Me)CH2CH2CH2CH2N]TiMe2 (14), [(η5-Me4C5)Si(Me)(CH2CH=CH2)NCH2CH=CH2]TiMe2 (16), [(η5-Me4C5)Si (Me)(CH=CH2)NCH2CH=CH2]TiMe2 (17), and [(η5-Me4C5)Si(Me)(CH2CH3)NCH2CH2CH3]TiMe2 (18), were prepared. The catalytic activity of the newly prepared complexes was lower than that of CGC when activated with [Ph3C][B(C6F5)4]/iBu3Al. However, the catalytic activity of these species was improved by using tetrabutylaluminoxane ([iBu2Al]2O) instead of iBu3Al and the activity of 14/[Ph3C][B(C6F5)4]/[iBu2Al]2O was comparable to that of CGC/[Ph3C][B(C6F5)4]/iBu3Al (4.7 and 5.0 × 106 g/mol-Ti, respectively). Advantageously, the newly prepared complexes produced higher molecular weight poly(ethylene-co-1-octene)s than CGC.http://www.mdpi.com/1420-3049/22/2/258olefin polymerizationtitanium complexconstrained geometryhalf-metallocene |
| spellingShingle | Seul Lee Seung Soo Park Jin Gu Kim Chung Sol Kim Bun Yeoul Lee Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization Molecules olefin polymerization titanium complex constrained geometry half-metallocene |
| title | Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization |
| title_full | Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization |
| title_fullStr | Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization |
| title_full_unstemmed | Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization |
| title_short | Preparation of “Constrained Geometry” Titanium Complexes of [1,2]Azasilinane Framework for Ethylene/1-Octene Copolymerization |
| title_sort | preparation of constrained geometry titanium complexes of 1 2 azasilinane framework for ethylene 1 octene copolymerization |
| topic | olefin polymerization titanium complex constrained geometry half-metallocene |
| url | http://www.mdpi.com/1420-3049/22/2/258 |
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