Photoluminescent Metal Organic Frameworks Research Articles

A postsynthetically modified MOF-808 as a fluorescent sensor for the detection of nitrofurazone antibiotic

The excessive use of nitrofuran drugs in human healthcare as well as in animal husbandry are a major threat to both the environment and human health. As a result, there is an urgent requirement for extensive research to develop materials that can efficiently detect these residual pollutants. However, developing sensor materials with high sensitivity, selectivity, and recyclability is still a challenging task. Herein, we design and synthesize a stable photoluminescent metal–organic framework (MOFs) named MOF-808-AAA, where we have first time integrated a fluorescent organic molecule, 3-anthracen-9-yl-acrylic acid (AAA), via solvent-assisted ligand exchange (SALE) method. Comprehensive structural characterization employing various techniques including PXRD, FT-IR spectra, N2 adsorption, 1H NMR, UV–Vis, and fluorescence spectra, confirmed the successful integration of AAA into the MOF-808 framework. The synthesized MOF-808-AAA demonstrates remarkable luminescence properties and exhibits quick sensitivity towards nitrofurazone (NFZ) with quenching constant (Ksv) of 2.98 × 104 M−1 and low detection limit of 0.51 µM in acetonitrile medium, demonstrating the efficacy of MOF-808-AAA as a promising fluorescent chemical sensor for NFZ detection. In addition, we have proposed a plausible turn off sensing mechanism based on photophysical and electrochemical studies.

Transformational Modulation of Fluorescence to Room Temperature Phosphorescence in Metal-Organic Frameworks with Flexible C-S-C Bonds.

Photoluminescent metal-organic frameworks (MOFs) have been a subject of considerable interest for many years. However, the regulation of excited states of MOFs at the single crystal level remains restricted due to a lack of control methods. The singlet-triplet emissive property can be significantly influenced by crystal conformational distortions. This review introduces an intelligent responsive MOF material, denoted as LIFM-SHL-3a, characterized by flexible C-S-C bonds. LIFM-SHL-3a integrates elastic structural dynamics with fluorescence and room temperature phosphorescence (RTP) modulation under heating conditions. The deformable carbon-sulfur bond essentially propels the distortion of molecular conformation and alters the stacking mode, as illustrated by single-crystal-to-single-crystal transformation detection. The deformation of flexible C-S-C bonds leads to different noncovalent interactions in the crystal system, thereby achieving modulation of the fluorescence (F) and RTP bands. In the final state structure, the ratio of fluorescence is 66.7%, and the ratio of RTP is 32.6%. This stands as a successful demonstration of modulating F/RTP within the dynamic MOF, unlocking potential applications in optical sensing and beyond. Especially, a PL thermometer with a relative sensitivity of 0.096-0.104%·K-1 in the range of 300-380 K and a H2S probe with a remarkably low LOD of 125.80 nM can be obtained using this responsive MOF material of LIFM-SHL-3a.

Er3+-Sensitized Upconversion/Down-Shifting Luminescence in Metal-Organic Frameworks.

Photoluminescent metal-organic frameworks (MOFs) are used as optical materials with excellent properties, of which the lanthanide-doped MOFs are able to emit in a broad region from visible to near-infrared due to their unique 4f-orbital electronic structure. Herein, Er3+ and Y3+ ions are selected as the metal centers of the MOFs and Er3+ is used as a sensitizer to absorb 980 nm excitation light. At the same time, Er3+ ions also act as activators that emit upconverting visible light and down-shifting near-infrared light. In addition, Tm3+, Ho3+, and Eu3+ ions were individually doped into the Er3+-doped MOFs to investigate the variation of energy-transfer paths in the presence of different lanthanide activators. Finally, the pathway of energy transfer in these Er3+-sensitized luminescent-MOFs was summarized. This work provides new insights for further development of both upconversion and down-shifting luminescence of MOFs.

