Point Symbol Research Articles

Synthesis, Structural Analysis and Bright Emission Performance of a New Family of 3D Lanthanide Coordination Polymers Based on 1,3‐phenylenediacetic Acid

AbstractA novel series of isostructural lanthanide coordination polymers with the general formula [Ln2(PDA)3(DMF)2] (where Ln3+= La, Nd, Pr, Tb, Sm and Eu, DMF= N,N’‐dimethylformamide and PDA =1,3‐phenylenediacetate) were hydrothermally synthesized and further characterized by vibrational spectroscopy, thermal analysis, scanning electron microscopy (SEM), energy dispersive X‐ray (EDX) analysis, and powder and single‐crystal X‐ray diffraction techniques. In addition, from the crystallographic data, it was possible to determine the topology of the structure, finding that the network consists of 5‐connected nodes with topological type: nov; 5/4/o8 and point symbol (44.66). To study the luminescence properties regarding potential energy transfers among the building blocks, lanthanum‐based samples doped with Tb (III) and Eu (III) (1 %, 2 %, 5 % and 10 %) were analyzed in solid state. Upon ligand sensitization, 4 f transitions could be observed confirming an “antenna effect” of the PDA ligand. These new compounds are potential materials for the construction of photoluminiscent devices.

Chiral Ca–Mn-frameworks with double helical chains and one-dimensional channels constructed from enantiomorphous lactate synthons

Under solvothermal synthetic condition, lactate derivatives (R)-5-(1- carboxyethoxy)isophthalic acid ((R)-H3CIA) and (S)-5-(1-carboxyethoxy)isophthalic acid ((S)–H3CIA) assembled with Ca(Ⅱ) and Mn(Ⅱ) ions to obtain enantiomers {[MnCa0.5((R)-CIA)(H2O)]·((CH3)2NH2CH3CO2)0.5(H2O)}n (HU21-R) and {[MnCa0.5((S)-CIA)(H2O)]·((CH3)2NH2CH3CO2)0.5(H2O)}n (HU21–S), respectively. Complexes HU21-R and HU21–S belong to orthorhombic crystal system with chiral space group I212121. Single crystal X-ray diffraction analysis revealed that all oxygen atoms of synthons (R)-CIA3- and (S)-CIA3- participated in the coordination with metal ions. Thus, semi-rigid (R)-CIA3- and (S)-CIA3- anions become rigid linkers in HU21-R and HU21–S. Fragments of (R)-CIA3- anion are connected by Ca(Ⅱ) ions to build right-handed double helical chains in HU21-R, while the enantiomeric left-handed double helixes are constructed by (S)-CIA3- fragments and Ca(Ⅱ) ions in HU21–S. Additionally, Mn(Ⅱ) centers and CIA3− anions resulted in a rare 4,4,4-connected net with point symbol of (42.62.82)3(42.64). Ca(Ⅱ) ions were further filed into Mn-CIA-framework to form a three dimensional structure with one dimensional channel. Moreover, magnetic test indicates that the framework has a canted antiferromagnetic behavior.

A water-stable Cd-MOF acts as new fluorescent probe for detecting Fe3+, Cr2O72−, 2,4,6-trinitrophenol and nitrofurazone

A new MOF [Cd3(NTB)2(DPE)]H2O (JNLU-12) was synthesized under solvothermal conditions based on tris(4-carboxyphenyl)amine (H3NTB) and 2,2'-bipyridine (bpy) as organic ligands. Single-crystal X-ray diffraction analyses revealed that JNLU-12 crystallized in the monoclinic system with C2/c space group, and the topological analysis showed that JNLU-12 had 3,8-connected net with the point symbol{43.612}{43}2. After soaking in water for 4 days, it was proved by XRD that JNLU-12 had good water stability. In the fluorescence sensing experiments of cations, anions, nitroaromatic compounds (NACs) and antibiotics, it can be measured that JNLU-12 had good selectivity, sensitivity, anti-interference and recyclingin Fe3+, Cr2O72−, TNP and NZF. The fluorescence quenching mechanism was explored. It was found that the competitive energy absorption, resonance energy transfer and electron transfer were jointly or partially influenced on fluorescence quenching of Fe3+, Cr2O72−, TNP and NZF.

