東華大學圖書館 |

語系: 繁體中文

說明(常見問題)

回圖書館首頁

手機版館藏查詢

登入

回首頁

切換: 標籤 | MARC模式 | ISBD

Bis(thiophenolate)pyridine Pincer Li...

Lenton, Taylor.

FindBook

Google Book

Amazon

博客來

Bis(thiophenolate)pyridine Pincer Ligands and Trivalent Zirconocene Complexes Relevant to Early Transition Metal Polymerization Catalysts.

紀錄類型:	書目-語言資料,印刷品 : Monograph/item
正題名/作者:	Bis(thiophenolate)pyridine Pincer Ligands and Trivalent Zirconocene Complexes Relevant to Early Transition Metal Polymerization Catalysts./
作者:	Lenton, Taylor.
面頁冊數:	122 p.
附註:	Source: Dissertation Abstracts International, Volume: 75-02(E), Section: B.
Contained By:	Dissertation Abstracts International75-02B(E).
標題:	Chemistry, General. -
電子資源:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3599568
ISBN:	9781303489563

Bis(thiophenolate)pyridine Pincer Ligands and Trivalent Zirconocene Complexes Relevant to Early Transition Metal Polymerization Catalysts.
Lenton, Taylor.

Bis(thiophenolate)pyridine Pincer Ligands and Trivalent Zirconocene Complexes Relevant to Early Transition Metal Polymerization Catalysts. - 122 p.

Source: Dissertation Abstracts International, Volume: 75-02(E), Section: B.

Thesis (Ph.D.)--California Institute of Technology, 2014.

Two major topics are covered: the first chapter is focused on the development of post-metallocene complexes for propylene polymerization. The second and third chapters investigate the consequences of diisobutylaluminum hydride (HAliBu2) additives in zirconocene based polymerization systems. The synthesis, structure, and solution behavior of early metal complexes with a new tridentate LX2 type ligand, bis(thiophenolate)pyridine ((SNS) = (2-C6H4S)2-2,6-C5H3N) are investigated. SNS complexes of Ti, Zr, and Ta having dialkylamido coligands were synthesized and structurally characterized. The zirconium complex, (SNS)Zr(NMe2)2, displays C2 symmetry in the solid state. Solid-state structures of tantalum complexes (SNS)Ta(NMe2)3 and (SNS)TaCl(NEt2)2 also display pronounced C2 twisting of the SNS ligand. 1D and 2D NMR experiments show that (SNS)Ta(NMe2)3 is fluxional with rotation about the Ta N(amide) bonds occurring on the NMR timescale. The fluxional behavior of (SNS)TaCl(NEt2)2 in solution was also studied by variable temperature 1H NMR. Observation of separate signals for the diastereotopic protons of the methylene unit of the diethylamide indicates that the complex remains locked on the NMR timescale in one diastereomeric conformation at temperatures below 50 °C. Reduction of Zr(IV) metallocenium cations with sodium amalgam (NaHg) produces EPR signals assignable to Zr(III) metallocene complexes. Thus, chloro-bridged heterobinuclear ansa-zirconocenium cation [((SBI))Zr(-Cl)2AlMe2]+B(C6F5)4 (SBI = rac-dimethylsilylbis(1-indenyl)), gives rise to an EPR signal assignable to the complex (SBI)ZrIII(-Cl)2AlMe2, while (SBI)ZrIII-Me and (SBI)ZrIII(-H)2AliBu2 are formed by reduction of [(SBI)Zr(-Me)2AlMe2]+ B(C6F5)4 and [(SBI)Zr(-H)3(AliBu2)2]+ B(C6F5)4, respectively. These products are also formed, along with (SBI)ZrIII-iBu and [(SBI)ZrIII]+ AlR4 when (SBI)ZrMe2 reacts with HAliBu2, eliminating isobutane en route to the Zr(III) complex. Studies concerning the interconversion reactions between these and other (SBI)Zr(III) complexes and reaction mechanisms involved in their formation are also reported. The addition of HAliBu2 to precatalyst [(SBI)Zr(micro-H)3(AliBu2)2]+ significantly slows the polymerization of propylene and changes the kinetics of polymerization from 1st to 2nd order with respect to propylene. This is likely due to competitive inhibition by HAliBu2. When the same reaction is investigated using [(nBuCp)2Zr(micro-H)3(AliBu2)2]+, hydroalumination between propylene and HAliBu2 is observed instead of propylene polymerization.

