Herein, a potential colorimetric and far-red fluorescent probe DCPS-1 for Ag+ was rationally developed based on a dicyanomethylene-4H-chromene chromophore. Its prominent and distinct changes in both color and fluorescence enable the on-site and naked-eye detection of Ag+ easily and quickly, accompanied with excellent sensitivity. No absorption and fluorescence response could be observed towards other metal ions. The fluorescence intensity of this probe showed a linear response to Ag+ in the concentration range of 0–10 μM with a detection limit of 21.1 nM. In addition, this probe had low toxicity to cells and gave distinct fluorescence changes in cell imaging. All these results demonstrate its promising application prospects for Ag+ sensing in both environmental and biology fields.

Two neutral merocyanine-based near-infrared fluorescent probes were for the first time developed through rational engineering of the classical cationic cyanine scaffold IR-780 for in vivo imaging of amyloid-β plaques. In vivo NIRF imaging revealed that the probe could penetrate the blood–brain barrier and efficiently differentiate the living transgenic and wild-type mice.

•Three salt solvates of azilsartan with 2-methylimidazole are prepared.•Azilsartan is high affinity to 1,4-dioxane molecule.•NH⋯O and OH⋯O interactions stabilizes the supramolecular arrangement.•AZ-2MI-H2O exhibits the improved solubility and retention stability in an aqueous medium.Three salt solvates of azilsartan (AZ) with 2-methylimidazole (2MI) (namely AZ-2MI-H2O, AZ-2MI-ACE and AZ-2MI-THF) and one azilsartan solvate (AZ-DIO, ACE = acetone, THF = tetrahydrofuran, and DIO = 1,4-dioxane) were manufactured by solvent-controlled self-assembly in aqueous-organic solutions. The experimental result of AZ-DIO shows that AZ is high affinity to DIO molecule, which has a unique ability to prevent salt formation between AZ and 2MI. Thermal studies of three salt solvates exhibit poor thermodynamic stability in environmental conditions. Solubility experiments show that AZ-2MI-ACE and AZ-2MI-THF are unstable and convert to AZ-2MI-H2O in aqueous solution, and that AZ-2MI-H2O exhibits increased solubility and retention stability in an aqueous medium compared with the commercial AZ-A crystalline form.Download high-res image (169KB)Download full-size image

•Phenyl-pyrazole-4-carboxylic acid derivatives had been synthesized and characterized.•Some compounds showed considerable XOR inhibitory effects in vitro in the nanomole.•16c exhibited a hypouricemic potency in a potassium oxonate-hypoxanthine-induced hyperuricemia mice.A diverse library of 1-phenyl-pyrazole-4-carboxylic acid derivatives were synthesized and evaluated for their inhibitory potency against xanthine oxidoreductase (XOR) in vitro and vivo, and the structure-activity relationship (SAR) analyses were also presented. Approximately half of the target compounds exhibited the inhibitory potency for XOR at the nanomolar level. Compounds 16c, 16d, and 16f emerged as the most potent xanthine oxidoreductase inhibitors with IC50 values of 5.7, 5.7 and 4.2 nM, respectively, in comparison to febuxostat (IC50 of 5.4 nM). Steady-state kinetics measurements indicated that 16c is a mixed-type inhibitor. A computer molecular docking study of 16c bound to XOR was performed to gain an insight into its bind mode and SAR for the series. A potassium oxonate-hypoxanthine-induced hyperuricemia model in mice was chosen to further confirm the hypouricemic effects of 16c and 16f, and the results demonstrated that 16c exhibits similar hypouricemic potency to febuxostat.1-Phenyl-pyrazole-4-carboxylic acid derivatives were synthesized and evaluated as xanthine oxidoreductase inhibitors. Compound 16c was a mixed-type xanthine oxidoreductase inhibitor with an IC50 of 5.7 nM and a considerable hypouricemic effect similar to febuxostat in mice.Download high-res image (160KB)Download full-size image

A highly sensitive colorimetric and red-emitting fluorescent dual probe was synthesized and applied to imaging palladium species based on the Tsuji–Trost reaction. Notably, it displayed specific and turn-on fluorescent response toward Pd0 with a vivid color change from yellow to purple in aqueous media. The detection limit was calculated to be as low as 0.78 nM. Furthermore, the probe was successfully applied for fluorescence imaging of palladium in living cells. All these properties made this probe a promising useful tool not only in environmental detection but also more widely in bioanalytical fields.

