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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]

[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 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]

• 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]

A novel multi-stimulus responsive small molecule fluorescent sensor DHS was developed. The DHS with solvent-dependent properties exhibits active AIE effects, which is rare in salamo-like compounds. DHS has an excellent reversible thermal response and pH fluorescence response under various external stimuli (temperature and acid-base conditions). In addition, DHS can be used as a highly selective and sensitive fluorescent probe for the sequential detection of Cu2+ and S2– in water. [Display omitted] • The sensor DHS exhibits active AIE effect. • The first salamo-like sensor is used to sense temperature changes reversibly. • DHS can be used for sequential detection of Cu2+ and S2- in high water content solution systems. A novel multi-stimulus responsive small molecule fluorescent sensor DHS was developed. DHS with solvent-dependent properties exhibited active AIE effects, which is rare in salamo-like compounds. DHS has an excellent reversible thermal response and pH fluorescence response under various external stimuli (temperature and acid-base conditions). The response mechanism is supported by relevant studies and theoretical calculations. In addition, DHS can be used as a highly selective and sensitive fluorescent probe for the sequential detection of Cu2+ and S2– in water. DHS exhibits very prominent detection limit (48.59 nM) for Cu2+, which is superior to most small molecule fluorescent sensors of the same type. The experiments showed that the sensor DHS can be used for the ions detection in portable test strips and actual water samples. This study reveals a new strategy for the construction of salamo-like compounds with AIE properties, which can be beneficial for research in the fields of temperature sensing, acidity detection and ion recognition. [ABSTRACT FROM AUTHOR]

Aggregation-induced emission–fluorescent carbon dots (AIE-CDs) have applications in both academia and industry. In this study, triphenylamine-based CDs (T-CDs) prepared in acetic acid showing both intramolecular charge transfer (ICT) and aggregation-induced emission (AIE) were designed and synthesized. Intriguingly, the T-CDs fluoresced with different colors in solvents of different polarities: for example, in acetic acid, they showed blue fluorescence. In contrast, in the presence of water, aggregation and precipitation occurred because of the hydrophobic nature of the compound. With time, the increasing aggregation resulted in a loss in intramolecular rotational degrees of freedom, resulting in bright red emissions as a result of ICT and AIE. Interestingly, the T-CDs could be used for intracellular imaging and the lysosome-specific targeting of live cells. [Display omitted] • Synthesis of T-CDs by solvothermal method. • T-CDs display bright red fluorescence in aggregated state. • T-CDs are available in different fluorescence colors in different solvents. • T-CDs are biocompatible and selectively accumulate in lysosomes. [ABSTRACT FROM AUTHOR]

Two unusual heterobimetallic [CuII 4 LnIII 2 ] complexes were constructed from a N 2 O 2 - and O 6 -donor bis(salamo)-based ligand (H 4 L), and characterized structurally. The intermolecular interactions were quantitatively analyzed by Hirshfeld surfaces, as well as, fluorescence properties have also been studied. [Display omitted] • Two structurally novel heterobimetallic hexanuclear [CuII 4 LnIII 2 ] complexes were prepared using a designed N 2 O 2 - and O 6 -donor bis(salamo)-based ligand. • The different natures of three-compartmental H 4 L lead to the site‐selective introduction of two various metalII/III atoms. • Quantitative analyses of intermolecular interactions were evaluated by Hirshfeld surfaces analyses. • The fluorescence properties were further discussed. Two unusual heterobimetallic [CuII 4 LnIII 2 ] complexes, [{Cu 4 (L) 2 La 2 (ƞ 2-NO 3) 6 (EtOH)}]·2Me 2 CO (1) and [{Cu 4 (L) 2 Ce 2 (ƞ 2-NO 3) 6 (EtOH)} 2 ]·4Me 2 CO·MeOH (2) were constructed from a N 2 O 2 - and O 6 -donor bis(salamo)-based ligand (H 4 L). The structures were characterized by physical chemistry and spectroscopy methods. The two complexes 1 and 2 have similar structures, two heterotrinuclear parts with the same structure are linked by the coordination between one CuII atom and oxime-type oxygen atoms to obtain the heterohexanuclear complexes 1 and 2. Four penta-coordinate CuII atoms are located at the N 2 O 2 cavities of the ligand (L)4- units, two LaIII/CeIII atoms are surrounded by the open-chain 18-crown-6 (O 6) coordination environment. At the same time, eight bridged phenol oxygen atoms connect the six CuII/LnIII atoms. Infinite three-dimensional supra-molecular structures are formed in complexes 1 and 2 through H-bonds. The intermolecular interactions were quantitatively analyzed by Hirshfeld surfaces, as well as, fluorescence properties have also been studied. [ABSTRACT FROM AUTHOR]