Metal (Mn2+, Co2+ and Cd2+) ions induced differentiation in mixed-ligands MOFs constructed from H3btb and H2bdc: Highly porous Structures, new topology nets and two-step gate-opening behaviors

Mix-ligands strategy is highly efficient for the rational construction of MOFs with particular structure motifs and high porosity, yet challenging and requiring matching in hierarchical coordination assembly and synergetic crystallization. The solvothermal reactions of 1,3,5-tris[4-carboxyphenyl]benzene (H3btb) and 1,4-benzenedicarboxylic acid (H2bdc) with different 3d metal ions, generated highly porous mixed-ligands MOFs of [(CH3)2NH2]2[Mn3(btb)2 (bdc)]·12DMF·3MeOH (Mn-btb-bdc) having anionic 3D frameworks constructed from linear [Mn3(COO)8] nodes, [Co4(btb)2(bdc)(H2O)3]·15DMF·7H2O (Co-btb-bdc) processing neutral frameworks constituted by linear [Co3(COO)6(H2O)4] and paddle-wheel [Co2(COO)4(H2O)2] nodes, as well as one single-ligand MOFs of [(CH3)2NH2][Cd(btb)(H2O)]·8DMF (Cd-btb-2fold) exhibiting 2-fold interpenetrated ths net frameworks due to the unsuccessful introduce of the coexisted bdc ligand. Two new topology net of 2,3,8-connected net with point symbol of (42·6)2(44·66·812·105·12)(6) and 2,3,4,6-connected net with Point Symbol of (4·82)4(42·811·102)2(84·122)(82) were found for Mn-btb-bdc and Co-btb-bdc. All these three MOFs are highly porous with void fractions of 60.9%, 52.2% and 61.4%, stemming from 3D-penetrated, 3D-penetrated and 1D channels, respectively. Such structural differentiations are attributed to the diversified electronic structure and coordination preference of different 3d metal ions, as well as the solvent template and temperature effects. Two-steps gate-opening behaviour in gas sorption isotherms was found in the flexible Mn-btb-bdc MOFs.

Three robust luminescent Cd(II) coordination polymers as multi-responsive fluorescent sensors for Cu2+, Hg2+, levofloxacin, and acetylacetone in water

Employing coordination polymers (CPs) developing effective organic contaminants and heavy metal ions luminescent detection systems is an ongoing challenge. Three ternary Cd(II) CPs namely [Cd(MIP)(L)0.5(H2O)]n (1), [Cd2(TPA)2(L)(H2O)]n (2), and [Cd2(DCTP)2(L)(H2O)]n (3), (L = 1,6-bis(2-((1H-imidazol-1-yl)methyl)-1H-benzo[d]imidazol-1-yl)hexane, H2MIP = 5-methylisophthalic acid, H2TPA = terephthalic acid, and H2DCTP = 2,5-dichloroterephthalic acid) containing new L ligands, were hydrothermally synthesized and characterized. 1 displays a (4,4)-connected 4,4L28 layer and further extended into the 3D supramolecular framework via π−π stacking interactions. 2 exhibits a (4,4,5)-connected trinodal network with the point symbol of {42.5.62.8}{42.52.72}{42.53.62.73}2. 3 takes on a (3,5,6)-connected framework with the point symbol {3.42.52.7}{3.82}2{33.44.5.62.82.92.10}2. 1 − 3 show highly good thermal stability, and highly acid-base tolerance. The limits of detection (LOD) of 1 − 3 were calculated as follows: for Cu2+, the LODs are 8.92 × 10−8, 5.74 × 10−7, and 9.37 × 10−8 mol L−1, respectively; for Hg²⁺, the LOD values are 3.73 × 10−7, 5.22 × 10−7, and 8.45 × 10−7 mol L−1, respectively. Regarding levofloxacin (LEV), the LODs for 1 − 3 were found to be 5.11 × 10−8 mol L−1, 2.45 × 10−8 mol L−1, and 8.54 × 10−8 mol L−1, respectively. Finally, for acetylacetone (acac), the LODs of 1 − 3 are 5.53 × 10−6, 5.66 × 10−6, and 1.23 × 10−6 mol L−1, respectively. 1 − 3 represent the first examples of exceptional multi-responsive sensing platforms for the detecting of Cu2+, Hg2+, LEV, and acac with high sensitivity, outstanding anti-interference abilities, and low LODs. The possible sensing mechanisms were investigated in detail.

