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A quinoline-containing semi-salamo-type ligand, HL, was synthesized and a dinuclear Ni(II) complex, [Ni2(L)2(NCS)2], was produced. The complex was experimentally analyzed by elemental analysis, fluorescence, and UV–Vis spectroscopy. X-ray single crystal diffraction experiments showed that the complex is a six-coordinate, structurally symmetric, phenoxy-bridged dinuclear Ni(II) dimer with the participation of SCN− in the coordination to satisfy charge neutrality. The self-assembly forms a 2-D supramolecular network structure through hydrogen bonding and π⋯π interactions. DFT calculations were performed on the complex to analyze its energy gaps, and UV–Vis experiment was verified by TD-DFT calculation. In addition, close intermolecular contacts were investigated by Hirshfeld surface analysis to quantify the crystal structure interaction. [ABSTRACT FROM AUTHOR]

New di- and tetranuclear Cu(II) complexes, [Cu2(HL)Cl2(MeOH)]·MeOH·2CH2Cl2 (1) and [Cu4(L)2(MeOH)2](NO3)2·EtOH (2), have been synthesized from CuCl2·2H2O, Cu(NO3)2·3H2O and a symmetric 5-bromosalicylaldehyde-decorated bis(salamo)-like ligand (H3L, (1E,3E)-2-hydroxy-5-methylisophthalaldehyde O,O-di(2-((((E)-5-bromo-2-hydroxybenzylidene)amino)-oxy)ethyl)dioxime), and characterized by elemental analyses, IR and UV–vis spectra. Single crystal structure analyses showed a dinuclear Cu(II) structure for 1 and a tetranuclear Cu(II) structure for 2. In 1, two Cu(II) ions are on one side of the double N2O2 cavities, and the phenol proton in the other cavity is attached. In 2, four Cu(II) ions are located in four N2O2 cavities of two fully deprotonated L3− units, giving a centrosymmetric double helix structure. The Hirshfeld surfaces analyses, Interaction Region Indicator (IRI), and DFT computations of H3L, 1, and 2 were studied. In addition, the electrochemical and fluorescence properties of 1 and 2 were also investigated. [ABSTRACT FROM AUTHOR]

A symmetrical N2O2-tetradentate dioxime chemical sensor H2L was synthesized for the first time. The sensor H2L can identify S2– ion with dual channels of fluorescence–ultraviolet spectra, and through the calculation of binding constant and detection limit of L-S system, it was showed that H2L can detect S2– ion with high efficiency and specificity. pH response experiments were carried out on L-S system and H2L to explore the pH range recognized by them. The recognition mechanism was determined by 1H NMR titration experiment. At the same time, a new method of macro recognition by means of naked eye recognition (under natural light and ultraviolet light of 365 nm) and filter paper recognition was developed. The practical application of the sensor H2L to detect H2S was evaluated in actual water samples and identification experiment of H2S. [ABSTRACT FROM AUTHOR]

The coordination behaviors of asymmetric quinoline-decorated half-salamo-type ligand HL1 with Cu(NO3)2·3H2O and Cu(OAc)2·H2O were studied. Two Cu(II) complexes, [Cu(L1)(NO3)]·CH3CH2OH (1) and [Cu2(L2)2] (2), were isolated and characterized by X-ray crystallography, FTIR, UV–vis, and fluorescence spectroscopies. Structural analyses showed that 1 is a mononuclear species, whereas 2 is a binuclear entity. Spontaneous cleavage along the oxime N-O bond close to quinoline ring of the ligand HL1 occurred upon reaction with Cu(OAc)2·H2O, yielding an unexpected complex 2. Moreover, DFT theoretical calculations and Hirshfeld surfaces analyses of the ligand HL1 and its corresponding Cu(II) complexes were investigated in detail. [ABSTRACT FROM AUTHOR]

Two structurally different Cu(II) and Co(II) complexes, [Cu(L)] (1) and [Co2(L)2]⋅2CH3OH (2), constructed from a new polyhalogen-substituted unsymmetric salamo-based ligand (H2L, 4-chloro-4′-bromo-6-bromo-6′-tert-butyl-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) were synthesized by wet-chemical methods. Complexes 1 and 2 were characterized through elemental analyses, IR and UV-vis spectroscopies and single crystal X-ray crystallography. In addition, the differences of the structures, electronic absorption characteristics and fluorescence property transitions from the ligand to complexes 1 and 2 were studied. The largest difference is that the ligand H2L can react with M(OAc)2 (M = Cu(II) and Co(II)) to give two complexes with distinct structures and behaviors. There are two chemically identical but crystallographically independent structural units (molecules A and B) in 1. Moreover, each Cu(II) ion (Cu1 or Cu2) is four-coordinate and possesses a square planar geometry, but both Co(II) ions of 2 are bridged by phenoxide ions and possess five-coordinate trigonal bipyramidal configurations. At the same time, Hirshfeld surface analyses showed there are short-range interaction features from the ligand to complexes 1 and 2, the O···H/H···O interactions of the ligand are significantly stronger than those of 1 and 2. [ABSTRACT FROM AUTHOR]

A bis(half-salamo)-type chemosensor LPBHSbased on phenanthroline, which can identify multiple targets continuously, was synthesized. The chemosensor LPBHS utilizes the N3O cavities to combine with metal cations, and further identify the anions after the complexes have been formed. The chemosensor LPBHS has an O-phenanthroline unit with excellent luminescence, so that the strong fluorescence of the chemosensor LPBHS can be observed under 365 nm UV light. The quenching of luminescence occurs after the introduction of Cu2+ and Co2+ into the chemosensor LPBHS, which can be identified in natural light by observing the change in color of the solution with the naked eye. The LPBHS-Cu2+ complex further recognizes HSˉ and PPi (pyrophosphoric acid), and strong luminescence are also observed under UV light after the addition of HSˉ and PPi to LPBHS-Cu2+. HSˉ and PPi can also be identified by the change in color of the solution under natural light with the naked eye. Using the strong fluorescence emission of LPBHS, a test strip was developed to detect Cu2+ and Co2+ rapidly, and the quenching of fluorescence was clearly observed under UV light. HSˉ and PPi can be further identified by the phenomenon of fluorescence recovery after Cu2+ detection on the test strip. [ABSTRACT FROM AUTHOR]

Two dinuclear Ni (II) and Zn (II) salamo‐type complexes, [Ni2(L)(μ‐OAc)(MeOH)]·2CHCl3 (1) and [{Zn2(L)(μ‐OMe)}3]·3CHCl3·MeOH (2), have been successfully synthesized by wet‐chemical method and characterized by elemental analyses, IR spectra, UV–Vis spectra and single crystal X‐ray diffraction. Complex 1 consists of two closely related dinuclear units 1A and 1B, and complex 2 consists of three closely related dinuclear units 2A, 2B and 2C. The five units are unique example of crystallographically independent but chemically identical molecules. The Ni (II) atoms of complex 1 are located in the N2O4 coordination cavities, possessing six‐coordinated distorted octahedral geometries, but all Zn (II) atoms in complex 2 are located in the N2O3 coordination cavities, possessing five‐coordinated distorted square‐pyramid and triangular bipyramid geometries, the geometries about the Zn (II) atoms (Zn3 and Zn6) that obtain in 2B and 2C where τ5 is very close to 0.500, which is τ5Zn3 = 0.5006 and τ5Zn6 = 0.4941, respectively. The interactions were quantitatively determined by Hirshfeld surfaces analyses. Significantly, fluorescence properties were also investigated. [ABSTRACT FROM AUTHOR]

