Macrocycles inserted in graphene: from coordination chemistry on graphene to graphitic carbon oxide

Abstract

Tuning electronic structures and properties through chemical modifications has become the focus of recent research on graphene. The adsorption of metal atoms on graphene showed strong potential but is limited due to weak binding. On the other hand, macrocyclic molecules are well known for their strong and selective binding with metal atoms in solutions through coordination bonds. The alliance of the two substances will largely benefit the two parallel fields: it will provide a scaffold for coordination chemistry as well as a controllable method for tuning the electronic structure of graphene through strong binding with metals. Here, using crown ether as an example, we demonstrate that the embedment of macrocyclic molecules into the graphene honeycomb lattice can be very thermochemically favored. The combination also leads to a family of new materials that has potential in many areas including photolysis and two-dimensional superconductivity.

Dense arrangement of crown ethers in graphene: novel graphitic carbon oxides with enhanced optoelectronic properties

“…Previous studies have demonstrated that these four types of crown ethers can effectively match the geometric structure of graphene and be seamlessly embedded within it. 34,35 This embedding not only significantly alters the electronic properties of graphene but also imparts to graphene the capability of selectively adsorbing metal ions. 34,35 It is worth noting that these four types of crown ether nanopores have been successfully synthesized within the graphene lattice.…”

“…30,31 Crown ether, 32 cyclic polyethers with the chemical formula of (CH 2 CH 2 O) n , can be embedded into the graphene lattice, taking advantage of the hexagonal symmetry of graphene. [33][34][35] The incorporation of crown ethers into the graphene lattice leads to the formation of nanopores with cyclic edges composed of ether groups COC. This will disrupt the p-conjugated structure of graphene, resulting in a significant alteration in its electronic properties.…”

Structural and computational investigation of an imine-based propeller-shaped macrocyclic cage

“…Numerous energy harnessing molecules are macrocyclic in nature, like chlorophyll made of porphyrins [14]. Recently, graphene has been proposed to have superconductivity [15] and is believed to be useful for water splitting applications if a macrocyclic architecture is suitably incorporated [16]. Hence, structural analysis of macrocyclic cages becomes important to design above mentioned useful frameworks.…”

Dehydration induced selective ion trapping by topology constrained atomically thin graphene-crown membranes

“…This membrane contains 4-aminobenzo-12-crown-4 (AB12C4) externally grafted to graphene oxide. As the hexagonal symmetry of graphene lattice naturally loans the possibility of embedding various types of crown-like pores within the graphene layer, 38 many parallel studies 31,35,39–41 have been focused on grafting various crown ethers within the lattice itself. Such structures can be geometrically identified as a result of removing a whole carbon hexagonal ring from graphene lattice and then replacing the continuing edge carbon atoms with the oxygen atoms.…”

“…The point to be noted here is that there is a possibility that properties of crown ether molecules will be modified during their introduction into graphene lattice due to different hybridization of carbon atoms of crown ether ring in both cases. 38,39 Importantly, the recent studies of Guo et al 39 demonstrated that the binding strength of alkali metal ions to the crown ether cavity can be increased by ∼14 times if the crown ether molecule is embedded into a hydrogenated graphene lattice. Though great promises have been made from these DFT studies, nevertheless, all these studies have been conducted in the absence of an aqueous solution.…”