New robust 2D cobalt (II) coordination polymer as an effective turn-on luminescent sensor to detect Tb3+ and pefloxacin

It is necessary to employ highly sensitive and rapid detection of antibiotics and heavy ions in the environment. A mixed-ligands ternary Co (II) coordination polymer containing new L ligands, {[Co(L)(mip)(H2O)]·2H2O}n (1), (L = 2,2′-bis-(2-pyridin-3-yl-vinyl)-3H,3′H-[5,5]bibenzoimidazole, H2mip= 5-methylisophthalic acid) was synthesized under solvothermal condition. Compound 1 displays a sql 2D layer with the point symbol of {44.62}. Compound 1 owns excellent thermal and pH stability and can effectively sensitize the luminescence of Tb3+ ions through the “antenna effect”. Compound 1 can serve as luminescent probe for detecting pefloxacin and Tb3+ with low detection limits. Especially Compound 1 is the first turn-on sensor for the detecting Tb3+ ions and pefloxacin via fluorescence enhancement. In addition, the sensing mechanism is discussed in detail.

Multifunctional fluorescent switch based on a 3D Co-CP for selective detection of hypochlorite, nitrofuran antibiotics and acetylacetone

The abuse of biological and environmental related materials, such as pharmaceutical antibiotics, volatile organic chemicals and toxic ions has become a topical issue that draws the global attention. Thus, the exploration of effective methods for the rapid recognition of contaminants at low concentrations is critical for curtailing pollution and identifing environmental risks. Previous reports have shown that NH2-functionalized LCPs can serve as effective traps of hypochlorite owing to their rapid chemical reaction with hypochlorite. Herein, we strategically prepared a novel three-dimensional (3D) CP, [Co2(edda)(datrz)(H2O)2]·EtOH (Co-CP), using NH2-decorated triazole ligand 3,5-diamino-1,2,4-triazole (datrz) combined with semirigid tetracarboxylic acid 5,5′-(ethane-1,2-diylbis(oxy)) diisophthalic acid (H4edda). The prepared Co-CP features a pcu topology with point symbol of {412.63}. This material exhibits high structural stability in acidic-basic aqueous solution of broad pH scope (1–11), which is favorable for fluorescence detection in aqueous medium. As expected, the open -NH2 sites within the framework endow this fluorescent CP with remarkable detectability towards hypochlorite in aqueous media. Furthermore, Co-CP also displays satisfactory fluorescence response for sensing nitrofuran antibiotics (NFT and NFZ) and acetylacetone with high sensitivity and selectivity along with great interference immunity. Through exhaustive theories calculations and experimental surveys, the possible mechanisms have also been thoroughly investigated. The CP-based multifunctional fluorescent switch designed in this work expands the application of such materials in biological and environmental related areas.

Metal Ion and Metal‐to‐Ligand Ratio Regulated Construction of Cu(II) and Co(II) Coordination Polymers as Efficient Catalysts for Ring‐Opening Polymerization of L‐Lactide

AbstractThree new coordination polymers (CPs), {[Cu(NDC)(Fbtx)(H2O)] ⋅ 1.5H2O}n (1), {[Co(NDC)(Fbtx)(H2O)2] ⋅ 0.5Fbtx}n (2), and [Co2(NDC)2(Fbtx)]n (3), were synthesized by employing acid‐base mixed ligands of rigid 1,4‐naphthalenedicarboxylic acid (H2NDC) and flexible bis(1,2,4‐triazole‐1‐ylmethyl)‐2,3,5,6‐tetrafluorobenzene (Fbtx) under both hydrothermal and microwave‐assisted reaction conditions. Single‐crystal structure analysis establishted that both compounds 1 and 2 exhibit two‐dimensional (2D) layered structures, while compound 3 features a three‐dimensional (3D) complicated framework. The geometries of metal ions vary from square pyramidal (in 1 and 3) to distorted octahedral (in 2). Topological strudy showed that compounds 1 and 2 have exposed common 4‐connected 44‐sql net, while compound 3 has made a novel 4,5‐connected net with point symbol of (43 ⋅ 62 ⋅ 7)(43 ⋅ 64 ⋅ 72 ⋅ 8). The catalytic performance of the three complexes for the solvent‐free ring‐opening polymerization of L‐lactide has been investigated. The results indicated that compound 3 with coordinatively unsaturated cobalt(II) sites showed good activity and the molecular weight of the polymer obtained was high. Moreover, the complex 3 catalyst could be recycled up to five times with the retention of both catalytic activity and crystal structure.

