A major challenge in luminescent materials is inefficient energy utilization, where a substantial fraction of absorbed energy is dissipated through non-radiative pathways. This limitation can be addressed at the molecular level by rational design of emissive systems. Combining suitable chromophores and/or supporting frameworks allows control over crystal packing, spin-orbit coupling and heavy-atom effects, as well as intermolecular energy transfer, thereby minimizing energy losses and enhancing emission efficiency of phosphorescence. In this context, we present structural and photoluminescence properties of a new hybrid organic-inorganic composite salt [1,4-nap(PMePh2)2][Pt(CN)2(Me-phpy)][I]·2MeCN (1) that integrates two previously recognized chromophores: the bisphosphonium-iodide fragment featuring anion-π interactions and the cycloplatinated anion. Photophysical analysis supported by TD-DFT calculations shows that the emission originates from the triplet charge transfer (CT) excited state 3(iodide → π*) (T1) localized within an anion-π ion pair. Composite 1 exhibits a room temperature phosphorescence quantum yield of 0.19, featuring nearly twofold enhancement compared to the precursor bisphosphonium iodide salt. This is attributed to the synergy of suppressed non-radiative decays and enhanced population of the emissive T1 state via triplet-triplet energy transfer (TTET) from its platinum counterpart. These results were achieved owing to the grafting of the [bisphosphonium]-[I-] supramolecular anion-π adduct into 1, demonstrating a strategic approach towards improved photoluminescence in molecular materials.

The one‐step syntheses of highly luminescent Cu(I) dimetallic complexes are reported using Cu(I) salts and the commercially available dppm ligand. Three crystalline phases A–C, obtained either with PF6− (A and B: [Cu2(μ2‐dppm)3](PF6)2) or TEF− (C: [Cu2(μ2‐dppm)3](TEF)2) anions, display distinct conformations and crystal packings that strongly influence photophysical properties. All phases show intense solid‐state thermally activated delayed fluorescence with room temperature quantum yields of nearly 100%. Emission energies and decay times are modulated by packing effects. Phases A and B exhibit pronounced mechanochromic luminescence upon gentle grinding, while phase C is mechanically insensitive, presumably due to its bulky and flexible counter‐anions. Density functional calculation/time‐dependent density functional calculations suggest that crystal packing impacts the structural molecular relaxation, in agreement with mechanochromic behaviors. In aerated CH2Cl2, these complexes generate singlet oxygen with quantum yield of up to 30%, highlighting their potential as photosensitizers.

A series of polymetallic Cu(i) assemblies C1-4 was selectively obtained by self-assembly of a preorganized trimetallic precursor B with 3,3 '-bipyridine ligand L1 and structurally related longer ligands L2-4, respectively, allowing to investigate the impact of ligands' backbones on architectures on the derivatives C1-4. While linkers L1 and L2 led to the formation of 1D coordination polymers (C1,2), the newly prepared alloxazine-functionalized ligands L3 and L4, promoting the appearance of steric constraints and pi-pi interactions, led to the formation of discrete hexametallacycles (C3,4). Structural characterization via X-ray diffraction confirmed the role of ligand design in determining the final architectures. The solid-state photophysical properties of ligands L3 and L4, trimetallic precursor B and derivatives C1-4. are reported. L3 and L4 exhibit weak yellow fluorescence at room temperature (RT), while the trimetallic precursor B displays intense yellow 3MLCT phosphorescence at RT. Assemblies C1-4 show varied photophysical behaviors including 3MLCT phosphorescence for C1, ligand centered phosphorescence and fluorescence for C2 and C4, respectively, while C3 is non-emissive. This study provides new insights into the steric and electronic factors governing Cu(i)-based luminescent materials' preparation, highlighting diverse photophysical behaviors including efficient RT emission performances.

A thermally and electrochemically stable 2D coordination polymer (CP) of formula [Cu2Br2L2]n (UDS-6) has been designed using the push-pull chromophore ligand 2-(9H-fluorenylidene)malononitrile (L) and the modest and yet non-innocent CuBr salt. Its X-ray structure reveals a series of piled 2D-layers separated by similar to 3.55 & Aring;, inside which pi-stacked L2 pairs are placed in a head-to-tail conformation (interplanar L & ctdot;L distance is similar to 3.41 & Aring;) and assembled by (C 00000000000000000 00000000000000000 00000000000000000 01111111111111110 00000000000000000 01111111111111110 00000000000000000 01111111111111110 00000000000000000 00000000000000000 00000000000000000 N)2Cu(mu-Br)2Cu(NC)2 rhomboids as secondary building units (SBUs) where each nitrile fragment links different L's. UDS-6 exhibits several interesting photonic properties such as a large absorption spectrum extending to similar to 1700 nm, a near-infrared (NIR) and anti-Kasha emission (lambda em similar to 1000 nm), exciton migration across the solid and photoconductivity, all of which drastically differ from those of L in the solid state (absorption extends to similar to 600 nm, lambda em similar to 700 nm, and L is not a photoconductor). Density functional theory (DFT) computations indicate that the lowest energy excited states are metal-halide-to-ligand charge transfer (MXLCT) states where the electron rich Cu2Br2 units and the electron withdrawing L act as the electron density donor and acceptor, respectively. UDS-6 is a photoconductor on its own and a mechanism study reveals the presence of photo-induced electron transfer (ET) in a 1 : 1 blend composed of tetraphenylporphyrinzinc(ii), ZnTPP, a well-known electron donor, and L within the structure of UDS-6 with a rate, kET, of 5.4 x 107 s-1, which assigns L as the electron acceptor and consequently the charge carrier in UDS-6. A novel broad-band-absorbing, NIR anti-Kasha, photoconducting coordination polymer (UDS-6) is rationally designed from CuBr and a simple push-pull dye. Its structural, photophysical, and electrochemical properties are investigated thoroughly.

