Doubling the Carbonate-Binding Capacity of Nanojars by the Formation of Expanded Nanojars

Abstract

Anion binding and extraction from solutions is currently a dynamic research topic in the field of supramolecular chemistry. A particularly challenging task is the extraction of anions with large hydration energies, such as the carbonate ion. Carbonate-binding complexes are also receiving increased interest due to their relevance to atmospheric CO2 fixation. Nanojars are a class of self-assembled, supramolecular coordination complexes that have been shown to bind highly hydrophilic anions and to extract even the most hydrophilic ones, including carbonate, from water into aliphatic solvents. Here we present an expanded nanojar that is able to bind two carbonate ions, thus doubling the previously reported carbonate-binding capacity of nanojars. The new nanojar is characterized by detailed single-crystal X-ray crystallographic studies in the solid state and electrospray ionization mass spectrometric (including tandem MS/MS) studies in solution.

Revealing the Hidden Costs of Organization in Host–Guest Chemistry Using Chloride-Binding Foldamers and Their Solvent Dependence

“…Supramolecular chemistry seeks to understand the rules that govern the binding of guests to hosts. Codification of this knowledge has the potential to be used in tailoring receptors for various applications, such as extraction of pollutants from water, − ion regulation in batteries, − and analyte sensing in water. − Establishment of the rules has benefitted immensely from the creativity and design of diverse synthetic receptors . There is now a growing interest in directed approaches to design receptors, e.g., screening and selection using dynamic combinatorial chemistry − or using de novo receptor design advanced with computational chemistry. − This last approach relies on the use of quantitative relationships that need to be derived from the qualitative rules of host–guest chemistry.…”

Supramolecular Incarceration and Extraction of Tetrafluoroberyllate from Water by Nanojars

“…Nanojars, supramolecular coordination complexes of the formula [anion⊂{ cis -Cu II (μ-OH)­(μ-pz)} n ] 2– [Cu n ; n = 26–36; pz = pyrazolate (C 3 H 3 N 2 – )], have been successfully used for the binding of oxoanions with large hydration energy such as CO 3 2– , − SO 4 2– , − SeO 3 2– , HPO 3 2– , HPO 4 2– , and HAsO 4 2– . Herein, we demonstrate that nanojars are excellent supramolecular binding agents not only for oxoanions but also for the fluoroanion BeF 4 2– , which was extracted from water and transferred into organic solvents (including aliphatic hydrocarbons) by liquid–liquid extraction.…”

Adaptive coordination assemblies based on a flexible tetraazacyclododecane ligand for promoting carbon dioxide fixation

“…4B(e) and (f)). Although many coordination hosts that can fix CO 2 by binding with carbonate have been reported, 95–102 the newly formed strong metal–oxygen interactions make these hosts unable to be reused. Thus, tube 1-Zn represents a rare coordination host that can catalyze CO 2 conversion like carbonic anhydrase.…”

“…Further experiments showed that after removal of CO 3 2encapsulated by cavity, the tube 1-Zn can be regenerated and reused (Figure 4B e-f). Although many coordination hosts that can fix CO 2 by binding with carbonate have been reported, [95][96][97][98][99][100][101][102] the new-formed strong metal-oxygen interactions make these hosts cannot be reused. Thus, tube 1-Zn represents a rare coordination host that can catalyze CO 2 conversion like carbonic anhydrase.…”

“…9–13 Coordination-directed self-assembly has been proven to be an effective approach toward the predictable construction of multicomponent artificial hosts, 14–77 where enhanced guest reactivity, 73,74,78–87 stabilization of metastable species, 88–90 and unusual reaction pathways 78,91–94 have been realized. While atmospheric CO 2 sequestration by selective binding of carbonate with coordination hosts has already been reported, 95–102 adaptive coordination hosts that contain multiple active metal sites and can reversibly encapsulate and release the carbonate are still rare.…”