The synthesis, characterization and crystallographic analysis is reported of a new Nickel Salphen complex and its radical copolymerization with n-butyl acrylate and methyl methacrylate to produce novel host macromolecules with tunable association against guest anions. Spectrophotometric titrations of the complex and of the polymers revealed that a supramolecular regulation of guest-binding accessibility was enabled by the number of Ni-Salphen units per chain. The latter content in turn, determined the chain size and molecular weight uniformity upon polymerization, and likely increased the strength in interchain/intrachain non-covalent interactions over the nickel center and the acrylic domains. The study also showed that incorporation of the monomer into the acrylic polymer backbone opened the possibility for the nickel binding site to gain access to host:guest stoichiometric discrimination, switching from 1 : 1 (major) and 1 : 2 (minor) both coexisting for the host when in the free form, to mostly 1 : 2 when in the polymerized version.

We describe the synthesis, crystallographic characterization of a new CuÀ Salphen compound and its use as a host Lewis-acid against guest anions in two versions: a) free molecule, b) copolymerized with methyl methacrylate:n-butyl acrylate (1 : 4wt.) as protective co-monomers. Higher contents in CuÀ Salphen yielded larger and more homogeneous polymer sizes. Polymer size together with glass transitions, heat capacity, thermal degradation, guest-saturation degrees and host-guest species distribution profiles from spectrophotometric titrations explained growths of up to 630-fold in K 11 and 180000-fold in K 12 for the host's binding site attributable to a solvophobic protection from the macromolecular structure. Spectrofluorimetry revealed blue-shifted × 13-16 larger luminescence for CuÀ Salphen in the polymers (λ em = 488-498 nm) than that of the non-polymerized counterpart (λ em = 510-543 nm) and "turnon" blue-shifted enhanced fluorescence upon guest association. We propose a cooperative incorporation of the guests occurring from the outer medium toward internally protected binding site pockets in the random coil polymer conformations.

Invited for this month's cover are Prof. Escµrcega-Bobadilla and Prof. Zelada-GuillØn, collaborators from the National Autonomous University of Mexico (UNAM). The cover picture shows the X-ray structure of a chartreuse fluorescent Salphen-Cu complex that upon copolymerization receives dielectric protection from the rest of the chain in solution. This enables cyan luminescence at higher intensity via anion-guest engulfment which renders dimmer-like turn-on emission. More information can be found in the Research Article by G. Zelada-GuillØn, M. V. Escµrcega-Bobadilla, and co-workers.

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In one word,h ow would you describe your research? Multidisciplinary.W ew ork in this way to tackle challenges either in basic science or in applied technology,w hich would be otherwise difficultt oa ddress from au nidisciplinary perspective. In this manner,w ea im to find new research avenues that could help in solving problems by using an approach based on supramolecular chemistry,self-assembly,nanoscience, and nanotechnology. Invited for this month'sc over are Prof.M artha Escµrcega-Bobadilla and Prof. Gustavo Zelada-GuillØn, collaborators from the National AutonomousU niversityo fM exico (UNAM). The cover picture shows the structure of ap olymerizable Ni-Salphen complex, determined by X-ray crystallography,w here the Ni center displays 1:1a nd 1:2h ost-guest stoichiometries toward anions, bothcoexisting in solution. Read the full text of the article at 10.1002/cplu.202000471.