Preparation of Dinuclear, Constrained Geometry Zirconium Complexes with Polymethylene Bridges and an Investigation of Their Polymerization Behavior

Noh, Seok-Kyun,Jiang, Wen-Long The Polymer Society of Korea 2004 Macromolecular Research Vol.12 No.1

We have prepared the polymethylene-bridged, dinuciear, half-sandwich constrained geometry catalysts (CGC)[Zr(η$\^$5/:η$^1$-C$\_$9/H$\_$5/SiMe$_2$NCMe$_3$)]$_2$[(CH$_2$)$\_$n/][n=6(9), n=12(10)]by treating 2 equivalents of ZrCl$_4$with the corresponding tetralithium salts of the ligands in toluene. $^1$H and $\^$13/C NMR spectra of the synthesized complexes provide firm evidence for the anticipated dinuciear structure. In $^1$H NMR spectra, two singlets representing the methyl group protons bonded at the Si atom of the CGC are present at 0.88 and 0.64 ppm, which are considerably downfield positions relative to the shifts of 0.02 and 0.05 ppm of the corresponding ligands. To investigate the catalytic behavior of the prepared dinuciear catalysts, we conducted copolymerizations of ethylene and styrene in the presence of MMAO. The prime observation is that the two dinuclear CGCs 9 and 10 are not efficient for copo-lymerization, which definitely distinguishes them from the corresponding titanium-based dinuclear CGC. These species are active catalysts, however, for ethylene homopolymerization; the activity of catalyst 10, which contains a 12-methylene bridge, is larger than that of 9 (6-methylene bridge), which indicates that the presence of the longer bridge between the two active sites contributes more effectively to facilitate the polymerization activity of the dinuciear CGC. The activities increase as the polymerization temperature increases from 40 to 70$^{\circ}C$. On the other hand, the molecular weights of the polyethylenes are reduced when the polymerization temperature is increased. We observe that dinuciear metallocenes having different-length bridges give different polymerization results, which reconfirms the significant role that the nature of the bridging ligand has in controlling the polymerization properties of dinuclear catalysts.

Reaction Properties of Dinuclear Metallocenes

Seok Kyun Noh,Eungyeong Jeong,Duang Huang Dan Qei,Won Seok Lyoo 한국고분자학회 2006 한국고분자학회 학술대회 연구논문 초록집 Vol.2006 No.10

Synthesis and styrene polymerization properties of dinuclear half-titanocene complexes with xylene linkage

Noh, Seok Kyun,Jung, Woosung,Oh, Hyunsook,Lee, Yong Rok,Lyoo, Won Seok Elsevier Sequoia 2006 Journal of organometallic chemistry Vol.691 No.23

<P><B>Graphical abstract</B></P><P>The new dinuclear half-sandwich complexes of titanium with xylene bridge, [Ti(η<SUP>5</SUP>-cyclopentadienyl)Cl<SUB>2</SUB>L]<SUB>2</SUB>[CH<SUB>2</SUB>–C<SUB>6</SUB>H<SUB>4</SUB>–CH<SUB>2</SUB>] (L=Cl (<B>3</B>), L=O-2,6-<I>i</I>Pr<SUB>2</SUB>C<SUB>6</SUB>H<SUB>3</SUB> (<B>4</B>), L=N(SiMe<SUB>3</SUB>)(2,6-Me<SUB>2</SUB>C<SUB>6</SUB>H<SUB>3</SUB>) (<B>5</B>)), have been synthesized by the reaction of the complex <B>3</B> with the corresponding lithium salts of aryloxy and anilide. Structure of these complexes has been characterized by <SUP>1</SUP>H and <SUP>13</SUP>C NMR. It was found that all three half-titanocenes were effective catalyst for the generation of SPS (syndiotactic polystyrene). Xylene bridged dinuclear catalyst (<B>4</B>) with aryloxy substituent exhibited very high activity (458kg of SPS/(mol of [Ti])h), at 40°C, whereas the analogous hexamethylene bridged dinuclear half-titanocene catalyst (<B>7</B>) showed a lower activity (80.7kg of SPS/(mol of [Ti])h) under the same conditions.</P><ce:figure></ce:figure> <P><B>Abstract</B></P><P>The new dinuclear half-sandwich complexes of titanium with xylene bridge, [Ti(η<SUP>5</SUP>-cyclopentadienyl)Cl<SUB>2</SUB>L]<SUB>2</SUB>[CH<SUB>2</SUB>–C<SUB>6</SUB>H<SUB>4</SUB>–CH<SUB>2</SUB>] (L=Cl (<B>3</B>), L=O-2,6-<I>i</I>Pr<SUB>2</SUB>C<SUB>6</SUB>H<SUB>3</SUB> (<B>4</B>), L=N(SiMe<SUB>3</SUB>)(2,6-Me<SUB>2</SUB>C<SUB>6</SUB>H<SUB>3</SUB>) (<B>5</B>)), have been synthesized. The complexes <B>4</B> and <B>5</B> have been prepared by the reaction of the complex <B>3</B> with the corresponding lithium salts of aryloxy and anilide. Structure of these complexes has been characterized by <SUP>1</SUP>H and <SUP>13</SUP>C NMR. The change of substituent from chloride, <B>3</B>, to anilide, <B>5</B>, at titanium resulted in chemical shift change of cyclopentadienyl protons from 6.92 and 6.79 to 6.13 and 5.95ppm probably due to the positive electron density delivery from the anilide group. It was found that all three half-titanocenes were effective catalyst for the generation of SPS (syndiotactic polystyrene). Xylene bridged dinuclear catalyst (<B>4</B>) with aryloxy substituent exhibited very high activity (458kg of SPS/(mol of [Ti])h), at 40°C, whereas the analogous hexamethylene bridged dinuclear half-titanocene catalyst (<B>7</B>) showed a lower activity (80.7kg of SPS/(mol of [Ti])h) under the same conditions. While the catalyst <B>3</B> was the most active catalyst among three complexes less than 40°C the catalyst <B>5</B> exhibited the highest activity at 70°C. Xylene linkage was suggested to be too stiff to permit any kind of intramolecular interaction between two active centers. Lack of steric disturbance due to the rigidity of the xylene bridge might give rise to the similar properties of dinuclear metallocene to the corresponding mononuclear metallocene to result in not only the facile coordination of monomer at the active center to lead high activity but also the easier β-H elimination comparing to the dinuclear catalysts with the flexible bridge to result in the formation of lower molecular weight polymer.</P>

