Submerging a Biomimetic Metallo‐Receptor in Water for Molecular Recognition: Micellar Incorporation or Water Solubilization? A Case Study

Abstract

Molecular recognition in water is an important topic, but ac hallenging task due to the very competitive nature of the medium. The focusofthis study is the comparison of two different strategies for the water solubilization of ab iomimetic metallo-receptor based on ap oly(imidazole) resorcinarene core. Thef irst relies on an ew synthetic path for the introduction of hydrophilic substituents on the receptor,a taremote distance from the coordination site. The second involves the incorporation of the organosoluble metallo-receptor into dodecylphosphocholine (DPC) micelles, which mimic the proteic surrounding of the active site of metallo-enzymes.T he resorcinarene ligand can be transferred into water through both strategies,i nw hich it binds Zn II over aw ide pH window.Q uite surprisingly,v ery similar metal ion affinities, pH responses, and recognition properties were observed with both strategies. The systems behavea s remarkable receptors for small organic anionsi nw ater at near-physiologicalp H. These results show that, provided the biomimetic site is well structured and presents ar ecognition pocket, the micellar environmenth as very little impacto n either metal ion binding or guest hosting.H ence, micellar incorporation represents an easy alternative to difficult synthetic work, even for the binding of charged species( metal cations or anions), which opens new perspectivesf or molecular recognition in water,w hether for sensing, transport, or catalysis.[a] Dr.Supporting information and the ORCID identification number(s) for the author(s) of this articlecan be found under: https://doi.

Halide Photoredox Chemistry

“…Some useful starting points for the design of such ligands exist in the field of anion sensing, ,,,,− but additional advances are needed, particularly in polar solvents. Cryptand ligands and supramolecular complexes that recognize and bind specific alkali metal cations are known, yet the corresponding chemistry for halides lags far behind. − Chromophores that bind specific halide ions and selectively reduce or oxidize them when illuminated with light could be envisioned to enable halide photoredox chemistry in contaminated water or in seawater.…”

Role of Comonomers in the Recognition of Anionic Biomolecules in Water: Hydrogen-Bonded Imprinted Polymeric Receptor

“…In general, the major difficulties encountered for molecular recognition in water originated from a very competitive nature of water medium to the electrostatic interactions and particularly for directional Hbonding. 33,34 We observed that the type of comonomer strongly influenced recognition behavior for a strongly hydrated anionic form of PPA in the rebinding solvent containing ≤50% H 2 O. Hence, MIPs prepared using the hydrophobic comonomer mAA (P2) displayed enhanced binding than those prepared using the hydrophilic comonomer HEMA (P1).…”

Impact of positive charge and ring-size on the interactions of calixarenes with DNA, RNA and nucleotides

“…[8][9][10] A major breakthrough in the development of fully biomimetic systems has been achieved recently with the optimized synthetic procedure for water-soluble structures, which are now readily available. [11][12][13] Permanently positively charged calix [4]arene 2 and calix [6]arene 4 (Scheme 1) studied within this report were among the first examples of our water soluble systems, at the time showing promising recognition of metal cations and primary amines in aqueous solution. 14,15 Previously published calixarene derivatives targeting DNA based their action on the substituents bearing multiple positive charges, which strongly interacted with a DNA negatively charged backbone, in several cases, strongly condensing plasmid-DNA into globular species followed by efficient DNAtransfection into the cells, 5,6 while dimeric derivatives did not cause DNA-condensation but were instead inserted into the DNA major groove.…”

“…8–10 A major breakthrough in the development of fully biomimetic systems has been achieved recently with the optimized synthetic procedure for water-soluble structures, which are now readily available. 11–13 Permanently positively charged calix[4]arene 2 and calix[6]arene 4 (Scheme 1) studied within this report were among the first examples of our water soluble systems, at the time showing promising recognition of metal cations and primary amines in aqueous solution. 14,15…”