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Controlling the optical activity of halide perovskite materials through modulation of the coordination configurations of the metal ions is important. Herein, a novel manganese‐based halide, specifically diaquatetrakis(methyldiphenylphosphine oxide)manganese(II) tetrachloridomanganate(II), [Mn(C13H13OP)4(H2O)2][MnCl4] or [Mn(MDPPO)4(H2O)2][MnCl4] (MDPPO is methyldiphenylphosphine oxide), was synthesized through the solvothermal reaction of MnCl2 with the neutral molecule MDPPO. In this compound, [Mn(MDPPO)4(H2O)2]2+ acts as the cation, while [MnCl4]2− serves as the anion, enabling the co‐existence of tetrahedral and octahedral structures within the same system. Remarkably, the compound exhibits efficient red‐light emission at 662 nm, distinct from the green‐light emission typically observed in MnX4‐based halides. Theoretical calculations show that the red emission comes from the charge transfer from the MDPPO to the Mn2+ of [MnCl4]2−. This work provides a new perspective for the design and synthesis of red‐light‐emitting manganese‐based halides with unique structures. [ABSTRACT FROM AUTHOR]

Hexaazamacrocyclic Schiff bases have been extensively combined with lanthanoid (Ln) ions to obtain complexes with a highly axial geometry. However, the use of flexible hexaazatetraamine macrocycles containing two pyridines and acyclic spacers is rather uncommon. Accordingly, we obtained [DyL(OAc)2]OAc·7H2O·EtOH and [DyLMe2(Cl)2]Cl·2H2O, where L and LMe2 are the 18-membered macrocycles 3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane and 3,10-dimethyl-3,6,10,13-tetraaza-1,8(2,6)-dipyridinacyclotetradecaphane, respectively, which contain ethylene and methylethylene spacers between their N3 moieties. [DyL(OAc)2]OAc·7H2O·EtOH represents the first crystallographically characterized lanthanoid complex of L, while [DyLMe2(Cl)2]Cl·2H2O contributes to increasing the scarce number of LnIII compounds containing LMe2. Furthermore, the crystal structure of L·12H2O was solved, and it was compared with those of other related macrocycles previously published. Likewise, the crystal structures of the DyIII complexes were compared with those of the lanthanoid and d-metal complexes of other 18-membered N6 donor macrocycles. This comparison showed some effect of the spacers employed, as well as the influence of the size of the ancillary ligands and the metal ion. Additionally, the distinct folding behaviors of these macrocycles influenced their coordination geometries. Moreover, the luminescent properties of [DyL(OAc)2]OAc·7H2O·EtOH and [DyLMe2(Cl)2]Cl·2H2O were also investigated, showing that both complexes are fluorescent, with the emission being sensitized by the ligands. [ABSTRACT FROM AUTHOR]

Herein, we present the synthesis and crystal structure of a series of heteronuclear metal–organic frameworks consisting of cobalt(II) and lanthanide(III) ions or yttrium(III) ions that are connected by oxydiacetato (oda2−) as a ligand. Our investigation led to the discovery of 16 new compounds that were categorized into two distinct structural types. Bigger lanthanide ions (La to Ho) and Y favor the formation of a neutral, highly porous hexagonal structure (space group P6/mcc). This assembly gives rise to nano-sized channels accommodating a significant number of crystallization water molecules (12–14 per formula unit). Conversely, smaller lanthanide ions (Sm to Lu) and Y favor the formation of an extended anionic cubic network neutralized by Co(II) hexaaqua ions (space group Fd3¯c). Both structures are assembled from the same building blocks, [Ln(oda)3]3− and Co(II), connected by either a syn–anti or an anti–anti carboxylate bridge. Both the hexagonal and cubic compounds show the same general formula [Ln2Co3(oda)6(H2O)6]·nH2O with different numbers of crystallization water molecules. Although the formation of different frameworks from the same combination of ligands and metal ions has already been reported, an exceptionally extended phenomenon is observed in this case, encompassing a total of seven isomers from Sm to Ho and Y. The synthesis of these compounds can be achieved either through a direct reaction at room temperature or by a hydrothermal reaction, and this has a marked influence on the obtained crystal structure. Our findings offer valuable data to discuss the rationale concerning the main chemical aspects of the synthetic strategies that can lead to the isolation of a unique pure phase, especially in systems where two structures are feasible. [ABSTRACT FROM AUTHOR]

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

Gold chloride clusters play an important role in catalysis and materials chemistry. Due to the diversity of their species and isomers, there is still a dearth of structural studies at the molecular level. In this work, anions of AunCln+3- and AunCln+5- (n = 2-4) clusters were obtained by laser desorption/ionization mass spectrometry (LDI MS), and the most stable isomers of AunCln+3- were determined after a thorough search and optimization at the TPSSh/aug-cc-pVTZ/ECP60MDF level. The results indicate that all isomers with the lowest energy have a planar zigzag skeleton. In each species, there is one Au(III) atom at the edge connected with four Cl atoms, which sets it from the other Au(I) atoms. Four growth pathways for AunCln+3- (n = 2-7) clusters are proposed (labelled R1, R2, R3 and R4). They are all associated with an aurophilic contact and are exothermic. The binding energies tend to stabilize at --41kcal/mol when the size of the cluster increases in all pathways. The pathway R1, which connects all the most stable isomers of the respective clusters, is characterized by cluster growth due to aurophilic interactions at the terminal atom of Au(I) in the zigzag chains. In the pathway of R4 involving Au-Au bonding in its initial structures (n < 3), the distance between intermediate gold atoms grows with cluster size, ultimately resulting in the transfer of the intermediate Au-Au bonding into aurophilic interaction. The size effect on the structure and aurophilic interactions of these clusters will be better understood based on these discoveries, potentially providing new insights into the active but elusive chemical species involved in the corresponding catalytic reactions or nanoparticle synthesis processes. [ABSTRACT FROM AUTHOR]

Methicillin-resistant Staphylococcus aureus (MRSA) infection has rapidly spread through various routes. A genomic analysis of clinical MRSA samples revealed an unknown protein, Sav2152, predicted to be a haloacid dehalogenase (HAD)-like hydrolase, making it a potential candidate for a novel drug target. In this study, we determined the crystal structure of Sav2152, which consists of a C2-type cap domain and a core domain. The core domain contains four motifs involved in phosphatase activity that depend on the presence of Mg2+ ions. Specifically, residues D10, D12, and D233, which closely correspond to key residues in structurally homolog proteins, are responsible for binding to the metal ion and are known to play critical roles in phosphatase activity. Our findings indicate that the Mg2+ ion known to stabilize local regions surrounding it, however, paradoxically, destabilizes the local region. Through mutant screening, we identified D10 and D12 as crucial residues for metal binding and maintaining structural stability via various uncharacterized intra-protein interactions, respectively. Substituting D10 with Ala effectively prevents the interaction with Mg2+ ions. The mutation of D12 disrupts important structural associations mediated by D12, leading to a decrease in the stability of Sav2152 and an enhancement in binding affinity to Mg2+ ions. Additionally, our study revealed that D237 can replace D12 and retain phosphatase activity. In summary, our work uncovers the novel role of metal ions in HAD-like phosphatase activity. [ABSTRACT FROM AUTHOR]

