Metal Complexes of Amphoteric Cryogels Based on Allylamine and Methacrylic Acid

Abstract

A series of macroporous amphoteric cryogels based on allylamine, methacrylic acid and acrylamide were synthesized by radical copolymerization of monomers in cryoconditions. The average molar composition of amphoteric cryogels was found from the potentiometric and conductimetric titration curves. The morphology of cryogels was evaluated by SEM. Cryogels are highly elastic and have continuous macroporous structure with 50-200 mm pores. The values of the isoelectric pH determined from the swelling experiments arranged between 3.5 and 4.3. Complexation of amphoteric with transition metal ions was studied. Cryogels with adsorbed copper, nickel, or cobalt ions have an intense colour due to formation of coordination and ionic bonds between metal ions and amine and/or carboxylic groups of cryogels. Metal ions entrapped within the pores of cryogels were reduced by treating aqueous solution of NaBH 4 . Formation of micron sized metals on the inner surface of cryogels was observed by SEM.

Metallodendrimers in three oxidation states with electronically interacting metals and stabilization of size-selected gold nanoparticles

“…Mixed-valent complexes that are indicators of electronic communication between neighbouring redox sites 35 are useful tools and models of electronic communication in nanomaterials 36 . The neutral Fe II metallodendrimers 3, 4, 5B and 6B have been oxidized in dichloromethane (DCM) to the deep-blue fully oxidized (Fe III Fe III ) metallodendrimers 3(PF 6 ) 6 , 4(PF 6 ) 12 , 5B(PF 6 ) 18 , 6B(PF 6 ) 54 using one equiv. ferricinium hexafluorophosphate (FcH þ PF 6 À ) per Fe centre.…”

“…Although biferrocene-and silicon-bridged biferrocene-terminated dendrimers are known 5,[14][15][16] , no dendrimers have yet been isolated in several oxidation states owing to instability of the oddelectron species. The flexibility of oxidation-state variation with the maintenance of stability for a large collection of metal centres located at the metallodendrimer periphery is highly desirable, however, because it would allow the design of nanodevices towards applications in molecular nanoelectronics including nanobatteries 17 and polyelectrolytes 18 .…”

Flow–Through Catalytic Rector Based on Macroporous Amphoteric Cryogels and Gold Nanoparticles

“…The reduction of substrates is easily monitored by measuring the decrease in the peak of absorption maxima at 414 nm, 400 nm and 380 nm for 2‐NP, 4‐NP and 4‐NA, respectively. The idea of application of amphoteric macroporous cryogels with immobilized nanoparticles of metals as flowing reactors in catalysis was outlined for the first time in our previous publications . In the present communication we report for the first time the preparation of gold nanoparticles (AuNPs) within macroporous amphoteric cryogels based on N,N‐dimethylaminoethylmethacrylate and methacrylic acid p(DMAEM‐co‐MAA) and evaluation of the catalytic activity of AuNPs immobilized within cryogel matrix in reduction of 4‐nitrophenol.…”

“…Cryogel catalysts could be promising due to the inherent features of these materials: macroporous structures, adjustable hydrophilicity and hydrophobicity, and flexible choice and combination of catalytic groups. Supporting of noble and transition metal ions in bulk of amphoteric macrogels followed by reduction to zero‐valent state will open new perspectives for development of effective catalytic systems for decomposition, isomerization, hydrogenation, and oxidation of various organic substrates . In this context design of monolithic support with microporous structure that can provide both nanoparticle loading and liquid flux is challenging task.…”

Complexation of macroporous amphoteric cryogels based on N,N‐dimethylaminoethyl methacrylate and methacrylic acid with dyes, surfactant, and protein

“…In spite of advances in studying of nonionic, anionic and cationic nanogel, microgel, and macrogel to our knowledge there is very limited information on macroporous amphoteric gels themselves and their complexation with various low‐ and high‐molecular weight compounds.…”