Subphthalocyanine-Stoppered [2]Rotaxanes: Synthesis and Size/Energy Threshold of Slippage

Boronic ester-templated pre-rotaxanes as versatile intermediates for rotaxane endo-functionalisation

We report on the synthesis of [2]rotaxanes from vicinal diols through dynamic covalent boronic ester templates, as well as the use of the boronic ester for rotaxane post-functionalisation. A boronic acid pincer ligand with two alkene-appended arms was condensed with a linear diol-containing thread, and ring-closing metathesis established a pre-rotaxane architecture along with a non-entangled isomer. Advanced NMR spectroscopy and mass spectrometry unambiguously assigned the isomers and revealed that the pre-rotaxane was in equilibrium with its hydrolyzed free [2]rotaxane form. The boronic ester handle in the pre-rotaxane could be synthetically addressed in a multitude of ways to obtain different endo-functionalised [2]rotaxanes, including with direct oxidation reactions, protodeboronation, functional group interconversions and Pd-catalysed cross-couplings.

Preparation and Optical and Electrochemical Properties of Boron (III) Octafluorosubphthalocyanines with One Triselenole and One Diselenet Ring

Unsymmetric boron (III) subphthalocyanines with a triselenole ring or a diselenete ring and eight fluoro groups were prepared by the reaction of 5,6-dicyano-4,7-diethylbenzo-[1,2,3]triselenole and tetrafluorophthalonitrile with trichloroborane in xylene. The reaction was accompanied by a contraction of the triselenole ring to the diselenete ring. The substrate, dicyanobenzo[1,2,3]triselenole, was prepared by a new procedure via a photolytic demethylenation reaction of 3,7-diethyl[1,3]diselenolophthalonitrile using a 10 W white LED light. While triselenolosubphthalocyanine was treated by triphenylphosphine to give the diselenete derivative, the reaction of diselenetosubphthalocyanine with Woolion's reagent produced the expanded triselenole ring. The diselenete derivative reacted with tetrakis(triphenylphosphine)platinum to yield the corresponding platinum complex with Se-Pt bonds. Q-band absorption for the products appeared at around λmax=590 nm in the UV-vis spectrum and weak emission was observed at about λe=620 nm. When diselenetosubphthalocyanine was treated with pentachloro antimonate in dichloromethane or sodium metal in hexane/tetrahydrofuran, the solution showed strong ESR signals. The structures of model compounds were optimized using the DFT method with the Gaussian 09 program at the B3LYP/6-31G (d, p) level.

Curved Nanographenes as Stoppers in a [2]Rotaxane with Two-Photon Excited Emission

Heptagon-containing distorted nanographenes are used as stoppers for the capping of a [2]rotaxane through a Michael-type addition reaction to vinyl sulfone groups. These curved aromatics are bulky enough to prevent the disassembly of the rotaxane but also give emissive and nonlinear (two-photon absorption and emission) optical properties to the structure.

Recent advances in subphthalocyanines and related subporphyrinoids

Subporphyrinoids constitute a class of extremely versatile and attractive compounds. Herein, a comprehensive review of the most recent advances in the fundamentals and applications of these cone-shaped aromatic macrocycles is presented.

Using Slippage to Construct a Prototypical Molecular "Lock & Lock" Box

We report a new slippage system based on p-tert-butylbenzyl-terminated imidazolium ions and di(ethylene glycol)-containing macrocycles and their use as linking units for the construction of a prototypical molecular "Lock & Lock" box from a resorcinarene-based cavitand "bowl" and a porphyrin "cover". The multivalent structure with four slippage linkers provided the molecular box with high stability, yet the system dissociated into its two components upon application of suitable external stimuli.