ISBN: 9781303489563Subjects--Topical Terms:

1021807
Chemistry, General.

Bis(thiophenolate)pyridine Pincer Ligands and Trivalent Zirconocene Complexes Relevant to Early Transition Metal Polymerization Catalysts.
LDR:03554nam a2200289 4500 001 1960797
005 20140624210011.5
008 150210s2014 ||||||||||||||||| ||eng d
020 $a 9781303489563
035 $a (MiAaPQ)AAI3599568
035 $a AAI3599568
040 $a MiAaPQ $c MiAaPQ
100 1 $a Lenton, Taylor. $3 2096526
245 1 0 $a Bis(thiophenolate)pyridine Pincer Ligands and Trivalent Zirconocene Complexes Relevant to Early Transition Metal Polymerization Catalysts.
300 $a 122 p.
500 $a Source: Dissertation Abstracts International, Volume: 75-02(E), Section: B.
500 $a Adviser: John E. Bercaw.
502 $a Thesis (Ph.D.)--California Institute of Technology, 2014.
520 $a Two major topics are covered: the first chapter is focused on the development of post-metallocene complexes for propylene polymerization. The second and third chapters investigate the consequences of diisobutylaluminum hydride (HAliBu2) additives in zirconocene based polymerization systems. The synthesis, structure, and solution behavior of early metal complexes with a new tridentate LX2 type ligand, bis(thiophenolate)pyridine ((SNS) = (2-C6H4S)2-2,6-C5H3N) are investigated. SNS complexes of Ti, Zr, and Ta having dialkylamido coligands were synthesized and structurally characterized. The zirconium complex, (SNS)Zr(NMe2)2, displays C2 symmetry in the solid state. Solid-state structures of tantalum complexes (SNS)Ta(NMe2)3 and (SNS)TaCl(NEt2)2 also display pronounced C2 twisting of the SNS ligand. 1D and 2D NMR experiments show that (SNS)Ta(NMe2)3 is fluxional with rotation about the Ta N(amide) bonds occurring on the NMR timescale. The fluxional behavior of (SNS)TaCl(NEt2)2 in solution was also studied by variable temperature 1H NMR. Observation of separate signals for the diastereotopic protons of the methylene unit of the diethylamide indicates that the complex remains locked on the NMR timescale in one diastereomeric conformation at temperatures below 50 °C. Reduction of Zr(IV) metallocenium cations with sodium amalgam (NaHg) produces EPR signals assignable to Zr(III) metallocene complexes. Thus, chloro-bridged heterobinuclear ansa-zirconocenium cation [((SBI))Zr(-Cl)2AlMe2]+B(C6F5)4 (SBI = rac-dimethylsilylbis(1-indenyl)), gives rise to an EPR signal assignable to the complex (SBI)ZrIII(-Cl)2AlMe2, while (SBI)ZrIII-Me and (SBI)ZrIII(-H)2AliBu2 are formed by reduction of [(SBI)Zr(-Me)2AlMe2]+ B(C6F5)4 and [(SBI)Zr(-H)3(AliBu2)2]+ B(C6F5)4, respectively. These products are also formed, along with (SBI)ZrIII-iBu and [(SBI)ZrIII]+ AlR4 when (SBI)ZrMe2 reacts with HAliBu2, eliminating isobutane en route to the Zr(III) complex. Studies concerning the interconversion reactions between these and other (SBI)Zr(III) complexes and reaction mechanisms involved in their formation are also reported. The addition of HAliBu2 to precatalyst [(SBI)Zr(micro-H)3(AliBu2)2]+ significantly slows the polymerization of propylene and changes the kinetics of polymerization from 1st to 2nd order with respect to propylene. This is likely due to competitive inhibition by HAliBu2. When the same reaction is investigated using [(nBuCp)2Zr(micro-H)3(AliBu2)2]+, hydroalumination between propylene and HAliBu2 is observed instead of propylene polymerization.
590 $a School code: 0037.
650 4 $a Chemistry, General. $3 1021807
650 4 $a Chemistry, Inorganic. $3 517253
650 4 $a Chemistry, Polymer. $3 1018428
690 $a 0485
690 $a 0488
690 $a 0495
710 2 $a California Institute of Technology. $b Chemistry. $3 2096080
773 0 $t Dissertation Abstracts International $g 75-02B(E).
790 $a 0037
791 $a Ph.D.
792 $a 2014
793 $a English
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3599568