Vapor-triggered Green-to-Yellow Luminescence Conversion due to the Variation of Ligand Orientations in Tetranuclear Copper(I) Complex

Abstract

The reaction of 3,6-ditert-butyl-1,8-bis(diphenylphosphino)-9-methyl-9H-carbazole (L) with CuBr resulted in the isolation of tetranuclear copper(I) complex Cu 4 Br 4 L 2 as two colorless crystal morphs, i.e., green-emitting 1G and yellow-emitting 1Y. As demonstrated by X-ray crystallography, the Cu 4 Br 4 moiety in both 1G and 1Y adopts the same chair conformations. When L is bonded perpendicularly to the Cu 4 plane, 1G with green emission is obtained, while it gives a yellow emission of 1Y once the L is parallelly bonded to Cu 4 plane. Theoretical computational studies suggest that the variation in ligand orientation results in a different degree of structural distortion in triplet state and thus different luminescent energy. Particularly, 1Y undergoes dramatic structural distortion from the ground (S 0 ) to triplet excied state (T 1 ). Interestingly, 1G can be converted into 1Y upon exposed to saturated hexane vapor, which would return to 1G upon exposure to acetonitrile vapor. As demonstrated experimentally and theoretically, the reversible luminescence transformation between 1G and 1Y is ascribed to the variation of ligand L orientations.

Sensitive luminescence mechanochromism and unique luminescence thermochromism tuned by bending the P–O–P skeleton in the diphosphonium/iodocuprate(i) hybrid

“…16,33 The absolute photoluminescence quantum yields are 83.11% (for 1) and 90.77% (for 2), which are much higher than most of the neutral Cu(I)-based hybrids. 16,22,24,26,53 The transitions can stem from the two emissive centers, i.e. the organic tripodal diphosphonium cations and inorganic (Cu 2 I 4 ) 2− / (Cu 4 I 6 ) 2− anions.…”

“…can be realized by delicately modulating the coordinated geometries and related energy states. [21][22][23][24][25][26][27] Currently, there is no general rule for the design of these kinds of smart materials, and the mechanisms of the various simultaneous chromisms still remain obscure. 12,28,29 Compared with neutral copper(I) iodide hybrids, ionic ones could be expected to show better stimuliresponsive behavior, because their relaxed intermolecular interactions or cation/anion packing modes can be more sensitive to external stimuli, and consequently, more versatile emitting energy states.…”

Selective Luminescence Response of a Zero-Dimensional Hybrid Antimony(III) Halide to Solvent Molecules: Size-Effect and Supramolecular Interactions

“…Studies indicated that supramolecular interactions have an vast impact on the structures and properties in OIHMs. ,− For instance, Xiong et al designed and synthesized an organic–inorganic perovskite ferroelectric material with large piezoelectric response by introducing halogen–halogen interactions in the structure . Here, hydrogen bonding interactions in 1 , 1·EtOH , 1·MeCN , and 1·AcOH have been investigated to acquire more insight into the solvatochromic PL.…”

Exploitation of a Half-Conjugate Polydentate Salamo–Salen Hybrid Ligand and Its Two Phenoxide-Bridged Heterohexanuclear 3d–s Double-Helical Cluster Complexes

“…As shown in Figures S13 and S14, each complex molecule is linked by four π···π interactions with its neighboring molecules, leading to the three-dimensional supramolecular structure. According to the structures of complexes 1 and 2 , it can be inferred that the coordination modes of metal ions are influenced not only by their outer electron orbitals but also by the molecules around them and counteranions. , …”