Three novel multinuclear NiII complexes, namely, bis{μ‐2‐methoxy‐6‐[8‐(pyridin‐2‐yl)‐3,6‐dioxa‐2,7‐diazaocta‐1,7‐dien‐1‐yl]phenolato}bis[thiocyanatonickel(II)], [Ni2(L)2(NCS)2], 1, bis{μ‐2‐methoxy‐6‐[8‐(pyridin‐2‐yl)‐3,6‐dioxa‐2,7‐diazaocta‐1,7‐dien‐1‐yl]phenolato}bis[azidonickel(II)], [Ni2(L)2(N3)2], 2, and catena‐poly[[{2‐methoxy‐6‐[8‐(pyridin‐2‐yl)‐3,6‐dioxa‐2,7‐diazaocta‐1,7‐dien‐1‐yl]phenolato}nickel(II)]‐μ‐dicyanamidato], [Ni(L)(dca)]n, 3 {dca is dicyanamide, C2N3, and HL is 2‐methoxy‐6‐[8‐(pyridin‐2‐yl)‐3,6‐dioxa‐2,7‐diazaocta‐1,7‐dien‐1‐yl]phenol, C16H17N3O4}, with a half‐salamo‐based pyridine‐containing HL ligand have been synthesized and characterized by FT–IR, UV–Vis absorption spectroscopy, X‐ray crystallography, Hirshfeld surface analysis and density functional theory (DFT) calculations. The central NiII ions in complexes 1–3 are hosted in the half‐salamo‐based N3O‐donor cavity of the organic ligand. Complex 1 is a centrosymmetric dimer and two [Ni(L)(NCS)] units form a centrosymmetric dimeric structure, which is bridged by two phenolate O atoms. The two N atoms at the axial ends are provided by two NCS− ligands. In complex 1, each NiII ion has a six‐coordinated octahedral geometry. Complex 2 is similar to 1, but they differ in that the auxiliary NCS− ligand is replaced by N3−. However, complex 3 is a one‐dimensional coordination polymer constructed from [Ni(L)(dca)] units, which are connected by the auxiliary bidentate dca ligand viaN‐donor atoms. As with complexes 1 and 2, the NiII ion in 3 has a six‐coordinated octahedral geometry. [ABSTRACT FROM AUTHOR]

Two new tetranuclear NiII complexes, [Ni4(L1)2(N3)4(MeOH)2]·CH3COCH3(1) and [Ni4(L2)2(N3)4(MeOH)2]·4CH3COCH3(2), were synthesized using NiCl2·6H2O, NaN3, and asymmetric salamo‐based ligands H2L1 and H2L2, respectively. The structural characterization was made by elemental analyses, infrared (IR) and ultraviolet‐visible (UV‐vis) spectra, and X‐ray diffraction analyses. The results of X‐ray diffraction analyses show that the NiII atoms in complexes 1 and 2 are distorted octahedral geometries. Interestingly, the degree of distortion of the ligands in complexes 1 and 2 is different, which indicates that the interaction of NiII ions on different ligands is different. Meanwhile, the investigation of molecular packing by employing the Hirshfeld surface analysis exhibits that the percentages of C–H/H–C, O–H/H–O, and H–H/H–H contacts of the complex 1 (or 2) are calculated to be 17.7%, 7.9%, and 53.7% (or 18.8%, 13.8%, and 52.5%), respectively, where the H–H/H–H contacts have the characteristics of strong contacts whereas the O–H/H–O hydrogen bonds are considerably weak, and the studies on fluorescence properties further confirm the NiII atoms have different binding abilities to the different ligands. [ABSTRACT FROM AUTHOR]

One homo-trinuclear 3d and five novel windmill-type hetero-pentanuclear 3d-4f complexes [Zn3(L)(OAc)2(H2O)]·CH2Cl2 (1), [Zn4(L)2Sm(NO3)2(EtOH)2]NO3·H2O·2CHCl3 (2), [Zn4(L)2Eu(NO3)2(EtOH)2]NO3·C2H5OH·2CHCl3 (3), [Zn4(L)2Gd(NO3)2(EtOH)2]NO3·C2H5OH·2CHCl3 (4), [Zn4(L)2Tb(NO3)2(EtOH)2]NO3·C2H5OH (5) and [Zn4(L)2Dy(NO3)2(EtOH)2]NO3·C2H5OH·2CHCl3 (6) were synthesized by the reactions of a new bis(Salamo)-based tetraoxime ligand (H4L) with Zn(OAc)2·2H2O and Ln(NO3)3·6H2O (Ln = Sm, Eu, Gd, Tb and Dy), respectively. The structures of complexes 1–6 were characterized via elemental analyses, FT-IR spectroscopy, UV-Vis spectroscopy and single crystal X-ray crystallography, and their fluorescence properties, catalytic activities and Hirshfeld surface analyses were studied. [ABSTRACT FROM AUTHOR]

[Display omitted] • Two hetero Eu/Tb-MOFs based on the same ligand H 3 BTB were synthesized solvothermally. • The two hetero Eu/Tb-MOFs exhibit different energy transfer efficiencies from Tb3+ to Eu3+. • The two hetero Eu/Tb-MOFs exhibit different performance in ratiomatric fluorescence detection of 2,6-dipicolinic acid (DPA). • The mechanism of sensing properties was discussed in detail. As one of the most important biomarkers of anthrax, accurate and sensitive detection of 2,6-dipicolinic acid (DPA) is essential to protect against anthrax disease or biological terrorist attack. This work presented seven MOFs of two different structures based on the same ligand H 3 BTB: five single Ln-MOFs [Ln(BTB)(DMF)] (Ln = Y3+ (1), Eu3+ (2) and Tb3+ (3)) and [Ln(BTB)(H 2 O)] (Ln = Eu3+ (5), Tb3+ (6)), and two optimized hetero Eu/Tb-MOFs [Tb 0.9 Eu 0.1 (BTB)(DMF)] (4) and [Tb 0.9 Eu 0.1 (BTB)(H 2 O)] (7). This work aimed at the crystal structures and energy transfer processes regulation of the fluorescence properties and detecting DPA. These two hetero Eu/Tb-MOFs 4 and 7 exhibit different energy transfer efficiency from Tb3+ to Eu3+ (4 : 15.23%; 7 : 96.86%), and the above energy transfer process could be influenced by DPA. Radiometric fluorescence detection of DPA was first studied in contrast by modulating the structure and energy transfer process in hetero Eu/Tb-MOFs. The detection limits of 4 and 7 for DPA were 0.078 μM (4) and 0.24 μM (7). In addition, 13 interferents did not affect the DPA detection. The high selectivity and good reproducibility of sensing DPA make hetero Eu/Tb-MOFs promising materials for applications in convenient bacillus anthracis detection. [ABSTRACT FROM AUTHOR]

A trinuclear Co(II) complex, [{CoL(C4H9OH)}2-(OAc)2Co]·C3H7NO, was synthesized by the reaction of a Salamo-type chelating ligand (H2L=4,42′-dinitro-2,2′-[1,2-ethylenedioxybis(nitrilomethylidyne)]diphenol) with cobalt(II) acetate tetrahydrate in n-butanol, and characterized by elemental analyses, X-ray crystallography, FT-IR and UV/Vis spectra. In the Co(II) complex, there are two ligand L2− units, two μ2-acetate ions, two coordinated n-butanol molecules and one non-coordinated N,N-dimethylformamide molecule. The Co(II) atoms in the structure of the Co(II) complex adopt slightly distorted octahedra geometries. Furthermore, through intermolecular C–H···O, O–H···O and C–H···π interactions, infinite layer-like, plane-like and 3D supramolecular structures are constructed. The fluorescence and electrochemical properties of the Co(II) complex have also been investigated. [ABSTRACT FROM AUTHOR]

