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Subtle structure tailoring of metal-free triazine luminogens for highly efficient ultralong organic phosphorescence
摘要： Highly efficient ultralong organic phosphorescence (UOP) based on a series of metal-free triazine luminogens was achieved via subtly structural tailoring of bromine substituted positions. Impressively, p-BrAT in solid state displayed high phosphorescence efficiency up to 9.7% with a long lifetime of 386 ms, which was one of the highest efficient UOP materials reported so far in metal-free compounds.
关键词： Isomerism,Ultralong organic phosphorescence (UOP),Crystal engineering,H-Aggregation,Intermolecular interactions
更新于2025-09-23 15:23:52
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Ru(II) and Ir(III) complexes containing ADA and DAD triple hydrogen bonding motifs: Potential tectons for the assembly of functional materials.
摘要： The synthesis and characterisation of series of [Ru(II)(bpy)2L] and [Ir(ppy)2L] complexes containing ligands L with the potential to engage in triple hydrogen bonding interactions is described. L1 and L2 comprise pyridyl triazole chelating units with pendant diaminotriazine units, capable of donor-acceptor-donor (DAD) hydrogen bonding, while L3 and L4 contain ADA hydrogen bonding units proximal to N^N and N^O cleating sites, respectively. X-ray crystallography shows the L1 and L2 containing Ru(II) complexes to assemble via R22(8) hydrogen bonding dimers, while [Ru(II)(bpy)2L4] assembles via extended hydrogen bonding motifs to form one dimensional chains. By contrast, the expected hydrogen bonding patterns are not observed for the Ru(II) and Ir(III) complexes of L3. Spectroscopic studies show that the absorption spectra of the complexes result from combinations of MLCT and LLCT transitions. The L1 and L2 complexes of Ir(III) and Ru(II) complexes are emissive in the solid state and it seems likely that hydrogen bonding to complementary species may facilitate tuning of their 3ILCT emission. Low frequency Raman spectra provide further evidence for ordered interactions in the solid state for the L4 complexes, consistent with the results from X-ray crystallography.
关键词： crystal engineering,ruthenium,Hydrogen bonding,iridium,X-ray crystallography
更新于2025-09-23 15:23:52
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Photomechanical organic crystals as smart materials for advanced applications
摘要： Photomechanical molecular crystals are receiving great attention due to their efficient conversion of light into mechanical work and surpassing advantages including faster response time, higher Young’s modulus and ordered structure various measured photomechanical crystals with different motions (contraction, expansion, bending, fragmentation, hopping, curling and twisting) are springing up in the forefront of smart materials research. The photomechanical motions of these single crystals during irradiation is triggered by solid-state photochemical reactions and accompanied with phase transformation. This short review intends to summarize recent developments in the growing research on photoresponsive molecular crystals. The basic mechanisms of different kinds of photomechanical materials are described in detail, the recent advances of photomechanical crystals for promising applications as smart materials are also highlighted.
关键词： crystal engineering,photomechanical crystals,photochemistry,molecular machines,photochromism
更新于2025-09-23 15:23:52
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Five new coordination polymers of s- and d-block metals: Structural diversities, magnetic properties and luminescence
摘要： In order to explore the metal ions-controlled syntheses of coordination polymers (CPs), the temperature and solvent ratio were fixed in the reaction processes. By selecting a series of s- and d-block metal ions, five new CPs, [ZnL0.5(H2O)2]n (1), [CoL0.5(H2O)2]n (2), [Mn(H2L)(H2O)2]n (3), [Ca(H2L)(H2O)2]n (4) and [Ba(H2L)(H2O)2]n (5), have been synthesized by employing a less-investigated oxalamide N,N′-bis(4-phthalic acid) (H4L) ligand. H4L shows very versatile coordination modes and leads to various frameworks, including isomorphous 2D grid-like layer based on M2O2 cores for 1 and 2, isomorphous 4-connected 3D PtS frameworks based on 1D [M(CO2)2]n chains for 3 and 4, and a 2D wave-like layer based on [BaO3]n chains for 5.2 and 3 reveal the antiferromagnetic and ferromagnetic properties, respectively, while 1, 4 and 5 possesses strong solid state luminescence.
