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Strong‐binding host–guest pairings in aqueous media have potential as "supramolecular glues" in biomedical techniques, complementing the widely‐used (strept)avidin‐biotin combination. We have previously found that squaraine dyes are bound very strongly by tetralactam macrocycles possessing anthracenyl units as cavity walls. Here we show that replacing the anthracenes with pentacyclic 5,7,12,14‐tetrahydro‐5,7,12,14‐tetraoxapentacene (TOP) units generates receptors which bind squaraines with increased affinities (around Ka=1010 m−1) and improved selectivities. Binding can be followed through changes to squaraine fluorescence and absorbance. The TOP units are easy to prepare and potentially variable, while the TOP‐based receptor shows improved photostability, both in itself and in complex with squaraines. The results suggest that this system could prove valuable in the further development of practical "synthavidin" chemistry. [ABSTRACT FROM AUTHOR]

A supramolecular three-component double-porphyrin tweezer (PT) is prepared by using heteroleptic complex formation along the HETTAP method. The higher stability of PT-(DABCO)(py) is the result of charge transfer from DABCO to the vacant [pi]* orbital of pyrazine across the porphyrin plane.

Strong-binding host-guest pairings in aqueous media have potential as "supramolecular glues" in biomedical techniques, complementing the widely-used (strept)avidin-biotin combination. We have previously found that squaraine dyes are bound very strongly by tetralactam macrocycles possessing anthracenyl units as cavity walls. Here we show that replacing the anthracenes with pentacyclic 5,7,12,14-tetrahydro-5,7,12,14-tetraoxapentacene (TOP) units generates receptors which bind squaraines with increased affinities (around K a =10 10  m -1 ) and improved selectivities. Binding can be followed through changes to squaraine fluorescence and absorbance. The TOP units are easy to prepare and potentially variable, while the TOP-based receptor shows improved photostability, both in itself and in complex with squaraines. The results suggest that this system could prove valuable in the further development of practical "synthavidin" chemistry., (© 2023 The Authors. Angewandte Chemie International Edition published by Wiley-VCH GmbH.)

We designed and synthesized a "hybrid" molecular container 1, which is structurally related to both cucurbit[n]uril (CB[n]) and pillar[n]arene type receptors. Receptor 1 was fully characterized by 1 H NMR, 13 C NMR, IR, MS and X-ray single crystal diffraction. The self-association behavior, host-guest recognition properties of 1, and the [salt] dependence of K a were investigated in detail by 1 H NMR and isothermal titration calorimetry (ITC). Optical transmittance and TEM measurements provide strong evidence that receptor 1 undergoes co-assemble with amphiphilic guest C10 in water to form supramolecular bilayer vesicles (diameter 25.6±2.7 nm, wall thickness ≈3.5 nm) that can encapsulate the hydrophilic anticancer drug doxorubicin (DOX) and the hydrophobic dye Nile red (NR). The release of encapsulated DOX or NR from the vesicles can be triggered by hexamethonium (8 c) or spermine (10) which leads to the disruption of the supramolecular vesicles., (© 2018 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Several five-component nanorotors ROT-3 that rotate at different rates were prepared by adding phenanthrolines of distinct lateral size as brake blocks to the four-component nanorotor ROT-2. The brake blocks interfere with the 180° rotor causing the rotational frequency to drop from 97 kHz to 5 kHz. The effect of the rotating brake blocks on the rotational frequency in ROT-3 is accurately predicted by a nanomechanical model called "conformational slippage". For quantification, the interaction of the brake blocks with the trajectory of the main rotator is gauged based on the number of interfering vs. non-interfering conformations as computed by PM6., (© 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)