A new tetranuclear Zn( II) complex, [{Zn(L)(μ- OAc)Zn( H2O)}2], based on an asymmetrical salamo-type bisoxime chelating ligand H3L (6-hydroxy-4′-chloro-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol) was synthesized and characterized by elemental analyses, differential thermal methods, single-crystal X-ray crystallography, and IR, UV-vis, and fluorescence spectra. The Zn( II) complex crystallizes in the triclinic system, space group P-1 with cell parameters a = 9.0742(6) Å, b = 11.8225(5) Å, c = 12.4182(8) Å, Z = 2, V = 1212.56(12) Å3, R1 = 0.0572, and wR2 = 0.1734. The environment of the tetranuclear Zn(II) complex is penta-coordinated having a slightly distorted trigonal bipyramidal geometry. Moreover, a 1D chain supramolecular structure is formed along the c-axis by the intermolecular C1-H1B⋯O14 hydrogen bonds; in the same manner, C2-H2C⋯Cg2 functions in the formation of supramolecular structures along the a-axis of the 1D chain. A 2D supramolecular structure along the ac plane extends infinitely under the force of intermolecular hydrogen bonds. Differential scanning calorimetry-thermogravimetry thermal analysis provides evidence of the coordination of Zn(II) atoms to the ligand H3L. The Zn(II) complex shows intense photoluminescence with a maximum emission at ~453 nm upon excitation at 360 nm. [ABSTRACT FROM AUTHOR]

A novel Schiff-base oxime sensor H 2 L with the ONON chelating moieties was designed and synthesized based on condensation reaction. Different methods such as elemental analyses, FT-IR, 1 H and 13 C NMR were fully utilized in characterizing the structure of sensor H 2 L. The UV–vis spectra of the Zn 2+ complex exhibit four clear isosbestic points which may be assigned to the ONON moieties binding to Zn 2+ . Sensor H 2 L operates on the CHEF and PET mechanisms, and the tendency of Zn 2+ to strongly enhance fluorescence of sensor H 2 L was explored. Fluorescence measurements show that sensor H 2 L has excellent fluorescent selectivity for Zn 2+ over many other metal ions based on intramolecular charge-transfer, and the results demonstrate that the binding between sensor H 2 L and Zn 2+ is chemically reversible. The crystal structure of the Zn 2+ complex has been characterized by X-ray crystallography. [ABSTRACT FROM AUTHOR]

A new mononuclear Zn(II) complex, [ZnL(HOAc)] (1) (H2L = 6,6′-diethoxy-2,2′-[1,2-ethylenedioxybis(nitrilomethylidyne)]diphenol), was synthesized by reaction of H2L and Zn(II) acetate under solvothermal conditions. Complex1acts as a metallohost possessing a pentadentate O5donor. Complex1molecules bonded to one Sr(II) or Ba(II) form two new hetero-trinuclear complexes, [(ZnL)2M(OAc)2] (M = Sr (2), Ba (3)). In2and3, Zn(II) ions are 5-coordinate, but the Sr(II) or Ba(II) ion is 10-coordinate by fourμ-phenolic oxygens from two L2−units, four oxygens from four ethoxy groups and two oxygens from twoμ-acetato ligands. Furthermore,1–3exhibit blue emissions with the maximum emission wavelengthsλmax = 477, 500, and 471 nm when excited at 360 nm. [ABSTRACT FROM PUBLISHER]

A novel single-armed Salamo-type bisoximes (H 3 L) has been designed and synthesized firstly. A new application of Salamo-type bisoximes in ion recognition is investigated in detail. H 3 L can act as a relay–sensor for ratiometric recognition of Zn 2+ /Cu 2+ with high selectivity and sensitivity. The Zn 2+ and Cu 2+ complexes behave successive sensing of H + /OH − through fluorescence intensity increasing (ON) and decreasing (OFF). Meanwhile, the crystal structures of the Zn 2+ and Cu 2+ complexes based on H 3 L, [Zn(L)( μ -OAc)Zn] and [Cu(L)(μ-OAc)Cu], have been determined by X-ray crystallographic analyses, respectively. [ABSTRACT FROM AUTHOR]

Three multinuclear complexes, [{Cu(HL)(OAc)Cu} 2 ]·CH 3 OH, [Zn(HL)(OAc)Zn(CH 3 CH 2 OH)] and [{Cd(HL)(OAc)Cd(CH 3 CH 2 OH)} 2 ]·2CHCl 3 , have been synthesized with an asymmetric Salamo-type ligand H 4 L, and characterized by FT-IR, UV–vis spectra and X-ray crystallography. The Cu(II) complex contains two crystallographically independent but chemically identical dinuclear complexes (molecules 1 and 2). Meanwhile, self-assembled infinite 1D, 2D and 3D structures are formed by intermolecular hydrogen bonds and C–H⋯π interactions of neighboring complexes in the solid state. The Zn(II) complex also forms a novel dinuclear structure. And a self-assembled infinite 2D structure is formed by C–H⋯π interaction of neighboring complexes in the solid state. Otherwise, the Cd(II) complex forms an infinite 1D structure by C–H⋯π interaction of the neighboring complex molecules. In addition, the photophysical properties of the Cu(II), Zn(II) and Cd(II) complexes have also been discussed. [ABSTRACT FROM AUTHOR]

Two multinuclear Co(II) complexes, [{Co(L)(i-PrOH)}2Co(H2O)]∙2CH3CN (1) and [{Co(L)(μ-OAc)Co(MeOH)2}2]∙2CH3COCH3(2), have been synthesized with a new asymmetric Salamo-type ligand (H3L  =  6-hydroxy-6′-ethoxy-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol). The Co(II) complexes were obtained by different solvents, and the structures are completely different. In the Co(II) complex1, the ratio of the ligand H3L to Co(II) atom is 2 : 3 and the Co(II) ions are all five-coordinate with trigonal bipyramidal geometries. In the Co(II) complex2, the ratio of the ligand H3L to Co(II) atom is 2 : 4. Two central Co(II) ions are six coordinate with distorted octahedral geometries and two terminal Co(II) ions are five coordinate with distorted trigonal bipyramidal geometries. Self-assembling of an infinite 1-D supramolecular chain is formed by C–H⋯πinteractions in1. Interestingly, an infinite 2-D-layer plane structure is formed by the self-assembling array of2linked by C–H⋯πinteractions.1and2exhibit blue emissions with the maximum emission wavelengthsλmax  =  403 and 395 nm when excited at 330 nm. [ABSTRACT FROM PUBLISHER]

Two trinuclear CoII and ZnII complexes, [(CoL)2(OAc)2Co] and [(ZnL)2(OAc)2Zn], with an asymmetric Salen-type bisoxime ligand [H2L = 4-( N, N-diethylamine)-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol] were synthesized and characterized by elemental analyses, IR, UV/Vis, and fluorescent spectroscopy. The crystal structures of the CoII and ZnII complexes were determined by single-crystal X-ray diffraction methods. The CoII atom is pentacoodinated by N2O2 donor atoms from the (L)2- unit and one oxygen atom from the coordinated acetate ion, resulting in a trigonal bipyramid arrangement. With the help of intermolecular hydrogen bonding C-H ···O and C-H ···π interactions, a self-assembled continual zigzag chain-like supramolecular structure is formed. The ZnII atom is pentacoodinated by N2O2 donor atoms from the (L)2- unit and one oxygen atom from the coordinated acetate ion, resulting in an almost regular trigonal bipyramid arrangement. A self-assembled continual 1D supramolecular chain-like structure is formed by intermolecular hydrogen bonding C-H ···O and C-H ···π interactions. Additionally, the photophysical properties of the CoII and ZnII complexes were discussed. [ABSTRACT FROM AUTHOR]

The twin arginine translocation (Tat) pathway transports fully-folded and assembled proteins in bacteria, archaea and plant thylakoids. The Tat pathway contributes to the virulence of numerous bacterial pathogens that cause disease in humans, cattle and poultry. Thus, the Tat pathway has the potential to be a novel therapeutic target. Deciphering the Tat protein transport mechanism has been challenging since the active translocon only assembles transiently in the presence of substrate and a proton motive force. To identify inhibitors of Tat transport that could be used as biochemical tools and possibly as drug development leads, we developed a high throughput screen (HTS) to assay the effects of compounds in chemical libraries against protein export by the Escherichia coli Tat pathway. The primary screen is a live cell assay based on a fluorescent Tat substrate that becomes degraded in the cytoplasm when Tat transport is inhibited. Consequently, low fluorescence in the presence of a putative Tat inhibitor was scored as a hit. Two diverse chemical libraries were screened, yielding average Z'-factors of 0.74 and 0.44, and hit rates of ~0.5% and 0.04%, respectively. Hits were evaluated by a series of secondary screens. Electric field gradient (Δψ) measurements were particularly important since the bacterial Tat transport requires a Δψ. Seven low IC50 hits were eliminated by Δψ assays, suggesting ionophore activity. As Δψ collapse is generally toxic to animal cells and efficient membrane permeability is generally favored during the selection of library compounds, these results suggest that secondary screening of hits against electrochemical effects should be done early during hit validation. Though none of the short-listed compounds inhibited Tat transport directly, the screening and follow-up assays developed provide a roadmap to pursue Tat transport inhibitors. [ABSTRACT FROM AUTHOR]