A tailor-made colorimetric and NIR fluorescent probe for Pd0 was developed by introducing allyl chloroformate into the methylene blue (MB) fluorophore. The probe exhibited vivid color change and significant fluorescence enhancement towards Pd0, accompanied with excellent selectivity and sensitivity. No absorption and fluorescence response could be observed towards other metal ions. The fluorescence intensity of this probe showed a linear response to Pd0 in the concentration range of 0–2 μM with a detection limit of 5.7 nM. Moreover, living cell imaging results indicated that this probe holds promising application prospects for detecting intracellular Pd0 species based on its low cytotoxicity and specific turn-on NIR emission.

Two polymorphs (AM-A and AM-B) of azilsartan medoxomil (AM) and four AM solvatomorphs with toluene (AM-TOL), 1,4-dioxane (AM-DIO), chloroform (AM-TCM) and N,N-dimethylacetamide (AM-DMA) have been prepared by the hydrolysis of azilsartan medoxomil potassium in aqueous-organic solutions. In the crystal structures of two polymorphs and three solvatomorphs (AM-TOL, AM-DIO and AM-TCM), two asymmetric AM molecules form the dimeric cycle-like structures via intermolecular NH⋯N hydrogen bonds in R22 (26) ring, while AM-DMA shows intramolecular NH⋯O hydrogen bond between AM and DMA molecules. The hydrogen bonds (CH⋯O or CH⋯N) and π···π (or CH···π) interactions are helpful to stabilize the conformational diversity of AM. The solvent-induced experiment shows that solvent molecules have great influence on the solvatomorph formation and DIO can form the most steady solvatomorph than other solvents. The thermal study demonstrates that toluene molecules in three solvatomorphs (AM-TOL, AM-DIO and AM-TCM) are the most difficult to remove from the cage. Our results illustrate that the solvent plays significant role in tuning the size of the cage and producing the conformational diversity of AM molecules.Download high-res image (293KB)Download full-size image

Carbon monoxide (CO) has captivated great attention in part due to the discovery of the therapeutic and cell-signalling role that CO plays in biological systems. The ever-increasing interest in CO has resulted in the development of rapid and facile approaches for the sensitive and selective detection of CO, which still remains challenging. Herein, the first example of a colorimetric and near-infrared fluorescent dual probe for carbon monoxide (CO) has been developed by assembling an allyl chloroformate moiety with a naphthofluorescein fluorophore, which enables the label-free and visual detection of CO. The living cell imaging results indicate that the probe shows great potential in sensing intracellular CO.

A chemosensor NBD-PMA with colorimetric and fluorometric responses for Pd2+ cations has been described. NBD-PMA selectively coordinated Pd2+ cations with a colour change from bright yellow to pink, which enabled detection of Pd2+ cations in environmental water samples with the naked eye. NBD-PMA also exhibited high selectivity and sensitivity for Pd2+ cations in fluorometry even in the presence of other metal cations, which makes it practically applicable for detecting Pd2+ cations in environmental samples and in living cells.

•A colorimetric and fluorescent dual probe for CO based on NBD.•The color changes from colorless to yellow which can be checked by naked eyes.•The probe can detect CO over other biologically relevant analytes.•The probe could be used as a convenient visual indicator for CO gas in air.A colorimetric and fluorescent dual probe for CO is designed and synthesized. The probe is capable of sensitive and specific detection of CO with naked-eye through colorimetric assay in phosphate buffer from colorless to yellow, which also features 75-fold turn-on fluorescence enhancement upon exciting at 480 nm with the detection limit of 26.3 nM. The probe shows great potential for sensing intracellular CO without the interference in living cell imaging. On the other hand, the probe could also be utilized as an efficient and convenient visual indicator for CO gas in air by naked eyes.

Inclusion complexes of fluconazole (HFlu) with β-cyclodextrin (β-CD) and hydroxypropyl- β-cyclodextrin (HP-β-CD) had been prepared by the coprecipitation method. The 1:1 stoichiometry of complexation for both inclusion complexes was achieved in the binary system by phase solubility and fluorimetric study. The inclusion complexes were also characterized by DSC-TGA analyses and ESI–MS spectra. The molecular assemblies were proposed that a triazolyl ring of HFlu was inserted into the narrower end of the CD cavity and the 2, 4-difluorophenyl ring into the wider end to generate 1-D chain structure on the basis of physical characters. The comparative work indicated that the higher stability was obviously observed for HFlu-HP-β-CD than for HFlu-β-CD, and provided a crucial clue to find out the dependency: cavity size, van der Waals and hydrophobic interactions as well as hydrogen bonding.

