Jump to main content
Jump to site search

Issue 15, 2014
Previous Article Next Article

Alkyl chlorido hydridotris(3,5-dimethylpyrazolyl)borate imido niobium and tantalum(V) complexes: synthesis, conformational states of alkyl groups in solid and solution, X-ray diffraction and multinuclear magnetic resonance spectroscopy studies

Author affiliations

Abstract

The alkylation of the starting pseudooctahedral dichlorido imido hydridotris(3,5-dimethylpyrazolyl)borate niobium and tantalum(V) compounds [MTp*Cl2(NtBu)] (M = Nb,Ta; Tp* = BH(3,5-Me2C3HN2)3) with MgClR in different conditions led to new alkyl chlorido imido derivatives [MTp*ClR(NtBu)] (M = Nb/Ta, R = CH2CH31a/1b, CH2Ph 2a/2b, CH2tBu 3a/3b, CH2SiMe34a/4b, CH2CMe2Ph 5a/5b), whereas the dimethyl derivatives [MTp*Me2(NtBu)] (M = Nb 6a, Ta 6b) could be isolated as unitary species when the reaction was carried out using 2 equivalents of the magnesium reagent MgClMe. However, the chlorido methyl [MTp*ClMe(NtBu)] (M = Nb 7a, Ta 7b) complexes were obtained by heating at 50 °C the dichlorido and dimethyl imido complexes mixtures in a 1 : 1 ratio. All of the complexes were studied by multinuclear magnetic resonance spectroscopy and the molecular structures of 1b, 2a/b, 3a/b, 4a and 5a/b were determined by X-ray diffraction methods. In the solid state the complexes 1b, 4a and 5a exhibit only a gaucheanti conformation and the complexes 2a/b, 3a/b and 5b exhibit only a gauchesyn conformation of the alkyl substituents, whereas both conformational states, which do not show mutual exchange in the NMR time scale, were observed for 3a/b in a benzene-d6 solution. The 15N chemical shifts of the complexes 1–7 are discussed.

Graphical abstract: Alkyl chlorido hydridotris(3,5-dimethylpyrazolyl)borate imido niobium and tantalum(v) complexes: synthesis, conformational states of alkyl groups in solid and solution, X-ray diffraction and multinuclear magnetic resonance spectroscopy studies

Back to tab navigation

Supplementary files

Publication details

The article was received on 28 Nov 2013, accepted on 11 Jan 2014 and first published on 13 Jan 2014


Article type: Paper
DOI: 10.1039/C3DT53353K
Author version available: Download Author version (PDF)
Citation: Dalton Trans., 2014,43, 5747-5758
  •   Request permissions

    Alkyl chlorido hydridotris(3,5-dimethylpyrazolyl)borate imido niobium and tantalum(V) complexes: synthesis, conformational states of alkyl groups in solid and solution, X-ray diffraction and multinuclear magnetic resonance spectroscopy studies

    M. Galájov, C. García, M. Gómez and P. Gómez-Sal, Dalton Trans., 2014, 43, 5747
    DOI: 10.1039/C3DT53353K

Search articles by author

Spotlight

Advertisements