A new Cu(II) complex with asymmetric Salamo-type ligand (H2L, 4-bromo-6′-ethoxy-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol) has been synthesized and characterized structurally. The X-ray crystal structure of the Cu(II) complex shows it to be a binuclear complex, in which each Cu(II) atom is in a distorted square-pyramidal geometry. The Cu(II) complex crystallizes in the monoclinic system, space groupP21/c, with unit cell parametersa= 14.7109(1),b= 8.6254(7),c= 30.124(3) Å, β = 100.7400(1), andZ= 4. The Cu(II) complex consists of two Cu(II) atoms, and two L2–units, and each Cu(II) complex molecule links four other molecules into an infinite 2D-layer supramolecular structure. Meanwhile, the Cu(II) complex exhibits emission with the maximum emission wavelength λmax= 443 nm when excited at λex= 340 nm. [ABSTRACT FROM PUBLISHER]

Presented here are two d metal-organic coordination polymers (CPs), [Zn(CO)( μ-OH)] ( 1) and [Cd(CO)(OX)(HO)] ( 2) (HOX = oxalic acid) constructed from squaric acid (HCO) tectons. Single-crystal X-ray diffraction studies indicated that both 1 and 2 show 3D structures. The two 3D CPs are assembled from 1D {[Zn( μ-OH)]} chains to 3D structure linked through CO ligands for 1 and 2D {[(Cd1)(CO)]} layers pillared by OX ligands for 2. The structure of compound 1 can be described as a trinodal (3,6,6)-connected net with the point symbol of {4}{4·6·8}{4·6}, whereas 2 possess a trinodal (4,5,6)-connected {4·8} {4·6·8} {4·6} topology. Furthermore, the fluorescent and thermal stabilities properties of these two compounds were investigated. [ABSTRACT FROM AUTHOR]

Tetranuclear zinc(II) citrates with N-heterocycle ligand, [Zn4(Hcit)2(phen)4(H2O)4]·2NO3·10H2O (1) and [Zn4(Hcit)2(bpy)4(H2O)6]·2NO3·12H2O (2) (H4cit?=?citric acid, phen?=?1,10-phenanthroline, bpy?=?2,2?-bipyridine), were synthesized from aqueous solution and characterized by Infrared, Powder X-ray diffraction, fluorescence spectra, and X-ray structural analyses. Complexes1and2are centrosymmetric tetranuclear species with two crystallographically independent Zn(II) ions, which display different coordination geometries, while the citrate ligand shows similar coordination modes and bridges three different Zn ions. In1, the Zn1 is five-coordinate by three oxygens from two citrates and two nitrogens from phen. There exist weak interactions between Zn1 and O4a atom of ?-carboxy group of citrate (Zn1?O4a?=?2.895?Å). Zn2 is six-coordinate by two oxygens from one citrate, two nitrogens from phen, and two water molecules. Zn1 and Zn2 are bridged by one citrate to form a dinuclear unit, which is further extended to a tetranuclear unit. In2, two citrates bridge two pairs of symmetry-related Zn(II) ions into a tetranuclear unit. The structural analyses of1and2indicate that different tetranuclear species are caused by arrangement of citrates with different steric hindrance of N-chelates.1H and13C NMR spectra indicate that2remains coordinated in D2O. Moreover, both1and2show strong fluorescent emission in dilute solution and solid state. Two tetranuclear zinc(II) citrates with N-heterocycle ligand, [Zn4(Hcit)2(phen)4(H2O)4]·2NO3·10H2O (1) and [Zn4(Hcit)2(bpy)4(H2O)6]·2NO3·12H2O (2) (H4cit?=?citric acid, phen?=?1,10-phenanthroline, bpy?=?2,2?-bipyridine), were synthesized from aqueous solution and characterized by Infrared, Powder X-ray diffraction, fluorescence spectra and X-ray structural analyses.1and2show strong fluorescent emission in dilute solution and solid state. [ABSTRACT FROM PUBLISHER]

Reactive oxygen species (ROS) in the body play an important role in various processes. It is well known that harmful high levels of ROS can cause many problems in living organisms in a variety of ways. One effective way to remove intracellular ROS is to use reducing materials that can enter the cell. Herein, we developed a strong reducing carbon nano-dot from a natural product, lutein, as an initial raw material. This is a hydrothermal synthesis method with the advantages of simplicity, high yield, mild reaction conditions, and environmental friendliness. The prepared carbon dots exhibit bright blue fluorescence, and have good water solubility and biocompatibility. In particular, the carbon dots can easily enter the cell and effectively remove ROS. Therefore, the carbon dots are thought to protect cells from oxidative damage by high levels of ROS. [ABSTRACT FROM AUTHOR]

An unusual self-assembled hetero-bimetallic [Ni(II)-Sm(III)] coordination polymer, [Ni(L)Sm(NO3)3(4,4′-bipy)]n, is prepared through a hexadentate chelating ligand 2,2′-[1,2-ethylenedioxybis(nitrilomethylidyne)]diphenol (H2L). The Ni(II)-Sm(III) coordination polymer is validated through elemental analyses, Fourier-transform infrared and UV-Visible spectroscopies, and X-ray single-crystal diffraction. The Ni(II) atom forms a twisted six-coordinated octahedron, and the Sm(III) atom is ten-coordinated, adopting a twisted bicapped square antiprism. An infinite three-dimensional-layer supramolecular structure is obtained through extensive π···π stacking and intermolecular hydrogen bonding interactions. The polymer has a good antibacterial effect against Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

Three multinuclear Cu (II), Zn (II) and Cd (II) complexes, [Cu2(L)(μ‐OAc)]·CHCl2 (1), [Zn2(L)(μ‐OAc)(H2O)]·3CHCl3 (2) and [{Cd2(L)(OAc)(CH3CH2OH)}2]·2CH3CH2OH (3) with a single‐armed salamo‐like dioxime ligand H3L have been synthesized, and characterized by FT‐IR, UV–vis, X‐ray crystallography and Hirshfeld surfaces analyses. The ligand H3L has a linear structure and C‐H···π interactions between the two molecules. The complex 1 is a dinuclear Cu (II) complex, Cu1 and Cu2 are all five‐coordinate possessing distorted square pyramidal geometries. The complex 2 also forms a dinuclear Zn (II) structure, and Zn1 and Zn2 are all five‐coordinate bearing distorted trigonal bipyramidal geometries. The complex 3 is a symmetrical tetranuclear Cd (II) complex, and Cd1 is a hexa‐coordinate having octahedral configuration and Cd2 is hepta‐coordinate with a pentagonal bipyramidal geometry, and it has π···π interactions inside the molecule. In addition, fluorescence properties of the ligand and its complexes 1–3 have also been discussed. [ABSTRACT FROM AUTHOR]

A new homo-trinuclear Ni(II) half-salamo-based complex [Ni3(L)2(μ-OAc)2(OAc)2(CH3OH)2]·2CH3OH was synthesized via the reaction of a tridentate ligand HL (2-[O-(1-ethyloxyamide)]oxime-4-bromophenol) and Ni(OAc)2·4H2O, and characterized using elemental analyses, IR spectra, UV-Vis absorption spectra, X-ray crystallography, and Hirshfeld analysis. Interestingly, single-crystal X-ray analysis showed that the two acetate molecules were bonded simultaneously with the Ni(II) atoms by mono-dentate chelating and bidentate bridging coordination modes, respectively, and the resulting hexa-coordinate geometries were ultimately formed. Furthermore, the Hirshfeld analysis of the complex was studied. Compared with HL, the complex fluorescence intensity was significantly lowered, indicating that the Ni(II) ions have fluorescence quenching characteristics. [ABSTRACT FROM AUTHOR]