Dinuclear Effects of Constrained Geometry Catalysts on Olefin Polymerization

( Seok Kyun Noh ),( Wenlong Jiang ),( Dongho Lee ) 한국공업화학회 2002 한국공업화학회 연구논문 초록집 Vol.2002 No.0

A various types of dinuclear constrained geometry catalysts(CGC) have been prepared to study dinuclear effects on ethylene and styrene polymerization. The selected bridging group in order to link two CGC were polymethylene and alkyldialkoxy. It was found that the prepared catalysts were homopolymerize ethylene and styrene as well as copolymerize efficiently to form the polymer containing various monomer ratio. The important features that we observed were not only the distinction of the structure of the bridging ligands in olefin polymerization. The polymerization activits of the catalysts having two different bridging ligand are much higher than those of the catalysts having polymethlene bridges. These results indicate that the nature of the bridging ligand plays an significant role to exhibit polymerization behavior of dinuclear metallocene.

Preparation of Dinuclear, Constrained Geometry Zirconium Complexes with Polymethylene Bridges and an Investigation of Their Polymerization Behavior

Seok Kyun Noh,Wen Long Jiang,Dong Ho Lee 한국고분자학회 2004 Macromolecular Research Vol.12 No.1

Metallocene 중합촉매

노석균(Seok Kyun Noh) 한국고분자학회 1994 고분자 과학과 기술 Vol.5 No.3

이핵 CGC의 구조적인 특성과 에틸렌/1-헥센의 공중합 거동과의 관계

노석균(Seok Kyun Noh),웽티레녕(Nguyen Thi Le Nhon),웬티레탄(Nguyen Thi Le Thanh),까오환투이미(Cao Phan Thuy My) 한국고분자학회 2011 폴리머 Vol.35 No.6

Para-xylene의 기본 구조로 연결된 4개의 이핵 CGC를 활용하여 에틸렌과 1-헥센의 공중합특성을 조사하여 중합촉매의 구조적인 특징이 중합에 미치는 영향을 조사하였다. 4가지의 이핵 constrained geometry catalyst(CGC) 중에서 3가지는 모두 para-xylene 다리로 연결되어 있으나 벤젠고리 부분에 각각 다른 치환체가 결합된 것으로서 치 환체는 수소(Catalyst 1), isopropyl(Catalyst 2), n-hexyl(Cataylst 3)이고, n-octyl(Catalyst 4)인 화합물이었 다. 이핵 메탈로센 4가지와 Dow 촉매를 사용하여 에틸렌과 1-헥센을 공중합시켜 다른 치환체를 가진 다리리간드의 구 조적인 특성변화가 촉매의 중합특성과 이로부터 생성되는 공중합체의 특성에 미치는 영향을 조사하였다. 실험 결과 다 리리간드의 특성에 따라 분명한 경향성과 차이점이 발견되었다. 중합활성은 치환체의 크기가 가장 작은 수소에서 가장 높았으며, isopropyl에서 가장 낮았으며 그 차이는 최대 3배 이상이었다. 반면 분자량은 치환체가 isopropyl인 촉매에서 생성된 공중합체가 가장 컸고, n-hexyl과 1-octyl 치환체 화합물에서 가장 작은 분자량의 공중합체가 생성되었으며 그 차이는 6배에 달하였다. 이핵 CGC의 공중합 특성은 치환체가 긴 알킬기인 n-hexyl 및 1-octyl 화합물이 가장 우수하여 동일한 조건에서 1-헥센을 가장 많이 함유하여 40% 이상의 1-헥센을 포함하는 에틸렌 공중합체를 제조할 수 있었다. 이러한 연구 결과는 촉매구조 변화에 의한 고분자 미세구조 조절이라는 고분자 합성의 가장 어려운 부분 이 xylene 다리를 가진 이핵 CGC의 치환체를 조절함으로써 가능함을 보여주는 결과이다. Effects of structural features of 4 dinuclear constrained geometry catalysts having paraxylene derivative bridge (DCGC) on copolymerization of ethylene and 1-hexene were investigated. The bridges of three catalysts have para-xylene backbone with a different substituent at benzene ring. The substituents were hydrogen (Catalyst 1), isopropyl (Catalyst 2), n-hexyl (Catalyst 3) and 1-octyl (Catalyst 4). It was found that Catalyst 1 having hydrogen as a substituent exhibited the greatest activity among the four dinuclear CGCs. On the other hand, Catalyst 2 containing isopropyl as a substituent showed the smallest activity. Very interestingly, Catalyst 2 was able to produce about 6 times higher molecular weight polymer than Catalyst 3 and 4. Catalyst 3 and 4 having a long alkyl chain substituent revealed the biggest comonomer response to generate polyethylene copolymer containing more than 40% 1-hexene contents. These results suggest that the control of the substituent of para-xylene bridge of dinuclear CGC can provide a proper method to adjust the microstructure of polyethylene copolymers.