The goal of this study was to investigate how the electron-donating capability around the lower valent metal ion and the electron-accepting capability of the higher valent metal ion influence metal to metal charge transfer (MMCT) properties in mixed-valence complexes. A series of trinuclear ruthenium complexes represented as [Ru2(ap-4-Me)3(CH3COO)N≡CRuCpMex(dppe)][PF6] (CpMex = polymethylcyclopentadienyl, x = 0, 1, and 5; and dppe = 1, 2-bis(diphenylphosphino)ethane, ap-4-Me = 2-anilino-4-methylpyridine) and their one-electron oxidized products were synthesized and fully characterized. The UV–vis-NIR spectra confirmed that as the electron donor character of the CpMex(dppe)RuCN fragment enhanced or the electron-accepting capability of the higher valent diruthenium cluster increased, the RuII → Ru V2 or Ru VI2 Ru2 MMCT bands shifted to lower energies, which was supported by TDDFT calculations. [ABSTRACT FROM AUTHOR]

In this study, we report a new syringe aldehyde-derived hydrazinyl-imidazole based fluorescent sensor (L) for sensitive detection of different inorganic quenchers (halide ions, bicarbonate ion, sulphide ion and transition metal ions). The chromophore (L) was obtained in good yield by the 1:1 condensation reaction of 2-hydrazino-4,5-dihydroimidazole hydrobromide and 4-hydroxy-3,5-dimethoxy benzaldehyde. L exhibited strong fluorescence in the visible region (around 380 nm) and its interaction with different quenchers was studied in details via fluorescence technique. For the halide ions series, its sensitivity is higher for NaF (Climit = 4 × 10− 4 M) than for NaCl while the fluorescence quenching occurred mainly through a dynamic process. Similar considerations were observed for HCO3− and S2− quencher too, when static and dynamic quenching take place simultaneously. Regarding transition metal ions, at a fixed ion concentration (4 × 10− 6 M), best performance was achieved for Cu2+ and Fe2+ (fluorescence intensity was reduced by 79% and 84.9% respectively), while for other metal ions, the sensor performance was evaluated and found to be very less (< 40%). Thus, minimum detection limits (10− 6 – 10− 5 M range) recommended the use of such derivatives as highly sensitive sensors capable to monitor delicate changes in varied environments. [ABSTRACT FROM AUTHOR]

A Metal-Organic Framework (MOF) based on a tricarboxylic acid ligand (H3L = biphenyl-2,4′,5-tricarboxylic acid), namely [Cd3(L)2(H2O)4] (1), had been prepared and characterized by elemental analysis, IR spectroscopy, powder X-ray diffraction (PXRD), thermogravimetric analyses (TGA), and single-crystal X-ray diffraction. Fluorescence studies showed that 1 has high quenching efficiency for testing acetone and Fe3+ ions in aqueous systems. Therefore, it can be used as a new type of fluorescence probe to detect solvent molecules and metal ions in water. [ABSTRACT FROM AUTHOR]

The reaction of the Schiff base 2-[1-(pyridin-2-yl)ethylideneamino]ethanol (HL), which is formed by reaction of 2-aminoethanol and 2-acetylpyridine with CuBr2 in ethanol results in the isolation of the new polymeric complex poly[hexa-µ-bromido-bis{2-[1-(pyridin-2-yl)ethylideneamino]ethanolato}tetracopper(II)], [Cu4Br6(C9H11N2O)2]n or [Cu4Br6L2]n. The asymmetric unit of the crystal structure of the polymeric [Cu4Br6L2]n complex is composed by four copper (II) cations, two monodeprotonated molecules of the ligand, and six bromide anions, which act as bridges. The ligand molecules act in a tridentate fashion through their azomethine nitrogen atoms, their pyridine nitrogen atoms, and their alcoholate O atoms. The crystal structure shows two types of geometries in the coordination polyhedrons around Cu2+ ions. Two copper cations are situated in a square-based pyramidal environment, while the two other copper cations adopt a tetrahedral geometry. Bromides anions acting as bridges between two metal ions connect the units, resulting in a tetranuclear polymer compound. [ABSTRACT FROM AUTHOR]

The asymmetric unit of the title compound, catena-poly[[[aqua­bis­(pyridine-κN)cadmium(II)]-μ2-4,4′-(1H-1,2,4-triazole-3,5-di­yl)dibenzoato-κ4O, O′:O′′, O′′′] 4.5-hydrate], {[Cd(C16H9N3O4)(C5H5N)2(H2O)]·4.5H2O}n or {[Cd(bct)(py)2(H2O)]·4.5H2O}n (I), consists of a Cd2+ cation coordinated to one bct2-carboxyl­ate dianion, two mol­ecules of pyridine and a water mol­ecule as well as four and a half water mol­ecules of crystallization. The metal ion in I possesses a penta­gonal-bipyramidal environment with the four O atoms of the two bidentately coordinated carboxyl­ate groups and the N atom of a pyridine mol­ecule forming the O4N equatorial plane, while the N atom of another pyridine ligand and the O atom of the water mol­ecule occupy the axial positions. The bct2-bridging ligand connects two metal ions via its carb­oxy­lic groups, resulting in the formation of a parallel linear polymeric chain running along the [1\overline{1}1] direction. The coordinated water mol­ecule of one chain forms a strong O--H...O hydrogen bond with the carboxyl­ate O atom of a neighboring chain, leading to the formation of double chains with a closest distance of 5.425(7)Å between the cadmium ions belonging to different chains. Aromatic π-π stacking inter­actions between the benzene fragments of the anions as well as between the coordinated pyridine mol­ecules belonging to different chains results in the formation of sheets oriented parallel to the (\overline{1}01) plane. As a result of hydrogen-bonding inter­actions involving the water mol­ecules of crystallization, the sheets are joined together in a three-dimensional network. [ABSTRACT FROM AUTHOR]

Seven novel 4-dimethylaminopyridine(dmap)-based metal complexes of [Zn(dmap)(cna)2]2 (1) (Hcna = cinnamic acid), [Zn(dmap)(dcpa)2]2 (2) (Hdcpa = 2,6-dichlorophenylacetic acid), [Zn(dmap)(mpba)2]2 (3) (Hmpba = 3-phenoxybenzoic acid), [Zn(dmap)(bdmba)2]2 (4) (Hbdmba = 4-bromo-3,5-dimethoxybenzoic acid), [Cd(damp)2(ibfa)2(H2O)2] (5) (Hibfa = ibuprofen), [Cd(dmap)2(H2O)4]·(dnba)2·H2O (6) (Hdnba = 3,5-dinitrobenzoic acid) and [Cd(dmap)2(bdmba)2(H2O)] (7) have been afforded by the introduction of the carboxylates as the auxiliary ligands and are structurally featured by distinct techniques of EA, IR spectra, TG and SCXRD analysis. The X-ray studies told that these complexes display mononuclear, binuclear to polymeric appearances with tetrahedral/square-pyramidal arrangement at the Zn2+, and octahedral/pentagonal-bipyramidal geometry for the Cd2+. The dmap in 1–7 are coordinated only in monodentate fashion with its ring N. The carboxylates coordinated to the metal ions in monodentate, chelating bidentate and bismonodentate bridging modes for 1–5 and 7. The carboxylates at 6 did not coordinated to the Cd and exhibited only as the counter ion to balance the charge. The CH3···O contacts from the N(CH3)2 of the dmap were built in all compounds, apart from 1 and 6. The π-associates originating from the aryl kernel of the anions were existed in 2–3 and 6–7. The intricate intra- and intermolecular classical H-bonds, CH···C, CH···O/CH3···O, CH···CH/CH3···CH/CH3···CH3, CH···Cl, CH3···Br, Br···Br, CH···π/CH2···π/CH3···π and π···π associations are elucidated by the X-ray crystallographic investigations, which push the discrete complexes into high-dimensional ordered supramolecular structures. In the seven prepared coordination complexes there are plenty of weak nonbonding interactions such as directional hydrogen bonds of O–H···O, intra- and interchain CH–C, CH–O/CH3–O, CH–CH/CH3–CH/CH3–CH3, CH–Cl, CH3–Br, Br–Br, CH–π/CH2–π/CH3–π and π–π interactions, on account of these collective weak interactions, these compounds displayed the 3D framework structures. [ABSTRACT FROM AUTHOR]

