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Lanthanide‐Mediated Ligand Transfer Reactions—A Route to Late Transition Metal Bisamido Complexes
Author(s) -
Kempe Rhett,
Noss Henrik,
Fuhrmann Hans
Publication year - 2001
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 - 10.1002/1521-3765(20010417)7:8<1630::aid-chem16300>3.0.co;2-a
Subject(s) - dimethoxyethane , chemistry , ligand (biochemistry) , crystal structure , polystyrene , ethylene , hexane , lanthanide , solvent , platinum , transition metal , catalysis , cyclooctadiene , metal , polymer chemistry , crystallography , medicinal chemistry , stereochemistry , organic chemistry , polymer , ion , biochemistry , receptor , electrode , electrolyte
The reaction of [{O(SiMe 2 Ap) 2 } 2 LnLi(thf) n ] 1 (Ln=Nd, n =2) and 2 (Ln=La, n =3) in hexane with [(dme)NiCl 2 ] (dme=dimethoxyethane) and [(cod)PtCl 2 ] (cod=1,5‐cyclooctadiene) leads to the dimeric Ni complex [{O(SiMe 2 Ap) 2 } 2 Ni 2 ] ( 3 ) and the mononuclear platinum compound [O(SiMe 2 Ap) 2 Pt] ( 4 ), respectively (O(SiMe 2 ApH) 2 =bis(4‐methyl‐2‐pyridylamino)tetramethyldisiloxane). Compounds 3 and 4 have been characterized by X‐ray crystal structure analysis. The ligand‐transfer reactions probably proceed via heterobimetallic intermediates. A model complex of such an intermediate [{O(SiMe 2 Ap) 2 } 2 NdPdMe] ( 7 ) was isolated by reacting 1 with [(cod)PdMeCl]. Applications of complex 3 in ethylene oligomerization were investigated. Highly branched oligomers with a very narrow molecular weight distribution ( M n =230 g mol −1 (relative to polystyrene standards), M w / M n =1.14) are produced when Et 3 Al 2 Cl 3 is employed as a co‐catalyst and CH 2 Cl 2 as the solvent (TOF=122 000 h −1 ). Treatment of one equivalent of 1 or 2 with two equivalents of [(cod)CuCl] results in the formation of the polycyclic tetranuclear complex [{O(SiMe 2 Ap) 2 } 2 Cu 4 ] ( 8 ). An X‐ray crystal structure analysis of 8 shows channels formed by a series of fourteen‐membered rings in the solid state.