Crystal and Molecular Structure of [Ni(Me4[14]hexaenatoN4)]2(CF3SO3)2: Conversion of a Metal-Stabilized π-Radical to a Diamagnetic Dimer with a Long Metal-Metal Bond and Eclipsed Macrocyclic Ligands upon Crystallization

S. M. Peng, James A. Ibers*, M. Millar, R. H. Holm

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

50 Scopus citations

Abstract

In dilute nonaqueous solutions the tetraaza macrocyclic complex [Ni(Me414]hexaenatoN4)]+ exists as a monomeric paramagnetic species, whose spectrum has previously been analyzed in terms of a Ni(II)-stabilized 15-π electron cation radical with the unpaired electron delocalized over the 14-membered ring system. However, as shown by the present three-dimensional x-ray diffraction study, the cation in the crystalline state forms a diamagnetic dimer. The trifluoromethanesulfonate salt crystallizes with one dipositive dimer per unit cell in the triclinic space group [Formula omitted] with a = 12.069 (2) Å, b = 11.889 (2) Å, c = 7.157 (1) Å, α = 98.28 (1)°, β = 105.25 (1)°, and γ = 60.04 (1)° at-117 (3) °C. The structure has been refined anisotropically by full-matrix least-squares techniques to conventional and weighted R indices of 0.049 and 0.084, based on 1978 observations (I ≥ 3σ(I)). There are number of unusual features associated with the structure. First, the dimers contain a weak Ni-Ni bond of length 3.063 (1) Å. Secondly, the macrocylic ligands of the dimers are eclipsed, maximizing rather than minimizing nonbonding interactions. Thirdly, the double bonds of the macrocyclic ligand are essentially delocalized. A qualitative bonding scheme is applied to account for these features.

Original languageEnglish (US)
Pages (from-to)8037-8041
Number of pages5
JournalJournal of the American Chemical Society
Volume98
Issue number25
DOIs
StatePublished - Dec 1 1976

ASJC Scopus subject areas

  • Catalysis
  • Chemistry(all)
  • Biochemistry
  • Colloid and Surface Chemistry

Fingerprint Dive into the research topics of 'Crystal and Molecular Structure of [Ni(Me<sub>4</sub>[14]hexaenatoN<sub>4</sub>)]<sub>2</sub>(CF<sub>3</sub>SO<sub>3</sub>)<sub>2</sub>: Conversion of a Metal-Stabilized π-Radical to a Diamagnetic Dimer with a Long Metal-Metal Bond and Eclipsed Macrocyclic Ligands upon Crystallization'. Together they form a unique fingerprint.

Cite this