1,2-Di($Ph_2CN$)benzene nickel dibromide, 1,2-di($Ph_2CN$)ethane nickel dibromide, 1-(diphenylphosphino)-2-(N-(2,6-diisopropylphenyl)iminomethane)benzene nickel dibromide, 1-(diphenylphosphino)-2-(N-(2,6-diisopropylphenyl)-iminomethane)benzene palladium methyl chloride, 3,3-di(2,6-dimethylphenyl)-2,2-bipyridine nickel dibromide and 3,3-di(2,6-dimethylphenyl)-2,2-bipyridine palladium dichloride have been prepared in high yield by the reaction of one equiv. of each ligand and corresponding metal sources in $CH_2Cl_2$. The X-ray crystallography reveals that the structure of nickel complexes is based on tetrahedral geometry and the structure of palladium complexes is based on square planer geometry respectively. All the nickel complexes provide the low activity for the polymerization of ethylene in the presence of MMAO cocatalyst. The palladium complex, 1-(diphenylphosphino)-2-(N-(2,6-diisopripyphenyl)-iminomethane)benzene palladium methyl chloride, is also low active but produces oligomeric olefin by the activation of weakly coordinating anion.
Group Ⅳ complexes with chelating 2-hydroxyphenyl benzotriazole ligands, 2-(3,5-diamyl-2-hydroxy)benzotriazole titanium trichloride, {2-(3,5-diamyl-2-hydroxy)benzotriazole}cyclopentadienyl titanium dichloride, {2-(3,5diamyl-2-hydroxy)benzotriazole}cyclopentadienyl zirconium dichloride, {2-(3-t-butyl-5-methyl-2-hydroxy)-5-chloro-benzotriazole} cyclopentadienyl zirconium dichloride, and (cyclopentadienyl zirconium trichloride)-[{2-(3,5-diamyl-2-hydroxy)benzotriazole} (cyclopentadienyl) zirconium dichloride] have been prepared in high yield by the reaction of HCI elimination. Bis 2-hydroxyphenyl benzotriazole zirconium complex, bis{2-(3,5-diamyl-2-hydroxy)-benzotriazole}zirconium dichloride, was obtained by the reaction of the amine elimination and following by the chlorination of TMSCI. 2-Hydroxyphenyl benzotriazole ligand allows various coordination mode with group 4 metals such as bidentate, tridentate and bimetallic. The zirconium complexes of mixed Cp and 2-hydroxyphenylbenzotriazole ligand show the high activity for the polymerization of ethylene in the presence of MMAO cocatalyst. High density and low molecular weight polyethylene was obtained.
Mixed ketoiminate/ketoimine/pentamethylcyclopentadienyl ($Cp^*$)complex of zirconium, [$(η^5-Cp^*)(CH_3C(O)CHC(NHR)CH_3}$-${CH_3C(O)CHC(NR)CH_3}ZrCI_2$]$(R=4-CF_3Ph)$ has been prepared in high yield by the reaction of one equiv 4-$CF_3$-phenyl-β -ketoimine and one equiv lithium $4CF_3$-phenyl-β -ketoiminate with one equiv $Cp^*ZrC1_3$ in $Et_2O$. Bis(ketoiminate)zirconium dichloride complexes, ${CH_3C(O)CHC(NHR)CH_3}$-${CH_3C(O)CHC(NR)CH_3}_2ZrCI_2$ (R=4-$CF_3Ph, 2,6-$Me_2Ph$) have been also prepared in high yield by the reaction of amine elimination of ketoimine ligands with $Zr(NMe_2)_4$ and following by chlorination reaction with TMSCI. The X-ray crystallography reveals that the mixed ketoiminate/ketoimine/pentamethylcyclopentadienyl $(Cp^*)$ complex of zirconiumis based on distorted octahedral geometry containing a ketoimine and aketoiminate. The ketoiminate ligand coordinates to the zirconium as a bidentate ligand, leaving the metal center coordinatively unsaturated and thus leading to an additional binding of a ketoimine ligand to the metal to stabilize the complex. The mixed ketoiminate/ketoimine/pentamethylcyclopentadienyl $(Cp^*)$ complex of zirconium provides the high activity for the polymerization of ethylene in the presence of MMAO cocatalyst. Low molecular weight and high-density polyethylene was obtained.
Titanium complexes with chelating 2-(methoxyphenyl)indenyl ligands,2-(2-methoxyphenyl)indenyl titanium trichloride, 2-(3-methoxyphenyl)indenyl titanium trichloride and 2-(4-methoxyphenyl)indenyl titanium trichloride have been prepared by the reaction of trimethylsilylindenyl ligands and $TiCl_4$ in $CH_2CI_2$.2-(methoxyphenyl)indenyl ligands allow different electronic and steric effects to the titanium metal, derived by 2, 3 and 4-methoxy group. The 2-(3-methoxyphenyl)indenyl titanium trichloride complex has provided syndiotactic polystyrene in high activity by the polymerization of styrene in the presence of MMAO cocatalyst. However 2-(2-methoxyphenyl)indenyl titanium trichloride has shown low activity because of presumably steric hindrance of methoxy group against monomer insertion to the titanium metal center. And 2-(4-methoxyphenyl)indenyl titanium trichloride has also shown low activity by means of low stability of the complex under the polymerization condition. The methoxy group of 2-(3-methoxyphenyl)indenyl titanium trichloride complex increase theelectron density of titanium metal center by the electron donating effect but does not affect the monomer insertion by the steric hindrance.