Detection of Radioactive Gas with Scintillating MOFs

AbstractHomogenous radioactive gas contamination constitutes the hardest challenge for radioprotection due to its elusive nature. Most common radioactive gas are 85Kr, 222Rn, and tritiated (3H) vapors. Each of them has different challenges, often leading to specialized single‐gas detectors. The state‐of‐the‐art detection either produces chemical‐radiological waste, is hard to implement online, or requires large volume. A new paradigm is presented for radioactive gas detection that can perform online detection on any gas and fit in the hand. This study use photoluminescent metal organic frameworks (MOFs) as both porous gas sponges and scintillators. The response of several zinc based MOF is studied, using a unique radioactive gas test bench. These tests showed that MOFs are able to both concentrate and detect successfully 85Kr. The investigation is completed with calibration with different activities. The study also reports detection of 222Rn, and measurement of its half‐life. Finally, the study is completed with the successful detection of tritiated dihydrogen, commonly known to be a hard radionuclide to detect due to its low energy and penetration range. This paper shows that scintillating MOFs are a powerful solid‐state approach and a practical solution to the challenge of radioactive gas measurements.

Construction and investigation of chiral and photoluminescent Metal-Organic framework based on Zn(II) ions and achiral methoxy-functionalized benzimidazolate linkers

A Zn(Ⅱ)-based metal–organic framework, namely MeOBim-Zn (1), has been prepared by the reaction between 5,6-dimethoxy-1H-benzo[d]imidazole (MeOBimH) and Zn(NO3)2 in the presence of aqueous ammonia through solvothermal method and characterized by single-crystal X-ray diffraction, TGA and FT-IR. 1 exhibits a (10,3)-a chiral network constructing from achiral MeOBim− linker and Zn(II) ions via spontaneous resolution. In addition, 1 shows photoluminescent emission at 433 nm upon photoexcitation at 365 nm and this emission may originate from dissipation of metal-perturbed π(MeOBim−) to π*(MeOBim−) intraligand (IL) excited state.

Metal-Organic Framework-Plant Nanobiohybrids as Living Sensors for On-Site Environmental Pollutant Detection.

Photoluminescent metal-organic frameworks (MOFs) were grown in a living plant (Syngonium podophyllum) via immersing their roots in an aqueous solution of disodium terephthalate and terbium chloride hexahydrate sequentially for 12 h without affecting their viability. Then, app-assisted living MOF-plant nanobiohybrids were used for the detection of various toxic metal ions and organic pollutants. Their performance and sensing mechanism were also evaluated. The results demonstrated that the living plants served as self-powered preconcentrators via their passive fluid transport systems and accumulated the pollutants around the embedded MOFs, resulting in relative changes in fluorescence intensity. Therefore, the living MOF-plant nanobiohybrids initiate superior selectivity and sensitivity (0.05-0.5 μM) in water for Ag+, Cd2+, and aniline with a "turn-up" fluorescence response and for Fe3+ and Cu2+ with "turn-down" fluorescence response in the linear range of 0.05-10 μM with excellent precision and accuracy of 5 and 10%, respectively. With the easy-to-read visual signals under ultraviolet light, the app translates plant luminescent signals into digital information on a smartphone for on-site monitoring of environmental pollutants with high sensitivity and specificity. These results suggest that interfacing synthetic and living materials may contribute to the development of smart sensors for on-site environmental pollutant sensing with high accuracy.

Correlating Pressure‐Induced Emission Modulation with Linker Rotation in a Photoluminescent MOF

AbstractConformational changes of linker units in metal‐organic frameworks (MOFs) are often responsible for gate‐opening phenomena in selective gas adsorption and stimuli‐responsive optical and electrical sensing behaviour. Herein, we show that pressure‐induced bathochromic shifts in both fluorescence emission and UV/Vis absorption spectra of a two‐fold interpenetrated Hf MOF, linked by 1,4‐phenylene‐bis(4‐ethynylbenzoate) ligands (Hf‐peb), are induced by rotation of the central phenyl ring of the linker, from a coplanar arrangement to a twisted, previously unseen conformer. Single‐crystal X‐ray diffraction, alongside in situ fluorescence and UV/Vis absorption spectroscopies, measured up to 2.1 GPa in a diamond anvil cell on single crystals, are in excellent agreement, correlating linker rotation with modulation of emission. Topologically isolating the 1,4‐phenylene‐bis(4‐ethynylbenzoate) units within a MOF facilitates concurrent structural and spectroscopic studies in the absence of intermolecular perturbation, allowing characterisation of the luminescence properties of a high‐energy, twisted conformation of the previously well‐studied chromophore. We expect the unique environment provided by network solids, and the capability of combining crystallographic and spectroscopic analysis, will greatly enhance understanding of luminescent molecules and lead to the development of novel sensors and adsorbents.

Correlating Pressure-Induced Emission Modulation with Linker Rotation in a Photoluminescent MOF.

