Oxidovanadium(V) Complexes with Aminoethanol Bis(phenolate) [O,N,O,O '] Ligands: Preparations, Structures, N-Dealkylation and Condensation Reactions

: Wichmann O, Sopo H, Lehtonen A, Sillanpaa R

Publisher: WILEY-BLACKWELL

: 2011

: European Journal of Inorganic Chemistry

: EUROPEAN JOURNAL OF INORGANIC CHEMISTRY

: EUR J INORG CHEM

: 8

: 1283

: 1291

: 9

: 1434-1948

DOI: https://doi.org/10.1002/ejic.201001251

The reactions between [VO(acac)(2)] (acac(-) = acetylacetonate ion) or [VO(OPr)(3)] and trianionic tetradentate N,N-bis(2-methylene-4,6-alkylphenolate)aminoethanolate ligands, [L1(3-) (4,6-dimethyl), L2(3-) (4-methyl, 6-tert-butyl), L3(3-) (4-tert-butyl, 6-methyl), L4(3-) (4,6-di-tert-butyl)], afford mononuclear complexes [VO(L1)] (1) and [VO(L2)] (2) with a trigonal bipyramidal coordination sphere around the V(V) ion, or dinuclear octahedral complexes [V(2)O(2)(L3)(2)] (3) and [V(2)O(2)(L4)(2)] (4). In methanol an adduct with the formula [VO(L1)(MeOH)]center dot 1/2MeOH (5) is obtained. According to multinuclear NMR spectroscopy all those complexes have a mononuclear structure in CDCl(3) solutions. In wet polar solvents complex 1 reacts with water and N-dealkylation occurs producing 3,5-dimethylsalicyl alcohol, which condensates with 1 and forms a new oxidovanadium complex 6. An ether bond links 3,5-dimethylsalicyl alcohol to the L1(3-) ligand. To support the reaction mechanism, we have found that in dry acetonitrile 1 reacts directly with salicyl alcohol forming compound 7, which is similar to 6. All compounds 1-7 have been characterized by elemental analysis, multinuclear NMR and X-ray diffraction.