Vanadate complexes bearing an imidazolidine-bridged bis(aryloxido) ligand: synthesis and solid state and solution structure

Dalton Trans. 2012 May 7;41(17):5188-92. doi: 10.1039/c2dt30153a. Epub 2012 Mar 22.

Abstract

A new imidazolidine-bridged bis(aryloxido) ligand precursor (H(2)L) [H(2)L = 2,2'-(imidazolidine-1,3-diylbis(methylene))bis(4-(1,1,3,3-tetramethylbutyl-2-yl)phenol)] was prepared in a relatively high yield (∼60%) via a single-step Mannich condensation of 4-(1,1,3,3-tetramethylbutyl)phenol, ethylenediamine and paraformaldehyde at 2:1:3 molar ratio and characterized by chemical and physical techniques including X-ray crystallography. Reactions of H(2)L with [VO(OEt)(3)] at 1:1 and 1:2 molar ratios in toluene afforded [V(L-κ(3)O,N,N,O)(O)(OEt)] (1) and [V(2)(μ-L-κ(4)O,N,N,O)(μ-OEt)(2)(O)(2)(OEt)(2)] (2), respectively. Alcoholysis of 1 with EtOH enables elimination of one molecule of H(2)L and the formation of 2. Compounds 1 and 2 were characterized by IR and NMR spectroscopy as well as ES-MS experiments. The definitive molecular structure of 2 was provided by a single-crystal analysis and revealed its dinuclear nature, featuring two octahedral vanadium centres bridged by both OEt groups and the L ligand. The (51)V, (1)H and (13)C NMR spectra as well as ES-MS showed that 2 does not stay intact in solution and undergoes dissociation to give 1 and [VO(OEt)(3)].

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Chemistry Techniques, Synthetic / methods*
  • Imidazolines / chemistry*
  • Ligands
  • Models, Molecular
  • Molecular Conformation
  • Organometallic Compounds / chemical synthesis*
  • Organometallic Compounds / chemistry*
  • Solutions
  • Vanadium / chemistry*

Substances

  • Imidazolines
  • Ligands
  • Organometallic Compounds
  • Solutions
  • Vanadium