Probing interactions through space using spin-spin coupling

Martin W. Stanford, Fergus R. Knight, Kasun S. Athukorala Arachchige, Paula Sanz Camacho, Sharon E. Ashbrook, Michael Buehl, Alexandra M. Z. Slawin, J. Derek Woollins*

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

30 Citations (Scopus)
4 Downloads (Pure)

Abstract

The series of eight 5-(TeY)-6-(SePh)acenaphthenes (Y = Fp (2), Tol (3), An-p (4), An-o (5), Tp (6), Mes (7), Tip (8), Nap (9)) were prepared and structurally characterised by X-ray crystallography, solution and solid-state NMR spectroscopy and density functional theory (DFT/B3LYP) calculations. All members of the series, except 5, adopt a BA type configuration comparable to the parent compound 1 (Y = Ph), aligning the Te-CY bond along the mean acenaphthene plane and promoting a nonbonded Se...Te-CY 3c-4e type interaction to form to stabilise the molecule (G-dependence). 5 (Y = An-o) adopts a BC type conformation in the solid but DFT calculations show this optimises to BA. Indication of strong through-space peri-interactions between Te and Se are observed in the Se-77 and Te-125 NMR spectra, with J(Te, Se) spin-spin coupling constants (SSCCs) in the range -688 to -748 Hz. Evidence supporting the presence of this interaction was also found in solid-state NMR spectra of some of the compounds which exhibit an indirect spin-spin coupling on the same order of magnitude as observed in solution. In order to quantify the steric bulk of the aryl groups (Y), we introduce the crystallographic steric parameter (theta), the cone angle measured from the furthest H atoms lying on the edges of the cone to the Te atom located at its vertex. Modification to Y has no apparent influence over the conformation of the molecule, the degree of molecular distortion occurring in the acenaphthene backbone or the extent of 3c-4e interaction; peri-distances for all eight compounds are within 0.08 angstrom and no apparent correlation is observed between the steric bulk of Y (theta) and the Se-77 chemical shifts or J(Te, Se) SSCCs. In contrast, a good correlation is found between theta and Te-125 chemical shifts. DFT calculations performed on all members of the series confirm the comparable covalent bonding between Te and Se in the series, with WBIs of ca. 0.1 obtained. Natural bond orbital analysis shows a noticeable donor-acceptor interaction between a p-type lone pair on Se and a sigma*(Te-C) antibonding orbital, confirming the onset of 3c-4e type bonding.

Original languageEnglish
Pages (from-to)6548-6560
Number of pages13
JournalDalton Transactions
Volume43
Issue number17
Early online date4 Mar 2014
DOIs
Publication statusPublished - 4 Mar 2014

Keywords

  • Peri-substituted naphthalenes
  • Centre-Dot-P
  • Nonbonded interactions
  • Distance dependence
  • Phosphorous ligands
  • X-ray
  • Acenaphthenes

Fingerprint

Dive into the research topics of 'Probing interactions through space using spin-spin coupling'. Together they form a unique fingerprint.

Cite this