The preparation of α‐hemihydrate gypsum (α‐HH) from phosphogypsum (PG) by atmospheric hydrothermal synthesis is a green and efficient method for the treatment of PG. The commonly used electrolyte solution today is mostly chlorine‐based. The prepared α‐HH based on chlorine salt solution is needlelike with a large aspect ratio, low strength, and high impurity. In this study, sodium‐ and calcium‐mixed cation acetate solution is designed and used as an organic multifunctional electrolyte to the synthesis of α‐HH for the first time. The effects of the mixed cation acetate electrolyte on crystal transformation, product morphology, and product purity of the prepared α‐HH were compared with those prepared with chloride solutions with the same mixed cations. Result showed that the morphology of α‐HH crystals prepared in acetate solutions is a stubby hexagonal prism. The aspect ratio of the prepared α‐HH crystals is close to 1, with 3‐day compressive strength four times higher than that of α‐HH prepared in chloride solutions. In addition, in comparison with chloride electrolyte, acetate electrolyte showed a complexation effect with impurity metal ions, which realized the efficient removal of impurities from PG and increased the purity of the synthesized α‐HH. [ABSTRACT FROM AUTHOR]

Two new bis(β-diketone) ligands based on triphenylamine have been prepared and crystallized. Treatment of 4,4′-diformyltriphenylamine with two phospholenes (2,2,2-trimethoxy-4,5-dimethyl-1,3,2-dioxaphospholene and 2,2,2-trimethoxy-4,5-diethyl-1,3,2-dioxaphospholene) afforded the bis(β-diketones) triphenylaminebis(2,4-pentanedione) (tpbaH2, 1); and triphenylaminebis(3,5-heptanedione) (tpbprH2, 2) as white solids. X-ray analysis of 1 and 2 shows that they are in the enol form. Also, their triphenylamine moieties have a chiral "propeller" shape; the centrosymmetric structures contain equal numbers of the two enantiomeric propellers. Reaction of 1 and 2 with [Cu(NH3)4]2+(aq) yielded dark-green solids. The Cu complex of 1 was insoluble in common solvents, but that of 2, Cu4(tpbpr)4 (3), is soluble in dichloromethane and chloroform. 3 is assigned the cyclic tetrameric structure Cu4(tpbpr)4 based on ESI–MS and microanalytical data. This is similar to the copper(II) β-diketonate molecular squares reported previously from our group. Molecular modeling indicates that Cu4(tpbpr)4 has Cu···Cu distances of ca. 21 Å, as compared to ca. 14 Å in the previous molecular squares. Crystal structures of two new bis(β-diketones) are reported, which are likely to form large supramolecular structures on reaction with metal ions such as Cu2+. [ABSTRACT FROM AUTHOR]

A benzothiazole-coupled NS4-macrocycle derivative L was synthesized via a three-step route for the detection of Hg2+. Chemosensor L, as a dual channel (UV-vis and fluorescence) receptor, undergoes a significant hypsochromic shift and fluorescence quenching in the presence of Hg(ClO4)2 in ethanol/DMSO (v/v, 9 : 1), showing remarkable selectivity towards Hg2+ over other metal ions both in single and competitive metal ion experiments. The observed chelation-enhanced quenching (CHEQ) effect seems to be attributed to the combination of the heavy atom effect and Hg2+⋯benzothiazole interaction. However, such Hg2+ sensing responses in both channels were not observed for non-perchlorate anions. To explain the anion-dependent Hg2+ sensing, systematic studies on the complexations of L with Hg(ClO4)2 and HgI2 were performed via UV-vis/fluorescence titrations, comparative NMR, and anion exchange. Taken together, the Hg2+ sensing critically depends on the Hg–Ntert bonding which triggers the hypsochromic shift or the CHEQ effect. A weaker coordinating ClO4− allows an endocyclic complex to form with the Hg–Ntert bond being responsive, while a stronger coordinating I− leads to exocyclic complexation without the Hg–Ntert bond being non-responsive. The crystal structure of the mercury(II) iodide complex [Hg2(L)I4] featuring an exocyclic dinuclear form also supports this explanation. This result could present a new perspective on the design of macrocycle-based chemosensors. [ABSTRACT FROM AUTHOR]

In the title compound, [FeII(C44H24Cl4N4)(C5H9N)2] or [FeII(TClPP)(t-BuNC)2] [where TClPP and t-BuNC are 5,10,15,20-tetrakis(4-chlorophenyl)porphyrinate and tert-butyl isocyanide ligands, respectively], the metal ion lies on an inversion center and is octahedrally coordinated by the N atoms of the porphyrin ring in the equatorial plane and by carbon atoms of the trans t-BuNC ligands in the axial sites. The Fe--N bond length of 2.0074 (14) Å suggests a low-spin complex (S = 0). The crystal packing of the title compound is sustained by C--H• • •Cl, C--H• • •N and C--H• • •Cg (Cg = the centroid of a pyrrole ring of the TClPP porphyrinate) interactions, leading to a three-dimensional network. The Hirshfeld surface (HS) analysis indicates that 61.4% of the intermolecular interactions are from H• • •H contacts while other contributions are from C• • •H/ H• • •C, O• • •H/H• • •O and N• • •H/H• • •N interactions, which comprise 21.3%, 13.3% and 3.6% of the HS, respectively. [ABSTRACT FROM AUTHOR]

Herein, a new tellurium and mercury containing mercuraazametallamacrocycle has been prepared via (2+2) condensation of bis(o‐aminophenyl)telluride and bis(o‐formylphenyl)mercury(II). The isolated bright yellow solid of mercuraazametallamacrocycle has adopted unsymmetrical figure‐of‐eight conformation in the crystal structure. To study the metallophilic interactions between closed shell metal ions, the macrocyclic ligand has been treated with two equiv. of AgOTf (OTf=trifluoromethansulfonate) and AgBF4, which afforded greenish‐yellow bimetallic silver complexes. The isolated silver complexes displayed intramolecular Hg⋅⋅⋅Ag, Te⋅⋅⋅Ag interactions as well as intermolecular Hg⋅⋅⋅Hg interactions and formed an extended 1D molecular chain by directing six atoms to interact as TeII⋅⋅⋅AgI⋅⋅⋅HgII⋅⋅⋅HgII⋅⋅⋅AgI⋅⋅⋅TeII in a non linear fashion. The Hg⋅⋅⋅Ag, Te⋅⋅⋅Ag interactions have also been studied in solution by 199Hg, 125Te NMR spectroscopy, absorption, and emission spectroscopy. In DFT calculations, the Atom in Molecule (AIM) analysis, non‐covalent interactions (NCI), natural bonding orbital (NBO) analysis strongly supported for experimental evidences and revealed that the intermolecular Hg⋅⋅⋅Hg interaction is stronger than the intramolecular Hg⋅⋅⋅Ag interactions. [ABSTRACT FROM AUTHOR]

