RESUMEN
Complexity in supramolecular polymer systems arises from interactions between different components, including solvent molecules. By varying their concentration or temperature in such multicomponent systems, complex phenomena can occur such as thermally bisignate and dilution-induced assembly of supramolecular polymers. Herein, we demonstrate that both these phenomena emerge from the same underlying interaction mechanism between the components. As a model system, amide-decorated supramolecular polymers of porphyrins were investigated in combination with aliphatic alcohols as hydrogen-bond scavengers, and thermodynamic mass-balance models were applied to map the three-dimensional assembly landscapes. These studies unveiled that the interaction between hydrogen-bond scavengers and monomers is temperature-dependent and becomes dominant at high monomer concentrations. With these insights, we could exploit competitive monomer-alcohol interactions to prompt the dilution-induced assembly of various common monomers as well as bisignate assembly events. Moreover, kinetic insights were obtained by navigating through the assembly landscape. Similar to phase diagrams of covalent polymers, these assembly landscapes provide a comprehensive picture of supramolecular polymerizations, which helps to precisely regulate the system properties. The generality of this approach using assembly landscapes makes it relevant for any supramolecular system, and this enhanced control will open the door to build complex and functional supramolecular polymer systems.
RESUMEN
In stacking-based supramolecular polymerization, chiral hydrogen bonding (H-bonding) monomers often prefer to adapt a homochiral monomer sequence. Herein, we investigated the polymerization of a chiral thiophene-fused cyclooctatetraene (COT) as a novel nonplanar-core monomer and found the first example of the formation of an alternating heterochiral supramolecular copolymer. Although single enantiomer (-) or (+)-COT alone did not polymerize, when (-) and (+)-COT were mixed together, supramolecular polymerization took place to give a stereochemically alternating copolymer. By means of the microcrystal electron crystallography of a shorter side-chained COT analogue, we found that the resulting heterochiral supramolecular copolymer adapted an alternating arrangement of H-bonded and polar π-stacked parts. A computational study using density-functional theory (DFT) suggested that such an alternating heterochiral preference occurs because it allows two thiophene amide moieties facing each other to effectively cancel their in-plane dipole moments.
RESUMEN
A 28-year-old man was referred to Hakodate Municipal Hospital for examination of multiple pulmonary nodules detected on a medical check-up. His chest CT demonstrated well-defined multiple nodules with random distribution. 18-fluorodeoxyglucose positron emission tomography (FDG-PET) showed abnormal uptake in the pulmonary nodules and the hilar, mediastinal lymph node. No other accumulation was observed outside the thorax. Transbronchial lung biopsy did not yield a diagnosis. Based on the high accumulation on FDG-PET, we suspected a malignant tumor and performed right S4 wedge resection under video assisted thoracoscopy. Considering the histologocal and immunohistological findings, we diagnosed pulmonary hyalinizing granuloma. No treatment was given and subsequently stable disease was obtained on chest radiography. The follow-up FDG-PET showed standardized uptake value reduction. Pulmonary hyalinizing granuloma is infrequent and benign, but has been reported to possibly progress to lymphoproliferative disease. Consequently, FDG-PET is valuable to evaluate the activity of the disease itself and the possibility of transition.