Ni(II) and Pd(II) complexes bearing novel bis(β‐ketoamino) ligand and their catalytic activity toward copolymerization of norbornene and 5‐norbornene‐2‐yl acetate combined with B(C₆F₅)₃

Abstract

Two complexes Mt{C10H8(O)C[N(C6H5)]CH3}2 [Mt = Ni(II); Mt = Pd(II)] were synthesized, and the solid‐state structures of the complexes have been determined by single‐crystal X‐ray diffractions. Homopolymerization of norbornene (NB) and copolymerization of NB and 5‐norbornene‐2‐yl acetate (NB‐OCOCH3) were carried out in toluene with both the two complexes mentioned above in combination with B(C6F5)3. Both the catalytic systems exhibited high activity toward the homopolymerization of NB (as high as 2.7 × 105 gpolymer/molNi h, for Ni(II)/B(C6F5)3 and 2.1 × 105 gpolymer/molPd h for Pd(II)/B(C6F5)3, respectively.). Although the Pd(II)/B(C6F5)3 shows very lower activity toward the copolymerization of NB with NB‐OCOCH3, Ni(II)/B(C6F5)3 shows a high activity and produces the addition‐type copolymer with relatively high molecular weights (MWs; 1.80–2.79 × 105 g/mol) as well as narrow MW distribution (1.89–2.30). The NB‐OCOCH3 content in the copolymers can be controlled up to 5.8–12.0% by varying the comonomer feed ratios from 10 to 50%. The copolymers exhibited high transparency, high glass transition temperature (Tg > 263.9 °C), better solubility, and mechanical properties compared with the homopolymer of NB. The reactivity ratios of the two monomers were determined to be rNB‐OCOMe = 0.08, rNB = 7.94 for Ni(II)/B(C6F5)3 system, and rNB‐OCOMe = 0.07, rNB = 6.49, for Pd(II)/B(C6F5)3 system by the Kelen‐Tüdõs method. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011

Novel Ni and Pd(benzocyclohexan‐ketonaphthylimino)2 complexes for copolymerization of norbornene with octene

“…The chemical shift of the complexes in 13 C‐NMR was moved to the downfield compared to the ligand, which further determine the successful of coordination. The structure of the Ni and Pd(bchkni) 2 catalysts were very similar to the catalysts which had been reported recently 40. According to the X‐ray crystallographic structure analysis, the coordination geometry of complexes were mononuclear and nearly ideally a four‐coordinate, square‐planar configuration.…”

Functionalization of vinylic addition polynorbornenes via efficient copolymerization of norbornene using Ni(II)‐Me complexes

“…For example, bis‐ligand complex A (Scheme ) combined with AlEt 3 and B(C 6 F 5 ) 3 was reported to copolymerize NB with 5‐norbornene‐2‐yl acetate (NBA) with a monomer conversion of about 36% in a long reaction time of 12 h 56. The same copolymerization was also realized by using complex B (Scheme ) activated by B(C 6 F 5 ) 3 in a moderate conversion (57%) within 30 min 57. In addition, copolymerization of NB with 5‐NB‐2‐carboxylic acid methyl ester in toluene by (Cp)Ni(Cl)(PPh 3 )/AlMe 3 /B(C 6 F 5 ) 3 system has been achieved in moderate yields (up to 68% in 2 h at room temperature) 59.…”

“…Nickel catalysts are expected to be an ideal candidate for the copolymerization of NB with its polar derivatives, but reports about such copolymerization are scarce. Recently, bis‐ligand Ni(II) complexes were reported to copolymerize NB with its derivatives after the first report of nickel compound catalyzed copolymerization 55–58. For example, bis‐ligand complex A (Scheme ) combined with AlEt 3 and B(C 6 F 5 ) 3 was reported to copolymerize NB with 5‐norbornene‐2‐yl acetate (NBA) with a monomer conversion of about 36% in a long reaction time of 12 h 56.…”

Well-defined phosphino-phenolate neutral nickel(ii) catalysts for efficient (co)polymerization of norbornene and ethylene

“…To replace a phenyl group in complex 1 by tert-butyl group (complex 3) resulted in a decrease in activity (entry 4 vs. entry 1). 47,69 Under the same conditions, salicylaldimine nickel complex 5 was also investigated, and only 50.9% monomer conversion was observed (entry 7), which was much lower than phosphino-phenolate complexes 1-3, although elongating the reaction time or elavating the B(C 6 F 5 ) 3 /Ni ratio would improve the monomer conversion to some extent (entries 8 and 9). With that said, complex 4 was still far more active than [N,O] or other bisligated complexes in former reports.…”