New representatives of 2,4,7‐trisubstituted 9,9‐dialkyl‐9H‐fluorenes were prepared and used for crystallographic investigations as well as initial binding studies towards metal ions and carbohydrates. The binding studies, which included 1H NMR spectroscopic titrations and fluorescence measurements, demonstrated the ability of the tested fluorene‐based compounds to act as complexing agents for ionic and neutral substrates. Depending on the nature of the subunits of the fluorene derivatives, "turn on" or "turn off" fluorescent chemosensors can be developed. Compounds composed of 4,6‐dimethylpyridin‐2‐yl‐aminomethyl moieties have the potential to be used as sensitive "turn‐on" chemosensors for some metal ions. [ABSTRACT FROM AUTHOR]

An efficient one-pot synthesis of 1,2-disubstituted benzimidazoles was developed via cyclocondensation starting from o-phenylenediamine with substituted aromatic aldehydes using catalyst vitamin B1 under ultrasound-assisted, and was characterized by HR-MS, FT-IR, 1H and 13C NMR spectroscopy. N-Ts-substituted 1,2-disubstituted benzimidazoles were formed when 2 equivalents of p-toluenesulfonic acid were added to the reaction. The reaction conditions of the method are environmentally friendly, no metal is required, the operation is simple, the substrates are extensive, the yield is high, and the catalyst is non-toxic and reusable. The crystal structure of compound 1-(2-methoxybenzyl)-2-(2-methoxyphenyl)-1H-benzoimidazole (3ab) in triclinic P21/n space group is presented. 4-(1-(2,3,4-Trihydroxybenzyl)-1H-benzoimidazol-2- yl)benzene-1,2,3-triol (3af) as a metal ion fluorescent probe, has excellent selectivity to Pb2+ and Ag+, and exhibits obvious discoloration. An efficient one-pot synthesis of 1,2-disubstituted benzimidazoles was developed via cyclocondensation starting from o-phenylenediamine with substituted aromatic aldehydes using catalyst vitamin B1 under ultrasound-assisted, and were characterized by HR-MS, FT-IR, 1H and 13C NMR spectroscopy. N-Ts-substituted 1,2-disubstituted benzimidazoles were formed when 2 equivalents of p-toluenesulfonic acid was added to the reaction. The crystal structure of compound 1-(2-methoxybenzyl)-2-(2-methoxyphenyl)-1H-benzoimidazole (3ab) in triclinic P21/n space group was presented. [ABSTRACT FROM AUTHOR]

Two isostructural organic-inorganic hybrid ruthenium-containing polyoxometalates (POMs), NaH5[(P2M18O62)]·(Ru(dmso)4Cl2)4·nH2O (M = W, n = 12 (1); M = Mo, n = 10 (2)), have been synthesized and characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric (TG) analyses, and elemental analyses. Single-crystal X-ray diffraction analyses indicate that they are co-crystals and that the two polyoxoanions are structurally similar aside from the identity of the metal ions present. Furthermore, the electrochemical behavior of the POMs was investigated in aqueous solution to establish the redox properties associated with having W versus Mo in the structures. [ABSTRACT FROM AUTHOR]

The adjoined 3d–4f metallacrown (MC) molecule DyIII2MnIII6(H2shi)(Hshi)(shi)7(py)9·2py·0.7H2O, 1, where H3shi is salicylhydroxamic acid and py is pyridine, has been synthesized and characterized by FT–IR spectroscopy and single-crystal X-ray diffraction. The core of the molecule consists of two metallacrown (MC) rings, an archetypal 12-MC-4 and a collapsed 11-MC-4, that are linked through a common ring DyIII center. For the 12-MC-4 portion of 1, the heterobimetallic composition of the MC ring with one DyIII and three MnIII ions is uncommon for metallacrowns as most 12-MC-4 rings are homometallic. In addition, the 12-MC-4 binds a DyIII cation in the central cavity of the MC. The coordination environment about the central DyIII ion has a triangular dodecahedron shape, which again is atypical. For 12-MC-4 molecules with a central lanthanide ion, the central lanthanide ion typically adopts a square antiprism geometry. The ring DyIII cation of the 12-MC-4, which has a biaugmented trigonal prism shape, is shared with the collapsed 11-MC-4 and serves to join both metallacrowns. The collapsed 11-MC-4 ring is also composed of three MnIII and one DyIII ions. For one of the ring metal–metal linkages, only an oxygen atom is present, and an eleven membered ring is generated. In addition, the DyIII center and one of the MnIII centers bind to ring oxygen atoms on the opposite side of the MC ring; thus, the potential cavity of the MC is collapsed, and the MC does not bind a central metal ion as is customary. [ABSTRACT FROM AUTHOR]

This short note describes the synthesis of a novel compound, 6,6′-di-(8″-quinoline)-2,2′-bypyridine (2), that bears a bipyridyl backbone and quinoline donors. Compound 2 coordinates with a cobalt(II) ion in a tetradentate manner and affords the complex [CoII(2)(TfO)2], whose molecular structure has been identified by single crystal X-ray diffraction crystallographic analysis. The coordination features of 2 were compared with those of 2,2′:6′,2″:6″,2‴-quaterpyridine (qtpy, 1), a well-studied tetradentate polypyridine ligand. Compound 2 presents a new example of tetradentate chelators for 3d metal ions. [ABSTRACT FROM AUTHOR]

Understanding the factors governing the self-assembly of organic ligands with metal ions is essential to engineering target molecular arrangements with the desired properties. Indeed, small modifications of the synthetic conditions lead to the obtention of different complexes, varying from discrete monomers to coordination polymers (CPs). Based on the potential coordinating ability of 2-furoic acid (2-FA), we prepared five Zn(II) and Cd(II) complexes to study the behavior of the furane O atom and the competitiveness of the M–O bond formation in methanol (MeOH). Reactions between M(OAc)2·2H2O (M = Zn(II), Cd(II)), 2-FA, and two p-substituted pyridine ligands (isonicotinamide (Isn) and 4-acetylpyridine (4-Acpy)) in MeOH yielded the two dimers [Zn(μ-2-FA)(2-FA)(Isn)2]2 (1) and [Cd(μ-2-FA)(2-FA)(Isn)2]2 (2), the dimeric paddle-wheel [Zn(μ-2-FA)2(4-Acpy)]2 (3), and the monomer [Cd(2-FA)2(4-Acpy)2(OH2)] (4). Their crystal structures have been studied, observing diverse coordination numbers between five and seven and diverse coordination modes of the carboxylate groups. Interestingly, the recrystallization of 4 in acetonitrile (ACN) resulted in a dissolution–recrystallization structural transformation (DRST), leading to an intricate coordination polymer (CP) with the formula {[Cd(μ-2-FA)(2-FA)(OH2)2]n[Cd(μ-2-FA)(2-FA)(4-Acpy)(OH2)]n} (5) exhibiting coordination of the furane O atom. Within this collection of arrangements, 2-FA displayed a great diversity of coordination modes that were combined and interchanged in the DRST process. Their photophysical properties in solution have been analyzed and their quantum yields calculated. Likewise, further insight into the DRST process was obtained from fluorescence measurements. From these results, a pathway for the structural transformation highlighting the crucial role of solvents has been proposed. [ABSTRACT FROM AUTHOR]

