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Preparation, Structure, and Ethylene (Co)Polymerization Behavior of Group IV Metal Complexes with an [OSSO]‐Carborane Ligand
Author(s) -
Hu Ping,
Wang JianQiang,
Wang Fosong,
Jin GuoXin
Publication year - 2011
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201100291
Subject(s) - chemistry , ligand (biochemistry) , steric effects , carborane , metal , stereochemistry , nuclear magnetic resonance spectroscopy , zirconium , crystallography , medicinal chemistry , extended x ray absorption fine structure , absorption spectroscopy , inorganic chemistry , organic chemistry , biochemistry , receptor , physics , quantum mechanics
The synthesis of Group IV metal complexes that contain a tetradentate dianionic [OSSO]‐carborane ligand [(HOC 6 H 2 t Bu 2 ‐4,6) 2 (CH 2 ) 2 S 2 C 2 (B 10 H 10 )] ( 1 a ) is described. Reactions of TiCl 4 and Ti(O i Pr) 4 with the [OSSO]‐type ligand 1 a afford six‐coordinated titanium complex [Ti(OC 6 H 2 t Bu 2 ‐4,6) 2 (CH 2 ) 2 S 2 C 2 (B 10 H 10 )Cl 2 ] ( 2 a ) and four‐coordinated titanium complex [Ti(OC 6 H 2 t Bu 2 ‐4,6) 2 (CH 2 ) 2 S 2 C 2 (B 10 H 10 )(O i Pr) 2 ] ( 2 b ), respectively. ZrCl 4 and HfCl 4 were treated with 1 a to give six‐coordinated zirconium complex [Zr(OC 6 H 2 t Bu 2 ‐4,6) 2 (CH 2 ) 2 S 2 C 2 (B 10 H 10 )Cl 2 (thf) 2 ] ( 2 c ) and six‐coordinated hafnium complex [Hf(OC 6 H 2 t Bu 2 ‐4,6) 2 (CH 2 ) 2 S 2 C 2 (B 10 H 10 )Cl 2 ] ( 2 d ). All the complexes were fully characterized by IR, NMR spectroscopy, and elemental analysis. In addition, X‐ray structure analyses were performed on complexes 2 a and 2 b and reveal the expected different coordination geometry due to steric hindrance effects. Extended X‐ray absorption fine structure (EXAFS) spectroscopy was performed on complexes 2 c and 2 d to describe the coordination chemistry of this ligand around Zr and Hf. Six‐coordinated titanium complex 2 a showed good activity toward ethylene polymerization as well as toward copolymerization of ethylene with 1‐hexene in the presence of methylaluminoxane (MAO) as cocatalyst (up to 1060 kg [mol (Ti)] −1 h −1 in the case of 10 atm of ethylene pressure).