Two phenoxo-bridged homopolynuclear Cu(II) bis(salamo) type complexes, 1 and 2 , have been successfully obtained and structurally characterized. The theoretical calculations and fluorescence properties were investigated in detail. [Display omitted] The dinuclear Cu(II) complex [Cu 2 (HL)Br 2 (MeOH)]·MeOH (1) and the tetranuclear Cu(II) complex [Cu 4 (L) 2 ](ClO 4) 2 ·2EtOH (2), based on a new bis(salamo) type ligand H 3 L, have been successfully self-assembled and structurally characterized by X-ray single crystal diffraction experiments. In complex 1 , the partially deprotonated ligand unit (HL)2– is coordinated with the Cu(II) ions. It is noteworthy that two bromine ions and one methanol molecule with balanced charges are involved in the coordination. Both central coordination Cu(II) ions are five-coordinated. Finally, complex 1 can form a two-dimensional planar network structure and a one-dimensional chain-like structure through intermolecular hydrogen bonds and C H π interactions, respectively. Meanwhile, complex 2 has a centrosymmetric structure with two phenolic oxygen atoms bridging two molecules of metallized ligand [Cu 2 (L)] units, where Cu1 is five-coordinated and Cu2 is four-coordinated. Thus, complex 2 forms a three-dimensional superamolecular network structure and a one-dimensional chain-like structure through intermolecular hydrogen bonds and π–π stacking interactions, respectively. The energy gaps between the HOMO and LUMO orbitals of complexes 1 and 2 were investigated by DFT calculations, indicating that the complexes are stable. The interaction sites of the ligand with the Cu2+ ions were examined by ESP investigation, and the results are consistent with the crystal structure. The weak intermolecular interaction forces of complexes 1 and 2 were explored by Hirshfeld surfaces and IRI analyses. The luminescent properties of complexes 1 and 2 were illustrated by fluorescence spectroscopy research. [ABSTRACT FROM AUTHOR]

[Display omitted] • Carbon dots with aggregation induced fluorescence were synthesized using a one-step solvothermal method. • The prepared carbon dots exhibit different fluorescence colors in different solvents. • The carbon dots were used to make an anti-counterfeiting luminous ink, which can be used for encryption in reversible double switch mode. Aggregation-induced emission luminogens (AIEgens) have garnered significant attention because of their outstanding photophysical characteristics. AIEgens are used in fluorescence imaging, sensors, tumor treatment, and other related fields. However, the synthese of these AIEgens are relatively complicated and requires expensive raw materials. These drawbacks limit their applications and development to a certain extent. In this study, using cheap and convenient materials, we developed a new type of carbon dots (O-CDs) using a one-step solvothermal method, which has the potential to become a new AIEgen. O-CDs exhibit different fluorescence colors in different solvents, and they exist as monomers in ethylic acid and, ethanol alcohol, etc., exhibiting blue fluorescence. After adding water, the fluorescence of O-CDs gradually turns orange red, because the internal rotation of the disulfide bond molecules is restricted and the AIE effect occurs. Using the unique AIE performance of O-CDs, we fabricated an anti-counterfeiting luminous ink, that can be used for encryption in the reversible double switch mode. [ABSTRACT FROM AUTHOR]

A colorimetric and fluorescent dual-channel glutamic acid (Glu) chemosensor AMS bearing an aldehyde group has been designed and synthesized. The experimental results of the competitive amino acids revealed that chemosensor is highly selective for recognizing Glu without the interference of other amino acids. Moreover, AMS -based fluorescence detection test strips were prepared to realize the simple and rapid detection of Glu in water. [Display omitted] • A high selectivity and sensitivity dual-channel chemosensor AMS was developed. • The lower detection limit is determined to be 7.5 × 10−7 M. • The AMS -based test strips can be used as a convenient tool for the detection of Glu in water. A colorimetric and fluorescent dual-channel glutamic acid (Glu) chemosensor 4-methyl-6-aldehyde-6′-methoxy-2,2′-[ethylenediyldioxybis(nitrilomethylidyne)]diphenol (AMS) bearing an aldehyde group has been designed and synthesized. This structurally simple chemosensor displays rapid response and high selectivity for Glu over other common amino acids in DMF/H 2 O (9: 1, v/v, buffered by 0.2 M Tris-phosphate buffer at pH = 7.0) solution. The chemosensor interacted with Glu to form intermolecular hydrogen bonds with significantly quenched fluorescence, switching from bright green fluorescence to no fluorescence. Moreover, AMS can also successfully detect glutamic acid by absorption spectroscopy, which exhibited an UV–vis spectrum change, while its color changed from pale yellow to colorless under natural light. The experimental results of the competitive amino acids revealed that chemosensor is highly selective for recognizing Glu without the interference of other amino acids. Job's plot indicates that the binding stoichiometry between the chemosensor AMS and the targeted amino acid Glu is 1:1. Hence, our experimental findings very strongly suggest that AMS can be used as chemosensor for detecting Glu in future. [ABSTRACT FROM AUTHOR]