关键词： Luminescence,Crystal structure,Crystal engineering,Coordination polymer,Magnetic property
更新于2025-09-23 15:22:29
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Fine-Tuning Aromatic Stacking and Single-Crystal Photoluminescence through Coordination Chemistry
摘要： Organic aromatics usually show a decrease in fluorescence efficiency in the solid state on account of well-known aggregation induced quenching. We have found that single crystals of coordination polymers consisting of γ-aminobutyric acid functionalized naphthalenediimide ligand (H2GABA-NDI) can give rise to highly emissive, broad, and red-shifted photoluminescence (PL) in the solid state. To better understand the origin of the bandwidth broadening with the π–π stacking distances, we performed time-resolved PL studies in a series of polymers with a variety of metal centers. We conclude that the broad steady-state PL signals is originated from a superposition of two emissive states with differing energy and lifetimes, with the lower energy one produced by the interchromophoric interactions mediated by π–π stacking of neighboring NDI units. Our work demonstrates that coordination chemistry is an effective tool to modulate interchromophoric couplings and that simple PL analysis can be used as a measure of the degree of π-stacking.
关键词： crystal engineering,luminescence,photochemistry,stacking interactions,coordination modes
更新于2025-09-23 15:22:29
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Synthesis, structure and photoluminescence properties of a three-dimensional cadmium(II) (4,5)-connected coordination network
摘要： The assembly of coordination polymers from metal ions and organic moieties is currently attracting considerable attention in crystal engineering due to their intriguing architectures and potential applications as functional materials. A new coordination polymer, namely poly[[(cid:2)2-trans-1,2-bis(pyridin-3-yl)-ethylene-(cid:3)2N:N0]bis((cid:2)4-4,40-oxydibenzoato-(cid:3)6O:O,O0:O00:O00,O000)dicadmium(II)], [Cd2(C14H8O5)2(C12H10N2)]n or [Cd2(4,40-OBB)2(3,30-BPE)]n, has been synthesized by the self-assembly of Cd(NO3)2(cid:2)4H2O, 4,40-oxydibenzoic acid (4,40-H2OBB) and trans-1,2-bis(pyridin-3-yl)ethene (3,30-BPE) under hydrothermal conditions. The title compound was structurally characterized by IR spectroscopy, elemental analysis and single-crystal X-ray diffraction analysis. Each CdII centre is coordinated by six carboxylate O atoms from four different 4,40-OBB2(cid:3) ligands and by one pyridyl N atom form a 3,30-BPE ligand. Adjacent crystallographically equivalent CdII ions are bridged by 4,40-OBB2(cid:3) ligands, affording a two-dimensional [Cd(4,40-OBB)]n net extending in the ac plane. Neighbouring [Cd(4,40-OBB)]n nets are interlinked by 3,30-BPE along the b axis to form a three-dimensional (3D) [Cd2(4,40-OBB)2(3,30-BPE)]n coordination network. In the network, each CdII centre is linked by four different 4,40-OBB2(cid:3) ligands and one 3,30-BPE ligand. Meanwhile, each 4,40-OBB2(cid:3) ligand connects four separate CdII ions. Therefore, if the 4,40-OBB2(cid:3) ligands and CdII ions are considered as 4- and 5-connecting nodes, the structure of the title compound can be simplified as a 3D (4,5)-connected binodal framework with the rare (4462)(4466) TCS topology (Pearson, 1985; Blake et al., 2011). The thermal stability and photoluminescence properties of the title compound have also been investigated.