Selecting different metal ions, two novel complexes {[Zn(BCbpy)(m‐BDC)(H2O)] ⋅ 2H2O}n (1) and [Co(H2O)6]0.5[Co0.5(BCbpy)(H2O)2](m‐BDC) ⋅ 3H2O ⋅ DMF (2) have been prepared and structurally characterized in the presence of the viologen ligand 1‐(4‐carboxybenzyl)‐4,4′‐bipyridinium (BCbpy) and 1,3‐benzenedicarboxylic acid (m‐H2BDC). The crystal structures and photochromic properties of two complexes have been investigated in this article. 1 possesses a two‐dimensional (2D) layered structure, while the structure of 2 is zero‐dimensional (0D). As expected, 1 and 2 were discovered to be photochromic accompanying electron transfer (ET). Interestingly, 1 can be dissolved in ethanol solution and deposited on filter paper, applied to a printing medium without ink. [ABSTRACT FROM AUTHOR]

Two new complexes [Co2(bia)2(2,2′-bpy)2] (1) and [Dy4(bia)6(2,2′-bpy)2(H2O)2]·8H2O (2) (H2bia = cis-1,3-dibenzyl-2-imidazolidone-4,5-dicarboxylic acid, 2,2′-bpy = 2,2′-bipyridine) have been synthesized by method of hydrothermal reactions and their crystal structures determined. In 1, two symmetrical Co atoms are connected through bia ligands forming a discrete rhomboid binuclear Co2 cluster. Complex 2 has a one-dimensional chain structure based on binuclear paddle-wheel Dy2 and rhomboid Dy2 units. The structure versatility indicates that the nature of the metal ion and variable conformations of bia ligand play a crucial role in modulating the cluster complexes. IR, elemental analysis and XRPD confirmed the phase purity of the bulk materials. Magnetic properties of 1 and 2 in the 300–2 K have been discussed. [ABSTRACT FROM AUTHOR]

Campylobacter jejuni PseI is a pseudaminic acid synthase that condenses the 2,4-diacetamido-2,4,6-trideoxy- l -altrose sugar (6-deoxy AltdiNAc) and phosphoenolpyruvate to generate pseudaminic acid, a sialic acid-like 9-carbon backbone α-keto sugar. Pseudaminic acid is conjugated to cell surface proteins and lipids and plays a key role in the mobility and virulence of C. jejuni and other pathogenic bacteria. To provide insights into the catalytic mechanism of PseI, we performed a structural study on PseI. PseI forms a two-domain structure and assembles into a domain-swapped homodimer. The PseI dimer has two cavities, each of which accommodates a metal ion using conserved histidine residues. A comparative analysis of structures and sequences suggests that the cavity of PseI functions as an active site that binds the 6-deoxy AltdiNAc and phosphoenolpyruvate substrates and mediates their condensation. Furthermore, we propose the substrate binding-induced structural rearrangement of PseI and predict 6-deoxy AltdiNAc recognition residues that are specific to PseI. • The crystal structure of the pseudaminic acid synthase, PseI, was determined. • PseI forms a domain-swapped dimer that features two intersubunit cavities. • Each cavity of PseI accommodates a metal ion and functions as an active site. • A comparative analysis of PseI and NeuB suggests the substrate-binding mode of PseI. [ABSTRACT FROM AUTHOR]

The control of the structure, shape, and components of metal-organic frameworks, in which metal ions and organic ligands coordinate to form crystalline nanopore structures, plays an important role in the use of many electrochemical applications, such as energy storage, high-performance photovoltaic devices, and supercapacitors. In this study, systematic controls of synthesis variables were performed to control the morphology of ZIF-8 during the ZIF-L-to-ZIF-8 transformation of ZIF-L, which has the same building block as ZIF-8 but forms a two-dimensional structure. Furthermore, additional precursors or surfactants (Zn2+, 2mIm, and CTAB) were introduced during the transition to determine whether the alteration could be regulated. Lastly, the partial substitution insertion of a new organic precursor, 2abIm, during the ZIF-L-to-ZIF-8 transformation of ZIF-L was achieved, and modulation of the adsorption and pore characteristics (suppression of gate-opening properties of ZIF-8) has been confirmed. [ABSTRACT FROM AUTHOR]

The series of divalent metal chloride complexes of 2,2'-[oxybis(methylidene)]dipyridine (L) was extended with the preparation of the title compound, [HgCl2(C12H12N2O)] or [HgLCl2] (1). The Hg2+ complex crystallizes in P21/n, isomorphic with dichloride Co2+, Cu2+, Zn2+ and Cd2+ complexes of L. Metal ions of the isotypic complexes are coordinated by two chlorine atoms, as well as the oxygen atom and both nitrogen atoms of L. The complexes have a squarepyramidal coordination geometry with a chlorine atom in the apical position. Supramolecular interactions in 1 include offset face-to-face interactions between inversion-related complexes, leading to the formation of sheets parallel to the ab plane. Weak intermolecular H· · ·Cl contacts link the sheets. Hirshfeld surface analysis indicates that H· · ·H (36.5%), Cl· · ·H/H· · ·Cl (36.5%) and C· · ·H/H· · ·C (11.6%) interactions are dominant. [ABSTRACT FROM AUTHOR]

The asymmetric unit of catena-poly[[[(1,4,8,11-tetraazacyclotetradecane-κ4N1,N4,N8,N11)nickel(II)]-μ2-5-carboxybenzene-1,3-dicarboxylato-μ2O1:O3] octahydrate], {[Ni(C9H4O6)(C10H24N4)]·8H2O}n (I), consists of a macrocyclic Ni2+ cation, a carboxylate dianion and eight highly disordered water molecules of crystallization. The components of the compound catena-poly[[[(1,4,8,11-tetraazacyclotetradecane-κ4N1,N4,N8,N11)nickel(II)]-μ2-5-carboxybenzene-1,3-dicarboxylato-κ2O1:O3] monohydrate], {[Ni(C9H4O6)(C10H24N4)]·H2O}n (II), are two crystallographically unique centrosymmetric macrocyclic dications, a carboxylate dianion and one water molecule of crystallization. In each compound, the metal ion is coordinated in the equatorial plane by the four secondary N atoms of the macrocyclic ligand, which adopts the most energetically stable trans-III conformation, and two mutually trans O atoms of the carboxylate anions in a slightly tetragonally distorted trans-NiN4O2 octahedral geometry. The crystals of both compounds are composed of parallel coordination polymeric chains running along the [010] direction in I and the [110] and [110] directions in II. The bridging carboxylate anions display different modes of coordination connected with the relative orientation of coordinated O atoms, i.e., remote in I and intermediate in II, thus resulting in essentially different distances between the Ni atoms in the chains [11.0657 (4) and 8.9089 (2) A ° in I and II, respectively]. As a result of hydrogen-bonding interactions, the chains are joined together in sheets oriented parallel to the (101) and (001) planes in I and II, respectively. [ABSTRACT FROM AUTHOR]

The bioavailability of copper (Cu) in human cells may depend on a complex interplay with zinc (Zn) ions. We investigated the ability of the Zn ion to target the human Cu-chaperone Atox1, a small cytosolic protein capable of anchoring Cu(I), by a conserved surface-exposed Cys-X-X-Cys (CXXC) motif, and deliver it to Cu-transporting ATPases in the trans-Golgi network. The crystal structure of Atox1 loaded with Zn displays the metal ion bridging the CXXC motifs of two Atox1 molecules in a homodimer. The identity and location of the Zn ion were confirmed through the anomalous scattering of the metal by collecting X-ray diffraction data near the Zn K-edge. Furthermore, soaking experiments of the Zn-loaded Atox1 crystals with a strong chelating agent, such as EDTA, caused only limited removal of the metal ion from the tetrahedral coordination cage, suggesting a potential role of Atox1 in Zn metabolism and, more generally, that Cu and Zn transport mechanisms could be interlocked in human cells. [ABSTRACT FROM AUTHOR]

