Abstract

Interaction of the tetradentate redox-active 6,6′-[1,2-phenylenebis(azanediyl)]bis(2,4-di-tert-butylphenol) (H4L) with TeCl4 leads to neutral diamagnetic compound TeL (1) in high yield. The molecule of 1 has a nearly planar TeN2O2 fragment, which suggests the formulation of 1 as TeIIL2−, in agreement with the results of DFT calculations and QTAIM and NBO analyses. Reduction of 1 with one equivalent of [CoCp2] leads to quantitative formation of the paramagnetic salt [CoCp2]+[1].−, which was characterised by single-crystal XRD. The solution EPR spectrum of [CoCp2]+[1].− at room temperature features a quintet due to splitting on two equivalent 14N nuclei. Below 150 K it turns into a broad singlet line with two weak satellites due to the splitting on the 125Te nucleus. Two-component relativistic DFT calculations perfectly reproduce the a(14N) HFI constants and A(125Te) value responsible for the low-temperature satellite splitting. Calculations predict that the additional electron in 1.− is localised mainly on L, while the spin density is delocalised over the whole molecule with significant localisation on the Te atom (≥30 %). All these data suggest that 1.− can be regarded as the first example of a structurally characterised monomeric tellurium–nitrogen radical anion.

Original languageEnglish
Pages (from-to)14688-14699
Number of pages12
JournalChemistry - A European Journal
Volume26
Issue number64
Early online date10 Aug 2020
DOIs
Publication statusPublished - 17 Nov 2020

Keywords

  • chelates
  • EPR spectroscopy
  • radical ions
  • relativistic density functional calculations
  • tellurium
  • CRYSTAL-STRUCTURE
  • DENSITY-FUNCTIONAL CALCULATIONS
  • X-RAY-STRUCTURE
  • ORDER REGULAR APPROXIMATION
  • VALENCE TAUTOMERISM
  • MAGNETIC-PROPERTIES
  • PHENYLENEDIAMINE BIS(PHENOLATE)
  • GAUSSIAN-BASIS SETS
  • METAL-COMPLEXES
  • ELECTRONIC-STRUCTURE

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