A new luminescent Cu(I) tetrametallic metallacycle B is reported that features very rare semi-bridging aqua ligands. When heated markedly above room temperature, this compound undergoes a post-synthetic transformation in the solid-state, affording the new luminescent metallacycle C. Thermogravimetric analysis, IR spectroscopy and single-crystal X-ray diffraction reveal that this alteration preserves the gross tetrametallic macrocycle structure, but is caused by the release of the coordinated water molecules with the concomitant formation of cuprophilic interactions. This transition induces a shift from eye-perceived green (B) to blue (C) room-temperature luminescence for these molecular solids. Photophysical measurements and time-dependent density-functional theory calculations have been conducted to identify the origins of the emission properties lying in these structurally related assemblies, and suggest that thermally activated delayed fluorescence dominates the radiative relaxation pathways. This study highlights the innovative feature of Cu(I) derivatives, offering access to stimuli-sensitive materials that can witness, a posteriori, the exceeding of critical temperatures in their environment.

The reaction of preassembled Cu(I) bimetallic units {Cu-2(dppm)(2)} and {Cu-2(dppa)(2)} (dppm: bis(diphenylphosphino)methane and dppa: bis(diphenylphosphino)amine) with pseudohalide linkers (azido, dicyanamide, and tricyanomethanide) allows for the quantitative and selective preparation of three discrete tetrametallic metallacycles of formula [Cu-4(mu(2)-dppm)(4)(N-3)(2)](PF6)(2), [Cu-4(mu(2)-dppm)(4)(N(CN)(2))(2)](PF6)(2), and [Cu-4(mu(2)-dppm)(4)(C(CN)(3))(4)]. To explore further the impact of the linker on the architecture and dimensionality of the molecular edifice, the study was extended to more sophisticated tetradentate cyanocarbanion ligands (tcnsMe(-): 2-(methylthio)-1,1,3,3-propanetetracarbonitrile and tcnsEt(-): 2-(ethylthio)-1,1,3,3-propanetetracarbonitrile). Three ladder-like one-dimensional coordination polymers and an octametallic metallacycle have been obtained. The careful comparison of the metric and geometrical intramolecular and intermolecular parameters observed in this series of seven derivatives allows for rationalization of their molecular architectures. The subtle balance between the length and steric hindrance of the ligand and the formation of noncovalent interaction networks greatly influences the topology and dimensionality of the resulting assemblies and will be discussed hereafter. The photophysical properties of these seven polymetallic Cu(I) compounds have also been also studied.

The preparation of a new series of luminescent one dimensional coordination polymers based on the association of a photoactive tetrametallic metallacycle Cu(I) precursor with pyridyl-caped ditopic linkers is reported. In spite of related molecular architectures, these coordination polymers present upon Ultraviolet visible light photoexcitation markedly contrasted solid-state luminescence behaviors including eye-perceived colors of the emitted light spanning all over the visible spectrum. Solid-state temperature-dependent photophysical measurements and Time-dependent density-functional theory calculations have been conducted to identify the relaxation pathways lying in these assemblies. Very importantly, thermal stability studies at high temperature for all these derivatives reveal an irreversible post-synthetic solid-state transition that impacts dramatically the photophysical properties of these newly obtained phases, highlighting an innovative family of stimuli-sensitive materials that can witness the exceeding of critical temperatures in their environment. Easy-prepared cheap photoluminescent Cu(I) assemblies bearing a large variety of photophysical properties are obtained via one-step high-yield reactions. This new family of compounds presents specific high-temperature solid-state post-synthetic transitions that impact dramatically their luminescence properties, affording an innovative class of solid-state high-temperature photoactive tracers. image