Enantiomeric ni-cluster organic frameworks containing helixes constructed from alanine derivatives

Chiral metal-organic frameworks (CMOFs) [Ni((L)-ccba)(1,3,5-tmib)(H2O)0.5]n (HU17-L ) and [Ni((D)-ccba)(1,3,5-tmib)(H2O)0.5]n (HU17-D ) were prepared from alanine derivatives (L)-H2ccba and (D)-H2ccba in the presence of auxiliary N-donor linker 1,3,5-tmib (H2ccba = 4-((1-carboxyethyl)-carbamoyl)benzoic acid, 1,3,5-tmib = 1,3,5-tris(2-methyl-1H-imidazol-1-yl)benzene). HU17-L and HU17-D are three-dimensional (3D) enantiomers based on dinuclear [Ni2(CO2)2(H2O)]2+ clusters. Helical motifs are their outstanding structural features. In HU17-L and HU17-D , (L)-ccba2- and (D)-ccba2- anions constructed left-handed (L)-ccba-Ni chain and right-handed (D)-ccba-Ni chain through chiral transfer, respectively. Moreover, achiral 1,3,5-tmib linkers were bridged together by Ni(II) centers to obtain left-handed 1,3,5-tmib-Ni chain in HU17-L and right-handed 1,3,5-tmib-Ni chain in HU17-D via asymmetric induction, respectively. Topological analysis revealed that these frameworks are 8-connected fcu nets with point symbol (424.64). Magnetic tests indicate that antiferromagnetic interactions exist in these complexes.

Synthesis, characterization, hysteretic two-step CO2 adsorption, and fluorescence properties of two isoreticular mixed-ligand pillared-layer frameworks

Two isostructural and isomorphrous metal–organic frameworks (MOFs), namely [Zn2(Brtpt)2 (bpBTD)]n (1) and {[Zn2 (ntpt)2 (bpBTD)]∙solvent}n (2), where bpBTD = bis(pyridin-4-yl)benzothiadiazole, H2Brtpt = 2-bromoterephthalic acid, H2ntpt = 2-nitroterephthalic acid, with thermal stability of 355 °C for 1 and 265 °C for 2 were hydro (solvo)thermally synthesized in DMF/H2O media at 100 °C. Single-crystal X-ray diffraction analysis revealed that 1 and 2 both possess 2-fold interpenetrating pillared-layer frameworks showing pcu net topology with the point symbol of 41,263. The sufficient extra-framework void spaces are approximately 30.1 % for 1 and 32.0 % for 2 with open channels along the b axis, where the window sizes are ca. 5.51 × 3.15 Å2 in edge for the former and ca. 5.47 × 3.44 Å2 and 3.12 × 3.44 Å2 in edge for the latter. Gas adsorption isotherms revealed that thermally activated 1 and 2 both hardly adsorb N2 with very low N2 uptakes at 77 K. Comparably, the CO2 adsorption isotherms of thermally activated 1 and 2 both revealed gate-opening (two-step) sorption behaviors with an apparent hysteretic adsorption–desorption process, where the maximum uptakes are 135.4 and 171.5 cm3 g−1 STP for 1 and 2, respectively, at 195 K and P/P0 = 1. Photoluminescence studies showed that 1 and 2 both emitted bpBTD-dominated ligand-centered emissions, being as cyan and pearl aqua color fluorescence centered at λem = 467 and 495 nm, respectively, in solid-state and as cyan color fluorescence centered at λem = 455 and 458 nm, respectively, in H2O suspensions.

