Pressure Control of Cuprophilic Interactions in a Luminescent Mechanochromic Copper Cluster

Abstract

For the development of applications based on mechanochromic luminescent materials, a comprehensive study of the mechanism responsible for the emission changes is required. We report the study of a mechanochromic copper iodide cluster under hydrostatic pressure, which allows control of crystal packing via modification of the intermolecular interactions. In situ single-crystal powder X-ray diffraction analysis and emission measurements under pressure permit one to establish a direct correlation between the molecular structure and luminescence properties and, in particular, to demonstrate that cuprophilic interactions are responsible for the stimuli-responsive luminescence properties of such multinuclear coordination compounds.

Mechano‐ and Photochromism from Bulk to Nanoscale: Data Storage on Individual Self‐Assembled Ribbons

“…Despite the presence in the literature of reports showing mechanochromic behavior for Pt(II) and other complexes, quantitative information on the mechanical stresses involved in such structural and photophysical transformations is currently largely lacking. Quantitative information is available for piezochromic and tribochromic crystals of organic molecules .…”

Aggregation‐Induced Emission Properties of Copper Iodide Clusters

“…The mechanochromic properties of these compounds have been attributed to modifications of the cuprophilic interactions induced by the appliedm echanical stress. Indeed, as hortening of the CuÀCu bond lengths has been determined to be responsible for the observed changes of the [46] This intramolecular mechanism contrasts with that of organic compounds and mononuclear complexes for which changes to the luminescence properties generally involve modificationso ft he intermolecular interactions upon mechanical stimulation. The intramolecular structural flexibility of [Cu 4 I 4 L 4 ]c lusters is additionally illustrated by the crystalline polymorphismt hat can be observed for several members of this family.…”

Observation of Contrary Thermo-responsive Trend for Single Crystal and Powder Samples in Mechano-, Thermo- and Solvato-responsive Luminescent Cubane [Ag4I4L4] Cluster

“…Consequently, complex 1 displayed unusual mechanochromic properties with tunable relative emission intensities of LE and HE bands and blue-shifting in response to mechanical stimuli. In contrast, the mechanochromic luminescent cubane Cu 4 I 4 -cluster-based compounds, the emission bands in the grinding process usually shift to longer wavelength with the concomitant increasing of emission intensity, lifetime and internal luminescence quantum yield 13,36 . The Raman spectra of the ground and unground samples are almost the same and do not reveal a new signal, indicating the lack of apparent phase transition in the grinding process (Figure S2).…”