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Formation and Rearrangement of Reduced Diiminepyridine Complexes of Zr and Hf
Author(s) -
Rahimi Naser,
Herbert David E.,
Budzelaar Peter H. M.
Publication year - 2018
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/ejic.201800918
Subject(s) - chemistry , dimer , isomerization , ligand (biochemistry) , crystallography , stereochemistry , monomer , divalent , catalysis , polymer , organic chemistry , biochemistry , receptor
Reduction of seven‐coordinate [( Et DIP)MCl 4 ] { Et DIP = 2,6‐(2,6‐Et 2 –C 6 H 3 N=CMe) 2 C 5 H 3 N; M = Zr or Hf} produces formally divalent complexes [( Et DIP)MCl 2 ] containing in reality a doubly reduced DIP ligand. The Hf complex is five‐coordinate, but the Zr analog crystallizes as a chloride‐bridged dimer with an unusual coordination geometry; the monomer‐dimer equilibrium is fast at room temperature. Reaction of [( Et DIP)HfCl 2 ] with MeMgBr or LiCH 2 SiMe 3 produced the corresponding dialkyls [( Et DIP)HfR 2 ]. An unexpected ligand isomerization to an amido/enamido form was observed for [( Et DIP)ZrCl 2 ], [( Et DIP)HfMe 2 ] and [( Et DIP)TiMe 2 ], and a mechanism is proposed based on DFT calculations.