Phosphorescent self-assembled PtII tetranuclear metallocycles

A series of rigid Pt(ii) diimine diacetylide complexes and their corresponding metallocyclic derivatives were synthesized through coordination-driven self-assembly. The photophysical properties of these complexes have been studied in detail, revealing exceptionally high RT phosphorescence quantum yields and lifetimes when the excited state becomes localized on the [small pi]-conjugated bridging-ligand following intramolecular charge-transfer sensitization

Electron-Rich Arene–Ruthenium Metalla-architectures Incorporating Tetrapyridyl–Tetrathiafulvene Donor Moieties

International audienceA series of arene ruthenium architectures have been prepared from coordination-driven self-assembly using dinuclear p-cymene ruthenium acceptors and π-donating tetratopic tetrapyridyl–tetrathiafulvalene donor ligands. The synthetic strategy, based on a geometric interaction approach, leads to four electroactive metalla-assemblies, 1–4 (one molecular cube and three metallaplates), that were characterized by NMR, ESI-MS, X-ray diffraction, and cyclic voltammetry. Rationalization of their formation discrepancy was completed by DFT calculations supported by structural features of their constituting TTF and Ru-complex components. Metalla-architectures possessing electron-rich cores (3, cis-4, and trans-4) interact strongly with picric acid (PA) to yield cocrystallized products, PA + metalla-assemblies, confirmed by single-crystal X-ray structure analyses

Self-assembled Containers based on Extended-Tetrathiafulvalene

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Self-assembled electron-rich receptors and guest release control

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Neutral versus polycationic coordination cages: a comparison regarding neutral guest inclusion

A neutral self-assembled container synthesized from a concave p-extended tetrathiafulvalene (exTTF) ligand and the cis-Pd(dctfb)2(cod) complex (dctfb = 3,5-dichloro-2,4,6-trifluorobenzene; cod = 1,5-cyclooctadiene) is described. This molecular host exhibits a good binding ability for fused polyaromatic substrates. The corresponding inclusion properties are compared with those of a previously described analogous octacationic cage, offering therefore the opportunity to address the effect of the cavity charge state over the binding of neutral molecules

Controlling the Host-Guest Interaction Mode through a Redox Stimulus

A proof-of-concept related to the redox-control of the binding/releasing process in a host-guest system is achieved by designing a neutral and robust Pt-based redox-active metallacage involving two extended-tetrathiafulvalene (exTTF) ligands. When neutral, the cage is able to bind a planar polyaromatic guest (coronene). Remarkably, the chemical or electrochemical oxidation of the host-guest complex leads to the reversible expulsion of the guest outside the cavity, which is assigned to a drastic change of the host-guest interaction mode, illustrating the key role of counteranions along the exchange process. The reversible process is supported by various experimental data (1 H NMR spectroscopy, ESI-FTICR, and spectroelectrochemistry) as well as by in-depth theoretical calculations performed at the density functional theory (DFT) level

Reversible Guest Uptake/Release by Redox-Controlled Assembly/Disassembly of a Coordination Cage

Controlling the guest expulsion process from a receptor is of critical importance in various fields. Several coordination-cages have been recently designed for this purpose, based on various types of stimuli to induce the guest release. Herein, we report the first example of a redox-triggered process from a coordination-cage. The latter integrates a cavity whose panels are based on the extended-tetrathiafulvalene unit. The unique combination of electronic and conformational features of this framework (i.e. high-p donating properties and drastic conformational changes upon oxidation) allows the reversible disassembling/reassembling of the redox-active cavity upon chemical oxidation/reduction respectively. This cage is able to bind the three-dimensional B12F122- anion in a 1:2 (host:guest) stoichiometry. The reversible redox-triggered disassembling of the cage could be also demonstrated in the case of the host-guest complex, offering a new option for guest delivering control

Controled Reversible Encapsulation within Redox-Responsive Self-Assembled Cages

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