Carbazole Based Smaragdyrins: Synthesis, Aromaticity Switching, and Formation of a Spiro-Dimer.

Carbazole-incorporated smaragdyrin BF2-complex 3 was synthesized by SNAr reaction of 3,5-dibromo-8-mesityl-BODIPY 1 with 3,6-di(tert-butyl)-1,8-di(pyrrol-2-yl)carbazole 2 as a nucleophile. Demetalation of 3 with ZrCl4 gave the corresponding smaragdyrin free base 4 in a good yield. Oxidations of 3 and 4 with MnO2 gave smaragdyrins 5 and 6, respectively, both followed by aromaticity switching, since the oxidized products showed a moderate paratropic ring current owing to their 20π-electronic circuits. Further, treatment of 4 with [RhCl(CO)2]2 in the presence of NaOAc gave RhI complex 7, and oxidation of 3 with RuCl3 in the presence of triethylamine led to the formation of a spiro dimer product, 8.

Assembly and Applications of Macrocyclic-Confinement-Derived Supramolecular Organic Luminescent Emissions from Cucurbiturils.

Cucurbit[n]urils (Q[n]s or CB[n]s), as a classical of artificial organic macrocyclic hosts, were found to have excellent advantages in the fabricating of tunable and smart organic luminescent materials in aqueous media and the solid state with high emitting efficiency under the rigid pumpkin-shaped structure-derived macrocyclic-confinement effect in recent years. This review aims to give a systematically up-to-date overview of the Q[n]-based supramolecular organic luminescent emissions from the confined spaces triggered host-guest complexes, including the assembly fashions and the mechanisms of the macrocycle-based luminescent complexes, as well as their applications. Finally, challenges and outlook are provided. Since this class of Q[n]-based supramolecular organic luminescent emissions, which have essentially derived from the cavity-dependent confinement effect and the resulting assembly fashions, emerged only a few years ago, we hope this review will provide valuable information for the further development of macrocycle-based light-emitting materials and other related research fields.

Cucurbit[8]uril-Assisted Nucleophilic Reaction: A Unique Supramolecular Approach for Cyanide Detection and Removal from Aqueous Solution.

A unique supramolecular approach of preparing and using a cucurbit[8]uril (Q[8])-based dynamic host-guest assembly for cyanide sensing in and removal from water has been successfully developed. The dicyanovinyl-attached cationic guest (1) was designed as the fluorescent response moiety for the detection of the cyanide anion via a nucleophilic addition reaction in the assist of the Q[8]-based 2:2 quaternary complexes. Furthermore, the reaction of cyanide with 1 further switched the Q[8]-based host-guest assemblies from the 2:2 complexes to the 1:1 supramolecular polymers that precipitate in water. Thus, the macrocyclic-based dynamic host-guest assembly has potential use in applications for solving the problem of toxic anion pollutants present in aqueous environments.

Simultaneous Implementation of N-Heterocycle-Fused Bridge and Modified Pyrrole Unit on Ni(II) Porphyrin Dimers.

The oxidation of NiII-porphyrin dimer 10 with PbO2 or MnO2 resulted in the simultaneous implementation of an N-heterocycle-fused bridge and a modified pyrrole to give three unprecedented porphyrin dimers 11, 12, and 13. The reduction of 12 smoothly afforded 14. The structures of these dimers were all unambiguously confirmed by X-ray crystallographic analysis. These dimers show significantly red-shifted absorption bands and perturbed electrochemical properties with a decreasing HOMO-LUMO gap in the order of 14 > 13 > 11 > 12.