Synthesis and structural characterization of group 4 metal alkoxide complexes of N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine and their use as initiators in the ring-opening polymerization (ROP) of rac-lactide under industrially relevant conditions.
A series of N,N,N',N'-tetrakis(2-hydroxyethyl)ethylenediamine (TOEEDH4) ligand precursors and their group 4 metal complexes have been prepared. The complexes have been characterized by single-crystal X-ray diffraction and (1)H NMR spectroscopy, highlighting the ability to systematically vary the number of TOEED ligands within the system. Initial catalytic data for the solvent-free, ring-opening polymerization of rac-lactide (rac-LA), a promising degradable polymer produced from renewable resources, is reported. At 135 °C, it has been demonstrated that the activity of the complexes is enhanced by increasing the number of labile isopropoxide groups. When the temperature was further increased to 165 °C, all complexes demonstrated a far higher activity irrespective of the identity of the metal or number of labile initiator groups. Polymerization kinetics were monitored in real time using FT-IR spectroscopy with a diamond composite insertion probe and Ti4(TOEED)(O(i)Pr)12 was demonstrated to convert over 95% of the rac-LA within 160 min.
Department of Chemistry, University of Bath , Claverton Down, Bath BA2 7AY, United Kingdom.
Christopher J
CJ
Chuck
Matthew G
MG
Davidson
Gerrit
G
Gobius du Sart
Petya K
PK
Ivanova-Mitseva
Gabriele I
GI
Kociok-Köhn
Lois B
LB
Manton
D056831:Coordination Complexes / Q000138:chemical synthesis* / Q000737:chemistry; D018360:Crystallography, X-Ray; D003959:Diamines / Q000737:chemistry*; D004146:Dioxanes / Q000737:chemistry*; D005030:Ethylenes / Q000737:chemistry*; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D058105:Polymerization; D017550:Spectroscopy, Fourier Transform Infrared; D014025:Titanium / Q000737:chemistry*; D015040:Zirconium / Q000737:chemistry*
D056831:Coordination Complexes; D003959:Diamines; D004146:Dioxanes; D005030:Ethylenes; D008024:Ligands; C586807:N,N,N',N''-tetrakis(2-hydroxyethylpropyl)ethylenediamine; C091880:dilactide; D015040:Zirconium; D014025:Titanium