In the present work, we report a detailed investigation of four supramolecular coordination complexes, Zn(Quino)2(CH3OH)22, Zn(Quino)2H2O 3, Mn(Quino)2(CH3OH)24 and Ca(Quino)2(CH3OH)25, obtained from the self-assembling of Zn(II), Mn(II) and Ca(II) acceptors with the N-phenyl-4-hydroxyquinoline ligand donor QuinoH 1, possessing the β,β′-diketonate moiety. The structure of the supramolecular arrangement of the isolated complexes have been investigated by single crystal X-ray crystallography. The synthetic N-phenyl quinolone-linker that forms a π–π stacking supramolecular synthon with the coordination preferences of metal ions has been used to construct coordination driven self-assembled "metallosupramolecular" architectures. [ABSTRACT FROM AUTHOR]

In the current work, the cabbage-like hydroxysodalite powder was produced from a clay-based waste deposited in the landfill of raw vegetable oil refinery through the microwave-assisted technique to treat the wastewater discharged from a zinc extraction industry. The selected waste was a Ca-bentonite, mainly containing montmorillonite, illite, and kaolinite which contaminated with the vegetable oil components. The effects of microwave irradiation power, and time on crystalline structure of products as well as uptake of heavy metal ions like zinc, cadmium, nickel, and aluminum were studied in details. The experimental results showed that the partial recrystallization of hydroxysodalite under the irradiation power of 200 W within 10–15 min contributes to the enhancement of adsorption efficiency. The maximal uptake of heavy metal ions was obtained in the relative crystallinity range of 22.5–43.0%. The prepared adsorbent possessed the higher efficiency, 94.0%, for the immobilization of Zn2+ from the concentrated wastewater, 413 mg L−1. The competitive adsorption of Cd2+, Ni2+, and Al3+ ions over the hydroxysodalite was extremely dependent on the ion concentration. Furthermore, the adsorption kinetics of Zn2+ over the hydroxysodalite particles follows the pseudo-second-order (PSO) model, indicating the chemical nature of treatment process. The equilibrium data were fitted by the Langmuir isotherm, confirming the homogenous, and monolayer adsorption. The presented route for the production of hydroxysodalite is facile, and rapid in comparison to hydrothermal method. [Display omitted] • The microwave-assisted method was used to produce hydroxysodalite (HS) from a waste. • The effluent discharged from zinc industry was treated by produced hydroxysodalite. • The enhancement in efficiency is due to partial recrystallization of HS, 22.5–43.0%. • The capacity of hydroxysodalite for uptake of Zn2+ was determined to be145 mg g−1. • Cd2+, Ni2+, and Al3+ ions can be removed competitively by adsorption over HS. [ABSTRACT FROM AUTHOR]

Two new two‐dimensional (2D) coordination polymers (CPs), namely, poly[diaqua[μ4‐2,2′‐(1,3,5,7‐tetraoxo‐1,2,3,5,6,7‐hexahydropyrrolo[3,4‐f]isoindole‐2,6‐diyl)diacetato‐κ4O:O′:O′′:O′′′]cadmium(II)], [Cd(C14H6N2O8)(H2O)2]n (1), and poly[[tetraaqua[μ4‐2,2′‐(1,3,5,7‐tetraoxo‐1,2,3,5,6,7‐hexahydropyrrolo[3,4‐f]isoindole‐2,6‐diyl)diacetato‐κ4O:O′:O′′:O′′′][μ2‐2,2′‐(1,3,5,7‐tetraoxo‐1,2,3,5,6,7‐hexahydropyrrolo[3,4‐f]isoindole‐2,6‐diyl)diacetato‐κ2O:O′]dizinc(II)] dihydrate], {[Zn(C14H6N2O8(H2O)2]·H2O}n (2), have been synthesized by the microwave‐irradiated reaction of Cd(CH3COO)2·2H2O and Zn(CH3COO)2·2H2O, respectively, with N,N′‐bis(glycinyl)pyromellitic diimide {BGPD, namely, 2,2′‐(1,3,5,7‐tetraoxo‐1,2,3,5,6,7‐hexahydropyrrolo[3,4‐f]isoindole‐2,6‐diyl)diacetic acid, H2L}. In the crystal structure of 1, the CdII ion is six‐coordinated by four carboxylate O atoms from four symmetry‐related L2− dianions and two coordinated water molecules, furnishing an octahedral coordination geometry. The bridging L2− dianion links four symmetry‐related CdII cations into a 2D layer‐like structure with a 3,4‐connected bex topology. In the crystal structure of 2, the ZnII ion is five‐coordinated by three carboxylate O atoms from three different L2− dianions and two coordination water molecules, furnishing a trigonal bipyramidal coordination geometry. Two crystallographically independent ligands serve as μ4‐ and μ2‐bridges, respectively, to connect the ZnII ions, thereby forming a 2D layer with a 3,3‐connected hcb topology. Crystal structure analysis reveals the presence of n→π* interactions between two carbonyl groups of the pyromellitic diimide moieties in 1 and 2. CP 1 exhibits an enhanced fluorescence emission compared with free H2L. The framework of 2 decomposes from 720 K, indicating its high thermal stability. A comparative analysis of a series of structures based on the BGPD ligand indicates that the metal‐ion size has a great influence on the connection modes of the metal ions due to different steric effects, which, in turn, affects the structures of the SBUs (secondary building units) and frameworks. [ABSTRACT FROM AUTHOR]

In this work, the fluorescent receptor 4‐(2,6‐di(furan‐2‐yl)pyridin‐4‐yl)‐N,N‐diphenylaniline (DFPDA) was successfully synthesized overall in three steps, which bears three acceptor moieties one pyridine and two furans connected to a donor triphenylamine The DFPDA was fully characterized through 1H‐NMR, 13C‐NMR, ESI mass and elemental analysis. Further, single X‐ray structure confirm the intermediate and final DFPDA molecules. When we employed DFPDA molecule for sensing of metal ion, it shows selective detection of Fe3+ over other metal ions (Cu2+, K+, Cd2+, Co2+, Mn2+, Ni2+, Ba2+, Hg2+, Al3+, Pb2+, Zn2+, Ca2+, Fe2+ as their respective salts) dissolving in 1 : 1 water/DMSO solution with the binding constant 3.75×10−5 M. The limit of detection of DFPDA was found to be 52 nM which is much lower than the environmental protection agency guidelines (5.37 μM). Therefore, we believe that the DFPDA 1 fluorescent receptor may become outstanding chromophore for practical applications. Competing financial interests: The authors declare no competing interests. [ABSTRACT FROM AUTHOR]