다리리간드의 구조가 이핵 CGC의 중합 특성과 생성된 에틸렌/스티렌 공중합체에 미치는 영향

노석균(Seok Kyun Noh),팜나탄(Nhat Thanh Pham),뉴옌티듀휴옌(Thi Dieu Huyen Nguyen),웽티레탄(Nguyen Thi Le Thanh) 한국고분자학회 2011 폴리머 Vol.35 No.1

굳은 특성을 가진 다리로 연결된 이핵 CGC 6개의 공중합특성을 조사하였다. 6개의 화합물 중에서 3개는 길이가 다른 para-phenyl (Catalyst 1), para-xylyl (Catalyst 2), para-diethylene phenyl (Catalyst 6) 다리를 가진 화합물이며, 나머지 3개는 다리리간드는 para-xylyl 다리 기본구조를 가졌으나 치환체가 isopropyl (Catalyst 3), n-hexyl (Cataylst 4), n-octyl (Catalyst 5)인 화합물이었다. 이핵메탈로센 6가지와 Dow 촉매를 사용하여 에틸렌과 스티렌을 공중합시켜 다리리간드의 특성변화가 촉매의 중합특성과 이로부터 생성되는 공중합체의 특성에 미치는 영향을 조사하였다. 실험 결과 다리리간드의 길이가 증가함에 따라 촉매의 중합활성이 4배까지 향상되었으며 이로부터 생성되는 공중합체의 분자량도 증가하였다. 또한 para-xylyl 리간드의 치환체가 isopropyl에서 n-hexyl 및 n-octyl로 변함에 따라 중합활성은 증가하였으나 이로부터 생성되는 분자량은 감소하였다. 본 연구 결과는 촉매구조 변화에 의한 고분자 미세구조 조절이라는 고분자 합성의 가장 어려운 부분이 이핵메탈로센을 활용하여 어느 정도 현실화될 수 있음을 보여주는 결과이다. Polymerization properties of six dinuclear constrained geometry catalysts (DCGC) were investigated. The different length bridges of three catalysts were para-phenyl (Catalyst 1), para-xylyl (Catalyst 2), and para-diethylene phenyl (Catalyst 6). The other three DCGC have the same para-xylyl bridge with the different substituents at the phenyl ring of the bridge. The selected substituents were isopropyl (Catalyst 3), n-hexyl (Cataylst 4), and n-octyl (Catalyst 5). It was found that the longer catalyst not only exhibited a greater activity but also prepared a higher molecular weight copolymer. The catalyst 3 having a bulky isopropyl substituent revealed the lower activity but formed the highest molecular weight polymer comparing with the other alkyl substituted DCGCs. These results were able to be understood on the basis of the electronic and steric characteristics of the bridge. This study confirms that the control of the bridge structure of DCGC may contribute to control the microstructure of polymers.

Indenyl 기를 포함하는 Constrained Geometry 촉매의 합성과 이들에 의한 에틸렌의 단일중합 및 공중합 연구

노석균(Seok Kyun Noh),김수찬(Su Chan Kim),오영우(Yeung Woo Oh),이동호(Dong Ho Lee),윤근병(Keun Byung Yoon),허완수(Wan Soo Huh) 한국고분자학회 1996 폴리머 Vol.20 No.2

실리카에 불균일화된 메탈로센 촉매의 모델화합물로서 합성된 Polysiloxane Bridged ansa - Metallocene 의 구조특성과 중합특성

노석균(Seok Kyun Noh),이철수(Chul Soo Lee),이동호(Dong Ho Lee),윤근병(Keun Byoung Yoon),강경석(Kyoung Seok Kang) 한국고분자학회 1997 폴리머 Vol.21 No.3