A homotrinuclear ZnII bis(salamo) coordination compound, [LZn3(OAc)2(H2O)] of a new bis(salamo)-like ligand, has been synthesized and structurally characterized using elemental analyses, IR, UV-Vis and fluorescent spectra, and Hirshfeld surface analysis. Hirshfeld surface analyses and X-ray crystallography revealed that complexation between ZnII acetate dihydrate and the ligand H4L afforded a 3:1 (ZnII:L) type coordination compound. Moreover, the X-ray crystal structure analysis demonstrated that two μ2-acetate anions bridge three ZnII atoms in a μ2-fashion forming a homo-trinuclear structure. There were two kinds of ZnII atoms coordination geometries (strongly distorted square pyramidal (Zn1) and distorted trigonal bipyramidal (Zn2 and Zn3)) in the ZnII coordination compound. In addition, a 3D supra-molecular structure was constructed by intermolecular C-H···π and π···π interactions in the ZnII coordination compound. Most importantly, the fluorescent and antimicrobial properties of H4L and its ZnII coordination compound were investigated. [ABSTRACT FROM AUTHOR]

A water stable tetrazolate‐containing metal‐organic framework, [Cd2(L)(OH)(H2O)2]n (1) [H3L = 5‐(4‐(tetrazol‐5‐yl)phenyl)isophthalic acid], was synthesized under solvothermal conditions and structurally characterized. Compound 1 displays a three dimensional porous network with one dimensional tubular channels based on trinuclear cluster [Cd3(μ3‐OH)N4C] units. Notably, 1 exhibits highly sensitive response to Cu2+ and Cr2O72– through luminescence quenching effects with the detection limit of 0.666 ppm for Cu2+ and 0.846 ppm for Cr2O72–, respectively. The possible mechanism of the luminescence quenching was discussed in detail. [ABSTRACT FROM AUTHOR]

Three new supramolecular complexes, [Cu(HL 1 )] ( 1 ), [Cu(L 2 )H 2 O] ( 2 ) and [Co 2 (L 2 ) 2 ]·3CH 3 CN ( 3 ), were designed and synthesized by the reaction of 5-hydroxy-4′,6′-dibromo-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol (H 3 L 1 ) with Cu(II) acetate hydrate (for 1 ); and 6-methoxy-4′,6′-dibromo-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol (H 2 L 2 ) with Cu(II) acetate hydrate (for 2 ) and cobalt(II) acetate tetrahydrate (for 3 ), respectively, and were characterized by element analyses, X-ray crystallography, FT-IR, UV–Vis and fluorescence spectra. Complex 1 is mononuclear and tetra-coordinated and adopts a distorted square-planar geometry, likewise, complex 2 is mononuclear and penta-coordinated with a square-pyramidal geometry, however, complex 3 is dinuclear with the two Co(II) atoms having the same coordination environments and adopt a trigonal bipyramidal geometry. These self-assembling complexes form different dimensional supramolecular structures through inter- and intramolecular hydrogen bonds. Meanwhile, photophysical properties of the three complexes have also been discussed. Furthermore, the fluorescence behaviors of the two Cu(II) complexes in DMF are discussed. [ABSTRACT FROM AUTHOR]

• A nonsymmetric salamo-type ligand H 2 L with an exposed aldehyde was synthesized. • Novel Zn(II) complex and Ni(II) CP were synthesized and characterized. • The theoretical calculations to verify the stability and electroneutrality of the Zn(II) complex and Ni(II) CP. In the first step, we synthesized a nonsymmetric salamo-like ligand, H 2 L, featuring 4-hydroxyisophthalaldehyde and 6‑methoxy-2-[ O -(1-ethoxyamide)]oxime phenol. In the subsequent phase, Zn(II) and Ni(II) complexes, namely [Zn 2 (L) 2 ]·2CH 3 CN·CH 3 OH and [Ni(L)(H 2 O)] n ·nCH 3 COCH 3 , were obtained by treating H 2 L with Zn(II) and Ni(II) ions via a solvent volatilization method. Structural characterizations were carried out using various techniques, including 1H NMR, MS, and X-ray diffraction analysis. Where the phenolic oxygen atoms (O4, O8) bridging two metal atoms (Zn1, Zn2), both five-coordinated Zn(II) atoms are in twisted triangular bipyramidal geometrical configurations, while the Ni(II) atom exhibits a six-coordinated octahedral geometric configuration, the formyl group only participates in the coordination of Ni(II) atom. The existence of multiple interactions, as well as charge distributions between the complexes or CPs (coordination polymers), has also been demonstrated through theoretical calculations IRI (Interaction region indicator), MESP (Molecular electrostatic potential) and Hirshfeld, etc. Fluorescence experiment revealed a significant enhancement in fluorescence intensity upon addition of Zn(OAc) 2 ·2H 2 O, while the fluorescence intensity was quenched upon addition of Ni(NO 3) 2 ·6H 2 O. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel symmetrically double-armed salamo type fluorescent sensor BMS was synthesized. • The high sensitivity and selectivity of BMS in the recognition of MnO 4 - were investigated. • The limit of detection (LOD), limit of quantification (LOQ), and the binding constant (K a) were calculated. • The recognition mechanism of MnO 4 - by BMS has been postulated. • The energy gaps before and after recognition were analyzed by DFT calculation. The symmetrically double-armed salamo type fluorescent sensor BMS , incorporating benzimidazole units, was designed and synthesized. Showcasing remarkable specificity and responsiveness to MnO 4 - within a DMSO:H 2 O (V/V = 9:1, pH = 7.2) Tris-HCl buffer medium, it enabled dual-channel detection of MnO 4 - through fluorescent and colorimetric changes. Critical experimental parameters, including detection and quantification thresholds (LOD and LOQ) along with binding affinity constants (K a), were calculated using the Origin software. A rational interaction mechanism between BMS and MnO 4 - was deduced, based on fluorescence titration, Electrospray Ionization Mass Spectrometry (ESI-MS), Ultraviolet–Visible Spectroscopy (UV–Vis), Infrared Spectroscopy (IR), Stern-Volmer plots, and Density Functional Theory (DFT) computations. Additionally, the sensor BMS was applied to monitor MnO 4 - in real water samples. Advancing its practical utility, BMS was fabricated into test strips for the selective detecting of MnO 4 -. [ABSTRACT FROM AUTHOR]

• A infrequent naphthyl-bis(salamo)-like fluorescence sensor SA was explored. • The probe can specifically recognize Al3+ and has strong anti-interference. • The interaction between probe SA and Al3+ ion was established by DFT study. • The probe can monitor Al3+ in actual water samples. A fluorescent chemical sensor SA for rapid detection of Al3+ ions based on an infrequent longer carbon-chain four-oxime naphthyl-bis(salamo)-like compound was established, and its structure was characterized using FT-IR, 1H NMR, 13C NMR and ESI-MS. In DMF:H 2 O (9:1, V/V) medium, the selective recognition experiment of sensor SA for Al3+ was carried out, and it was found that the measurement solution with Al3+ added at 446 nm shows obvious fluorescence enhancement and blue shift, which is caused by ICT and CHEF effects. Compared with the reported probes, the probe has a lower detection limit and a short response time, which provides a relatively simple and effective method for the detection of Al3+ ions. A reasonable mechanism for the interaction of the probe SA with Al3+ ions was proposed based on fluorescence titration experiments, job, mass spectrometry, NMR titration and the theoretical computational study of DFT. [Display omitted] [ABSTRACT FROM AUTHOR]

