Elena Cariati

TT-2Py reacts with CuI to give orange emissive ( 1 ), green ( 2 ), yellow ( 3 ) and non-emissive ( 4 ) where TT-2Py is coordinated as mono-, bi- or tridentate with emissions of molecular or supramolecular origin.

1,2-Dichloroethane was found to stabilize the lattice of chloride anions associated with the protonated porphyrin of formula [C₄₄H₃₂N₄]Cl₂·4C₂H₄Cl₂. The synthesis and X-ray characterization of this compound are reported and compared with analogous solvates. The porphyrin macrocycle displays a distorted saddle conformation, with chloride anions positioned above and below the mean plane of the ring, further surrounded by two dichloroethane molecules that stabilize the crystal packing. The Second-Harmonic Generation response was evaluated using the Kurtz–Perry powder technique with a ND:YAG laser (1064 nm).

1,2-Dichloroethane was found to stabilize the lattice of chloride anions associated with the protonated porphyrin of formula [C₄₄H₃₂N₄]Cl₂ 4C₂H₄Cl₂. The synthesis and X-ray characterization of this compound are reported and compared with analogous solvates. The porphyrin macrocycle displays a distorted saddle conformation, with chloride anions positioned above and below the mean plane of the ring, further surrounded by two dichloroethane molecules that stabilize the crystal packing. Second Harmonic Generation response was evaluated using the Kurtz−Perry powder technique with a ND:YAG laser (1064 nm).

Cyclic triimidazoles endowed with one or three benzaldehyde substituent(s) display in their crystalline state only long-lived features of molecular and aggregate (CO–π and π–π) origin.

Excitation dependent, multiemissive single component organic materials are receiving evergrowing attention for various applications. In this regard, intermolecular interactions have revealed efficaceous in positively affecting photoluminescent features. Here, the photophysical properties of TT-2PyH⁺ NO₃ ^- characterized by fluorescence and dual phosphorescence with ultralong contribution, are interpreted through DFT-TDDFT calculations and crystal structure analysis. The compound's locked molecular conformation through intramolecular hydrogen bond is at the basis of suppression of the low energy fluorescence displayed by its parent neutral derivative. On the other side, π-π interactions are deemed responsible for the ultralong RTP features and the highly dense network of intermolecular hydrogen bonds provides a rigid molecular environment which efficiently restrict the non-radiative deactivation channels of triplet excitons.

Recently developed luminescent neutral 0D mono-, di-, tri- and tetranuclear Cu( i ) complexes with N-donor ligands are gathered and analyzed with a focus on their synthesis, luminescent behavior and responsiveness to external stimuli.

Cyclic triimidazole, TT, is an emerging scaffold to prepare multiemissive organic and coordination systems to be exploited in various fields. TTs with dual emission, RTP from aqueous aggregates, mechanochromism and vapochromism are discussed here.

Materials based on small molecules characterized by multi‐component short and long‐lived emissive behaviour are extremely desirable for various applications. The derivative of cyclic triimidazole (TT) functionalized with a carboxylic group, namely TT‐COOH, is isolated, investigated and used as coordinative ligand to obtain a series of isomorphous mononuclear complexes of general formula [M(TT‐COO)₂(H₂O)₂] (M=Mn(II), Co(II), Ni(II), Cu(II), Zn(II) and Cd(II)). Crystals of TT‐COOH display aggregation induced enhanced emission (AIEE) comprising dual fluorescence and dual phosphorescence of molecular origin together with an aggregation induced long lived, low energy phosphorescence. Emissive features are retained in crystals of the Zn(II) and Cd(II) complexes, where the metal plays the role of an external heavy atom perturber, but strongly quenched in the others. The mechanisms involved in the photophysics of TT‐COOH and its metal complexes have been disclosed thanks to combined structural, spectroscopic and computational investigations which reveal the presence of anti‐Kasha emissions.