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Stimuli-responsive catalysts with exceptional kinetics and complete recoverability for efficient recyclability are essential in, for example, converting pollutants and hazardous organic compounds into less harmful chemicals. Here, we used a novel approach to stabilize silver nanoparticles (NPs) through magneto/hydro-responsive anionic polymer brushes that consist of poly (acrylic acid) (PAA) moieties at the amine functional groups of chitosan. Two types of responsive catalyst systems with variable silver loading (wt.%) of high and low (PAAgCHI/Fe3O4/Ag (H, L)) were prepared. The catalytic activity was evaluated by monitoring the reduction of organic dye compounds, 4-nitrophenol and methyl orange in the presence of NaBH4. The high dispersity and hydrophilic nature of the catalyst provided exceptional kinetics for dye reduction that surpassed previously reported nanocatalysts for organic dye reduction. Dynamic light scattering (DLS) measurements were carried out to study the colloidal stability of the nanocatalysts. The hybrid materials not only showed enhanced colloidal stability due to electrostatic repulsion among adjacent polymer brushes but also offered more rapid kinetics when compared with as-prepared Ag nanoparticles (AgNPs), which results from super-hydrophilicity and easy accumulation/diffusion of dye species within polymer brushes. Such remarkable kinetics, biodegradability, biocompatibility, low cost and facile magnetic recoverability of the Ag nanocatalysts reported here contribute to their ranking among the top catalyst systems reported in the literature. It was observed that the apparent catalytic rate constant for the reduction of methyl orange dye was enhanced, PAAgCHI/Fe3O4/Ag (H) ca. 35-fold and PAAgCHI/Fe3O4/Ag (L) ca. 23-fold, when compared against the as prepared AgNPs. Finally, the regeneration and recyclability of the nanocatalyst systems were studied over 15 consecutive cycles. It was demonstrated that the nanomaterials display excellent recyclability without a notable loss in catalytic activity. [ABSTRACT FROM AUTHOR]

Tröger's base analogs (TBAs) and their derivatives are versatile, Λ-shaped, tetracyclic chiral building blocks utilized in numerous fields of research. Although various methods for the enantiopurification of TBAs have been demonstrated in the literature, none has achieved it with the use of metal–organic frameworks (MOFs). This investigation introduces a convenient and scalable method to obtain enantiopure TBAs with the formation and digestion of a chiral MOF composed of fully recoverable and non-hazardous starting materials, namely, cyclodextrin-based metal–organic framework (CD-MOF). [ABSTRACT FROM AUTHOR]

In this study, six sol‐gel copper/magnesium substituted derivatives of 58S‐BG, that is, a mol% series of 60SiO2–4P2O5–5CuO–(31–x) CaO/xMgO (where x = 0, 1, 3, 5, 8, and 10), were synthesized as new multifunctional bioactive glasses (BGs). Afterwards, the effect of MgO/CaO substitution on the in vitro formation of nanohydroxyapatite (HA), osteoblast‐like cell responses, and bioactive glasses antibacterial performance were studied. X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and scanning electron microscopy (SEM) results revealed that Cu‐substituted 58S‐BG consisting of 5 mol% MgO (BG‐5/5) had capability of the formation of HA on its surface while, Cu‐substituted 58S‐BGs consisting 8 mol% and 10 mol% MgO (BG‐5/8 and BG‐5/10) displayed lower bioactivity. The In vitro investigations proved that the highest values of both differentiation and proliferation of MC3T3‐E1 cells can be obtained from a 5 mol% MgO substituted BG. Furthermore, these novel Cu/Mg‐substituted 58S‐BGs displayed antibacterial effect against methicillin‐resistant staphylococcus aureus bacteria. Taken together, the results suggest the equally substituted BG‐5/5 (ie., the one consists of 5 mol% of both CuO and MgO) as a promising candidate for bone tissue engineering, among all newly designed BGs in this work, owing to its desirable cell proliferation, ALP activity, and antibacterial properties. [ABSTRACT FROM AUTHOR]

The production of azo derivatives of a di-amino analogue of Tröger’s base (Hünlich base), by employing the standard procedures of diazotization, azo-coupling and Williamson etherification is described here. These versatile molecules possess a Λ-shaped core, photoswitchable groups and some carry two modifiable extremities to enable further synthesis or molecular assembly. The synthesis is straightforward and requires inexpensive starting materials, which facilitates their application to different fields of research such as light-driven molecular machine design. [ABSTRACT FROM AUTHOR]

The production of azo derivatives of a di-amino analogue of Tröger's base (Hünlich base), by employing the standard procedures of diazotization, azo-coupling and Williamson etherification is described here. These versatile molecules possess a Λ-shaped core, photoswitchable groups and some carry two modifiable extremities to enable further synthesis or molecular assembly. The synthesis is straightforward and requires inexpensive starting materials, which facilitates their application to different fields of research such as light-driven molecular machine design. [ABSTRACT FROM AUTHOR]