Knight Fergus R, Diamond Louise M, Athukorala Arachchige Kasun S, Sanz Camacho Paula, Randall Rebecca A M, Ashbrook Sharon E, Bühl Michael, Slawin Alexandra M Z, Woollins J Derek
EaStCHEM School of Chemistry and Centre for Magnetic Resonance, University of St Andrews, St Andrews, KY16 9ST (UK).
Chemistry. 2015 Feb 23;21(9):3613-27. doi: 10.1002/chem.201405599. Epub 2014 Dec 22.
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.
合成了三个相关系列的带有萘、苊和苊烯骨架的周边取代双碲化物（Nap/Acenap/Aceyl(TeY)₂ （Nap = 萘-1,8-二基 N；Acenap = 苊-5,6-二基 A；Aceyl = 苊烯-5,6-二基 Ay；Y = Ph 1；Fp 2；Tol 3；An-p- 4；An-o- 5；Tp 6；Mes 7；Tip 8）），并通过X射线晶体学确定了它们的固态结构。分子构象根据两个C9-C-Te-C(Y)二面角（θ）进行分类；在固态中，所有成员均采用AB或CCt构型，较大的Te(芳基)部分专门呈现CCt变体。对于被庞大的Te(芳基)基团取代的化合物，获得了3289 - 3848 Hz的异常大的J((¹²⁵)Te,(¹²⁵)Te)自旋-自旋耦合常数，这意味着这些物种被锁定在CCt型构象中。相比之下，含有较小Te(芳基)部分的化合物预计在溶液中相当动态，并提供小得多的J值（2050 - 2676 Hz），这是具有较低耦合的AB构象体数量较多的特征。这种通过空间耦合的构象依赖性得到了密度泛函理论计算的支持。
