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Preparation, Structure, and Ethylene Polymerization Behavior of Half‐Sandwich Picolyl‐Functionalized Carborane Iridium, Ruthenium, and Rhodium Complexes
Author(s) -
Wang Xin,
Jin GuoXin
Publication year - 2005
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.200500280
Subject(s) - rhodium , methylaluminoxane , chemistry , carborane , denticity , ruthenium , catalysis , iridium , ethylene , polymer chemistry , polymerization , chelation , medicinal chemistry , metal , metallocene , polymer , inorganic chemistry , organic chemistry
The synthesis of half‐sandwich transition‐metal complexes containing the Cab N and Cab N,S chelate ligands (HCab N =HC 2 B 10 H 10 CH 2 C 5 H 4 N ( 1 ), LiCab N,S =LiSC 2 B 10 H 10 CH 2 C 5 H 4 N ( 4 )) is described. Compounds 1 and 4 were treated with chloride‐bridged dimers [{Ir(Cp*)Cl 2 } 2 ] (Cp*=η 5 ‐C 5 Me 5 ), [{Ru( p ‐cymene)Cl 2 } 2 ] and [{Rh(Cp*)Cl 2 } 2 ] to give half‐sandwich complexes [Ir(Cp*)Cl(Cab N )] ( 2 ), [Ru( p ‐cymene)Cl(Cab N )] ( 3 ), and [Rh(Cp*)Cl(Cab N,S )] ( 5 ), respectively. Addition reaction of LiCab S (Cab S =SC 2 (H)B 10 H 10 ) to the rhodium complex 5 yields [Rh(Cp*)(Cab S )(Cab N,S )] ( 6 ). All the complexes were characterized by IR and NMR spectroscopy, and by elemental analysis. In addition, X‐ray structure analyses were performed on complexes 2 , 3 , 5 , and 6 , in which the potential C,N‐ and N,S‐chelate ligands were found to coordinate in a bidentate mode. The carborane complex 2 shows catalytic activities up to 3.7×10 5 g PE mol −1 Ir h −1 for the polymerization of ethylene in the presence of methylaluminoxane (MAO) as cocatalyst. The polymer obtained from this homogeneous catalytic reaction has a spherical morphology. Catalytic activities and the molecular weight of polyethylene have been investigated for various reaction conditions.