올레핀 중합을 위한 새로운 단일자리 촉매의 합성과 규명을 위하여 본 연구를 실시 하였다. 뒷전이금속(late transition metal)을 이용한 새로운 유기금속화합물의 합성과 규명 및 중합 활성을 실시 하였다. 1,2-Di$(Ph_2CN)$benzene $NiBr_2$, 1,2-di$(Ph_2CN)$ethane $NiBr_2$, 1-(diphenylphosphino)-2-(N-(2,6-diisopropylphenyl)iminomethane) benzene $NiBr_2$. 1-(diphenylphosphino)-2-(N-(2,6-diisopropylphenyl)-iminomethane)benzene PdMeCI, 3,3-di(2,6-dimethylphenyl)-2,2-bipyridine $NiBr_2$ 그리고 3,3-di(2,6-dimethylphenyl)-2,2-bipyridine $PdCl_2$은 각각의 금속화합물과 리간드를 반응하여 합성하였으며 이들 화합물에 대한 구조는 x-선 구조 분석을 통하여 규명하였다. 그 결과 니클화합물은 Tetrahedral 구조를 가지고 있으며 팔라디움 금속 화합물은 Square Planer 한 구조를 가지고 있었다. MMAO를 조촉매로 하여 올레핀중합을 실시 한 결과 니클화합물들은 낮은 중합 활성을 보여주고 있으며 이러한 결과는 니클화합물이 Tetrahedral 구조를 갖는 것에 기인한다.
메탈로센 촉매를 위한 많이 연구된 Cp 리칸드를 대체하는 새로운 리간드를 개발하기 위한 연구로써 2-하이드록시 벤조트리아졸 리간드를 포함한 4 족 화합물을 합성하여 올레핀 중합 활성올 실시 하였다. 2-하이드록시 벤조트리아졸 리간드는 Bidentate, Tridentate, 또는Bimetallic 등 다양한 결합모드를 가지고 있다. 2-(3,5-diamyl-2-hydroxy)$benzotriazoleTiCI_3$, {2-(3,5-diamyl-2-hydroxy)benzotriazole}$CpTiCI_2$, {2-(3,5-diamyl-2-hydroxy)benzotriazole}$CpZrCI_2$, {2-(3-t-butyl-5-methyl-2-hydroxy)-5-chloro-benzotriazoIe}$CpZrCI_2$, $(CpZrCI_3)$口[{2-(3,5-diamyl-2-hydroxy)benzotriazole}$CpZrCI_2$], ${2-(3，5-diamyl-2-hydroxy)-benzotriazole}_2ZrCl_2$ 은 각각의 금속과 리간드를 반응하여 합성하였으며 이들 화합물에 대한 올레핀 중합 활성을 실시한 결과 높은 활성을 보여 주었다.
Cp 리간드를 대체하는 새로운 리간드를 개발하기 위한 또 다른연구로써 Ketoiminate 를 포함한 4 족 화합물의 합성 및 구조의 규명 그리고 올레핀 중합 활성에 대한 연구를 실시 하였다. Zirconium 화합물인 $[(η^5-Cp^*){CH_3C(O)CHC(NHR)CH_3}-{CH_3C(O)CHC(NR)CH_3}ZrCI_2]$ (R=$4CF_3Ph$)은 $Cp^*ZrCl_3$ 와 Ketoiminate 그리고 Ketoimine 을 각각 1 당량씩 반응하여 합성하였으며 x-선 구조분석결과 Zirconium 금속은 Octahedral 구조를 가지고 있으며 Ketoimine 의 산소가 금속에 결합하면서 화합물을 안정화 시키는 것으로 판단된다. MMAO 를 조촉매로 하여 올레핀 중합을 실시 한 결과 이 화합물은 높은 활성을 보여 주었다. 또 한편 두 당량의 Ketoiminate 리간드와 $Zr(NMe_2)_4$ 를 아민제거 반응으로 먼저 반응시킨 다음 이것을 다시 TMSCI 를 이용하여 클로리네이션 시키면 ${CH_3C(O)CHC(NHR)CH_3}-{CH_3C(O)CHC(NR)CH_3}_2ZrCI_2$ (R=4$-CF_3Ph$ , 2,6$Me_2Ph$)를 얻을 수 있다. 그러나 이 화합물의 경우에는 MMAO 를 조촉매로 하여 올레핀 중합을 실시 한 결과 낮은 활성을 보여 주었다.
교대배열 폴리스티렌을 중합하기 위한 촉매로 Half Titanocene 화합물이 많이 연구되고 있다. Cp 를 대신하여 Indene 에 전자 효과를 많이 줄 수 있는 methoxyphenyl 치환체를 도입한 리간드를 이용하여Titanium 화합물을 합성하고 이를 이용하여 교대배열 폴리스티렌을 중합하였다. $2-(2-methoxyphenyl)indenylTiC1_3$, $2-(3methoxyphenyl)indenylTiCI_3$, $2-(4-methoxyphenyl) indenylTiC1_3$ 을 합성하였으며 MMAO 를 조촉매로 하여 스티렌의 중합을 실시한 결과 높은 활성을 보여 주었으며 고분자의 구조를 분석한 결과 교대배열 폴리스티렌을 얻을 수 있었다. 3 위치에 methoxy 치환기가 도입된 $2-(3-methoxyphenyl)indenyITiC1_3$가 가장 우수한 활성을 보여 주었다.
