In this report we investigated two-dimensionally triptycene end-capped QPPs in terms of their solution and solid-state behavior.For this purpose,a triphenylene based ortho-diamine decorated with two triptycenyl units as well as a phenylene diamine with two non-annulated triptycene units have been synthesized.Sequences of condensation reactions with a pyrene-based tetraketone and ortho-diamines yielded a series of QPPs and UV/Vis investigations of the corresponding compounds led to the conclusion,that the QPPs form dimers in solution,which was further supported by MALDI-TIMS-TOF-MS.Single-crystal X-ray analysis of the triply and quadruply triptycene end-capped QPPs furthermore showed shortπ-π-distances of 3.3-3.4?and a perfect shape match during the dimerization of the triply triptycenyl end-capped QPP making it possible synthon for crystal engineering.
A break junction technique has been established to explore conductive behavior at the single molecular level,and recent interest has shifted toward the evaluation of bimolecular systems interacting through noncovalent intermolecular forces.This requires precise control over the orientation of the two molecules so that they can adapt an appropriate face-to-face arrangement between two electrodes.Herein,we present an approach using a tripodal triptycene scaffold that allows for accurate positioning of electroactive subunits with an upright configuration on substrate surfaces.We incorporated electron-donating tetrathiafulvalene or electron-accepting anthraquinone into the molecular scaffold and confirmed that the resulting molecules retain the electronic properties particular to their attached subunits.Self-assembled monolayers(SAMs)of these molecules were prepared on Au(111)and characterized by XPS and STM.STM break junction techniques were applied to the SAMs,revealing two electrical conduction regimes;one arises from single-molecules sandwiched between two electrodes,and the second from intermolecularly interacting homodimers that bridge between electrodes.This observation demonstrates the validity of the approach of using tripodal triptycene scaffolds to precisely direct electroactive subunits to undergo intermolecular pairing.We believe that the present work will provide a new avenue for evaluating the heterodimers at the single molecular level.
Colin J.MartinTomoya FukuiRyosuke TakeharaShintaro FujiiTakanori Fukushima
This work reports the investigation of a new triptycene-derived oxacalixarene(TDOC)as the stationary phase for gas chromatography(GC)with high-resolution performance for a wide range of analytes and isomers.The TDOC scaffold is composed of triptycene and 1,8-naphthyridine moieties,inherently differing from the conventional calixarenes in structures and properties.As a result,the TDOC column exhibited outstanding column efficiency of 5679 plates/m by n-dodecane at 120℃.It showed advantageous performance for separations of the mixtures with various analytes and achieved high resolution of diverse isomers(skeletal,positional and cis-/trans-isomers)from apolar to polar nature.Moreover,the TDOC column exhibited high thermal stability up to 310℃.To date,the TDOC-based materials have not been reported in chromatography.This work demonstrates the good potential of the triptycene-derived heterocalixarenes as a new class of stationary phases for chromatographic analyses.
Aggregate science has led to the existence of functional properties at the aggregate level that significantly differs from those of corresponding single-molecule species,leading to a number of novel conceptual materials with state-dependent functionality.For developing such materials,new molecular scaffolds that allow modulating the structural and functional properties of aggregates in a controlled manner could be extremely helpful.In this study,we report a class of spiro-fused bicyclo[3,2,2]octatriene triptycene derivatives with a unique 3 D molecular scaffolding structure that displays aggregation-induced emission(AIE)activity with bright solid-state blue luminescence.The core scaffold features a Y-shaped bicyclo[3,2,2]octatriene backbone and a vertical crossover arrangement of adjacent spiro-conjugated rings.Unlike classic bicyclo[2,2,2]octatrienes with high rigidity,this stereoscopic bicyclo[3,2,2]octatriene containing a seven-membered ring allows retaining certain flexibility in the molecular scaffold,which results in a weak fluorescence in dilute solutions(Φ_(F)<10%).However,the corresponding molecular aggregates emit intense fluorescence(Φ_(F)=50%-75%)and show prominent AIE activity because of the restriction of intramolecular scaffold motions.Moreover,in principle,these stereoscopic scaffold constructions with partially restricted flexibility facilitate the assembly of multiple different crystalline packing structures in both porous and nonporous forms depending on the growth conditions of crystalline aggregates.The obtained crystals with regular voids(12.85×6.89Aeach)show reversible luminescence in response to the adsorption/desorption of iodine vapor.These materials based on an unusual 3 D scaffold exhibit a high degree of structural modulation at the aggregate level and demonstrate potential applications in chemical sensing and flexible optoelectronics,which may open up the exploration of highly stereoscopic molecular building blocks for developing functional aggregates.
This work presents a novel strategy for engineering a GC stationary phase with high selectivity,inertness and thermal stability by introducing the 3Dπ-rich TP moieties to the terminals of a polar chain polymer.Herein,we provide the first example,i.e.,a new TP-terminated polycaprolactone polymer(TPP)as the stationary phase for GC analyses.As demonstrated,the TPP column achieved distinctly improved inertness to fatty acids and aldehydes,and dramatically enhanced thermal stability(about 100°C higher)over the PCL column.Also,the TPP column exhibited high resolving capability towards the positional isomers of phenols,anilines and alkylated/halobenzenes and showed good potential in detecting minor impurities in chemical products.Importantly,the proposed strategy is facile,feasible and generally applicable to analogous polymers.