Cd(II) coordination complexes built from semirigid bis(dimethylbenzimidazole) ligand and different carboxylates: Fluorescent sensor and recognition mechanism for p-nitrophenol, erythromycin and 2,6-dichloro-4-nitroaniline

Three Cd(II) coordination complexes, formulated as [Cd(dbim)(p-phda)]n (1), [Cd(dbim)1.5(suc)]n (2), [Cd(dbim)0.5(m-bdc)(2H2O)]n (3) (dbim = 1-(4-((2,5-dimethyl-3aH-benzo[d]imidazol-1(7aH)-yl)methyl)benzyl)-3a,7a-dihydro-2,5-dimethyl-1H-benzo[d]imidazole, p-H2phda = p-phenylenediacetic acid, H2suc = succinic acid, m-H2bdc = 1,3-benzenedicarboxylic acid), have been obtained by hydrothermal reactions. Complex 1 features a 4-connected 2D topological net with a point symbol of 44·62. Complex 2 possesses a 3-connected 2D layer with a point symbol of 63. Complex 3 presents a chain structure ornamented with uncoordinated Lewis basic O donor. Complex 3 shows highly sensing for p-Nitrophenol, Erythromycin and 2,6-Dichloro-4-nitroaniline with fluorescence quenching/enhancement, by energy transfer process. The binding constants were calculated as 2.9 × 104 mol−1 for p-Nitrophenol, 5.3 × 103 mol−1 for Erythromycin and 7.2 × 103 mol−1 for 2,6-Dichloro-4-nitroaniline, respectively. The study indicates that Complex 3 can be as a rare sensory material for efficiently detecting p-Nitrophenol, Erythromycin and 2,6-Dichloro-4-nitroaniline.

Various dicarboxylates induced six Zn(II)/Cd(II) coordination polymers containing a new benzoimidazolyl terpyridine ligand: syntheses, structural diversity, luminescence and gas adsorption properties

Six Zn(II)/Cd(II) coordination polymers (CPs), namely, {[Zn2(bimphtpy)(p-bdc)1.5(OH)]·(H2O)0.5}n (1), [Zn2(bimphtpy)2(tdc)2]n (2), {[Zn(bimphtpy)(cpoa)]·4H2O}n (3), [Cd2(bimphtpy)(p-bdc)2(H2O)]n (4), {[Cd2(bimphtpy)(m-bdc)2(H2O)2]·(H2O)0.75}n (5), and {[Cd(bimphtpy)(qda)]·H2O}n (6), constructed from N-heterocyclic ligand 4'-(4-(benzimidazol-1-yl)phenyl)-4,2':6',4''-terpyridine (bimphtpy) and five dicarboxylic acids, (p-H2bdc = 1,4-benzenedicarboxylic acid, H2tdc = 2,5-thiophenedicarboxylic acid, H2cpoa =4-carboxyphenoxyacetatic acid, m-H2bdc = 1,3-benzenedicarboxylic acid, H2qda = hydroquinone-o,o'-diacetic acid), have been solvothermally synthesized and structurally characterized mainly by single-crystal X-ray diffraction along with elemental analysis, IR spectroscopy, PXRD and TG analysis. Complex 1 exhibits a 2D + 2D → 3D polycatenated framework with bilayers showing the uninodal 5-c (4,4)Ia topology if Zn2(CO2)(OH) SBU (secondary building unit) are considered. Complex 2 reveals a 2D → 2D polycatenane of two-fold interpenetrated network with rods threading loops showing 63-hcb topology. Complex 3 presents a highly undulated 2D 44-sql sheet with thickness of about 18.5 Å. Complex 4 displays a single 3D network constructed by binuclear Cd2(CO2)4O2 SBU showing the uninodal 6-c pcu topology. Complex 5 features a 2D + 2D → 3D polycatenated framework showing an unidentified topology with point symbol of {42·6·72·9}{42·6}{6·72}{64·8·10}. Complex 6 shows a single 3D network constructed by binuclear Cd2O4C2 SBU with 8-c cds topology. Moreover, the fluorescent properties of complexes 1–6 in the solid state at room temperature as well as the adsorption properties of complex 3 are also investigated, suggesting their potential applications as luminescence materials and gas adsorption selectivity materials.

A two-dimensional coordination polymer bearing an Evans-Showell-type polyoxometalate: Synthesis, structure and biological insight†

