Transition Metal-catalyzed Polymerization Research Articles

Nickel catalyzed synthesis of branched polyethylene waxes using a hybrid steric strategy

Previous work suggests that the mixing of different substituents may have an unexpected effect on transition metal-catalyzed polymerization of ethylene. In this study, we synthesized a series of pyridine-imine Ni(II) complexes bearing o-diarylmethyl and o-aryl substituents. The hybrid steric Ni(II) complexes exhibited moderate activities (0.80–8.5 × 105 g·mol−1·h−1) and yielded branched (54–79/1000 C) polyethylene waxes with appropriate molecular weights (1.8 to 6.8 kg/mol) in ethylene polymerization. Surprisingly, methoxy and bimethoxy nickel catalysts exhibited very low polymerization activity commonality as well as significant different molecular weight polyethylene variability. The complexation of methoxy with diethylaluminum chloride resulting in simultaneous suppression of chain growth and chain transfer may be responsible for the above phenomenon. In addition, high temperature carbon spectra show that these polyethylene waxes are predominantly methyl branched.

Synthesis and characterization of poly(9-ethynyl-9-hydroxyfluorene)

Transition metal-catalyzed polymerizations of 9-ethynyl-9-hydroxyfluorene (EHF) were investigated. EHF was easily polymerized by various transition metal catalysts to give in relatively high yields of polymer. The MoCl5-based catalysts exhibited high catalytic activities, whereas the WCl6-based catalysts showed low catalytic activities for the present polymerization. The highest polymer yield (85%) was obtained when the (NBD)PdCl2 catalyst was used. The polymer structure was identified by such various instrumental methods as NMR, IR, and UV–visible spectroscopies to have a conjugated backbone with the fluorene and hydroxy groups. Poly(EHF) was stable to air oxidation and was soluble in such organic solvents as benzene, chlorobenzene, chloroform, DMF, and DMSO. The cyclovoltammograms of polymer exhibited the irreversible electrochemical behaviors. The oxidation of poly(EHF) was started to occur at 0.42V (vs Ag/AgNO3), where the vinylene unit of conjugated polymer backbone might be oxidized in the scan. And poly(EHF) also shows the irreversible reduction starting at −1.15V.

Transition metal-catalyzed polymerization of polar allyl and diallyl monomers

Abstract

Synthesis of a norbornene monomer having cyclic carbonate moiety based on CO2 fixation and its transition metal-catalyzed polymerizations

A norbornene monomer bearing cyclic carbonate moiety (NB-CC) was successfully synthesized from the corresponding precursor having epoxy moiety by its reaction with carbon dioxide under atmospheric pressure, which was efficiently catalyzed by lithium bromide. NB-CC underwent the ring-opening metathesis polymerization (ROMP) catalyzed by a ruthenium carbene complex to give the corresponding poly(norbornene), of which side chain inherited the cyclic carbonate moiety from the monomer without any deterioration. The same ROMP system was applicable to the copolymerization of NB-CC and 5-butyl-2-norbornene (BNB), which afforded the corresponding copolymer with a composition ratio same as a feed ratio. In addition, by using a catalytic system consisted of palladium (II) acetate/tricyclohexylphosphine/triphenylcarbenium tetrakis(pentafluorophenyl)borate, the copolymerization of NB-CC and BNC proceeded successfully in a vinyl addition polymerization mode to give the corresponding poly(norbornene) having CC moiety in the side chain. © 2010 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 48: 3896–3902, 2010

Disubstituted Polyacetylene Brushes Grown via Surface-Directed Tungsten-Catalyzed Polymerization

Disubstituted polyacetylene brushes were grown from modified silicon and quartz surfaces using a transition metal-catalyzed polymerization technique employing tungsten hexachloride/tetraphenyl tin (WCl6/Ph4Sn). The substrate surfaces were initially functionalized with terminal alkyne functional groups by using an alkyne-functionalized silane, O-(propagyloxy)-N-(triethoxysilylpropyl) urethane, as a surface coupling agent. Surface polymerization of 5-decyne under microwave irradiation at 150 degrees C for 30 min was performed on the functional surfaces to produce surfaces consisting of grafted poly(1,2-dibutylacetylene) brushes. The alkyne-functionalized and polymer-coated surfaces were characterized using surface contact angle measurements, film thickness measurements, atomic force microscopy, and X-ray photoelectron spectroscopy, and fluorescence spectrometer measurements were performed to analyze the surfaces at each step of the modification process. This simple technique demonstrates a novel way of synthesizing a poly(1,2-dibutylacetylene) brush layer on silicon substrate, and it has future potential in the fabrication of selectively functionalized surfaces on the nanoscale via this new synthetic approach.

遷移金属触媒重合の新展開 Ｉ シリレンおよびゲルミレン架橋４族メタロセン錯体によるプロピレンの重合

遷移金属触媒重合の新展開 Ｉ シリレンおよびゲルミレン架橋４族メタロセン錯体によるプロピレンの重合

Transition metal-based polymer chemistry: a critical micro-review

This micro-review summarizes mainly recent (i.e. mostly later than 1995) and important developments in transition metal-catalyzed polymerization and their impact on polymer synthesis. It is not intended to be entirely comprehensive, yet will focus on significant improvements or interesting aspects in certain areas of polymer chemistry. For this particular reason, not all transition metal-based polymerizations will be fully covered. Instead, besides providing a 'snapshot' of the state of the art, it was a major intention to outline the main advantages and disadvantages of certain important polymerizations in a critical, yet hopefully objective way.

遷移金属触媒重合の新展開 Ｉ 共有結合でシリカゲル表面に固定化したメタロセン錯体触媒

オレフィン重合触媒となる4族遷移金属のメタロセン錯体を, シリカゲルなどの固体担体表面に共有結合で固定化する, 新規な方法を開発した. シクロペンタジエニル環上に, 置換基としてビニル基を有するジルコノセン錯体を用い, このビニル基ヘヒドロシリル化, ヒドロホウ素化などによって固定化反応の際のアンカーとなる官能基を導入した. 一方担体表面上のヒドロキシ基をビニル基へ変換することにより固定化反応に用いることができた. えられた固定化触媒を用いてエチレンの重合を試みたところヒドロホウ素化法による固定化触媒が高い活性を示し, 本法が固定化の手法として有効であることが明らかとなった.