Conformational changes of linker units in metal‐organic frameworks (MOFs) are often responsible for gate‐opening phenomena in selective gas adsorption and stimuli‐responsive optical and electrical sensing behaviour. Herein, we show that pressure‐induced bathochromic shifts in both fluorescence emission and UV/Vis absorption spectra of a two‐fold interpenetrated Hf MOF, linked by 1,4‐phenylene‐bis(4‐ethynylbenzoate) ligands (Hf‐peb), are induced by rotation of the central phenyl ring of the linker, from a coplanar arrangement to a twisted, previously unseen conformer. Single‐crystal X‐ray diffraction, alongside in situ fluorescence and UV/Vis absorption spectroscopies, measured up to 2.1 GPa in a diamond anvil cell on single crystals, are in excellent agreement, correlating linker rotation with modulation of emission. Topologically isolating the 1,4‐phenylene‐bis(4‐ethynylbenzoate) units within a MOF facilitates concurrent structural and spectroscopic studies in the absence of intermolecular perturbation, allowing characterisation of the luminescence properties of a high‐energy, twisted conformation of the previously well‐studied chromophore. We expect the unique environment provided by network solids, and the capability of combining crystallographic and spectroscopic analysis, will greatly enhance understanding of luminescent molecules and lead to the development of novel sensors and adsorbents.

Photoluminescent metal–organic frameworks and their application for sensing biomolecules

This review focuses on the recent development of luminescent MOFs with synthetic approaches and their application in sensing biomolecules.

Celebrating the First Impact Factor of Advanced Science

The popularity of Advanced Science has been increasing steadily in the 1.5 years since its launch. We have published many excellent articles and have seen readership broaden consistently each month. The number of full text downloads of published articles has increased rapidly over the course of the last 18 months and citations of published articles are also on the rise. Advanced Science was accepted for coverage in Web of Science at the beginning of 2016 and, based on the first issue published in December 2014, we just received our first impact factor of 6.0. This early success has been made possible in part by the enthusiastic support of our editorial advisory board and many top authors. I recently met one of our authors, Cyrille Boyer, whose work is featured on the front cover of this issue at a conference and he stated: “I believe Advanced Science is an excellent multidisciplinary journal. I read it every week and I always find new and exciting research. I especially like that it covers research in different fields: materials science, energy, drug delivery, chemistry, and more, written by high profile authors and I'm sure the journal will have a very high first impact factor. I absolutely believe this journal has a great future.” In this issue, we are happy to present a collection of review articles that cover topics of highest interest ranging from drug delivery systems to perovskite solar cells and engineering cooling roofs. Like all articles published in Advanced Science, these not to be missed articles are available as open access and can be read without a subscription. The outstanding contributions featured here cover a wide range of topics. David Cahen (Weizmann Institute of Science, Israel) and Liming Ding (National Center for Nanoscience and Technology, Beijing, China) review advances in perovskite solar cells. The understanding of surface adhesion in nature is in the focus of a review article by Shutao Wang (Chinese Academy of Sciences, Beijing, China). Yuanhua Sang and Hong Liu (Shandong University, Jinan, China) summarize the current state of 1D ferroelectric nanostructures and their prospects for future applications. A more application-oriented topic is presented by Ming Gu (Swinburne University of Technology Hawthorn, Australia) who looks into the topic of radiative cooling. Tierui Zhang (Northwest University, Xi'an, China) presents a comprehensive and timely review on Zn2+-containing catalysts for efficient energy conversion. Jie-Peng Zhang (Sun Yat-Sen University, Guangzhou, China) summarizes recent progresses in the use of photoluminescent metal-organic frameworks for gas sensing. Light-activated drug delivery systems using lanthanide-doped up-conversion nanoparticles are presented to our readers by Cyrille Boyer and May Lim (University of New South Wales, Sydney, Australia). In a much more physics-oriented review Tie-Jun Zhu (Zhejiang University, Hangzhou, China) and Jian He (Clemson University, USA) report on defect engineering in thermoelectric materials. The article by Jian-Xin Tang (Soochow University, Suzhou, China) comprehensively reviews the most recent progress of the light manipulation in organic photovoltaics. Last but not least, Wei Feng (Tianjin University, China) reviews the synthesis, structures, and applications of two-dimensional fluorinated graphene. We would like to thank all invited authors for their inspiring manuscripts, their trust in the journal and their contribution to the future success of Advanced Science. I hope that you will enjoy this collection of articles. If you are interested in contributing an open access article of your own that anyone can freely access do not hesitate to contact us. We are happy to discuss any potential topic with you. On behalf of the editorial team,