• A new heterobimetallic [Cu(II) 2 Pr(III)] complex with a symmetric flexible bis(salamo)-type ligand was synthesized and characterized structurally. • There are two different metal-binding sites of N 2 O 2 and O 6 (two being specific for the 3d metal ions and the other for the 4f metal ion) for the synthesis of heteropolynuclear 3d-4f complex with a flexible bis(salamo)‐type ligand. • Hirshfeld surface analysis and luminescence of the [Cu(II) 2 Pr(III)] complex was investigated. A new heterobimetallic 3d-4f [Cu(II) 2 Pr(III)] complex [Cu 2 Pr(L)(ƞ 2-NO 3) 3 (EtOH) 2 ]·2EtOH with a symmetric flexible bis(salamo)-type ligand, (1E,1′E)-2,3-dihydroxynaphthalene-1,4-dicarbaldehyde O,O -di(3-((((E)-3-ethoxy-2-hydroxybenzylidene)amino)oxy)propyl)dioxime (H 4 L), has been synthesized and characterized structurally. Single crystal X-ray diffraction analysis showed that the ligand was fasten by different metal ions to form a hetero-trinuclear complex with C-shaped structure, where two N 2 O 2 -donors of the completely deprotonated ligand (L)4− unit and two oxygen atoms from two ethanol molecules coordinate with Cu(II) atoms (Cu1, Cu2), respectively, to form two five-coordinated square pyramid geometries. Meanwhile, where the O 6 cavity coordination sphere of the ligand (L)4− unit and six oxygen atoms from three nitrate groups coordinate with the Pr(III) atom together to form a twelve-coordinated icosahedron. Due to the Cu(II) atom in the O 6 cavity was replaced by the Pr(III) atom, it shows that the hetero-trinuclear complex after self-assembly is more stable than the homo-trinuclear complex. At the same time, through UV–Vis titration spectrometric analysis, we can observed that the hetero-trinuclear [Cu(II) 2 Pr(III)] complex is obtained by 1 equiv. Pr(NO 3) 3 ·5H 2 O and 2 equiv. Cu(NO 3) 2 ·3H 2 O and 1 equiv. H 4 L. Significantly, fluorescence properties and Hirshfeld surfaces analyses of the [Cu(II) 2 Pr(III)] complex was also studied. A new heterobimetallic [Cu(II) 2 Pr(III)] complex with a symmetric flexible bis(salamo)-type ligand, (1E,1′E)-2,3-dihydroxynaphthalene-1,4-dicarbaldehyde O,O-di(3-((((E)-3-ethoxy-2-hydroxybenzylidene)amino)oxy)propyl)dioxime (H 4 L), has been synthesized and characterized structurally. Two five-coordinated Cu(II) atoms and one twelve-coordinated icosahedron Pr(III) atom are located in different coordination environments, respectively, fluorescence properties, Hirshfeld surfaces analyses and DFT calculations of the [Cu(II) 2 Pr(III)] complex was also studied. [Display omitted]. [ABSTRACT FROM AUTHOR]

