Unusual Intermolecular “Through-Space” J Couplings in P–Se Heterocycles

Abstract

Solid-state NMR spectra of new P-Se heterocycles based on peri-substituted naphthalene motifs show the presence of unusual J couplings between Se and P. These couplings are between atoms in adjacent molecules and occur "through space", rather than through conventional covalent bonds. Experimental measurements are supported by relativistic DFT calculations, which confirm the presence of couplings between nonbonded atoms, and provide information on the pathway of the interaction. This observation improves the understanding of J couplings and offers insight into the factors that affect crystal packing in solids, for future synthetic exploitation.

Combining solid-state NMR spectroscopy with first-principles calculations – a guide to NMR crystallography

“…However, examples of J-coupling interactions that can be formally described as through space in nature have been observed. 47,[57][58][59][60] A recent study by Sanz-Camacho et al, 57 found that in the solid state, intermolecular 31 that occurs as a result of the coupling and confirms the coupling is mediated by the P and Se lone-pairs.…”

Perspective: Current advances in solid-state NMR spectroscopy

“…39 These have also found application in the study of the interactions that affect crystal packing in the solid state, including hydrogen bonding 40 and unusual "through space" J couplings. 41,42 Recent work has shown that hybrid functionals (which incorporate a portion of exact exchange from Hartree-Fock theory) can improve the prediction of solid-state properties. Although their implementation is expensive in plane wave codes, they can be usefully employed to predict NMR parameters in fragment-based approaches and have shown promising results for 13 C chemical shifts of molecular organic crystals.…”

Polymorphism, Weak Interactions and Phase Transitions in Chalcogen–Phosphorus Heterocycles

“…[25] The syntheses of 5 and 13 have been reported elsewhere. [17] Naphtho[1,8-cd]1,2-dithiole isopropylphosphine [NapS 2 PiPr] (1) A1m solution of lithium triethylborohydride (superhydride) in THF (11.2 mL, 11.2 mmol) was added dropwise to as olution of naphtho[1,8-cd]1,2-dithiole (1.3 g, 6.8 mmol) in THF (100 mL). The mixture was stirred at room temperature for 15 min, after which as olution of dichloroisopropylphosphine (1.5 mL, 10.2 mmol) in THF (10 mL) was added dropwise to the mixture.…”

“…In order to do this, all possible polymorphs and phase transitions as well as their thermodynamic stability and the kinetics of the phase transition must be known,a nd this requirest he use of different (and complementary) techniques to address all of these complex questions. [16] In 2015, Sanz Camacho et al [17] established the presence of extremelyu nusual through-space interactions between Se and Patoms of adjacent molecules in naphthalene(Nap)-based systems.T his intermolecular J coupling was shown to be present for two compounds (5 and 13 in this work), but only resolved in the 77 Se spectrum of 13.T he J values calculated by periodic DFT confirmt hat al arger interaction is expected for 13,a sa consequence of the differentp acking motifso ft he two compounds. To understand the effect of these unusual interactions on the stability,c onformationa nd solid-state packing of the compounds, the series hasb een extended here, both to include ad ifferent chalcogen (S) and to vary the oxidation state of the Pa tom, potentially precluding this atom's participating in additional interactions.…”