A new salamo-like fluorescent chemosensor H 2 L was synthesized, which can selectively recognize Cu2+ and B 4 O 7 2− ions. The sensing mechanism of the sensor was studied through the relevant experiments. The H 2 L sensor's good biocompatibility and excellent water solubility make it very advantageous in practical applications, the sensor H 2 L powder can be used for fingerprint visualization, it can also be loaded on portable test paper for ion detection, and the mixture of the sensor H 2 L and B 4 O 7 2− ions can be used as ink to print safety information. [Display omitted] • A salamo-like fluorescence sensor H 2 L was designed and synthesized. • The sensor H 2 L can selectively recognize Cu2+ and B 4 O 7 2−. • The sensor H 2 L powder can be used for fingerprint visualization. • The mixture of H 2 L and B 4 O 7 2− ions can be used as ink to print safety information. • H 2 L can be loaded on a portable test strip for actual testing of Cu2+ and B 4 O 7 2−. An innovative salamo-like fluorescent chemical sensor H 2 L , has been prepared that can be utilized to selectively detect Cu2+ and B 4 O 7 2− ions. Cu2+ ions can bind to oxime state nitrogen and phenol state oxygen atoms in the chemosensor H 2 L , triggering the LMCT effect leading to fluorescence enhancement. The crystal structure of the copper(II) complex, named as [Cu(L)], has been achieved via X-ray crystallography, and the sensing mechanism has been confirmed by further theoretical calculations with DFT. Besides, the sensor H 2 L recognizes B 4 O 7 2− ions causing an ICT effect resulting in bright blue fluorescence. Moreover, the sensor has relatively high selectivity and sensitivity for Cu2+ and B 4 O 7 2− ions, and the detection limits are 1.02 × 10−7 and 2.06 × 10−7 M, respectively. In addition, the good biocompatibility and excellent water solubility of the sensor H 2 L make it very advantageous in practical applications, using H 2 L powder for fingerprint visualization, using H 2 L to identify the phenomenon of B 4 O 7 2− ions emitting bright blue fluorescence, making it an ink that can print encrypted messages on A4 paper, in addition to this, based on H 2 L , the real water sample was tested for Cu2+ ion recognition, and finally the test strip experiment was carried out. [ABSTRACT FROM AUTHOR]

• A novel bifunctional half-salamo-based sensor JQS was designed and synthesized. • Sensor JQS exhibited high selectivity for Zn2+ and Al3+ ions with distinguishable fluorescent signals. • Combined with the DFT calculation, the sensing mechanisms of JQS toward Zn2+ and Al3+ were proposed. Efficient detection of cationic pollutants released into the environment has become a matter of necessity and challenging task for the health of human beings. To address this, a novel half salamo-based fluorescent sensor JQS was developed and the sensing behavior toward various metal ions was comprehensively studied. The spectroscopic results demonstrated a prominent fluorescence enhancement upon Zn2+ and Al3+ ions were introduced into the sensor solution, and the response occurred at different emission wavelengths (451 nm for Zn2+, 426 nm for Al3+) with different colors, which could be easily distinguished by naked-eye. Various experimental analyses combined with theoretical calculation, the sensing mechanism was proposed. The selective recognition of Zn2+ and Al3+ by JQS was achieved through coordination binding, which leads to the inhibits of photoinduced electronic transfer effect and chelation enhanced fluorescent process. The detection limits of JQS toward Zn2+ and Al3+ were separately calculated to be 0.21 & 0.097 μM. Additionally, the sensing of Zn2+ & Al3+ in real water samples proved its potential for practical utility. A novel bifunctional half salamo-based sensor JQS was designed and synthesized, which exhibited high selectivity for Zn2+and Al3+ ions with distinguishable fluorescent signals. [Display omitted] [ABSTRACT FROM AUTHOR]

Despite the numerous reports on carbon dots (CDs) synthesized from o-phenylenediamine (o-pd), the precise mechanism of fluorescence and formation processes of o-pd CDs have not been investigated. In this study, we purified o-pd CDs and obtained five compounds with yellow, green and blue emission. For the first time, two actual molecular fluorophores named 2,3-Diaminophenazine (DAP) and 2-Amino-3-hydroxyphenazine (AHP) were confirmed. More sophisticated investigations showed the DAP was dominant for the yellow emission, which confirmed molecule states in detail. More interestingly, DAP could form nanoparticles (NPs) with various sizes at different concentrations. In this regard, we propose that the formation processes of o-pd CDs were similar to those of carbonized polymer dots (CPDs), where DAP structures initially aggregated with themselves to form polymeric clusters, further carbonization of polymeric clusters endowed the polymer clusters with a preliminary core-shell structure. With the collapse of the shell and aromatization of the core, the CPDs like structure formed eventually. This study supplements those on the yellow-emissive fluorophores region and could be the potential reference for the preparation of CDs in a similar system. Two fluorophores corresponded to yellow emission named DAP and AHP were separated from o-pd CDs solution by HPLC for the first time, further investigation suggested these CDs formed from the aggregation of DAP. [Display omitted] • The chemical structure of DAP and AHP were confirmed for the first time. • The blank of yellow-emissive fluorophores was supplemented. • The existence of molecule state prepared by rigid precursor was first verified. • The formation of CDs was originated from DAP. • The multi-colors LEDs with high CRI were successfully prepared by fluorophores. [ABSTRACT FROM AUTHOR]

[Display omitted] • The nitrogen heterocycles improve the application value of salamo compounds. • It is rare that the probe can recognize anions stably in a solution with high water content. • The probe achieves the purpose of recognition by oxidative hydrolysis of C = N bond. A unique fluorescent probe Ni-DAS was developed by a nitrogenous heterocyclic oligo(N,O-donor) salamo-based compound DAS. DAS exhibits AIE and ESIPT effects which are extremely infrequent in salamo-based multi-oxime compounds. In addition, Ni-DAS can be used as a fluorescent probe with high selectivity and sensitivity to recognize Cr 2 O 7 2- in DMF with 80 % water content, which enhances the value of the probe for application in real environments, and outperforms most similar molecular fluorescence probes. The probe Ni-DAS can recognize Cr 2 O 7 2- by oxidative hydrolysis of C = N bonds, which promotes further research on theory of C = N bond hydrolysis, and the binding ratio and recognition mechanism were verified and supported by relevant theoretical calculations (DFT & MESP). The experiments showed that the probe Ni-DAS can be used for ion detection in real environments. It provides a new strategy for the oxidative hydrolysis of C = N bond and the structure of salamo-based compounds with AIE nature, and offers new ideas for study ion recognition and acidity detection. [ABSTRACT FROM AUTHOR]

• A double-armed salamo-like ligand was developed. • The crystal structure of the first double-armed salamo-like M(II) complex was reported. • The presence of two bridged acetate groups plays a crucial role in the stability of the complex. • Fluorescence properties and theoretical calculations were investigated. The first double-armed salamo-based tri-nuclear Ni(II) complex, named as [Ni 3 (L)(μ 2 -OAc) 2 ]·3CHCl 3 was successfully self-assembled, and elucidated via elemental analyses, spectroscopic technology and theoretical analyses. The results indicated that one ligand H 4 L has coordinated with three Ni(II) atoms in a 1:3 ratio unreported previously. One of the three Ni(II) atoms is located at the cavity of the N 2 O 2 donor, while other two Ni(II) atoms are sited at the NO 2 cavities formed by double-armed salicylaldehyde moieties, respectively, and further coordinated via two bridging μ 2 -acetate groups, which is a quite novel structure. The fluorescent properties and a range of theory calculations in the ligand and its Ni(II) complex were researched in detail. A novel double-armed salamo-like tri-nuclear Ni(II) complex, [Ni 3 (L)(μ-OAc) 2 ]·3CHCl 3 was successfully self-assembled for the first time. X-ray single-crystal diffraction results showed that the Ni(II) complex is formed by a 1:3 coordination ratio between H 4 L and three Ni(II) atoms and presents a novel structure. Besides, infrared spectroscopy, UV-vis spectroscopy, a series of theoretical calculations and fluorescence properties of H 4 L and its Ni(II) complex were studied. [Display omitted] [ABSTRACT FROM AUTHOR]