Microwave Synthesis of a photoluminescent Metal-Organic Framework based on a rigid tetraphosphonate linker

In this manuscript, microwave-assisted synthesis was used to prepare a new organic building block and a Metal-Organic Framework based on this unit. The tetrapodal organic linker [1,1′-biphenyl]-3,3′,5,5′-tetrayltetrakis(phosphonic acid) (H8btp) was combined with lanthanide cations affording the isotypical 2D lanthanide-organic frameworks [Ln4(H6btp)2(H4btp)2(H8btp)(H2O)16]·12H2O [where Ln3+=La3+ (1), (La0.9Eu0.1)3+ (2) and (La0.9Tb0.1)3+ (3)]. 1 was isolated as large single-crystals and its crystal structure was solved by single-crystal X-ray diffraction. Phase identification of the Eu3+- (2) and Tb3+-based (3) materials was performed by powder X-ray diffraction. Compound 1 consists of two-dimensional double-deck layers, characterized by an unprecedented tetranodal 2,4,4,4-connected layered network, with total point symbol {4·85}2{42·84}{43·82·10}4{4}2. Supramolecular π–π interactions exist both within and between layers. 1–3 were fully characterized in the solid-state by a plethora of techniques [elemental and thermogravimetric analyses, electron microscopy (SEM and EDS), FT-IR spectroscopy and solid-state NMR]. Photoluminescence properties of the optically-active mixed-lanthanide materials 2 and 3 reveal that the employed H8−xbtp−x residues are better suited to sensitize Tb3+ than Eu3+, with the measured lifetimes being of 0.83±0.01 and 0.22±0.01ms, respectively.

Biomimetic Taste Receptors with Chiral Recognition by Photoluminescent Metal-Organic Frameworks Chelated with Polyaniline Helices.

The adsorption of phenylaniline (Phe) enantiomers on (+)-polyaniline (PAN)-chelated [In(OH)(bdc)]n microcrystals was carefully designed and studied by using the Job titration, circular dichroism, X-ray photoelectron spectroscopy, and photoluminescence to mimic heterotrimeric guanine nucleotide-binding protein (G protein)-coupled receptors in selective, but not specific, ligand binding with chiral recognition and signal transduction. Six essential working principles across different length scales are unraveled: 1) a chiral (+)-PAN (host), 2) specific sites for Phe-(+)/PAN (guest-host) binding, 3) a conformational change of (+)-PAN after binding with Phe enantiomers, 4) different degrees of packing for (+)-PAN, 5) interactions between (+)-PAN and the underlying signal-generating framework (i.e., [In(OH)(bdc)]n microcrystals), and 6) a systematic photoluminescent signal combination by using principal-component analysis from the other three polymer-chelated metal-organic frameworkds (MOFs), such as poly(acrylic acid) (PAA), sodium alginate (SA), and polyvinylpyrrolidone (PVP) to enhance the selectivity and discrimination capabilities.

A photoluminescent metal–organic framework with threefold interpenetrated diamond topological net

A new 3D metal–organic framework, [Zn3(IN)6]⋅DMF⋅H2O (1, H-IN=isonicotinic acid), has been solvothermally synthesized and structurally characterized by single crystal X-ray diffraction. Structural analysis shows that compound 1 possesses a three-dimensional framework with 4-connected threefold interpenetrated diamond (dia) topological network where the Zn(II) centers are all 4-coordinated. Moreover, the photoluminescent property of this compound is investigated in the solid state at room temperature.

Photoluminescent Metal–Organic Frameworks – Rapid Preparation, Catalytic Activity, and Framework Relationships

