Tuning underwater adhesion with cation–π interactions

Abstract

In this Article we described a ruthenium-catalysed carbonyl addition method for alcohol production via simple unsubstituted hydra-zone intermediates, but we inadvertently omitted the citation of two papers that had previously reported a similar carbanion reactivity 1,2. In these papers, the authors illustrated a series of substituted hindered hydrazones (for example, tert-butyl-, trityl-and diphenyl-4-pyri-dylmethyl) for additions to carbonyl compounds; however, to yield the target alcohols under these circumstances, the lithium salts of these hydrazones had to be pre-formed, with subsequent CC bond formation and removal of bulky substituents on azo-intermediates via radical decomposition. References 1. Baldwin, J. E. et al. Azo anions in synthesis: use of trityl-and diphenyl-4-pyridylmethylhydrazones for reductive C−C bond formation. Tetrahedron 42, 4235−4246 (1986). 2. Baldwin, J. E., Bottaro, J. C., Kolhe, J. N. & Adlington, R. M. Azo anions in synthesis. Use of trityl-and diphenyl-4-pyridylmethyl-hydrazones for reductive CC bond formation from aldehydes and ketones. J. Chem. Soc. Chem. Commun. 22−23 (1984). Addendum: Aldehydes as alkyl carbanion equivalents for additions to carbonyl compounds © 2 0 1 7 M a c m i l l a n P u b l i s h e r s L i m i t e d , p a r t o f S p r i n g e r N a t u r e. A l l r i g h t s r e s e r v e d .

RNA-Seq reveals a central role for lectin, C1q and von Willebrand factor A domains in the defensive glue of a terrestrial slug

“…Aromatic side chains are ubiquitous in the carbohydrate binding modules of glycoside hydrolases, where they play a primary role in determining specificity and affinity (Boraston et al 2004). In many cases it is the hydrophobicity of aromatic side chains that is essential (Boraston et al 2004), but aromatic side chains can also serve as good cross-linking sites because the electron-rich pi orbitals interact well with positively charged side chains, creating unusually high binding energies for non-covalent interactions (Dougherty 2007; Gebbie et al 2017). Such cation pi interactions may play an important role in the cohesive strength of the mussel byssus (Gebbie et al 2017).…”

“…In many cases it is the hydrophobicity of aromatic side chains that is essential (Boraston et al 2004), but aromatic side chains can also serve as good cross-linking sites because the electron-rich pi orbitals interact well with positively charged side chains, creating unusually high binding energies for non-covalent interactions (Dougherty 2007; Gebbie et al 2017). Such cation pi interactions may play an important role in the cohesive strength of the mussel byssus (Gebbie et al 2017). It is particularly noteworthy that the position of the aromatic residues was strongly conserved in the C-lectins and C1q-containing proteins.…”

Phase transitions as intermediate steps in the formation of molecularly engineered protein fibers

“…The role of coacervates formed by liquid–liquid phase separation has been intensively studied, especially in the field of understanding the function of underwater adhesives by marine organisms 17,18 . In studies based on mussel and sandcastle worm adhesives, it was found that the coacervation step preassembles the protein constituents of the adhesives, which in combination with the low surface energy and cohesiveness results in a very efficient function 19–22 . The role of coacervates in the formation of biological materials such as squid beak has also been described, in which again the preassembled state of proteins and low surface energy of the coacervate leads to efficient infiltration of a scaffold and subsequently to the formation of mechanically excellent structures 12,13 .…”

Metal Coordination‐Mediated Functional Grading and Self‐Healing in Mussel Byssus Cuticle

“…It was reported that the cuticle showed twofold decrease in hardness after removing metals from it. [3,11] To design a promising artificial surface coatings with high stiffness, extensibility, and self-healing capability, it is important to understand the molecular strengthening and self-healing mechanisms in mussel cuticles. [9] However, the detailed enhancing and self-healing mechanisms of the iron are still unclear due to the lack of insights into the reactions at the molecular level.…”