• The quinoline-decorated N 3 O-donor half-salamo type ligand HL was designed and synthesized. • Two novel Co(Ⅱ) complexes [Co(L)Cl] (1) and [Co(L)(NCS)] (2) were obtained by the reaction of HL with different Co(Ⅱ) salts. • Quantitative analyses of intermolecular interactions in the crystalline structures were performed by Hirshfeld surfaces analysis. Self-assembly through a quinoline-decorated N 3 O donor half-salamo-type tetradentate ligand HL and coordinative preference of Co(II) ion, two novel Co(II) complexes [Co(L)Cl] (1) and [Co(L)(NCS)] (2) were synthesized and characterized. X-ray crystallography revealed that both complexes 1 and 2 have similar mononuclear structure, in which the five-coordinated Co(II) atoms are not only surrounded by the N 3 O cavity of the deprotonated ligand (L)− unit, but also coordinated with different Cl− and NCS− anions. For the involvement of different anions, the crystal structures of the two complexes exhibit intermolecular C H···Cl and C H···S hydrogen interactions in building supramolecular assemblies, respectively. The two complexes are stabilized by C H···O, C H···N, C H···C, C H···S bonds and C H···π, π···π interactions. The spectral properties of the complexes were investigated through UV–Vis and fluorescence spectroscopy. In addition, the detailed analyses of Hirshfeld surfaces and fingerprint plots provide the basis of the intermolecular interactions in building crystal blocks. Two novel Co(II) complexes, [Co(L)Cl] (1) and [Co(L)(NCS)] (2) with a quinoline-decorated half-salamo type ligand HL were synthesized and characterized structurally. In addition, spectroscopic properties, DFT calculations and Hirshfeld surfaces analyses of HL and its two Co(II) complexes were investigated in detail. [Display omitted] [ABSTRACT FROM AUTHOR]

• An unexpected mono-nuclear Cu(II) complex was successfully prepared. • The complex is formed by the reaction of Cu(II) acetate with H 2 L1, not by the H 3 L. • DFT, ESP and Hirshfeld surfaces analyses of the Cu(II) complex were investigated. An unexpected mono-nuclear Cu(II) complex [Cu(L1)] was successfully prepared by a bis(salamo)-type ligand H 3 L and Cu(OAc) 2 ·H 2 O in ethanol/acetone mixed solvent, and its structure and properties were analyzed. The crystal structure analysis showed that the Cu(II) complex is obtained by the reaction of copper(II) acetate with a new single salamo-type ligand H 2 L1, not obtained from the original ligand H 3 L. The molecular front orbitals HOMO and LUMO of the ligand H 3 L and the Cu(II) complex were analyzed by quantum chemical calculations, and the results showed that the energy gap of the Cu(II) complex is reduced due to the combination of orbitals compared to the ligand. The theoretical reaction sites of the ligand H 3 L with the Cu(II) were analyzed by ESP studies, and the results showed that the crystal structure of the Cu(II) complex is consistent with the theoretical predictions. Hirshfeld surfaces analyses confirmed the rich and diverse interactions present in the Cu(II) complex, which is essential for the stability of the molecules. [Display omitted] The unexpected Cu(II) complex [Cu(L1)] was successfully prepared by a bis(salamo)-type ligand H 3 L, and its structure and properties were analyzed. Unexpectedly, the obtained complex was not formed by the original ligand, but the new ligand formed, H 2 L1, reacted with copper acetate to obtain a mononuclear copper complex due to the catalytic effect of copper acetate on the ligand at N O bond in the oxime group leading to the breakage of the ligand. [ABSTRACT FROM AUTHOR]

• Complexes 1 and 2 were successfully prepared and characterized structurally. • Complex 2 is not obtained from H 3 L but from a new ligand H 2 L1. • Theoretical calculations and fluorescence properties were investigated in detail. Two unusual bis(salamo)-based Co(II) complexes, [Co 2 (L)(OMe)]·2MeOH (1) and [Co 4 (L1) 4 (MeOH) 4 ] (2) were designed and successfully prepared, and characterized structurally. The crystal structure analysis showed that complex 1 is composed of one fully deprotonated ligand (L)3− moity, two divalent Co(II) atoms and one bridge-coordinated methanol molecule, while complex 2 is an asymmetric homotetranuclear structure made up of four Co(II) atoms, four fully deprotonated (L1)2− units and four coordinated methanol molecules. It is noteworthy that the reaction of cobalt(II) nitrate with H 3 L produces complex 2. This complex is not obtained from the original ligand H 3 L but from a new ligand H 2 L1. Therefore, the phenomenon can be used to prepare metal(II/III) complexes with excellent structure. The molecular frontier orbitals HOMO and LUMO of H 3 L and complexes 1 and 2 were analyzed by DFT calculations, and the results showed that the energy gaps of the complexes were reduced due to the combination of the orbitals compared to the ligand. The reaction sites of H 3 L with Co(II) atoms were analyzed by ESP studies, and the results showed that the crystal structures of the complexes are consistent with the theoretical predictions. Hirshfeld surface analyses indicated the different interactions in the complexes, and revealed that the main contributions to the crystal stacking were from H H, C H and H O interactions. The interactions in the complexes were further explored by IRI research, the results exhibited that there are abundant interactions in complexes 1 and 2 , which are important for their construction of supramolecules. The fluorescence strengths of complexes 1 and 2 are significantly lower compared to H 3 L, which can be attributed to the ligand to metal charge transition (LMCT). [ABSTRACT FROM AUTHOR]

• A new salamo-like fluorescence sensor, EAMS, was developed that can be used for highly sensitive detection of ClO− and SCN− by ratiometric fluorescence. • The sensor EAMS has excellent reproducibility and can be recycled at least five times. • During the reversible detection of analytes by the sensor EAMS , the environmental contamination by these two ions is eliminated by redox interaction between ClO− and SCN−. It is widely acknowledged that ClO− and SCN− can have a deleterious influence on the environment and organisms. As a result, novel approaches for detecting ClO− and SCN− are urgently required. Herein, a new Salamo-like fluorescence sensor (denoted as EAMS) was synthesized, and its high sensitivity and rapid recognition of ClO− and SCN− were achieved through the cleavage and generation of Schiff base (imine) bonds in its molecular structure. Upon addition of ClO−, the fluorescence intensity of the sensor EAMS decreased continuously at 395 nm. Notably, when introducing SCN−, the fluorescence intensity of the sensor EAMS was recovered. The sensor EAMS can sensitively and selectively detect ClO− and SCN− with a detection limit of 2.46 nM and 3.27 nM, respectively. Moreover, the sensor EAMS has excellent reversibility and regeneration, effectively reducing the burden on the environment. Tests in actual water samples also confirmed that the sensor EAMS could be used in the real environment, and has the characteristics of fast response, high selectivity, and high sensitivity. As an innovative, sensitive and low-cost sensor, the sensor EAMS has a good application prospect in pollution detection and pathological research of clinical diseases. [Display omitted] [ABSTRACT FROM AUTHOR]

