Building large supramolecular nanocapsules with europium cations

Abstract

A new tripodal ligand has been designed by connecting pyridine-based coordination units to a rigid triptycene moiety. Its reaction with europium(III) provides three-dimensional tetranuclear edifices, whose structural and photophysical characteristics as well as host-guest interactions are discussed in this contribution.

Chiral transcription in self-assembled tetrahedral Eu4L6 chiral cages displaying sizable circularly polarized luminescence

“…The relative quantum yields ( ɸ rel ) of the supramolecular tetrahedral cages were found to be surprisingly high, ranging from 16(1) to 18(1)%. To the best of our knowledge, these values are the highest among the rarely reported ɸ rel from supramolecular tetrahedral cages that comprise of a similar pyridyldicarbonyl antenna 9 . All the excited state decays are similar amongst themselves ( τ =~1.6 ms) and to other supramolecular tetrahedron Eu compounds with a nine-coordinated geometry and a well-protected core 9 .…”

“…To the best of our knowledge, these values are the highest among the rarely reported ɸ rel from supramolecular tetrahedral cages that comprise of a similar pyridyldicarbonyl antenna 9 . All the excited state decays are similar amongst themselves ( τ =~1.6 ms) and to other supramolecular tetrahedron Eu compounds with a nine-coordinated geometry and a well-protected core 9 . The relatively long mono-exponential nature of the decays suggests the presence of a single non-polarized light emitting species in solution as well as efficient energy transfer for the europium complexes 40 .…”

Designing Artificial 3D Helicates: Unprecedented Self‐Assembly of Homo‐octanuclear Tetrapods with Europium

“…[11, 12] Recently,s everalt etranuclear tetrahedral complexes built with lanthanides have been investigated. [13][14][15] These polynuclear edifices may exhibit several functionalities such as selective host-guest interactions, [16,17] light emission in the NIR-visible region, energy transfer and conversion.I nt his context, as patial extension of the central tetrahedron in the direction of C 3 axes is ac hallenging task allowing the introduction of additional binding sites for metalliccations in order to obtain helicoidal homo-or hetero-octanuclear complexes with tetrahedral topology.T here are only few reports on octanuclear lanthanide-containing assemblies, [18] but any system exploits similar concept. Herein we report on an unprecedented strict selfassembly of an octanuclear helicate resulting from the reaction of an ew polydentate ligand L1 with europium(III).…”

Metal-Controlled Diastereoselective Self-Assembly and Circularly Polarized Luminescence of a Chiral Heptanuclear Europium Wheel

“…1, 2 In particular the circularly polarized luminescence (CPL) observed in chiral lanthanide complexes is of high current interest in biological probing and display technologies 1, 3-6 due to the attractive properties of lanthanide ions (large Stokes shift, long lifetimes, narrow emission bands, high quantum yields). 7 However, enantiopure lanthanide complexes are mostly limited to few examples of mononuclear compounds 1, 83, 94, 5, 10, 11 and dinuclear helicates 12-14 Although the supramolecular chemistry of lanthanide ions is less developed with respect to d-block metal ions, reports of lanthanide based polynuclear assemblies 15-20 which have pre-programmed new original structures 21-23 and of nanosized complexes that show fascinating optical, 24 and magnetic properties 25 are rapidly increasing. However, the high kinetic lability and lack of stereochemical preferences of lanthanide ions renders very difficult the control of their coordination sphere.…”