An optimized microwave-assisted synthesis has been used to prepare an isotypical series of 3D Ln3+ metal–organic frameworks (MOFs) based on residues of 2,5-pyridinedicarboxylic (pydc), namely, [Ln2(pydc)3(H2O)2] with Ln3+ = Ce3+ (1), (La0.95Eu0.05)3+ (1-LaEu), (La0.95Tb0.05)3+ (1-LaTb), and (La0.90Eu0.05Tb0.05)3+ (1-LaEuTb). The materials can be readily isolated as microcrystals after 1 min of reaction time at 120 °C. The compounds have been extensively studied in the solid state by vibrational spectroscopy (FTIR and FT-Raman), thermogravimetry, powder X-ray diffraction, elemental analysis, and electron microscopy (SEM, SEM mapping, and TEM). The structural relationships between the isolated materials and other solids reported in the literature have been investigated in detail from a structural and topological perspective with attention focused on the different connectivities of the employed organic ligand. The 3D densely packed [Ln2(pydc)3(H2O)2] compounds are very similar to the previously reported microporous 3D [Ce2(pydc)2(Hpydc)(H2O)2]Cl·(9 + y)H2O; layered [{Ce2(pydc)2(Hpydc)2(H2O)4}·2H2O]n can be isolated at lower temperatures and transforms to [Ce2(pydc)3(H2O)2] under certain experimental conditions. Compound 1 is an effective solid catalyst for the ring opening of styrene with methanol under mild reaction conditions (55 °C) to give 2-methoxy-2-phenylethanol in 100 % selectivity and ca. 80 % conversion. The mixed-lanthanide materials are effective UV-to-visible light converters (red 1-LaEu, green 1-LaTb, and orange 1-LaEuTb). The compounds have very high absolute emission quantum yields (43 % for 1-LaEu and 75 % for 1-LaTb) under indirect excitation of the UV ligand bands with lifetimes of 0.50 and 1.06 ms for 1-LaEu and 1-LaTb, respectively, and these properties result from effective intersystem crossing and ligand-to-metal transfer processes.

Two photoluminescent metal–organic frameworks with highly-connected topological nets

Presented here are two three-dimensional metal–organic frameworks [H2N(CH3)2]2[Cd5(bdt)3(btc)2(H2O)2]·3(H2O) (1) (H2bdt = 1,4-benzeneditetrazol-5-yl; H3btc = 1,3,5-benzenetricarboxylic acid) and [Cd5(Hbdt)2(bdt)(btc)2(H2O)2]·4H2O (2) with integrated topological nets, where the trinuclear cadmium units act as 10-connected nodes. Since both compounds are built from a dual-ligand assembly approach, the topological analyses on the networks of compounds 1 and 2 are also considered as the integration of two nets. For compound 1, its net is integrating an xbe net of Cd–bdt connectivity and kgd net of Cd–btc connectivity, while the net of compound 2 is integrating a fry net of Cd–bdt connectivity and kgd net of Cd–btc connectivity. Furthermore, the luminescence properties of the two compounds are investigated in the solid state at room temperature.

Two photoluminescent metal–organic frameworks based on a BODIPY-derived bipyridine ligand

Two new metal–organic open frameworks (MOFs) [Zn3L2(btc)2(H2O)]·(guests) (1), [CdL(bdc)]·(guests) (2), were successfully prepared by using a photoluminescent BODIPY-based bipyridine linker, L, and auxiliary ligands 1,4-benzenedicarboxylate (H2bdc) and 1,3,5-benzenetricarboxylate (H3btc), respectively. MOF 1 has a 2-fold interpenetrating three-dimensional (3D) framework with an 8-connecting body centered cubic (bcu) net, built upon a paddlewheel cluster [Zn2(O2CR)4], a tetrahedrally connecting Zn and a 3-connected btc3− ligand. MOF 2 has a highly open framework with a kagome-type net. It is a pillared layered structure made of 2D [Cd(bdc)] kagome sheets and L as pillars. MOF 1 was shown to exhibit permanent porosity and adsorption of N2, H2, CO2 and CH4. Both MOFs exhibited strong photoluminescent emissions at room temperature with peaks at 540 nm upon excitation, owing to a ligand L-based excited state.

