ic3019327_si_001.cif (205.34 kB)
Coordination Chemistry of N,N,N′,N′‑Tetrakis(3,5-substituted benzyl-2-oxide)-2,2′-(ethylenedioxy)diethanamine Modified Group 4 Metal Alkoxides
dataset
posted on 2012-11-05, 00:00 authored by Timothy J. Boyle, Daniel T. Yonemoto, Leigh Anna Steele, Joshua Farrell, Peter Renehan, Taylor HuhtaThe coordination behavior of a set of (ethylenedioxy)diethanamine-based
tetraphenol ligands with a series of Group 4 metal alkoxides ([M(OR)4]) was determined. The ligands were synthesized from a modified
Mannich reaction and fully characterized as N,N,N′,N′-tetrakis(3,5-tert-butyl-benzyl-2-hydroxy)-2,2′-(ethylenedioxy)diethanamine,
termed H4-OEA-DBP4 (1), and N,N,N′,N′-tetrakis(3,5-chloro-benzyl-2-hydroxy)-2,2′-(ethylenedioxy)diethanamine,
termed H4-OEA-DCP4 (2). The reaction
of 1 with a set of [M(OR)4] [M = Ti, Zr, or
Hf; OR = iso-propoxide (OPri), neo-pentoxide (ONep), or tert-butoxide (OBut)] precursors led to the
isolation of [(OPri)2Ti]2(μ-OEA-DBP4) (3), [(ONep)2Ti]2(μ-OEA-DBP4) (4), and [(OBut)2M]2(μ-OEA-DBP4) where M = Ti (5), Zr (6), or Hf (7). In addition, the [(ONep)2Ti]2(μ-OEA-DCP4) (4a) derivative
was isolated from the reaction of 2 and [Ti(ONep)4], demonstrating the similarity of coordination behavior between
the two OEA-R4 ligands. For 3–7, the metal center adopts a slightly distorted octahedral
geometry by binding the two O atoms of the phenoxide moiety, as well
as one N and one O atom from the OEA moieties, while retaining two
of the original OR ligands. Solution NMR demonstrates inequivalent
protons for the majority of the bound OEA ligands, which argues for
retention of structure in solution. The synthesis and characterization
of these compounds are presented in detail.