Synthesis and Reversible Hydration of a Pseudoprotein, a Fully Organic Polymeric Desiccant by Multiple Single‐Crystal‐to‐Single‐Crystal Transformations

Abstract

A diphenylalanine derivative, N3-Phe-Phe-NHCH2CCH, was designed for topochemical azide-alkyne cycloaddition (TAAC) polymerization. This dipeptide adopted β-sheet arrangement as designed, in its crystals, but the azide and alkyne were not fitly aligned for their topochemical reaction. However, the voids present around these groups allowed them to attain a reactive geometry upon heating and their consequent TAAC polymerization to a pseudoprotein in a single-crystal-to-single-crystal (SCSC) fashion. This motion led to the creation of channels in the product crystal and it absorbed water from the surroundings to fill these channels as H-bonded water wire. The pseudoprotein undergo reversible hydration/dehydration in SCSC fashion many times under mild conditions: hydration at low relative humidity and dehydration at low temperature. Vapor sorption analyses suggest that this fully organic polymer might be useful as an energy-efficient desiccant material for controlling indoor humidity.

Quantification of Noncovalent Interactions in Azide–Pnictogen, –Chalcogen, and –Halogen Contacts

“…Overall, considering the complexity of further decomposing single contributions to the interaction energy into specific parts of the molecular systems, the unbiased azide–X interaction is estimated to be 1.5 to 3.0 kcal mol −1 . We are convinced that these stabilizing interactions are of importance, not only for the arrangement of azide moieties in supramolecular assemblies and crystal engineering (e.g., click chemistry in the solid state), [81–85] but are also the basis for conformational bias in azido‐functionalized nucleic acids, peptides, proteins, and carbohydrates. Future investigations will reveal whether azido‐based interactions have a similar potential to facilitate catalysis, as has been extensively and successfully explored for halogen and chalcogen bonding.…”

Metal- and halide-free, solid-state polymeric water vapor sorbents for efficient water-sorption-driven cooling and atmospheric water harvesting

“…46,53 Among all, PAETA-Ac shows the highest water sorption capacity (B0.87 g g À1 at 25 1C, 80% RH), higher than other metal-and halide-free polymeric sorbents reported in the literature under the same conditions, such as an epoxy-functionalized porous organic polymer (ep-POP, o0.4 g g À1 ), and a pseudoprotein-based fully organic polymeric desiccant (o0.09 g g À1 ). 22,40 Importantly, the water vapor sorption capacity of PAETA-Ac hydrogel is among the best in the reported hygroscopic polymers in their pure form and traditional desiccants (e.g., silica gel and zeolite), even though the PAETA-Ac hydrogel was crosslinked in this case (Fig. S3, ESI †).…”

“…36,37 Recently, organic materials have been investigated as alternative water vapor sorbents because of their low-cost, less toxicity, and the wide pool of potential candidates. Hygroscopic polymers, [20][21][22][38][39][40][41][42][43][44][45][46] like poly(acrylic acid) sodium salt (PAAS), 21,38 chloride-doped polypyrrole (PPy-Cl), 20,43,44 sodium alginate (Alg), 41 poly(diallyldimethylammonium chloride) (PDDA), 45 etc., as well as glycerin, 23 and ionic liquid, 24,29,36,46 are mostly reported. However, much like the inorganic salt-based sorbents, the non-crosslinked hygroscopic polymers, glycerin, and ionic liquid, all work in liquid form.…”

Solid‐State Synthesis of Two Different Polymers in a Single Crystal: A Miscible Polymer Blend from a Topochemical Reaction

“…Depending on the orientation in the crystal, the cycloaddition can produce either the 1,4‐disubstituted ( trans ) or 1,5‐disubstituted ( cis ) product. Polymers containing cis ‐triazole, or trans ‐triazole,,, linkages have been synthesized by TAAC polymerization. To pursue our interest in the synthesis of polyol polymers connected by enzyme‐stable triazole linkages, we synthesized the tetrol 1 decorated with alkyne and azide groups (see Scheme S1 in the Supporting Information) and allowed it to crystallize from a mixture of acetone and chloroform (1:1; v/v) by slow evaporation.…”