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Macrocycle formation that relies upontransmetal coordination of appropriately placed pyridine ligands within an arylene ethynylene construct provides rapid and reliable access to molecular rotators encapsulated within macrocyclic stators. Showing no significant close contacts to the central rotators, X‐ray crystallography of Ag^I‐coordinated macrocycles provides plausibility for unobstructed rotation or wobbling of rotators within the central cavity. Solid‐state¹³C NMR of Pd^II‐coordinated macrocycles supports the notion of unobstructed movement of simple arenes in the crystal lattice. Solution¹H NMR studies indicate complete and immediate macrocycle formation upon the introduction of Pd^IIto the pyridyl‐based ligand at room temperature. Moreover, the formed macrocycle is stable in solution; a lack of significant changes in the¹H NMR spectrum upon cooling to −50 °C is consistent with the absence of dynamic behavior. The synthetic route to these macrocycles is expedient and modular, providing access to rather complex constructs in four simple steps involving Sonogashira coupling and deprotection reactions.

Field‐stepped NMR spectroscopy at up to 36 T using the series‐connected hybrid (SCH) magnet at the U.S. National High Magnetic Field Laboratory is demonstrated for acquiring ultra‐wideline powder spectra of nuclei with very large quadrupolar interactions. Historically, NMR evolved from the continuous‐wave (cw) field‐swept method in the early days to the pulsed Fourier‐transform method in the modern era. Spectra acquired using field sweeping are generally considered to be equivalent to those acquired using the pulsed method. Here, it is shown that field‐stepped wideline spectra of half‐integer spin quadrupolar nuclei acquired using WURST/CPMG methods can be significantly different from those acquired with the frequency‐stepped method commonly used with superconducting magnets. The inequivalence arises from magnetic field‐dependent NMR interactions such as the anisotropic chemical shift and second‐order quadrupolar interactions; the latter is often the main interaction leading to ultra‐wideline powder patterns of half‐integer spin quadrupolar nuclei. This inequivalence needs be taken into account to accurately and correctly determine the quadrupolar coupling and chemical shift parameters. A simulation protocol is developed for spectral fitting to facilitate analysis of field‐stepped ultra‐wideline NMR spectra acquired using powered magnets. A MATLAB program which implements this protocol is available on request.

Solid‐state nuclear magnetic resonance (SSNMR) spectroscopy has largely overtaken nuclear quadrupole resonance (NQR) spectroscopy for the study of quadrupolar nuclei. In addition to information on the electric field gradient,SSNMRspectra may offer additional information concerning otherNMRinteractions such as magnetic shielding. With continued technological advances contributing to developments such as higher magnetic fields,SSNMRboasts several practical advantages overNQR. However,NQRis still a relevant technique, as it may often be the most practical approach in cases of extremely large quadrupolar coupling constants. Here, we discuss the advantages and disadvantages ofSSNMRandNQRspectroscopies, with the quadrupolar halogens serving as examples. The purpose of this article is to serve as a guide on usingSSNMRandNQRas complementary tools, covering some of their practicalities, limitations, and experimental challenges.