Impact of Intermolecular Non‐Covalent Interactions in a CuI8PdII1 Discrete Assembly: Conformers’ Geometries and Stimuli‐Sensitive Luminescence Properties

• Published in: Chemistry : a European journal 2022-04, Vol.28 (24), p.n/a
• Main Authors: Moutier, Florent, Schiller, Jana, Lecourt, Constance, Khalil, Ali Moustafa, Delmas, Vincent, Calvez, Guillaume, Costuas, Karine, Lescop, Christophe
• Format: Article
• Language: English
• Subjects: Assembly; Chemical Sciences; Chemistry; Conformation; conformers; Coordination chemistry; Cristallography; Luminescence; Mathematical analysis; mechanochromism; New species; Optical properties; Phases; polymetallic Cu(I) ion complexes; Stability; Stimuli; TD DFT calculations; Thermal stress
• ISSN: 0947-6539; 1521-3765
• DOI: 10.1002/chem.202104497

A new highly solid‐state luminescent phase of a previously reported weakly luminescent CuI8PdII1 dicationic assembly is reported revealing the high geometrical versatility of this moiety that importantly alters its luminescent properties. This very minor new species Bc is based on a different conformer scaffold than the one encountered in the previously reported Bo form and, essentially differs from Bo by displaying shorter CuI‐CuI intermetallic distances. DFT calculations allow concluding that the predominance in the solid‐state of the weakly luminescent and less stable Bo phase is due to the extra stability induced by a larger number of intermolecular non‐covalent π‐CH interactions in its crystalline packing and not by the intrinsic stability of the CuI8PdII1 dicationic moiety. Calculations also revealed that a more stable conformation Bcalc is expected in vacuum, which bears a different distribution of CuI‐CuI intermetallic distances than the dications in Bo and Bc phases. Taking into account that the geometrical alterations are associated to drastic changes of luminescence properties, this confer to the CuI8PdII1 assembly high potentiality as stimuli‐sensitive luminescent materials. Indeed, by applying mechanical or thermal stress to samples of Bo phase, new phases Bg and Bm, respectively, were obtained. Alterations of the solid‐state photophysical properties of these new species compared to those recorded for Bo are reported together with a combined experimental and computed study of the structures/properties relationships observed in these phases. A combined experimental and computational study highlights the crucial role played by intermolecular non‐covalent weak‐interactions in the conformer selection, the solid‐state organization and the photophysical properties observed in a series of phases of a CuI8PdII2 multimetallic assembly. Rationalization of the structure/properties relationships allows understanding their mechanical and thermal stimuli‐sensitive responses.