The solubility of febuxostat in ethyl acetate, methanol, ethanol, and acetone was determined respectively by the gravimetric method from (293.15 to 328.15) K under atmospheric pressure, and the experimental data were well-correlated by the Apelblat and van’t Hoff equations. The experimental solubility data and their correlation equation obtained would be useful for the solvent selection of febuxostat crystallization.

A novel PtS-type porous Cu(II) complex, {[Cu3(dmtrz)2(OX)2(H2O)2]·8.5H2O}n (1) was synthesized through diffusion reaction, which showed single-crystal-to-single-crystal transformation during a reversible dehydration and rehydration process accompanied by a colour change.

Six Cd(II) coordination polymers with a flexible fulconazole ligand, {[Cd(HFlu)2(H2O)2](ClO4)2}n (1), {[Cd(HFlu)3(NO3)]2(NO3)2·H2O}n (2), {[Cd(HFlu)2(SCN)](ClO4)}n (3), {[Cd(HFlu)2(SCN)](NO3)}n (4), {[Cd(HFlu)2Cl](SCN)}n (5) and {[Cd(HFlu)2(SCN)2]·2H2O}n (6) [HFlu = 2-(2′,4′-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol] have been synthesized and characterized by single-crystal X-ray diffraction. Complex 1 presents a 1-D chain-like structure with anti–gauche (A-G) conformation of HFlu. Complex 2 shows a 1-D ladder-like structure with both A-G and anti–anti (A-A) conformations of HFlu, and complexes 3, 4 and 5 show the 2-D grid structures bridged by A-G and A-A HFlu. However, in the 2-D grid network of 6, only A-A conformation of HFlu is observed. The conformational change of the HFlu ligand is induced step-by-step by the addition of the SCN− inorganic anion. The thermal stability and fluorescence of these complexes have also been studied.

Six fluconazole-bridged cobalt(II) coordination polymers, namely [Co(HFlu)2(H2O)2](ClO4)2 (1), [Co(HFlu)2(H2O)(AcO)](AcO)·2C2H5OH (2), [Co(HFlu)2Cl2]·2C2H5OH (3), [Co3(Flu)2(acac)4]·C2H5OH (4), [Co(HFlu)2(malo)(H2O)]·3H2O (5), and [Co(HFlu)2(fum)(H2O)2]·H2O (6) (HFlu = 2-(2′,4′-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol, AcOH = acetate acid, Hacac = acetylacetonate, H2malo = malonate acid, H2fum = fumaric acid), have been synthesized and structurally characterized, and the thermal, fluorescent and magnetic properties investigated. The crystal structures display the one-dimensional cationic double-bridged chain consisting of 20-membered macrocycles to be parallel in 1 and perpendicular in 2. The structure of 3 consists of two-dimensional neutral rhombic grid in bc plane with (4,4) topology and alternative P/M helices intersecting at the Co sites along b direction. Complex 4 shows one-dimensional polymeric chain, in which binuclear Co2(Flu)2(acac)2 units act as bridging blocks to link Co(acac)2 nodes through triazolyl nitrogen atoms. The structure of 5 shows dimeric 20-membered macrometallacyclic motif. Complex 6 shows HFlu-bridged one-dimensional chain, which is stabilized by hydrogen-bonding interactions to produce alternative hydrophobic and hydrophilic architecture. Complexes 1–3 and 5–6 exhibit the similar electronic absorption and fluorescent spectra as those of HFlu, while complex 4 shows a fluorescent quenching phenomenon. Fluorescence titration of HFlu suggests that the fluorescent intensities at the maximal emission decrease upon the addition of Co(acac)2. The variable-temperature magnetic measurement of 4 reveals weak ferromagnetic interaction combined with the spin–orbit coupling effect in the 1-D Co(II) chain.Six new cobalt(II) complexes with fluconazole have been prepared and fully characterized by physical methods. The coordination capabilities of anions to Co(II) ion have a great influence on the coordination mode of HFlu and molecular assembly to generate dimeric to two dimensional helical structure. The fluorescence, thermal stability and magnetic property have also been investigated.