关键词： coordination polymer,crystal engineering,crystal structure,photoluminescence properties,TCS network,cadmium(II),topology
更新于2025-09-23 15:21:01
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Null Exciton Splitting in Chromophoric Greek Cross?(+) Aggregate
摘要： Exciton interactions in molecular aggregates play a crucial role in tailoring the optical behaviour of p-conjugated materials. Though vital for optoelectronic applications, ideal Greek cross-dipole (a = 908) stacking of chromophores remains elusive. We report a novel Greek cross (+) assembly of 1,7-dibromoperylene-3,4,9,10-tetracarboxylic tetrabutylester (PTE-Br2) which exhibits null exciton coupling mediated monomer-like optical characteristics in the crystalline state. In contrast, nonzero exciton coupling in X-type (a = 70.28, PTE-Br0) and J-type (a = 08, q = 48.48, PTE-Br4) assemblies have perturbed optical properties. Additionally, the semi-classical Marcus theory of charge-transfer rates predicts a selective hole transport phenomenon in the orthogonally stacked PTE-Br2. Precise rotation angle dependent optoelectronic properties in crystalline PTE-Br2 can have consequences in the rational design of novel p-conjugated materials for photonic and molecular electronic applications.
关键词： crystal engineering,chromophore aggregate,fluorescence,charge mobility,exciton splitting
更新于2025-09-23 15:21:01
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Self-Assembly 2D/3D Perovskite by Crystal Engineering for Efficient Air-Processed, Air-Stable Inverted Planar Perovskite Solar Cells
摘要： Two dimensional (2D) perovskite have shown great stability but poor photovoltaic performance. In this work, the 2D/3D hybrid perovskite solar cell is fabricated by an air-processed strategy, 2D/3D hybrid perovskite crystal-assistance method. The Isobutyl amine (iBA) reassembles to form the high-n-value 2D perovskite. The best solar cell is fabricated by iBA doped crystal based method, realizing a champion power conversion efficiency (PCE) of 18.29%. The ambient stability tests show that it can retain~75% of its original efficiency after 35 days storage in ambient environment with a relative humidity level of 50 ± 10% without any encapsulation, which are two times and three times slower performance decay than devices based on undoped 3D crystal and the solution-mixing precursors in the same situation, respectively.
关键词： stability,self-assembly,perovskite solar cells,crystal engineering,2D/3D
更新于2025-09-23 15:19:57
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Improved Chemical Stability of Organometal Halide Perovskite Solar Cells against Moisture and Heat by Ag Doping
摘要： Organometal halide perovskite (OHP) solar cells have been intensively studied because of their promising optoelectronic features, which has resulted in a high power conversion efficiency > 23%. Although OHP solar cells exhibit high power conversion efficiencies, their relatively poor stability is a significant obstacle to their practical use. We report that the chemical stability of OHP solar cells with respect to both moisture and heat can be improved by adding a small amount of Ag to the precursor. Ag doping increases the size of the OHP grains and reduces the size of the amorphous intergranular regions at the grain boundaries, and thereby hinders the infiltration of moisture into the OHP films and their thermal degradation. Quantum mechanical simulation reveals that Ag doping increases the energies of both the hydration reaction and heat-induced vacancy formation in OHP crystals. This procedure also improves the power conversion efficiencies of the resulting solar cells.
关键词： Perovskite solar cells,doping,thermal stability,moisture stability,Crystal engineering
更新于2025-09-23 15:19:57
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Crystal Multi-Conformational Control Through Deformable Carbon-Sulfur Bond for Singlet-Triplet Emissive Tuning
摘要： Crystal-state luminophores have been of great interest in optoelectronics for years, whereas the excited state regulation at the crystal level is still restricted by the lack of control ways. We report that the singlet–triplet emissive property can be profoundly regulated by crystal conformational distortions. Employing fluoro-substituted tetrakis(arylthio)benzene luminophores as prototype, we found that couples of molecular conformations formed during different crystallizations. The deformable carbon–sulphur bond essentially drove the distortion of the molecular conformation and varied the stacking mode, together with diverse non-covalent interactions, leading to the proportional adjustment of the fluorescence and phosphorescence bands. This intrinsic strategy was further applied for solid-state multicolor emission and mechanoluminescence, probably offering new insights for design of smart crystal luminescent materials.
关键词： Luminescence,Crystal engineering,Noncovalent interactions,Molecular Stacking,Single-crystal conformation
更新于2025-09-19 17:15:36