title: Conformational dependence of through-space tellurium-tellurium spin-spin coupling in peri-substituted bis(tellurides).
abstract: Three related series of peri-substituted bis(tellurides) bearing naphthalene, acenaphthene and acenaphthylene backbones (Nap/Acenap/Aceyl(TeY)2 (Nap = naphthalene-1,8-diyl N; Acenap = acenaphthene-5,6-diyl A; Aceyl = acenaphthylene-5,6-diyl Ay; Y = Ph 1; Fp 2; Tol 3; An-p- 4; An-o- 5; Tp 6; Mes 7; Tip 8) have been synthesised and their solid-state structures determined by X-ray crystallography. Molecular conformations were classified as a function of the two C9-C-Te-C(Y) dihedral angles (θ); in the solid all members adopt AB or CCt configurations, with larger Te(aryl) moieties exclusively imposing the CCt variant. Exceptionally large J((125)Te,(125)Te) spin-spin coupling constants between 3289-3848 Hz were obtained for compounds substituted by bulky Te(aryl) groups, implying these species are locked in a CCt-type conformation. In contrast, compounds incorporating smaller Te(aryl) moieties are predicted to be rather dynamic in solution and afford much smaller J values (2050-2676 Hz), characteristic of greater populations of AB conformers with lower couplings. This conformational dependence of through-space coupling is supported by DFT calculations.
authors.affiliation: EaStCHEM School of Chemistry and Centre for Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST (UK).
authors.forename: Fergus R
authors.initials: FR
authors.lastname: Knight
authors.forename: Louise M
authors.initials: LM
authors.lastname: Diamond
authors.forename: Kasun S
authors.initials: KS
authors.lastname: Athukorala Arachchige
authors.forename: Paula
authors.initials: P
authors.lastname: Sanz Camacho
authors.forename: Rebecca A M
authors.initials: RA
authors.lastname: Randall
authors.forename: Sharon E
authors.initials: SE
authors.lastname: Ashbrook
authors.forename: Michael
authors.initials: M
authors.lastname: Bühl
authors.forename: Alexandra M Z
authors.initials: AM
authors.lastname: Slawin
authors.forename: J Derek
authors.initials: JD
authors.lastname: Woollins
keywords: DFT calculations; NMR spectroscopy; X-ray crystallography; bis(tellurides); conformational dependence; spin-spin coupling