Reactions applying amidation- or esterification-type processes and diazonium salts chemistry constitute the most commonly applied synthetic approaches for the modification of graphene-family materials. This work presents a critical assessment of the amidation and esterification methodologies reported in the recent literature, as well as a discussion of the reactions that apply diazonium salts. Common misunderstandings from the reported covalent functionalization methods are discussed, and a direct link between the reaction mechanisms and the basic principles of organic chemistry is taken into special consideration.
Carbon-based nanomaterials functionalized by cationic polymers are interesting starting materials for the development of nanotheranostic systems. In this study, polyethylenimine (PEI) and its pre-synthesized derivatives were conjugated to carbon-encapsulated iron nanoparticles (CEINs). Branched PEIs of various molecular weight were derivatized. The aim of the polymer modification was to introduce carboxylic functionality to the PEI structure. Two different synthetic pathways were proposed: the amide-type reaction with succinic acid anhydride and reductive amination using p-formylbenzoic acid. The polyethylenimine derivatives were analyzed by means of spectroscopic methods (NMR and FT-IR). In order to determine the ratio of primary, secondary and tertiary amine groups in the modified polymers, inverted-gate 13C NMR spectroscopy was applied. Next, CEINs modified with two different surface carboxylic linkers were functionalized using pristine PEI and its derivatives. The conjugation of the polymer to the surface-modified nanoparticles was carried out using the carbodiimide–amine type reaction. The success of the conjugation process was confirmed by thermogravimetry and infrared spectroscopy. The morphological details were analyzed using transmission electron microscopy, whilst the surface zeta potential and the average particle size were determined by dynamic light scattering. It was found that the molecular weight of the polymer and the type of the surface linker were the key factors which crucially influenced the functionalization yield and the physicochemical features of the synthesized nanoplatforms. The best dispersion stability in aqueous media and the smallest mean hydrodynamic particle size was found for CEINs with the longer carboxylic linker.
Sumanene is a buckybowl molecule that is continuously attracting the attention of the scientific community because of its unique geometrical and physicochemical properties. This Minireview systematically summarizes advances and considerations regarding the applied supramolecular chemistry of sumanene. This work highlights the major fields in which potential or real applications of sumanene molecule have been reported to date, such as the design of sumanene‐containing functional supramolecular materials and architectures, sumanene‐based drug‐delivery systems, or sumanene‐tethered ion‐selective molecular receptors. An assessment of the current status in the applied supramolecular chemistry of sumanene is provided, together with an emphasis on the key advances being made. Discussion on those milestones that are still to be achieved within this emerging field is also provided.
The first sumanene–ferrocene probes for efficient and selective caesium cation (Cs+) recognition are reported. The working mechanism of the sumanene moiety as the sensing unit was based on the site-selective cation–π interaction in its neutral state. The interactions with Cs+ were characterized by high association constant values together with low limits of detection.