Excitation wavelength-dependent multi-coloured and white-light emissive pyrene-based hydrazones: suppression of Kasha's rule.

Multi-coloured and white-light emissions from pyrene-based hydrazones are described. They exhibit excitation wavelength-dependent emissions in solution due to the suppression of Kasha's rule. Interestingly, in dimethylformamide, 1-3 emit light that covers all the regions of primary colours as a function of excitation wavelength, and 1 and 2 emit white light (λex = 420 nm) in isopropanol.

Carbohydrate recognition using metal-ligand assemblies.

Carbohydrate-binding proteins, known as lectins, play a wide range of vital roles in cellular and pathological processes. Mimicking lectins to achieve specific molecular recognition of carbohydrates in organic and aqueous media using artificial receptors is challenging due to the synthetic hurdles of receptors and structural similarities between sugars. Carbohydrate recognition using non-covalent interactions remains a vast topic. This review summarises the recognition of carbohydrates using metal-ligand assemblies, including metallosupramolecules, macrocycles, and cages. It also highlights the challenges and future directions in the field.

Selection of a suitable ZIF-8/ionic liquid (IL) based composite for selective CO2 capture: the role of anions at the interface.

The effective capture of CO2 from the atmosphere is much needed to reduce its environmental impact. The design and development of CO2 capturing materials is getting much attention. A zeolitic imidazolate framework (ZIF) can replace many of the conventional materials in gas separation due to its stability and high performance. Here, we analyzed the effect of encapsulation of ionic liquids (ILs) into the pores of ZIF-8 for selective CO2 capture and separation. The [BMIM]+ cation with a series of anions was selected to study suitable carbon capture materials using density functional theory (DFT) approaches. Our calculations suggest that the nitrogen containing anions are not well adsorbed on the ZIF-8 surface but their gas separation performance is not affected by these interfacial interactions. This is confirmed from the CO2/N2 and CO2/CH4 selectivity of these composites, calculated using grand canonical Monte Carlo (GCMC) simulations. A suitable force field for the composites was identified by comparing the available force fields with the experiments. The IL@ZIF-8 composite shows better CO2 selectivity compared to pristine ZIF-8. Fluorinated hydrophobic anions (such as [BF4]-, [PF6]- and [Tf2N]-) in the composites show better CO2 adsorption and significant CO2 selectivity than pristine ZIF-8, especially at low pressure. The nature of the anion plays an important role in CO2 separation, rather than its stability at the pores of ZIF-8. Close scrutiny of the results reveal that the CO2 selectivity of these composite materials depends on the anion of the IL and thus through the selection of a suitable anion we can significantly enhance the CO2 selectivity for different flue gas mixtures. Our molecular level design shows that the selection of suitable anions in IL based composites is very important in identifying potential carbon capture materials for industrial applications.