A photoswitchable arylazopyrazole (AAP) derivative binds with cucurbit[8]uril (CB[8]) and methylviologen (MV2+) to form a 1:1:1 heteroternary host–guest complex with a binding constant of K a=2×103  m −1. The excellent photoswitching properties of AAP are preserved in the inclusion complex. Irradiation with light of a wavelength of 365 and 520 nm leads to quantitative E‐ to Z‐ isomerization and vice versa, respectively. Formation of the Z‐isomer leads to dissociation of the complex as evidenced using 1H NMR spectroscopy. AAP derivatives are then used to immobilize bioactive molecules and photorelease them on demand. When Arg‐Gly‐Asp‐AAP (AAP–RGD) peptides are attached to surface bound CB[8]/MV2+ complexes, cells adhere and can be released upon irradiation. The heteroternary host–guest system offers highly reversible binding properties due to efficient photoswitching and these properties are attractive for designing smart surfaces.

Single-chain polymer nanoparticles (SCNPs) are protein-inspired materials based on intramolecularly cross-linked polymer chains. We report here the development of SCNPs as uniquely sized nanocarriers that are capable of drug encapsulation independent of the polarity of the employed medium. Synthetic routes are presented for SCNP preparation in both organic and aqueous environments. Importantly, the SCNPs in organic media were successfully rendered water soluble, resulting in two complementary pathways toward water-soluble SCNPs with comparable resultant physicochemical characteristics. The solvatochromic dye Nile red was successfully encapsulated inside the SCNPs following both pathways, enabling probing of the SCNP interior. Moreover, the antibiotic rifampicin was encapsulated in organic medium, the loaded nanocarriers were rendered water soluble, and a controlled release of rifampicin was evidenced. The absence of discernible cytotoxic effects and promising cellular uptake behavior bode well for the application of SCNPs in controlled therapeutics delivery.

The stereoselective synthesis of ε-isomers of dimethyl esters of 1,3-diaminotruxillic acid in three steps is reported. The first step is the ortho-palladation of (Z)-2-aryl-4-aryliden-5(4H)-oxazolones 1 to give dinuclear complexes 2 with bridging carboxylates. The reaction occurs through regioselective activation of the ortho-CH bond of the 4-arylidene ring in carboxylic acids. The second step is the [2+2]-photocycloaddition of the CC exocyclic bonds of the oxazolone skeleton in 2 to afford the corresponding dinuclear ortho-palladated cyclobutanes 3. This key step was performed very efficiently by using LED light sources with different wavelengths (465, 525 or 625 nm) in flow microreactors. The final step involved the depalladation of 3 by hydrogenation in methanol to afford the ε-1,3-diaminotruxillic acid derivatives as single isomers.

Naturally occurring glycoconjugates possess carbohydrate moieties that fulfill essential roles in many biological functions. Through conjugation of carbohydrates to therapeutics or imaging agents, naturally occurring glycoconjugates are mimicked and efficient targeting or increased cellular uptake of glycoconjugated macromolecules is achieved. In this work, linear and cyclic glucose moieties were functionalized with methacrylates via enzymatic synthesis and used as building blocks for intramolecular cross-linked single-chain glycopolymer nanoparticles (glyco-SCNPs). A set of water-soluble sub-10 nm-sized glyco-SCNPs was prepared by thiol-Michael addition cross-linking in water. Bioactivity of various glucose-conjugated glycopolymers and glyco-SCNPs was evaluated in binding studies with the glucose-specific lectin Concanavalin A and by comparing their cellular uptake efficiency in HeLa cells. Cytotoxicity studies did not reveal discernible cytotoxic effects, making these SCNPs promising candidates for ligand-based targeted imaging and drug delivery.

The role of choline chloride in biomass delignification by a deep eutectic solvent (DES) containing lactic acid was investigated. In this study, the influence of choline chloride on pulping of Eucalyptus globulus chips was determined. Pulping experiments were performed at 120 °C for 8 h with a DES to wood ratio of 20:1. Various experiments were performed to study the influence of choline chloride on lignin solubility, cleaving reactions, and mass transfer in order to gain an understanding of the observed pulping results. It was found that the chloride anion is the active component of choline chloride. In fact, the inexpensive salt NaCl performed as well as choline chloride in that respect. Furthermore, choline chloride is already effective in a 1:250 M ratio to lactic acid. Studies on milled wood lignin show that choline chloride increases the cleavage rate of β-O-4 and thereby increases the delignification rate of biomass. Furthermore, choline chloride slightly decreased the solubility of lignin in DESs and due to an increase in viscosity decreased the estimated mass transfer coefficient. Overall, the delignification rate of Eucalyptus by lactic acid increased by the addition of halide salts.