An Evans-Showell-type polyoxometalate (POM) based coordination polymer (CP), [H2(Co2Mo10H4O38)2(Co3(L)3(HL)2(H2O)6)(HL)2]·14H2O (1), {L = 4,4′-bipyridine}, was synthesized under hydrothermal conditions and structurally characterized by infrared spectroscopy (IR), elemental analysis, powder X-ray diffraction (PXRD), diffuse reflectance spectroscopy (DRS) and single crystal X-ray diffraction methods. In 1, two [Co2Mo10H4O38]6− POMs are joined together via two Co-O interactions to form a dimer which is centrosymmetric. Here, the dimers act as repeating units and are expanded by another crystallographically independent Co ion in the structure. Binding of the cations to the O atoms of the POM and the N atoms of organic ligand resulted in the formation of a 2D CP structure. Compound 1 is the first example of an inorganic-organic polymer architecture constructed from Evans-Showell-type POM in which Co cations act as metal nodes. The topology of 1 can be rationalized as a 2D square lattice (sql) coordination network with point symbol {44.62} in which [Co2Mo10H4O38]6− and 4,4′-bipyridine units act as linkers and the Co cations as nodes. The cytotoxicity effects of the POM were evaluated on the cancer CT26 and normal L929 cell lines by an MTT assay from which an IC50 value of cancer CT26 cells of approximately 366 ppm was obtained, but normal L929 cells did not show significant toxicity.

Colorimetric recognition of a biomarker of trichloroethylene in human urine and photocatalytic dye degradation employing unprecedented Co(II) MOF luminescent probe

The Co(II) ion was combined with the ligand Bis(2-Carboxyethyl)isocyanurate at room temperature to form a new MOF, [Co(Cei)]n. This polymer was then characterised using various techniques including FT-IR analysis, Powder X-ray diffraction, thermal analysis, and SEM-EDAX analysis. Single crystal X-ray analysis reveals that the compound [Co(Cei)]n forms a 12-c connected uninodal net with a point symbol of {324.436.56}. This net has an underlying net with face-centred cubic (fcu) topology, which can effectively detect TCA in human urine. Furthermore, it demonstrates exceptional specificity by detecting concentrations as low as 1.09 ppm in real human urine. Extensive study has been conducted on the recyclability and photocatalytic effectiveness of [Co(Cei)]n for the degradation of organic dyes. Out of the 13 dyes studied, the photocatalytic breakdown efficiency of [Co(Cei)]n is highest for the potentially dangerous organic dyes Neutral Red (NR), with highest percentages of degradation i.e. 93.44 %.

Enhanced Catalytic Activity of a Copper(II) Metal-Organic Framework Constructed via Semireversible Single-Crystal-to-Single-Crystal Dehydration.

Herein, we present a copper(II) metal-organic framework, [Cu2(btec)(OH2)4]·2H2O (1) [(btec)4- = 1,2,4,5-benzenetetracarboxylate], that undergoes single-crystal-to-single-crystal transformations into two anhydrous phases 2' and 2″ with the chemical formula [Cu2(btec)], triggered by two-step dehydration at 403 and 433 K, respectively. After immersion in water for 3 days at room temperature, 2' transformed into [Cu2(btec)(OH2)] (3), while both 2' and 2″ took 1 week to revert to 1. Dynamic vapor sorption studies validated water-induced reversible structural transformations at 70% relative humidity (RH). According to single-crystal X-ray diffraction (SC-XRD), the local coordination geometry of the Cu2+ ion in 2' changed from a saturated octahedron to a coordinatively unsaturated square-based pyramid in 3, manifested by changes in color and dimensionality. From a topological point of view, all of the scaffolds show a binodal (3,6)-connected kgd topology with the point symbol {43}2{46}. In addition, the materials were thoroughly characterized using routine spectroscopic data and various analytical techniques. The catalytic activity of the microporous materials in the liquid-phase oxidation of styrene in acetonitrile, using 30% (wt) H2O2 as the oxidant, was investigated. The excellent performance of the monohydrous phase 3 was shown to be superior to the pristine framework and the anhydrous counterparts, as evidenced by a good turnover number (TON) and turnover frequency (TOF) = 82.6 and 21.0 h-1, respectively. Within 4 h, the substrates were catalytically oxidized to the desired products with up to 67% conversion and 100% benzaldehyde selectivity. It is worth noting that the accessible active metal sites and higher surface area enhanced the catalytic properties of 3. Furthermore, the maintenance of catalytic efficiency over five cycles and reusability are illustrated and discussed in terms of the structural differences of the microporous frameworks. Thus, a preliminary reaction mechanism for the selective oxidation of styrene is proposed. This study not only provides a fascinating example of MOF chromism achieved by thermal activation and rehydration but also sheds some light on the relationship between pore-surface- or metal-engineered sites in MOFs and their heterogeneous catalytic performances.