Four new fluconazole-bridged zinc(II) and cadmium(II) complexes with dicarboxylate co-ligands, namely [Zn(HFlu)(TPA)]n (1), {[Cd(HFlu)2(TPA)]·2CH3OH}n (2), [Zn(HFlu)2(Suc)(H2O)2]·H2O (3), and [Cd(HFlu)2(Suc)(H2O)2]·H2O (4), have been synthesized and characterized by elemental analysis, IR, TG, and single-crystal X-ray diffraction (HFlu = 2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol, H2TPA = terephthalic acid, and H2Suc = succinic acid). Complex 1 displays a 2-D corrugated network with common (4,4) topology, in which two types of grids constructed by two bridging TPA dianions and two HFlu ligands are found. Complex 2 shows an unusual (3,6) coordination layer consisting of alternative PMPM Cd–HFlu helical chains in which the Cd(II) nodes are also fixed by terephthalate dianions in a cis fashion. The isostructural complexes 3 and 4 have 20-membered dimeric macrocyclic motifs with the Zn···Zn and Cd···Cd distances of 11.258(2) and 11.528(2) Å, respectively. The fluorescence and thermal stability of complexes 1–4 have also been investigated.Four new complexes with fluconazole have been prepared by introducing dicarboxylate co-ligands. Terephthalic acid induces to generate a 2-D corrugated network with common (4,4) topology in 1 and an unusual (3,6) layer with alternative Cd–HFlu helical chains in 2. Succinic induces to generate two isostructural dinuclear units in 3 and 4. The fluorescence and thermal stability have also been investigated.

Two new isostructural coordination polymers, namely, [M(malo)(HFlu)]n (M = Zn for 1 and Cu for 2, malo = malonate dianion, HFlu = fluconazole), have been prepared by a solution diffusion method. The polymers show rare three-dimensional 3-fold interpenetrated dia-f coordination frameworks with (2.2.1) Hopf links and (6.3.3) Torus links. The tetranuclear M4(malo)4 cluster as a secondary building unit becomes the decorated vertex in the dia-f net. Polymer 1 shows an intense fluorescent emission, while polymer 2 shows a quenching phenomenon in the solid state at room temperature. Magnetic susceptibility studies for 2 reveal a ferromagnetic coupling interaction in the anti-syn carboxylate-bridged Cu(II) clusters. Comparable experiments with Ni(II) and Cd(II) resulting in discrete dinuclear structures are also reported.

Four novel coordination polymers, one-dimensional chains [M(PTE)2(N3)2]n (M = Mn for 1 and Co for 2), and two-dimensional layers [M(PTE)2(dca)2]n (M = Mn for 3 and Co for 4) (PTE = 1-(2,4-difluorophenyl-2-(1H-1,2,4-triazol-1-yl)ethanone, dca = dicyanamide anion, N(CN)2−), have been synthesized under mild ambient conditions and structurally characterized by single crystal X-ray diffraction. In all four crystal structures, the metal atoms adopt octahedral coordination geometry with six nitrogen atoms from two monodentate PTE ligands and four azido (or dca) bridging ligands. The crystal structures of 1 and 2 are isostructural 1-D polymeric chains, alternatively linked by double end-on and double end-to-end azido bridges. However, the bent dca ligands as bidentate μ2-1,5 bridging ligands interlink the octahedral metal units to lead to 2-D (4,4) grid networks in 3 and 4. Temperature-dependent magnetic measurements in 2–300 K have been performed for these four polymers, and suggest alternative ferro- and antiferromagnetic couplings for end-on and end-to-end azido bridges in 1, and the dominant ferromagnetic coupling in 2, respectively. Both polymers 3 and 4 show weak antiferromagnetic exchanges through the μ2-1,5-dca bridges. The effects of auxiliary coligands on the structure and the nature of these magnetic exchanges are discussed in the light of the crystal structures in detail.Four azido-/dca-bridged coordination polymers with PTE have been synthesized and structurally characterized. [M(PTE)2(N3)2]n (M = Mn 1 and Co 2) show isostructural 1-D chain linked by alternative double end-to-end and double end-on azido bridges. [M(PTE)2(dca)2]n (M = Mn 3 and Co 4) show isostructural 2-D dca-bridged (4,4) grid. The magneto-structural relationships are investigated in detail based on the crystal structures.

Two two-dimensional coordination complexes, {[Cu4(BTM)6(OPA)4] · 4DMF · 3H2O}n (1) and {[Cu(BDTM)(OH)](ClO4) · 2H2O}n (2) (BTM = bis(1,2,4-triazol-1-yl)methane, BDTM = bis(3,5-dimethyl-1,2,4-triazol-1-yl)methane, OPA2− = ortho-phthalic dianion, DMF = N,N-dimethylformamide), were synthesized and structurally characterized. Each Cu(II) ion locates in a distorted square pyramidal geometry in 1, in which OPA2− ligands bridge Cu2+ ions along a axis to form a magnetic transmission chain and BTM ligands act as flexible spacers to construct the two-dimensional layer structure. In 2, each Cu2+ ion adopts tetra-coordination geometry to two hydroxyl groups and two triazolyl nitrogen atoms from two different BDTM ligands. Two hydroxyl groups bridge two Cu2+ ions to form a rhombic diamond, and four BDTM ligands connect four diamonds to form a 36-membered macrocyclic structure with large channels along a axis. Magnetic properties revealed that both OPA2− and OH− mediate anti-ferromagnetic interactions between Cu2+ ions with J = − 0.06(3) and −301.9(2) cm−1 for 1 and 2, respectively.