• Successfully synthesized a salamo-type probe NBS for detecting Cu2+ and B 4 O 7 2ˉ. • The additions of Cu2+ and B 4 O 7 2ˉ have opposite fluorescence behavior on NBS. • The detection mechanisms were proposed based on experimental and theoretical researches. A novel salamo-type fluorescent probe NBS (5-(N,N′-diethylamino)-2,2′-[ ethylenedioxybis (nitrilomethylidyne)]phenolnaphthol) for selectively recognition of Cu2+ and B 4 O 7 2ˉ was successfully synthesized. According to the Cu2+ recognition experiment, the probe NBS underwent a coordination process with Cu2+, leading to fluorescence quenching. Theoretical analysis of the recognition mechanism was conducted through DFT calculations. The binding ratio of NBS to Cu2+ was further determined to be 1:1 through high-resolution mass spectrometry. The limit of detection (LOD) of NBS for Cu2+ was calculated to be 3.57 × 10−8 M, and the association constant (K a) was 5.45 × 104 M −1. In addition, the probe NBS can also be used for selective detection of B 4 O 7 2ˉ, which was theoretically analyzed through molecular electrostatic potential. The limit of detection (LOD) of NBS for B 4 O 7 2ˉ was calculated to be 7.13 × 10−8 M, and the association constant was 5.66 × 104 M −1. At the same time, the probe can also quantitatively detect Cu2+ in water samples. A novel asymmetric salamo-type fluorescent probe NBS for detecting Cu2+ and B 4 O 7 2ˉ was successfully synthesized. In a mixed solvent DMF : H 2 O (9:1, V/V, pH=7.2), the NBS probe exhibits good selectivity for Cu2+ and B 4 O 7 2ˉ. The detection limit (LOD), quantification limit (LOQ), and association constant (Ka) of the NBS probe for detecting Cu2+ and B 4 O 7 2ˉ were determined. In addition, based on high-resolution mass spectrometry, Job's plots, DFT calculations, and molecular electrostatic potential analysis, reasonable mechanisms for the interaction between the probe NBS and Cu2+ and B 4 O 7 2ˉ were proposed. Meanwhile, the probe NBS can also be used for quantitative detection of Cu2+ in water samples. [Display omitted] [ABSTRACT FROM AUTHOR]

• A new salamo-like compound H 3 L exhibits strong fluorescence response to Zn2+ions. • The complex sensor l -Zn2+ has high selectivity and sensitivity towards phosphates. • The sensor l -Zn2+ can detect phosphates in complex environments. A new bis(salamo)-like compound H 3 L was designed and synthesized. With the addition of Zn2+ ions to the H 3 L solution, the fluorescence intensity increased significantly and the color changed from blue-cyan to bright green. Based on ESI-MS, UV–Vis spectroscopy and DFT calculations, a plausible mechanism for the interaction of the compound H 3 L with Zn2+ ions is proposed. The in situ complex sensor l -Zn2+ formed by the coordination of the compound H 3 L with Zn2+ions has been used for various anion recognition. The results showed that the sensor l -Zn2+ has high selectivity and sensitivity to phosphates. The fluorescence experiments of the compound H 3 L and sensor l -Zn2+ at different pH values showed that fluorescence response is good in neutral and weak base environment. Simple test paper strips and the detection in real water samples were applied for the detection of phosphates in complex environment. A new salamo-like compound H 3 L was designed and synthesized. With the addition of Zn2+ ions to the H 3 L solution, the fluorescence intensity increased significantly and the color changed from blue-cyan to bright green. The in situ complex sensor l -Zn2+ formed by the coordination of the compound H 3 L with Zn2+ions has been used for phosphates recognition. [Display omitted] [ABSTRACT FROM AUTHOR]

• A novel fluorescence probe Ni(II)-CP was constructed. • The sensing Ni(II)-CP is highly selective and sensitive to Cr 2 O 7 2− and 4-NP. • The mechanism of Ni(II)-CP to 4-NP is attributed to PET and RET, while Cr 2 O 7 2− is ascribed to RET. The elaborately designed nonsymmetric salamo-like ligand (H 2 L, 4-chloro-4′-bromo-6-bromo-6′-tert-butyl-2,2′-[ethylenedioxybis(nitrilomethylidyne)]diphenol), has been employed to construct a novel fluorescent coordination polymer (CPs). Ingeniously, bearing the host ligand H 2 L and auxiliary ligand 4,4ʹ-bipyridine (4,4ʹ-bipy), a tailored luminescent probe, namely [Ni(L)(4,4ʹ-bipy)] n (Ni(II)-CP), was prepared and determined through single crystal X-ray diffraction experiment. Interestingly, the Ni(II) atom possesses a slightly twisted hexa-coordinate octahedron configuration. At the same time, an infinite one-dimensional (1D) chain-shaped structure was formed with the intervention strategy of auxiliary ligand. The luminescence properties studied describe the unusual selectivity, sensitivity and recyclability of the detection of 4-nitrophenol (4-NP) and Cr 2 O 7 2−. In addition, possible fluorescence quenching mechanisms were also explored. [Display omitted] [ABSTRACT FROM AUTHOR]

Four Zn(II) coordination polymers (CPs), [Zn(4-pzpt) 2 (H 2 O)] n ( 1 ), {[Zn(4-pzpt) 2 ]·CH 3 OH} n ( 2 ), [Zn 2 (4-pzpt) 2 (suc)(H 2 O)] n ( 3 ) and [Zn 2 (4-pzpt) 2 (ndc)] n ( 4 ) were obtained from 3-(pyridin-4-yl)-5-(pyrazin-2-yl)-1H-1,2,4-triazole (4-Hpzpt), 1,4-Naphthalenedicarboxylic acid (H 2 ndc) and succinic acid (H 2 suc) ligands. Structural analysis reveals that 1 represents a five coordinated 0D structure. 2 possess a network featuring 2D 4 4 grid-like layers structure. 3 displays a network featuring 2D (6 3 )- hcb layered structure. 4 shows a rare 3D (4,4)-connected topology with a Schläfli symbol of (4.6 4. 7) 2 (6 4. 7 2 ). Complexes 1 and 2 can mutual conversion between different solvent ratios. Luminescence properties reveal that 1 and 2 exhibit excellent selectivity for Hg 2+ and Cr 2 O 7 2- ions in aqueous solution, in which suggests that 1 and 2 is a promising multifunctional sensing materials. The possible sensing mechanism is also discussed. [ABSTRACT FROM AUTHOR]

A new cyanide probe has been prepared by one-step synthesis and evaluated by UV–vis and fluorescent method. This probe is combined by a fluorene part and a hemicyanine group through a conjugated linker, which is found to show rapid response, high selectivity and sensitivity for cyanide anions with significant dual colorimetric and fluorescent signal changes in aqueous solution. An intramolecular charge transfer (ICT) effect plays a key role in the CN − sensing properties, and the details of this mechanism are further supported by DFT and TD-DFT calculations. The theoretical study shows that the introduction of CN - twists the original plane structure and blocks the ICT process in the whole molecule, which brings about the absorption blue-shift and the fluorescence quenching. [ABSTRACT FROM AUTHOR]

• A novel double-armed salamo-based probe DAS for detecting tryptophan and Al3+was successfully designed and synthesized. • A sharp fluorescence enhancement was observed when tryptophan was added. • The DAS solution produced strong-green fluorescence under UV light when Al3+ was added. • According to the results obtained, the mechanism of tryptophan recognition is presumed to be FRET while the mechanism of Al3+ is presumed to be CHEF. A novel double-armed salamo-based probe DAS for detecting tryptophan and Al3+was successfully designed and synthesized. The probe DAS showed good selectivity to tryptophan and Al3+ in the mixed solvent DMF: H 2 O (9: 1, V / V, pH = 7.2). The limit of detection (LOD), the limit of quantification (LOQ) and the association constant (Ka) of the probe DAS for detecting tryptophan and Al3+ were determined by calculating. Compared with other reported probes, this probe showed a lower detection limit and provided a relatively simple and effective method for the detection of tryptophan. Besides, compared with the probe used to detect Al3+, the DAS probe in this study also showed relatively good detection ability, and the significant color change after adding Al3+ played a very important role in the detection process. In addition, plausible mechanisms for the interaction of the probe DAS with tryptophan and Al3+ are proposed according to the ESI-MS, Job's plot, and DFT calculations. A novel double-armed salamo-based probe DAS for detecting tryptophan and Al3+ was successfully designed and synthesized. The probe DAS showed good selectivity to tryptophan and Al3+ in the mixed solvent DMF: H 2 O (9: 1, V / V, pH=7.2). The limit of detection (LOD), the limit of quantification (LOQ) and the association constant (Ka) of the probe DAS for detecting tryptophan and Al3+ were determined by calculating. In addition, plausible mechanisms for the interaction of the probe DAS with tryptophan and Al3+ are proposed according to the ESI-MS, Job's plot, and DFT calculations. [Display omitted] [ABSTRACT FROM AUTHOR]