[Display omitted] • A novel F-doped silicon quantum dots were successfully synthesized by a one-pot hydrothermal method. • The resulting F-SiQDs exhibited conspicuous optical bleaching resistance and the fluorescence quantum yield reached 25.19%. • The obtained F-SiQDs achieved a high selectivity and sensitivity to new coccine, accompanied by fluorescence quenching. • The fluorescent nanosensor for detection of new coccine was productively demonstrated in food samples. As a kind of common colorant, new coccine has been applied in many scenes of daily life. In this study, innovative F-doped silicon quantum dots (F-SiQDs) which prepared by a facile one-step hydrothermal treatment were designed for the detection of new coccine. Systematic studies demonstrate that the obtained F-SiQDs exhibited excellent dispersibility and photostability, with the optimal emission at 475 nm and fluorescence quantum yield reached to 25.19%. The fluorescence intensity can be quenched by new coccine due to the principle of IFE, and the corresponding process was decreased rapidly within 1 min. At the same time, the quenching process showed a notable linear relationship within the concentration of new coccine range from 1–100 μmol/L and 100–200 μmol/L with the detection limits of 0.33 and 0.18 μmol/L, respectively. The developed F-SiQDs were successfully adopted to the determination of new coccine in food samples, and also achieved the desired detection results after being coated on the filter-paper. This work highlights the merits of simplicity, fast response and highly selective for new coccine detection, and implements a potential avenue for the utilization of F-SiQDs in the guidance of food safety and food management. [ABSTRACT FROM AUTHOR]

• The first 3d-3d′ heterobimetallic [Cu(II) 2 Mn(II)] bis(salamo)-based complex was synthesized and characterized structurally. • The different natures of the N 2 O 2 and O 6 sites of H 4 L lead to the site‐selective introduction of two various metal(II) atoms. • Unusual fluorescence behavior of the [Cu(II) 2 Mn(II)] complex was reported. The first 3d-3d′ heterobimetallic [Cu(II) 2 Mn(II)] complex, [Cu 2 Mn(L)(µ 2 -NO 3) 2 ] was reported, and formed by an acyclic tricompartmental bis(salamo)-based ligand H 4 L and different metal salts. Its structure was characterized by physicochemical and spectroscopic methods. The ligand H 4 L has two identical N 2 O 2 sites and one O 6 site separated by phenoxy groups. Two penta-coordinate Cu(II) atoms and one octa-coordinated Mn(II) atom are located respectively in these two different coordination environments. Through the analysis of the Hirshfeld surfaces of the [Cu(II) 2 Mn(II)] complex, the intermolecular interactions involved in the crystal structure can be shown, and the corresponding quantitative information is given by fingerprint. The [Cu(II) 2 Mn(II)] complex units are combined by intermolecular C-H•••O hydrogen bonds to form a two-dimensional supramolecular structure. Unusual fluorescence behavior of the [Cu(II) 2 Mn(II)] complex was further studied. [Display omitted] [ABSTRACT FROM AUTHOR]

• A salamo-like mononuclear Cu(II) complex probe L-Cu2+ was synthesized and characterized structurally. • The sensing mechanisms of the probe L-Cu2+ towards CN− and Cys-Cys were fully verified through fluorescence, UV and ESI-mass experiments. • Test strips are available for fast visual identification of CN− and Cys-Cys using the probe L-Cu2+. A highly selective "off-on" fluorogenic sensor (L-Cu2+), as an aldehyde-exposed salamo-based mononuclear Cu(II) complex, was designed and used as an effective sensor for the double pronged sensing of cyanide ion (CN−) and Cystine (Cys-Cys). By combining and calculating with experimental data, it can be fully characterized by a variety of spectroscopy techniques. The LODs of CN− and Cys-Cys were calculated to be 3.3792 × 10−7 and 1.2757 × 10−7 M. Consequently, the developed sensor showed good sensitivity and selectivity for CN− and Cys-Cys in DMF/water (v / v , 9:1) solution. Meanwhile, the designed complex sensor can discriminate and detect CN− ion but not other multiple anions. No interference from other ions was observed during the detection of CN− and Cys-Cys. Finally, we made known the rationality of fluorogenic "turn on" response phenomenon of L-Cu2+ to CN− and Cys-Cys by means of ESI-mass spectrometry, FT-IR spectra analyses to further understand experimental consideration results observed. [ABSTRACT FROM AUTHOR]

An aldehyde-added salamo-type proportional probe AA-TNS has been developed to selectively identify CN− ions through fluorescence turn-on, accompanied by a conversion from closed to extended structure during the detection process. [Display omitted] • An aldehyde-appended salamo-type optical probe AA-TNS is developed. • The probe AA - TNS could specifically detected CN− ions by proportional response. • Interestingly, theoretical calculations show that the molecular structure has undergone a transformation from a closed to an extended form. In this work, an aldehyde-appended salamo-type optical probe AA - TNS was synthesized for high-efficiency detection of cyanide ions. Spectral experiments indicated that the probe AA - TNS exhibits a proportional fluorescence response to cyanide ions before/after the detection reaction, accompanied by a remarkable fluorescence turn-on. The probe AA - TNS followed an induced dehydrogenation sensing mechanism, with fast response time and excellent sensitivity. Most importantly, the theoretical calculation revealed that the molecular structure has undergone a transformation from a closed to an extended form, which may be one of the important reasons for the luminescence. This was slightly different from the previously reported probe molecules, which provides some enlightenment for future exploration of salamo-type optical probes. The superior recyclability of the probe molecule was also proved by spectral data and solution fluorescence. Moreover, the probe AA - TNS could directly distinguish cyanide ions in liquid environment and solid-state contact. [ABSTRACT FROM AUTHOR]