Four novel fluconazole-bridged Zn(II) complexes, [Zn(HFlu)Cl2(DMF)]2 (1), {[Zn(HFlu)2(H2O)2](NO3)2·2DMF}n (2), {[Zn(HFlu)2(H2O)2](NO3)2}n (3) and {[Zn(HFlu)(SCN)2]·H2O}n (4) [HFlu = 2-(2,4-difluorophenyl)-1,3-bis(1,2,4-triazol-1-yl)-propan-2-ol], have been synthesized and structurally characterized by X-ray diffraction method. The structure of dimeric complex 1 consists of 20-membered macrometallacyclic ring-like structure, in which the Zn(II) ion is in a five-coordinated distorted trigonal bipyramidal geometry with the Zn⋯Zn distance of 10.265(3) Å across the cis HFlu ligand. Complex 2 shows infinite 1-D macrocyclic double chain structure with the central Zn(II) ions being six-coordinated by four HFlu ligands and two apical water molecules and with the intrachain Zn⋯Zn distance of 10.722(3) Å across the trans HFlu ligand. The crystal structure of complex 3 is analogous to that of complex 2 with the intrachain Zn⋯Zn distance of 10.654(2) Å. The structure of complex 4 consists of infinite 1-D coordination polymeric chain with the tetrahedral coordination geometry of Zn(II) ion and with the intrachain Zn⋯Zn distance of 11.173(2) Å across the cis HFlu ligand. Complexes 1–4 show the similar fluorescence emission to the free HFlu ligand at ambient temperature and the thermal stabilities of the complexes have also been investigated.

•A two-photon probe (DCIP-1) with NIR emission based on dicyanoisophorone group, for the in vivo fluorescence imaging of amyloid-β plaques, was reported.•The probe showed turn-on fluorescence (13-fold) with a large Stokes shift upon inserting into the hydrophobic pockets of Aβ aggregates.•The in vivo imaging studies indicated that the probe can penetrate the blood–brain barrier efficiently and discriminate APP/PS1 transgenic mice from WT controls.A dicyanoisophorone-based probe with two-photon absorption and NIR emission was developed for the in vivo fluorescence imaging of amyloid-β plaques, which exhibited high selectivity toward Aβ aggregates over other intracellular proteins. The detection limit was calculated to be as low as 109 nM. In vivo imaging studies indicated that the probe could penetrate the blood–brain barrier and label Aβ plaques in the living transgenic mice, and its specific binding to cerebral Aβ plaques was further confirmed by one- and two-photon ex vivo fluorescence imaging. All these results featured its promising application prospects for amyloid-β sensing in basic research and biomedical research.

•Two new febuxostat salts with 2-methylimidazole (2:1) and di-2-pyridylamine (1:1) were synthesized.•Two febuxostat salts have been characterized by different physical methods.•Equilibrium solubility and dissolution rates for two salts were carried out and discussed.•The work suggests that the salt form is a good strategy to improve the febuxostat solubility.Novel crystalline forms of febuxostat (HFEB) salts were synthesized by liquid-assisted cogrinding with 2-methylimidazole (2MI) and di-2-pyridylamine (DPA) and characterized by Hirshfeld surface analysis, IR, 1H NMR, single crystal and powder X-ray diffractions, TGA and DSC. Two new HFEB salts featured different stoichiometries: 2:1 molecular ratio in HFEB-2MI and 1:1 molecular ratio in HFEB-DPA. For HFEB-2MI salt, two HFEB molecules lost one proton forming a singly charged hydrogen carboxylate anion H(FEB)2−, which interacted with the disordered 2MI cation via the N3H3A⋯O1i (i: −x, −y, −z+1) and N4H4B⋯O1ii (ii: x, y+1, z−1) hydrogen bonds to form one-dimensional structure. For HFEB-DPA salt, one proton transferred from one HFEB to DPA, which were further connected by N4H1⋯O1 and N3H2⋯O2 hydrogen bonds to form an R22(8) ring motif. HFEB-2MI and HFEB-DPA salts exhibited increased equilibrium solubilities and intrinsic dissolution rates compared to those of HFEB in aqueous medium.