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Alkyl substituents triggered an unexpected formation of mono‐and dinuclear zirconium hydrazonate complexes: synthesis, characterization and their catalytic behavior toward ethylene polymerization
Author(s) -
Duan XinE,
Yuan Bo,
Li Rui,
Vignesh Arumugam,
Bariashir Chantsalnyam,
Li Zilong,
Bai ShengDi,
Ma Yanping,
Chao JianBin,
Tong HongBo,
Sun WenHua
Publication year - 2020
Publication title -
applied organometallic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.53
H-Index - 71
eISSN - 1099-0739
pISSN - 0268-2605
DOI - 10.1002/aoc.5586
Subject(s) - chemistry , zirconium , methylaluminoxane , adduct , ligand (biochemistry) , alkyl , polymerization , crystallography , hydrogen bond , crystal structure , ethylene , intramolecular force , catalysis , tetrachloride , polymer chemistry , medicinal chemistry , molecule , stereochemistry , metallocene , inorganic chemistry , organic chemistry , biochemistry , receptor , tin , polymer
Mononuclear zirconium complex 3a of the molecular identity [Zr[ η 2 ‐(C 4 H 3 O)C (Et) = NNPh]Cl 3 (THF) 2 ], dinuclear zirconium complexes 3b [{Zr[ η 2 ‐(C 4 H 3 O)C( i ‐Pr) = NNPh] 2 } 2 ( μ 2 ‐Cl) 3 ( μ 3 ‐Cl) 2 Li(Et 2 O)] and 3c [{Zr[ η 2 ‐(C 4 H 3 O)C( t ‐Bu) = NNPh] 2 } 2 Cl 2 ( μ 2 ‐Cl) 2 ] have been synthesized by the treatment of lithium salt of (C 4 H 3 O)C(R) = NNHPh (R = CH 3 CH 2 , 1a ; R = (CH 3 ) 2 CH, 1b ; R = (CH 3 ) 3 C, 1c ), with different molar ratios of anhydrous zirconium tetrachloride. Of these, complex 3b was formed with lithium adduct and no such adduct was found in complex 3c . Compound 1a and all the zirconium complexes ( 3a ‐ 3c ) were structurally characterized by single‐crystal X‐ray diffraction studies. Thus, it revealed that each hydrazonato ligand acts in a strained η 2 ‐coordination fashion for the three zirconium complexes. The molecular structures of the three zirconium complexes ( 3a ‐ 3c ) reveal the existence of intramolecular hydrogen bonding interactions. Interestingly, complexes 3a and 3b assemble into a two‐dimensional network structure through intermolecular hydrogen‐bonding interactions. Upon activation with methylaluminoxane (MAO), all the complexes namely 3a , 3b , and 3c exhibited moderate catalytic activities toward ethylene polymerization and produced high molecular weight polyethylene with narrow molecular weight distributions.