Solid-State NMR Study of Halogen-Bonded Adducts

Abstract

Nuclear magnetic resonance (NMR) spectroscopy offers unique insights into halogen bonds. NMR parameters such as chemical shifts, quadrupolar coupling constants, J coupling constants, and dipolar coupling constants are in principle sensitive to the formation and local structure of a halogen bond. Carrying out NMR experiments on halogen-bonded adducts in the solid state may provide several advantages over solution studies including (1) the absence of solvent which can interact with halogen bond donor sites and complicate spectral interpretation, (2) the lack of a need for single crystals or even long-range crystalline order, and (3) the potential to measure complete NMR interaction tensors rather than simply their isotropic values. In this chapter, we provide an overview of the NMR interactions and experiments which are relevant to the study of nuclei which are often found in halogen bonds (RX···Y) including (13)C, (35/37)Cl, (79/81)Br, (127)I, (77)Se, and (14/15)N. Experimental examples based on iodoperfluorobenzene halides, bis(trimethylammonium)alkane diiodide, and selenocyanate complexes, as well as haloanilinium halides, are discussed. Of particular interest is the sensitivity of the isotropic chemical shifts, the chemical shift tensor spans, and the halide nuclear electric quadrupolar coupling tensors to the halogen bond geometry in such compounds. Technical limitations associated with the NMR spectroscopy of covalently-bonded halogens are underlined.

The halogen bond with isocyano carbon reduces isocyanide odor

“…NMR 35,36 and IR/ Raman 37,38 spectroscopies could also be used for XB recognition in the solid state; however, these techniques are not common as they provide only collateral identification of XB by detection of spectral changes for bonded and nonbonded forms; these changes are usually less significant in the solid state than in solutions. Another complication is that the solid-state NMR for XB donor sites (Cl, Br, and I) usually gives very broad signals because of the large quadruple moments of their NMR-active nuclei and thus it requires the application of the ultrahigh field NMR spectroscopy to obtain accurate data 35,[39][40][41] . At the same time, the identification of XB by IR/Raman methods requires the registration of usually hard-to-reach far-IR area.…”

1,3,5-Tri(iodoethynyl)-2,4,6-trifluorobenzene: halogen-bonded frameworks and NMR spectroscopic analysis

“…Solid-state NMR has been shown to be a versatile technique to probe the chemical and electronic environment of the halogen bond, with three recent literature reviews available (Szell & Bryce, 2016a;Bryce & Viger-Gravel, 2015;Vioglio, Catalano et al, 2016). From the information available, notable trends in the chemical shifts of the halogen-bond donor and halogen-bond acceptor have been observed (Viger-Gravel et al, 2013;Szell & Bryce, 2016b;.…”

87Sr, 119Sn, 127I Single and {1H/19F}‐Double Resonance Solid‐State NMR Experiments: Application to Inorganic Materials and Nanobuilding Blocks

“…Iodine occurs even more widely in materials science, notably because of its variety of oxidation states (from ‐I to +VII), and because it can be found not only as an anion (e. g. I − , IO 3 − , IO 4 − …) in inorganic materials, but also as part of an organic molecule in materials constructed on the basis of halogen‐bonding interactions for example . Among the different classes of materials involving iodine, those developed in view of the immobilization of radioactive iodine‐129, one of the longest half‐life radionuclides (∼ 16 × 10 6 years), are worth mentioning .…”