Pd(II) complexes bearing di‐ and monochelate fluorinated β‐ketonaphthyliminato ligand and their catalytic properties towards vinyl‐addition polymerization and copolymerization of norbornene and ester‐functionalized norbornene derivative

Abstract

Fluorinated β-ketonaphthyliminate ligand CF 3 C(O)CHC[HN(naphthyl)]CH 3 (L1) and Pd(II) complexes with dichelate fluorinated β-ketonaphthyliminato ligand, {CF 3 C(O)CHC[N(naphthyl)]CH 3 } 2 Pd (C1), as well as with monochelate fluorinated β-ketonaphthyliminato ligand, {CF 3 C(O)CHC[N(naphthyl)]CH 3 }Pd(CH 3 )(PPh 3 ) (C2), were synthesized and their solid-state structures were confirmed using X-ray crystallographic analysis. The Pd(II) complexes were employed as precursors to catalyze norbornene (NB) homo-and copolymerization with ester-functionalized NB derivative using B(C 6 F 5 ) 3 as a co-catalyst. High activity up to 2.3 × 10 5 g polymer mol Pd À1 h À1 for the C1/B(C 6 F 5 ) 3 system and 3.4 × 10 6 g polymer mol Pd À1 h À1 for the C2/B(C 6 F 5 ) 3 system was exhibited in NB homopolymerization. Moreover, the Pd(II) complexes exhibited a high level of tolerance towards the ester-functionalized MB monomer. In comparison with the C1/B(C 6 F 5 ) 3 system, the C2/B (C 6 F 5 ) 3 system exhibited better catalytic property towards the copolymerization of NB with 5-norbornene-2-carboxylic acid methyl ester (NB-COOCH 3 ), and soluble vinyl-addition-type copolymers were obtained with relatively high molecular weights (3.6 × 10 4 -7.5 × 10 4 g mol À1 ) as well as narrow molecular weight distributions (1.49-2.15) depending on the variation of monomer feed ratios. The NB-COOCH 3 insertion ratio in all copolymers could be controlled in the range 2.8-21.0 mol% by tuning a content of 10-50 mol% NB-COOCH 3 in the monomer feed ratios. Copolymerization kinetics were expressed by the NB and NB-COOCH 3 monomer reactivity ratios: r NB-COOCH3 = 0.18, r NB = 1.28 were determined for the C1/B(C 6 F 5 ) 3 system and r NB-COOCH3 = 0.19, r NB = 3.57 for the C2/B(C 6 F 5 ) 3 system using the Kelen-Tüdõs method.

Switchable Polymerization of Norbornene Derivatives by a Ferrocene‐Palladium(II) Heteroscorpionate Complex

“…A large discrepancy was found between the experimental and theoretical values of the molecular weights, suggesting a poorly controlled polymerization process, with the PDI (PDI = M w / M n ) values ranging from 1.5–3.6. A similar wide distribution of PDI values is observed in the literature for the polymerization of norbornenes by group 10 metals , , , , , . The polymerization activity for palladium complexes toward norbornene is largely dependent on the coordination environment around the metal center and the substituents on the monomer and can vary greatly from just a few numbers to several millions , , , .…”

“…Amongst transition metal catalysts, palladium‐based systems are highly active toward norbornene polymerization and produce high molecular weight vinyl polynorbornenes , . Most palladium catalysts feature bidentate or monodentate supporting ligands since an open coordination sphere is necessary for monomer coordination , , , . Commonly employed systems also require the use of strong Lewis acids/alkylating reagents (i.e.…”

Bis(β-ketoimino)nickel(II) Complexes for Random Copolymerization of Norbornene and Methyl 5-Norbornene-2-carboxylate with Controlled Ester Group Incorporation

“…The ester group itself helps to improve the compatibility of polyolefins. , In addition, this group can be altered to other chemical functionalities by participating in post-polymerization modification, such as hydrolysis, , transesterification, − and amidation. , Therefore, a COC functionalized with ester groups is expected to have a role as a versatile platform that can be transformed to functional materials suitable for desired applications. Late transition metal complexes with low oxophilicity, mostly Ni­(II) and Pd­(II) complexes, have been used as catalysts for the vinyl addition copolymerization of NB and polar monomer with ester functionality and have shown promising catalytic performance. − Several previous studies have confirmed that Ni­(II) catalysts achieve higher catalytic activity than Pd­(II) catalysts. ,, Numerous ligands have been investigated for Ni­(II)-based catalyst systems. In particular, Ni­(II) complexes bearing N,O-chelating β-ketoimine ligands that form bis­(β-ketoimino)­nickel­(II) complexes have been reported to exhibit moderate catalytic activity. − …”

On the Electronic Nature of Bis((<i>Z</i>)-1-(benzo[<i>d</i>]oxazol-2-yl)-3.3.3-trifluoroprop-1-en-2-ate)palladium

“…Indeed, analysis of 2 by single crystal X-ray diffraction studies clearly display the square planar configuration with a typical trans-bis-κ 2 -N,O ligand donor set (τ 4 = 0.00). [14][15][16][17][18][19][20][21][22][23][24] In this Note, we re-examined the synthesis and properties of 2 using a combination of Density Functional Theory (DFT) and spectroscopic techniques (IR, UV-Vis., NMR, etc.). This work demonstrates that the title complex is, in fact, diamagnetic and hence NMR spectra ( 1 H, 13 C, 19 F) of the compound can be measured.…”