Zinc(II)-MOF: A Versatile Luminescent Sensor for Selective Molecular Recognition of Flame Retardants and Antibiotics.

An exceptional Zinc(II)-organic framework with the formula [{Zn(L4-py)(bdc)}·DMF]n (Zn-MOF) has been constructed solvothermally using a novel linker L4-py {2,7-bis(3-(pyridin-4-ylethynyl)phenyl)benzo[lmn][3,8]phenanthroline-1,3,6,8(2H,7H)-tetraone}, coligand H2bdc (1,4-benzenedicarboxylic acid), and ZnBF4·xH2O. The ligand L4-py has been fabricated after functionalization of NDA (1,4,5,8-naphthalenetetracarboxylic dianhydride) core with 3-(pyridin-4-ylethynyl)phenyl group. The single-crystal X-ray analysis reveals that Zn-MOF exhibits a comprehensive three-dimensional (3D) framework architecture and features (4)-connected uninodal dia; 4/6/c1; sqc6 topology with point symbol {66} and two-dimensional (2D) + 2D, parallel polycatenation. Notably, Zn-MOF displayed excellent fluorescence phenomenon and stability in water as well as in methanol solvents and was harnessed as a versatile sensor, demonstrating selective and sensitive molecular recognition of flame retardants and antibiotics. Notably, Zn-MOF displayed 57 and 49.5% quenching efficiency for the flame-retardant pentabromophenol (PBP) and 3,3',5,5'-tetrabromobisphenol A (TBPA), respectively. Whereas an outstanding 90% quenching efficiency was observed for antibiotics, tetracycline (TC) and secnidazole (SD). The mechanistic investigations of this luminescence quenching suggest that this might be primarily occurring via the Fourier resonance energy transfer (FRET) and photoinduced electron transfer (PET) mechanisms, which might be assisted by the competitive absorption and host-guest interactions. The π-electron-rich framework structure of sensor Zn-MOF activates this mechanism.

A New Tripodal Zwitterionic Ligand-Based Cationic Manganese(II) Metal-Organic Framework: Synthesis, Characterization and Photochromic Property

A new flexible tripodal 1,1′,1′′-(((1,3,5-triazin-2,4,6-triyl)tris(benzene-4,1-diyl))tris(methylene))tris(3-carboxypyridin-1-ium) bromide (H3taznaBr3) ligand and its new Manganese(II) compound, namely {[Mn(µ6-tazna)]Cl2·4H2O}n(OGU − 1, OGU: Osmangazi University), were synthesized and structurally characterized by IR spectroscopy, elemental analysis, X-ray single-crystal and powder diffraction techniques. Single crystal X-ray diffraction analysis revealed that the OGU − 1 is 3D framework, possessing 1D channels along the b-axis with dimensions of 9.39 × 13.63 Å2, in which 1D channels are filled with chloride ions and lattice water molecules. The OGU − 1 displayed a 6,6-connected net with a point symbol of {48.66.8}{49.66}. Furthermore, thermal (TG, DTA and DTA) and photochromic properties of the OGU − 1 were investigated and it exhibited color change under 365 nm UV light.

Synthesis, Structural Characterization and Hirshfeld Surface Analysis of a Novel Cd(II) Coordination Polymer with Mixed N- and O-donor Linker

In the present study, we report the room temperature synthesis of a novel two-dimensional (2D) coordination polymer (CP) having the formula {[Cd(H-PCA)2(H2O)].0.5(H2O).0.5(CH3OH)}n (CP1), where H-PCA represents 4-pyrazolecarboxylate. The synthesis of CP1 was achieved through a one-pot reaction, involving the self-assembly of Cd(OAc)2·2H2O and the multitopic mixed N- and O-donor ligand, 4-pyrazolecarboxylic acid (H2-PCA), in methanol. This method demonstrated high yield and purity, enabling the facile production of multigram quantities of CP1 within a short timeframe. Notably, the synthetic procedure selectively deprotonates the carboxylic acid group while retaining the pyrazole moiety in its protonated form.CP1 has been thoroughly characterized using various analytical techniques, including single-crystal X-ray diffraction, FTIR spectroscopy, elemental analysis, scanning electron microscopy, thermogravimetric analysis, and powder X-ray diffraction. The structural analysis revealed that CP1 features a 3, 5-connected binodal net with the point symbol {4.5.6}{4.55.63.7}, leading to a unique –ths net topology. Through hydrogen bonding connections between adjacent 2D sheets, CP1 further extends into a three-dimensional (3D) supramolecular network due to the presence of coordinated water molecules and the protonated pyrazole group. Additionally, a 3D Hirshfeld Surface analysis accompanied by quantitative 2D fingerprint plots was also investigated to explore the intermolecular interactions.

