An Fe3O4@SiO2/Schiff base/Pd complex as an efficient, heterogeneous magnetically recoverable and reusable catalyst for the N-arylation of O-alkyl primary carbamates.

Synthetic receptors to recognize biological glycans are in great need for modern glycoscience and technology, but their design and synthesis have been a daunting challenge due to strong solvation of carbohydrates in water and structural complexity of the guest. Molecular imprinting in surfactant micelles with amide cross-linkers provides a convenient one-pot method to prepare nanoparticle receptors for glycosides, glycans, and glycoproteins, taking advantage of hydrogen-bonding interactions near the surfactant/water interface. Biologically competitive micromolar binding affinities were obtained in water and subtle structural differences of glycans could be distinguished.

Protein receptors bind their peptide ligands by a combination of hydrophobic and hydrogen-bonding interactions to achieve high affinity and selectivity. Construction of synthetic receptors for peptides by the same principle, however, is challenging because of the complexity of the guest molecules and subtle structural differences among closely related sequences. Molecular imprinting of peptides in surface− core doubly-cross-linked micelles yielded hydrophobic pockets complementary to the hydrophobic side chains of peptides. Amide-functionalized bis(acrylamide) cross-linkers such as N,N′-methylenebis(acrylamide) (MBAm) used in the core cross-linking installed a layer of hydrogen bonds at the surfactant/water interface and was found to enhance the molecular recognition of peptides in water, particularly hydrophilic ones rich in polar residues. An extremely strong imprinting effect was obtained, with the imprinted/nonimprinted ratio ranging from 3000 to 10000 for model tripeptides. These hydrogen bonds allowed distinction of closely related peptide sequences and enabled a general, simple, one-pot preparation of highly selective receptors for binding complex hydrophilic peptides with <200 nM affinity in aqueous buffer.

A convenient and efficient selective mono N-arylation of primary O-alkyl thiocarbamates and carbamates is reported by a recyclable magnetic Cu(ii) nanocatalyst.