The employment of the new Schiff base ligand 2‐[(4‐chloro‐2‐hydroxybenzylideneamino)methyl]phenol (H2L) bearing O2N donors for the preparation of a novel Co6 cluster is reported. The hexanuclear cobalt complex, namely, di‐μ2‐acetatotetrakis{μ2‐2‐[(4‐chloro‐2‐oxidobenzylideneamino)methyl]phenolato}tetra‐μ3‐methanolato‐tetracobalt(II)dicobalt(III), [CoII4CoIII2(C14H10ClNO2)4(CH3COO)2(CH3O)4], was obtained using Co(CH3COO)2·4H2O and H2L as starting materials in MeOH under solvothermal conditions. The six metal ions are linked together by the μ3‐O atoms of four deprotonated MeOH molecules, two CH3COO− units and six phenolate O atoms of four L2− ligands to form a defect disk‐shaped topology. DC magnetic susceptibility investigations revealed the existence of antiferromagnetic interactions in the Co6 cluster. [ABSTRACT FROM AUTHOR]

Four novel metal–organic frameworks (MOFs), H3O[Ln(Ox)1.5(formate)] (Ln = Tb (1), Dy (2), Ho (3), Er (4), Ox = oxalate) were synthesized, and their structures and properties were analyzed. They were prepared by solvothermal reaction under acidic condition with structure‐directing agents (H4dobpdc; 4,4′‐dihydroxy‐[1,1′‐biphenyl]‐3,3′‐dicarboxylic acid) and the corresponding Ln metal ion(s). Single‐crystal X‐ray diffraction analysis revealed that 1 and 2 (Group I) are isostructural as Cmca space group to 3 and 4 (Group II) as Pnma space group, respectively. This result probably comes from the change in structure according to the size of the lanthanide metal. TGA showed that the framework is thermally stable up to about 300 °C for all 1–4. Furthermore, we measured N2 adsorption at 77 K and CO2 adsorption at 195 K, and compound 2–4 had a type I adsorption isotherm graph and adsorbed CO2. In the study, we prepared and characterized four novel Ln‐MOFs, H3O[Ln(Ox)1.5(formate)] (Ln = Tb (1), Dy (2), Ho (3), Er (4), Ox = oxalate) by an unique in situ synthetic method. [ABSTRACT FROM AUTHOR]

Insulin-cleaving membrane protease (ICMP), an outmember protein of Pseudomonas aeruginosa (P. aeruginosa), plays a critical role in the pathogenesis of the bacterium. ICMP has been reported to be involved in the process of iron uptake. In this study, we report the high-resolution structure of ICMP determined by single-wavelength anomalous diffraction (SAD), which shows an atypical HxxE motif that differs from the canonical zinc dependent M75 peptidases and a "V-shaped" cleft that is observed to coordinate the metal ion for the first time. Crystals from the selenomethionine-substituted ICMP(Se-Met ICMP) diffract to 1.9 Å resolution and belong to space group P21, with unit-cell parameters a = 87.93, b = 78.14, c = 9.92 Å, α = 90°, β = 113.5°, γ = 90°. ICMP consists of two up-and-down helix bundles, which are arranged into an inverted "V" shape. Unexpectedly, no electron densities of metal ions are observed around the ICMP HxxE motif, which is shown to be involved in metal coordination in zinc-dependent M75 peptidases. In contrast, we find a metal ion at the opening cleft of the V-shaped structure of ICMP, where the ICMP residues Asp211, Glu316, Cys319, Asp322, and Asp397 are observed to coordinate the metal via hydrogen-bond interactions. Such observations might imply new potential substrate-binding and catalytic sites. The current work therefore provides novel insights into the diversity of the HxxE-motif-containing peptidase and paves the way for future studies aiming to delineate the mechanism of ICMP catalysis. • The high-resolution structure of ICMP was determined and reported for the first time. • A new potential substrate-binding and catalytic site of ICMP was found. • This study provides novel insights into the diversity of the HxxE motif in zinc-dependent M75 peptidases. [ABSTRACT FROM AUTHOR]

The rational design of heterometallic compounds bearing s-block metal ions have been a difficult task for chemists owing to their lack of preferential geometries. However, some strategies, such as the design of coordinating pockets with different sizes and/or donor atoms, have offered great results. In this work, this strategy has been tested using Ca(II) as an s-block metal ion and a compound previously obtained by our group with the formula [Zn3(μ-ACA)6(4-phpy)2], which contains tetrahedral N,O- and octahedral O-coordinating pockets as a model structure. From this work, the corresponding heterometallic compound with the formula [Zn2Ca(μ-ACA)6(4-phpy)2]·EtOH (1) has been successfully synthesized, and fully characterized, and its crystal structure has been elucidated. Furthermore, we have compiled all the crystal structures containing [Zn2M] pinwheel secondary building units (SBUs), where M stands for an s-block metal ion, and the observed tendencies, as well as the promising applications as template SBUs for the preparation of 1D–3D coordination polymers, have been discussed. Finally, solid-state UV-Vis and photoluminescence have been recorded and compared with the homometallic [Zn3(μ-ACA)6(4-phpy)2] compound. [ABSTRACT FROM AUTHOR]

In the title compound [Fe2(C2O4)(C8H8N4)4](CH3C6H4SO3)2·2.75H2O, the two FeII ions have a highly distorted octa­hedral FeN4O2 environment formed by two bidentate triazole-based chelating ligands and a bis-bidentate oxalate bridging anion that connects the metal ions. Stabilization within the crystal structure is provided via a system of O--H⋯O and N--H⋯O hydrogen bonding, which determines the formation of a two-dimensional architecture along the a-axis direction. [ABSTRACT FROM AUTHOR]

We report the synthesis and characterization of three di-copper compounds, [Cu2phen2CMP(µ-OH)(µ-X)]·3H2O (with X = Cl− (1) and Br− (2)) and [Cu2phen2CMP(µ-OH)(µ-NO3)]·[Cu2phen2CMP(µ-OH)(NO3)]·7H2O (3). 1 and 3 present a dinuclear core assembled by an unusual bis-monodentate phosphate and µ2-hydroxo double bridge, further supported by bridging anions. The spontaneous self-assembly of an extended coordination structure of higher dimensionality, although possible in principle, has been hindered by the use of strongly coordinating counterions (Cl−, Br−) and, unexpectedly, even by the less coordinating nitrate ions. The neutral complexes feature unsaturated coordination sites, having both the N(3) and O(2) of the cytosine moieties of the CMP ligands still available for coordination. π···π Stacking and hydrogen bonding interactions established between the discrete chiral entities mainly drive the self-assembling of a 3D supramolecular network. Small hydrophilic voids are defined within the 3D net, which are filled by solvent water molecules. These small nuclearity complexes with coordinatively unsaturated CMP ligands are likely to act as tectons. They could be used as complex-as-ligands for further binding additional metal ions in a predictable manner, favoring a more rational synthetic approach aimed to a stricter structural and chemical control of the resulting material. [ABSTRACT FROM AUTHOR]

In the asymmetric unit of the title compound, trans-diaqua(1,4,8,11-tetraazacyclotetradecane-k4N¹,N4,N8,N11)zinc(II) trans-bis(hydrogen 4-phosphonatobiphenyl-40-carboxylato-kO)(1,4,8,11-tetraazacyclotetradecane-k4N¹,N4,N8,N11)-zinc(II), [Zn(C10H24N4)(H2O)2][Zn(C13H9O5P)2(C10H24N4)], both Zn atoms lie on crystallographic inversion centres and the atoms of the macrocycle in the cation are disordered over two sets of sites. In both macrocyclic units, the metal ions possess a tetragonally elongated ZnN4O2 octahedral environment formed by the four secondary N atoms of the macrocyclic ligand in the equatorial plane and the two trans O atoms of the water molecules or anions in the axial positions, with the macrocyclic ligands adopting the most energetically favourable trans-III conformation. The average Zn--N bond lengths in both macrocyclic units do not differ significantly [2.112 (12) Å for the anion and 2.101 (3) Å for the cation] and are shorter than the average axial Zn--O bond lengths [2.189 (4) Å for phosphonate and 2.295 (4) Å for aqua ligands]. In the crystal, the complex cations and anions are connected via hydrogen-bonding interactions between the N--H groups of the macrocycles, the O--H groups of coordinated water molecules and the P--O--H groups of the acids as proton donors, and the O atoms of the phosphonate and carboxylate groups as acceptors, resulting in the formation of layers lying parallel to the (110) plane. [ABSTRACT FROM AUTHOR]

