PMID- 22076737
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20120312
LR  - 20111129
IS  - 1521-3765 (Electronic)
IS  - 0947-6539 (Linking)
VI  - 17
IP  - 49
DP  - 2011 Dec 2
TI  - Group 4 dimethylsilylenebisamido complexes bearing the 
      6-[2-(diethylboryl)phenyl]pyrid-2-yl motif: synthesis and use in tandem 
      ring-opening metathesis/vinyl-insertion copolymerization of cyclic olefins with 
      ethylene.
PG  - 13832-46
LID - 10.1002/chem.201101829 [doi]
AB  - Two novel Zr(IV)- and Hf(IV)-based bisamido complexes bearing the 
      6-[2-(diethylboryl)phenyl]pyrid-2-yl motif, that is, 
      [ZrCl(2)Me(2)Si(DbppN)(2)(thf)] (9) and [HfCl(2)Me(2)Si(DbppN)(2)(thf)(2)] 
      (10) (DbppN=6-[2-(diethylboryl)phenyl]pyridine-2-amido) have been prepared. Their 
      reactivities have been compared with that of a model precatalyst that does not 
      bear the aminoborane motif. Upon activation with methylalumoxane, precatalysts 9 
      and 10 are active in the homopolymerization of ethylene (E) yielding high-density 
      polyethylene (HDPE). In the copolymerization of E with cyclopentene (CPE), for 
      example by the action of 9, the presence of CPE resulted in a dramatic increase 
      in the polymerization activity of E, while CPE incorporation remained close to or 
      at zero. In the vinyl-insertion copolymerization of norborn-2-ene (NBE) with E by 
      the action of 9, statistical cyclic olefin copolymers of these two monomers were 
      obtained. At higher NBE concentrations, however, 9 gave rise to reversible 
      ring-opening metathesis (ROMP)/vinyl-insertion polymerization (VIP) of NBE with 
      E, resulting in the formation of multi-block copolymers of the general formula 
      poly(NBE)(ROMP)-co-poly(NBE)(VIP)-co-poly(E). This particular feature of 
      precatalyst 9, that is, the ability to induce a reversible alpha-H elimination/alpha-H 
      addition reaction, is attributed to the unique role of the 
      6-[2-(diethylboryl)phenyl]pyrid-2-yl ligand. Accordingly, a model precatalyst 
      lacking this ligand does not have the ability to induce alpha-H elimination/alpha-H 
      addition reactions. The different (11)B NMR shifts of various 
      diethylborylphenylpyrid-2-ylamines and -amides permit a ranking of the strengths 
      of the B-N bonds in these compounds. This strength of the B-N bond is correlated 
      with the propensity of 9/MAO to produce 
      poly(NBE)(ROMP)-co-poly(NBE)(VIP)-co-poly(E) at different temperatures.
CI  - Copyright (c) 2011 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
FAU - Zou, Yuanlin
AU  - Zou Y
AD  - Leibniz-Institut fur Oberflachenmodifizierung, Permoserstrasse 15, 04318 Leipzig, 
      Germany.
FAU - Wang, Dongren
AU  - Wang D
FAU - Wurst, Klaus
AU  - Wurst K
FAU - Kuhnel, Christa
AU  - Kuhnel C
FAU - Reinhardt, Ingrid
AU  - Reinhardt I
FAU - Decker, Ulrich
AU  - Decker U
FAU - Gurram, Venkatanavarana
AU  - Gurram V
FAU - Camadanli, Sebnem
AU  - Camadanli S
FAU - Buchmeiser, Michael R
AU  - Buchmeiser MR
LA  - eng
PT  - Journal Article
DEP - 20111110
PL  - Germany
TA  - Chemistry
JT  - Chemistry (Weinheim an der Bergstrasse, Germany)
JID - 9513783
EDAT- 2011/11/15 06:00
MHDA- 2011/11/15 06:01
CRDT- 2011/11/15 06:00
PHST- 2011/06/15 00:00 [received]
PHST- 2011/11/15 06:00 [entrez]
PHST- 2011/11/15 06:00 [pubmed]
PHST- 2011/11/15 06:01 [medline]
AID - 10.1002/chem.201101829 [doi]
PST - ppublish
SO  - Chemistry. 2011 Dec 2;17(49):13832-46. doi: 10.1002/chem.201101829. Epub 2011 Nov 
      10.