Triboluminescence of a new family of CuI-NHC complexes in crystalline solid and in amorphous polymer films

Chromic triboluminescence of self-assembled platinum(II) complexes

A series of Pt(II) complexes bearing N-heterocyclic carbenes, [Pt(CN)₂(Rim-Mepy)] (Rim-MepyH⁺ = 3-alkyl-1-(4-methyl-(2-pyridinyl))-1H-imidazolium, R = Me, Et, ⁱPr, or ^tBu), exhibits triboluminescence in the visible range from blue to red, as well as the corresponding intense photoluminescence. Remarkably, among the complexes, the ⁱPr-substituted one exhibits chromic triboluminescence behaviour during the process of rubbing and also vapour exposure.

Emission and Luminescent Vapochromism Control of Octahedral Cu4 I4 Complexes by Conformationally Restricted P,N Ligands

A conformationally restricted P,N-ligand capable of the design of polynuclear copper(I) complexes was synthesized via the reaction of primary pyridylphosphine, paraformaldehyde, and benzhydrylamine. The reaction of the ligand with copper(I) iodide leads to the tetranuclear copper(I) complex with the octahedral type of copper-iodide core. Different orientation of coordination bonds of the ligands relative to the P,N₂ -heterocyclic fragments and to the Cu₄ I₄ cores leads to the existence of two types of conformers of the complex with "compact" or "stretched" geometry of the Cu₄ I₄ cluster. This lability of the complex allowed for obtaining two crystalline phases displaying green or red luminescence. The TDDFT computations along with XRD structural analysis gave a strong interpretation of the green emission belonging to the "compact" form of the complex and belonging of the red emission to the "stretched" form. Moreover, both crystalline phases demonstrate the strong vapochromic responses of luminescence on the vapors of wide range of solvents.

Ethylene binding in mono- and binuclear CuI complexes with tetradentate pyridinophane ligands

Herein we report a series of Cu^I complexes supported by tetradentate ^RN4 pyridinophane ligands that coordinate to ethylene forming either mononuclear complexes with ethylene coordinated in an η²-mode or a binuclear complex where ethylene binds to two Cu atoms in a μ-η²-η²-mode, depending on the steric effects of the ^RN4 ligand and the reaction conditions. In the binuclear complex with bridging ethylene, the CC bond is significantly elongated, with a bond length of 1.444(8) Å according to X-ray diffraction analysis. This complex represents the only examination a μ-η²-η²-coordinated Cu-olefin complex reported to date, featuring one of the longest reported CC bonds. The spectroscopic characterization, structure, electrochemical properties and solution behavior are analyzed in this study. Coordination of ethylene was found to be reversible in these complexes and more favored in less sterically hindered ^RN4 ligands, so that ethylene binding is observed in a coordinating solvent (MeCN) environment. In the case of the ^MeN4 ligand, the ethylene complex is photoluminescent in the solid state. The ethylene binding modes in mono- and binuclear complexes are elucidated through Natural Bond Orbital and QTAIM analyses.

Versatile Method of Generating Triboluminescence in Polymer Films Blended with Common Luminophores

Herein we report a versatile method for the preparation of triboluminescent polymer films by physical blending with common luminophores. This method does not require the presence of a crystalline phase or the use of materials known to be triboluminescent. Emission is generated in response to friction of the polymer surface via triboelectrification, either by rubbing directly or through an inert coating layer, even with low applied stress (<0.1 MPa). Our findings offer a convenient and practical method of preparation of triboluminescent, amorphous polymer films with easily tunable emission properties.

Photo- and triboluminescent pyridinophane Cu complexes: New organometallic tools for mechanoresponsive materials

The development of mechanoresponsive polymers has emerged as a new, attractive area of research in which changes at the molecular level exert macrolevel effects in the bulk material, and vice...

Triboluminescence Phenomenon Based on the Metal Complex Compounds-A Short Review

Triboluminescence (TL) is a phenomenon of light emission resulting from the mechanical force applied to a substance. Although TL has been observed for many ages, the radiation mechanism is still under investigation. One of the exemplary compounds which possesses triboluminescent properties are copper(I) thiocyanate bipyridine triphenylphosphine complex [Cu(NCS)(py)₂(PPh₃)], europium tetrakis dibenzoylmethide triethylammonium EuD₄TEA, tris(bipyridine)ruthenium(II) chloride [Ru(bpy)₃]Cl₂, and bis(triphenylphosphine oxide)manganese(II) bromide Mn(Ph₃PO)₂Br₂. Due to the effortless synthesis route and distinct photo- and triboluminescent properties, these compounds may be useful model substances for the research on the triboluminescence mechanism. The advance of TL studies may lead to the development of a new group of sensors based on force-responsive (mechanical stimuli) materials. This review constitutes a comprehensive theoretical study containing available information about the coordination of metal complex synthesis methodologies with their physical, chemical, and spectroscopic properties.