Gas-phase ion-mobility spectrometry provides a unique platform to study the effect of mobile charge(s) or charge location on collisional cross section and ion separation. Here, we evaluate the effects of cation/anion adduction in a series of xylene and pyridyl macrocycles that contain ureas and thioureas. We explore how zinc binding led to unexpected deprotonation of the thiourea macrocyclic host in positive polarity ionization and subsequently how charge isomerism due to cation (zinc metal) and anion (chloride counterion) adduction or proton competition among acceptors can affect the measured collisional cross sections in helium and nitrogen buffer gases. Our approach uses synthetic chemistry to design macrocycle targets and a combination of ion-mobility spectrometry mass spectrometry experiments and quantum mechanics calculations to characterize their structural properties. We demonstrate that charge isomerism significantly improves ion-mobility resolution and allows for determination of the metal binding mechanism in metal–inclusion macrocyclic complexes. Additionally, charge isomers can be populated in molecules where individual protons are shared between acceptors. In these cases, interactions via drift gas collisions magnify the conformational differences. Finally, for the macrocyclic systems we report here, charge isomers are observed in both helium and nitrogen drift gases with similar resolution. The separation factor does not simply increase with increasing drift gas polarizability. Our study sheds light on important properties of charge isomerism and offers strategies to take advantage of this phenomenon in analytical separations.

Herein, two different monomers, pyrrole (Py) and ethylenedioxythiophene (EDOT), are loaded into a self-assembled bis-urea host 1 and oxidatively polymerized within its nanochannels, dramatically changing the properties of the crystalline complexes. Molecular dynamics (MD) simulation of both monomers within the channel demonstrates that they diffuse through the confinement upon applying thermal energy, which may facilitate the polymerization reaction. The structures of these host–guest complexes are characterized before and after polymerization using solid-state and photophysical measurements. The host maintains its columnar morphology during polymerization at 90 °C using iodine as an oxidizing agent. Intriguingly, upon dissolution of the host and recovery by filtration, the polymers exhibit memory of their nanoreactor environment, displaying unusual order by scanning electron microscopy, powder X-ray diffraction, and small- and wide-angle X-ray analysis. Solid-state 13C cross-polarized magic angle spinning NMR suggests that polypyrrole (PPy) exhibits primarily α,α′ linkages with some contributions from the quinoid form. Similarly, poly(ethylenedioxythiophene) (PEDOT) also exhibits formation of primarily α,α′ linkages with minor quinoid contributions. Both the 1·PPy and 1·PEDOT crystals show a 103-fold increase in conductivity to ∼10–6 S/cm versus host 1 crystals, which are nonconductive ∼10–9 S/cm. Overall, supramolecular polymerization strategies have the potential to readily modulate the properties of nanostructured materials.

Supramolecular self-assembly of brominated triphenyl amine bis-urea macrocycles leads to the formation of porous organic crystals with small elliptical 4.3 Å × 6.5 Å unidirectional pores. Here, this porous material has been applied in a simple vapor loading technique for the enrichment of isomeric mixtures of xylene. The host exhibits selectivity toward loading linear isomers present in the mixture that better match the channel topography. The same crystals were reused for multiple separations, highlighting the robust nature of the crystals. Host−guest complexes with each xylene constitutional isomer as well as with ethylbenzene were separately prepared by single-crystal-to-single-crystal guest exchange and their structures analyzed by single-crystal X-ray diffraction. Room-temperature xylene isomer enrichment employing these porous organic crystals provides insight toward energy efficient alternatives for separating complex petrochemical feed mixtures.

Herein, we probe the hydrogen bond-driven selfassembly of a triphenylamine (TPA) bis-urea macrocycle in the presence and absence of guests. Comprised of methylene urea-bridged TPAs with exterior tridodecyloxy benzene solubilizing groups, the macrocycle exhibits concentration-dependent aggregate formation in THF and H 2 O/THF mixtures as characterized by 1 H NMR and DOSY experiments. Its assembly processes were further probed by temperaturedependent UV/Vis and fluorescence spectroscopy. Upon heating, UV/Vis spectra exhibit a hypsochromic shift in the λ max , while fluorescence spectra show an increase in emission intensity. Conversely, the protected macrocycle that lacks hydrogen bond donors demonstrates no significant change. Thermodynamic analysis indicates a cooperative self-assembly pathway with distinct nucleation and elongation regimes. The morphology and structure of the aggregate were elucidated by dynamic light scattering, atomic force microscopy, scanning and transmission electron microscopy. Variable temperature emission spectra were utilized to monitor the impact of guests, such as diphenylacetylene, that can be bound in the columnar channels. The findings suggest that the elongation of assemblies is influenced by the presence of these guests. In comparison, diphenyl sulfoxide, likely functioning as a chain stopper, limited the assembly size. These studies suggest that judicious selection of (co)monomers may modulate the function and utility of these supramolecular systems.

BackgroundUnlike subcutaneous lipomas, thoracic cavity lipomas are extremely rare and can develop to be quite large without causing any symptoms. However, managing massive lipoma that involves both chest cavities is usually challenging, especially when considering the approach for excision.CaseWe report our experience of surgical management of a case of a 46-year-old male with huge intrathoracic lipoma that extends bilaterally and is known to be the largest of such kind. The tumor was resected successfully using median sternotomy. Histological analysis confirmed features of lipoma. ConclusionTo remove a bilateral intrathoracic lipoma, various surgical approaches have been documented. In our experience, a median sternotomy allows better exposure, which aids in complete surgical extirpation resulting in the prevention of recurrence.