Fabrication of Unique Mixed-Valent CoICoII and CuICuII Metal-Organic Frameworks (MOFs) for Desulfurization of Fuels: A Combined Experimental and Theoretical Approach toward Green Fuel.

Herein, metal-organic framework (MOF)-based adsorbents are designed with distinct hard and soft metal building units, namely, [Co2ICoII(PD)2(BP)] (Co_PD-BP) and [Cu2ICuII(PD)2(BP)] (Cu_PD-BP), where H2PD = pyrazine-1,4-diide-2,3-dicarboxylic acid and BP = 4,4'-bipyridine. The designed MOFs were characterized via spectral and SCXRD techniques, which confirm the mixed-valent states (+1 and +2) of the metal ions. Topological analysis revealed the rare ths and gwg topologies for Co MOF, while Cu-MOF exhibits a unique 8T21 topology in the 8-c net (point symbol for net: {424·64}). Moreover, severe environmental issues can be resolved by effectively removing heterocyclic organosulfur compounds from fuels via adsorptive desulfurization. Further, the developed MOFs were investigated for sulfur removal via adsorptive desulfurization from a model fuel consisting of dibenzothiophene (DBT), benzothiophene (BT), and thiophene (T) in the liquid phase using n-octane as a solvent. The findings revealed that Cu_PD-BP effectively removes the DBT with a removal efficiency of 86% at 300 ppm and an operating temperature of 25 °C, with a recyclability of up to four cycles. The adsorption kinetic analysis showed that the pseudo-first-order model could fit better with the experimental data indicating the physisorption process. Further, the studies revealed that adsorption capacity increased with the increasing initial DBT concentration with a remarkable capacity of 70.5 mg/g, and the adsorption process was well described by the Langmuir isotherm. The plausible reason behind the enhanced removal efficiency shown by Cu_PD-BP as compared to Co_PD-BP could be the soft-soft interactions between soft sulfur and soft Cu metal centers. Interestingly, density functional theory (DFT) studies were done in order to predict the mechanism of binding of thiophenic compounds with Cu_PD-BP, which further ascertained that along with other interactions, the S···π and S···Cu interactions predominate, resulting in a high uptake of DBT as compared to others. In essence, Cu_PD-BP turns out to be a promising adsorbent in the field of fuel desulfurization for the benefit of mankind.

Construction of 2D layered metal‐organic frameworks based on the norbornene‐derived ligand with fascinating magnetic and luminescent properties

AbstractThree new two‐dimensional metal‐organic frameworks (MOFs), namely [Cu3(NDIC)3 ⋅ C2H5OH ⋅ 2H2O]n (1), [Co2(NDIC)2 ⋅ 2 C3H7NO ⋅ H2O]n ⋅ nC2H5OH (2) and [(Zn3O)2(Zn(H2O)4)(NDIC)6 ⋅ C3H7NO ⋅ C2H5OH ⋅ C2H5O ⋅ 7H2O]n (3) based on the ligand 5‐norbonene‐2,3‐dicarboximide isophthalic acid (H2NDIC) have been synthesized under solvothermal condition, which have been further characterized by single crystal X‐ray diffraction analysis, powder X‐ray diffraction ( PXRD) elemental analysis, ICP, TG and FT‐IR spectroscopy. The ligand displayed distinctive coordination modes to connect mononuclear metal ion, binuclear and trinuclear metal clusters to generate different 2D layered structures in compound 1–3. Compound 1 shows KGM type network based on paddle‐wheel Cu2(COO)4 as secondary building units (SBUs). Compounds 2 and 3 have the undulating 2D (4, 4) SQL topology with the point symbol (44 ⋅ 62) based on Co2(COO)4 and Zn3(μ3‐O)(COO)4 as SBUs, respectively. The magnetic properties of compound 1–2 and the luminescent property of compound 3 and its fluorescent detection for Fe3+ has been investigated and discussed.