A new highly solid-state luminescent dicationic Cu(i)(4) metallacycle A based on a mixed P,As ligand assembly is reported for the first time. Surprisingly, as compared to a previously described related Cu(i)4 metallacycle B based on a similar P,P ligand, a moderate effect of the presence of arsenic atoms in the photophysical processes is observed. A thorough combined experimental and theoretical study is conducted revealing that, in Cu(i) polymetallic assemblies bearing pnictogen ligands, the substitution of a phosphorus atom by an arsenic atom does not cause systematically an alteration of the SOC values and therefore an improvement of the radiative relaxation rates. Intermolecular constraints applied on the gross molecular backbones can play a major role, inducing subtle but noticeable structural alteration impacting optical changes that may differentiate the photophysics of the assemblies regarding the pnictogen atom present. In line with this point, luminescence thermochromism and mechanochromism are observed and analyzed for both A and B assemblies, which moreover also display in the solid state at high temperature an original irreversible thermal crystalline transition that impacts photophysical properties. All in all, this study highlights the subtle and competitive effects that can rule out the photophysics of Cu(i) polymetallic assemblies based on organo-pnictogen ligands and reveals their stimuli-sensitive behaviours, allowing the facile preparation of different phases bearing contrast efficient luminescence properties.

The prediction of the metal cluster within a coordination polymer or complex, as well as the dimensionality of the resulting polymer or complex (i.e., 0D, 1D, 2D, or 3D), is often challenging. This is the case for Ph2P(CH2)mPPh2 ligands (1 ≤ m ≤ 8) and CuX salts, particularly for X = I. This work endeavors a systematic statistical analysis combining studies in the literature and new data, mapping the nature of the resulting CuI aggregates with eight different diphoshphines in 2:1, 3:2, 1:1, 2:3, and 1:2 CuI:Ph2P(CH2)mPPh2 molar ratios as a function of m, which lead to either pure products or mixtures. Several trends are made relating stoichiometry and chain length to the CuI cluster formed (i.e., globular vs. quasi-planar). Four new X-ray structures were determined: [Cu3I2(L1)3]I, Cu3I3(L2)2, Cu2I2(L6)2, and Cu4I4(L8)2, where m is, respectively, 1, 2, 6, and 8, in which the CuxIy central aggregates adopt triangular bipyramid, diamond, rhomboid, and cubane shaped motifs, respectively. Photophysical measurements assisted the establishment of trends considering the paucity of the crystallographic structures. During this study, it was also found that the 0D-complex Cu2I2(Ph2P(CH2)5PPh2)2 exhibits thermally activated delayed fluorescence.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

An entry from the Cambridge Structural Database, the world’s repository for small molecule crystal structures. The entry contains experimental data from a crystal diffraction study. The deposited dataset for this entry is freely available from the CCDC and typically includes 3D coordinates, cell parameters, space group, experimental conditions and quality measures.

A new highly solid-state luminescent phase of a previously reported weakly luminescent CuI 8 PdII 1 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 CuI 8 PdII 1 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 CuI 8 PdII 1 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.

Three luminescent tetranuclear macrocycles are obtained selectively, applying coordination-driven supramolecular processes to the reaction of 3,3′-bipyridine ligand with in situ formed Cu(i) bimetallic units bearing a coordination angle of ca. 120°.

New luminescent Cu( i ) discrete assemblies D and FM and 1D coordination polymer E are reported. Deep insights of self-assembly processes based on flexible Cu( i ) precursors are highlighted together with the preservation in solution of Cu( i ) assemblies.

Pre-organized adaptive Cu(I) bimetallic precursors can be successfully engaged in coordination-driven supramolecular reactions. Selective formation either of a large family of compact metallacycles or of polymetallic discrete assemblies and one-dimensional coordination polymers is rationalized taking into account the relative amplitudes of conformational flexibility allowed by the precursors used. It reveals the originality of the self-assembly processes conducted with such Cu(I)-based building blocks. In addition, exalted luminescence properties can be embedded in the resulting supramolecular assemblies due to the specific photophysical behaviors of Cu(I)-luminophores. General and straightforward access toward coordination-driven supramolecular assemblies featuring original architectures and multifunctional luminescence properties is therefore highlighted, taking advantage of both the specificities of the coordination chemistry and the electronic structure of derivatives based on the Cu(I) ion.

The tridentate dpmp ligand was reacted with CuI salt and cyano ligand affording selectively and unexpectedly the polymetallic Cu11 complex 2 along one‐step reaction. The formation of this derivative 2 can be explained by self‐assembling processes controlled by adaptive coordination‐driven supramolecular chemistry. The solid‐state photophysical behavior of 2 was studied suggesting TADF properties.

The assembly of binuclear Cu(i) metallaclips with 2,2'-bis-dipyrrin based metalloligands gives rise to a diversity of architectures featuring a recurring π-stacked compact tetranuclear metallacycle but differing in their nuclearity and dimensionality depending on the nature of the capping ligands and metal cations.