A biomimetic tongue by photoluminescent metal–organic frameworks

The taste sensing capabilities of a “biomimetic tongue” based on the photoluminescence (PL) responses of metal–organic frameworks (MOFs), [In(OH)(bdc)]n (bdc=1,4-benzenedicarboxylate), [Tb(btc)]n (MOF-76, btc=benzene-1,3,5-tricarboxylate), and [Ca3(btc)2(DMF)2(H2O)2]·3H2O are proven on aqueous solutions of five basic tastants: sucrose (sweet), caffeine (bitter), citric acid (sour), sodium chloride (salty) and monosodium glutamate (umami). For [In(OH)(bdc)]n, the tastant interacts stereochemically with poly(acrylic acid) (PAA) and alters its conformations. The frequency and magnitude of chelation between COO− pendant groups of PAA and In3+ nodes of [In(OH)(bdc)]n framework influence the corresponding PL reponses. For MOF-76, the tastant interacts with incorporated water in MOF-76 through hydrogen bonding. The limitation of O–H bond stretching of water results in the enhancement of the PL intensity. For [Ca3(BTC)2(DMF)2(H2O)2]·3H2O, it is added as a third MOF component to increase the precision on taste discrimination. The significance of MOF-based “biomimetic tongue” includes: (1) PAA on [In(OH)(bdc)]n mimics the taste receptor cells (TRCs) for their structural flexibility, (2) the Weber-Fechner law of human sensing that sensation is proportional to the logarithm of the stimulus intensity is observed between the PL emission response of MOF-76 and the concentration of tastant, (3) the strength of taste is quantified by the τ scale and the PL emission intensity of MOF-76, which are dependent on the logarithmic tastant concentration, (4) the tastant is identified by the shape of the 3D principal component analysis contour map (i.e., pattern recognition method), and (5) the fabrication of [In(OH)(bdc)]n/PAA film by brushing is illustrated.

Tuning Structural Topologies of Three Photoluminescent Metal–Organic Frameworks via Isomeric Biphenyldicarboxylates

Three new cadmium compounds, [Cd(2,4'-bpdc)(bib)(0.5)] (1; 2,4'-bpdc = biphenyl-2,4'-dicarboxylate and bib = 1,4-bis(2-methyl-imidazol-1-yl)butane), {[Cd(2)(3,4'-bpdc)(2)(bib)(1.5)(H(2)O)](n)·H(2)O}(n) (2; 3,4'-bpdc = biphenyl-3,4'-dicarboxylate), and [Cd (4,4'-bpdc)(bib)] (3; 4,4'-bpdc = biphenyl-4,4'-dicarboxylate), have been successfully synthesized by the assembly of Cd(2+) ions, bib ligands, and isomeric bpdc ligands, respectively. This paper presents a comparative study on the tuning of structural topologies using three isomers of biphenyldicarboxylates as bridging ligands. Compound 1 based on 2,4'-bpdc features a three-dimensional (3D) framework with 6-connected mab topology. Compound 2 based on 3,4'-bpdc is another 3D framework, but it possesses a rare 3-fold interpenetrating 4,6-connected fsh net, while compound 3 based on linear 4,4'-bpdc shows unusual 2D → 3D parallel polycatenation of (4,4) layers. Furthermore, the luminescent properties of three compounds are investigated in the solid state.

High Photoluminescent Metal–Organic Frameworks as Optical Markers for the Identification of Gunshot Residues

Gunshot residue (GSR) are solid particles produced when a firearm is discharged, and its detection is important evidence in forensic investigations. Currently, scanning electron microscopy coupled to energy dispersive spectroscopy (SEM-EDS) is the standard technique adopted for the analysis and identification of GSR; however, this methodology is inefficient for lead-free ammunition. Herein, we report the inclusion of high photoluminescent metal-organic frameworks in ammunition to allow for the visual detection of GSR. The tests indicated that marked GSR is easily visible in proportions above 5.0 wt %. A total of 1 g of marker suffices to tag 100 0.38 mm bullets or 62 0.40 mm bullets.

Photoluminescent metal-organic framework with hex topology constructed from infinite rod-shaped secondary building units and single e, e- trans-1,4-cyclohexanedicarboxylic dianion

Hydrothermal reaction produced a three-dimensional zinc 1,4-cyclohexanedicarboxylate formulated as Zn 5(μ 3-OH) 2( trans-chdc) 4 (chdc = 1,4-cyclohexanedicarboxylic dianion) in high purity and good yield, which is constructed from infinite rod-shaped Zn–O–C secondary building units interconnected by –C 6H 12-cyclohexane rings of the ligands. The topology of the framework can be regarded as hex type. Though it is synthesized from 1,4-cyclohexanedicarboxylic acid with mixed conformations ( trans and cis), interestingly, the ligands in the compound Zn 5(μ 3-OH) 2( trans-chdc) 4 are uniformly in e, e- trans conformation. This may be related to its synthetic conditions. Photoluminescence measurement reveals that the compound exhibits intense violet-blue fluorescent emission at room temperature. Origin of the emission can be assigned to intraligand transitions by comparison of the fluorescent emission bands for the free ligand chdcH 2 and the compound Zn 5(μ 3-OH) 2( trans-chdc) 4.