A new salamo-type probe H 2 L and its Co2+ complex [Co 3 (L) 2 (MeOH) 2 (μ -OAc) 2 ]·2MeOH were synthesized and characterized structurally. Fluorescence of Co2+ selectively response showed "off" when cations were sequentially detected. Meanwhile, the mechanism of recognition of Co2+ by H 2 L was got. DFT calculation and Hirshfeld surfaces analyses were investigated to further understand the experimental results observed. [Display omitted] • The probe H 2 L could efficiently detect Co2+ ion. • The probe H 2 L could detect Co2+. Meanwhile, H 2 L and Co2+ complex were characterized. • Hirshfeld surfaces analyses and DFT calculation were studied. A new salamo-type fluorescence probe H 2 L was synthesized by a series of reactions and corroborated by single-crystal X-ray crystallography and 1H NMR spectra. Fluorescence of Co2+ selectively response showed "off" when cations were sequentially detected. The LOD of H 2 L to Co2+ was calculated to be 3.73 × 10-7 M in DMF/water (9:1, v/v) solution system. Meanwhile, the single crystal of the Co2+ complex with H 2 L was obtained by solvent evaporation. The structure of the complex [Co 3 (L) 2 (MeOH) 2 (μ -OAc) 2 ]·2MeOH was validated by single-crystal X-ray diffraction, IR, and elemental analyses, and the mechanism of recognition of Co2+ by H 2 L was got. Density functional theory (DFT) and Hirshfeld surface analyses were investigated to further understand the experimental results observed. [ABSTRACT FROM AUTHOR]

A newly designed symmetrical multi-halogen-substituted bis(salamo)-based tetraoxime ligand H 3 L and its three penta-coordinated homo-binuclear Co(II) and Zn(II) complexes have been successfully synthesized and characterized structurally. Hirshfeld surfaces, DFT calculations and luminescences of the three complexes were investigated in detail. [Display omitted] A new symmetrical multi-halogen-substituted bis(salamo)-based tetraoxime ligand H 3 L and its corresponding penta-coordinated homo-binuclear Co(II) and Zn(II) complexes have been successfully synthesized. The three complexes, [{Co 2 (L)(OCH 3)} 2 ]·CHCl 3 (1), [{Zn 2 (L)(OCH 3)} 2 ]·CH 3 OH (2) and [{Co 2 (L)(OCH 2 CH 3)} 3 ]·2CH 3 CH 2 OH·CHCl 3 (3), have been characterized by elemental analyses, FT-IR and UV–Vis absorption spectroscopy as well as X-ray single-crystal structure analyses. In complexes 1 and 2 , two crystallographically independent but chemically identical binuclear complex molecules A and B were detected by X-ray analysis. However, in complex 3 , three crystallographically independent but chemically identical binuclear complex molecules A, B and C were detected. All the penta-coordinated Co(II) and Zn(II) atoms in complexes 1 and 2 are located in the N 2 O 2 cavities of the completely deprotonated (L)3- units and coordinated to one oxygen atom from one μ 2 -bridged methoxyl group. The coordination environment of the Co(II) atoms in complexes 1 and 3 are similar, except that the μ 2 -bridged methoxyl group is replaced with the μ 2 -bridged ethoxyl group. Additionally, both of complexes 1 and 3 form 3D supramolecular structures through abundant intermolecular interactions, while complex 2 forms 1D supramolecular structure through intermolecular hydrogen bonds. The C H···π interactions have been established in complexes 1 and 2 , where the π-system of H 3 L participates as π-donor. Through the means of Hirshfeld surfaces and 2D fingerprint plot analyses, existing different non-covalent supramolecular interactions in the Co(II) and Zn(II) complexes have been explained. Furthermore, to obtain a better understanding of the fluorescence properties of H 3 L and its complexes 1 – 3 , fluorescence titration experiments have been performed. [ABSTRACT FROM AUTHOR]