Sensitive and accurate detection of specific metal ions is important for sensor development and can advance analytical science and support environmental and human medical examinations. Fluorescent proteins (FPs) can be quenched by specific metal ions and spectroscopically show a unique fluorescence-quenching sensitivity, suggesting their potential application as FP-based metal biosensors. Since the characteristics of the fluorescence quenching are difficult to predict, spectroscopic analysis of new FPs is important for the development of FP-based biosensors. Here we reported the spectroscopic and structural analysis of metal-induced fluorescence quenching of the photoconvertible fluorescent protein DendFP. The spectroscopic analysis showed that Fe2+, Fe3+, and Cu2+ significantly reduced the fluorescence emission of DendFP. The metal titration experiments showed that the dissociation constants (Kd) of Fe2+, Fe3+, and Cu2+ for DendFP were 24.59, 41.66, and 137.18 μM, respectively. The tetrameric interface of DendFP, which the metal ions cannot bind to, was analyzed. Structural comparison of the metal-binding sites of DendFP with those of iq-mEmerald and Dronpa suggested that quenchable DendFP has a unique metal-binding site on the β-barrel that does not utilize the histidine pair for metal binding. [ABSTRACT FROM AUTHOR]

The synthesis, crystal structure and properties of [Cu(tmeda)(bdc)(H2O)2]n (1), where bdc2- (C8H4O42-) is the benzene-1,4-dicarboxylate dianion and tmeda is N,N,N′,N′-tetramethylethylenediamine, are reported. The metal ion in 1 is coordinated by a chelating tmeda molecule, two monodentate bdc2- ions and two water molecules to generate a tetragonally-elongated cis-CuN2O4 octahedron. Each bdc2- ion bridges two adjacent Cu(II) ions to generate zigzag polymeric chains and the packing is consolidated by O − H···O hydrogen bonds. Spectroscopic and thermal studies of 1 are consistent with the crystal structure. Complex 1 shows excellent activity against four bacterial strains, Bacillus spizizenii, Escherichia coli, Klebsiella pneumonia and Staphylococcus aureus. [ABSTRACT FROM AUTHOR]

A new N-containing coordination polymer, namely, [Ni(L)(dpa)·2.5H2O]n (1) (H2L = 4,4'-azanediyldibenzoic acid, dpa = 4,4'-dipyridylamine) has been constructed under hydrothermal conditions. Structural analysis reveals that complex 1 exhibits a 3D 4-connected binodal net. With functional amino group, complex 1 is developed to detect heavy metal ions by colorimetric method. Notably, 1 can selectively detect Hg2+ and it is free from the interference of other metal ions. The linear range for Hg2+ detection is 0.1 to 0.5 mL. XPS shows that the N atoms of amino groups in 1 are responsible for the Hg2+ detection. [ABSTRACT FROM AUTHOR]

Metallo‐β‐lactamase (MBL) superfamily proteins have a common αβ/βα sandwich fold and perform a variety of functions through metal‐mediated catalysis. However, because of the enormous scale of this superfamily, only a small percentage of the proteins belonging to the superfamily have been annotated structurally or functionally to date. Therefore, much remains unknown about the MBL superfamily proteins. Here, TW9814, a hypothetical MBL superfamily protein, was structurally and functionally investigated. Guided by the crystal structure of dimeric TW9814, it was demonstrated that TW9814 functions as a phosphodiesterase (PDE) in the presence of divalent metal ions such as manganese(II) or nickel(II). A docking model between TW9814 and the substrate bis(p‐nitrophenyl)phosphate (bpNPP) showed the importance of the dimerization of TW9814 for its bpNPP‐hydrolyzing activity and for the interaction between the enzyme and the substrate. TW9814 showed outstanding catalytic efficiency (kcat/Km) under alkaline conditions compared with other PDEs. The activity of TW9814 appears to be regulated through a disulfide bond, which is a feature that is not present in other MBL superfamily members. This study provides a platform for the functional characterization of other hypothetical proteins of the MBL or other superfamilies. [ABSTRACT FROM AUTHOR]

A structure–function characterization of Synechococcus elongatus enolase (SeEN) is presented, representing the first structural report on a cyanobacterial enolase. X‐ray crystal structures of SeEN in its apoenzyme form and in complex with phosphoenolpyruvate are reported at 2.05 and 2.30 Å resolution, respectively. SeEN displays the typical fold of enolases, with a conformationally flexible loop that closes the active site upon substrate binding, assisted by two metal ions that stabilize the negatively charged groups. The enzyme exhibits a catalytic efficiency of 1.2 × 105 M−1 s−1 for the dehydration of 2‐phospho‐d‐glycerate, which is comparable to the kinetic parameters of related enzymes. These results expand the understanding of the biophysical features of these enzymes, broadening the toolbox for metabolic engineering applications. [ABSTRACT FROM AUTHOR]

• Three compounds containing 1-carboxyethyl-4,4′-bipyridine have been synthesized. • Compounds 1 and 3 exhibit photochromism, while 2 reveals hydrochromism upon heating. • Photo-controlled fluorescence and ink-free erasable printing abilities are discussed. Herein, three compounds containing the neutral viologen derivative, 1-carboxyethyl-4,4′-bipyridine (CEbpy) have been synthesized, (CEbpy)·(H 2 TPDC)·2H 2 O (1) [Co(CEbpy)(TPDC)(H 2 O) 4 ]·3H 2 O (2) and [Cd 3 (CEbpy) 2 (TPDC) 3 ·7H 2 O] n (3) (H 2 TPDC = thiophene-2,5-dicarboxylic acid). Compound 1 is a supramolecular assembly, linked by non-covalent interactions to constitute the donor-acceptor (D-A) system. Compound 2 owns a zero-dimensional (0D) isolated structure in which metal ions are coordinated with CEbpy and fully deprotonated (TPDC)2- ligands. Compound 3 exhibits a three-dimensional (3D) framework of trinuclear metal clusters, where each metal atom forms its own distinct linear one-dimensional (1D) chain along a specific axis. Although the three compounds comprise the same bipyridinium moiety and aromatic acid, their chromic behaviors are different. Compounds 1 and 3 exhibit reversible photochromism, while 2 reveals hydrochromism upon heating. Additionally, photo-modulated fluorescence as well as their potential applications in inkless erasable printing have been studied. [Display omitted] [ABSTRACT FROM AUTHOR]

[Display omitted] • Double metal oxalates, MM'(C 2 O 4) 2 ⋅4H 2 O. • Triple metal oxalates, MM'M"(C 2 O 4) 3 ⋅6H 2 O. • Structural characteristics. • 57Fe-Mössbauer spectroscopy. • Discussion of hyperfine parameters. 57Fe-Mössbauer spectra of double MM'(C 2 O 4) 2 ⋅4H 2 O (M = Fe, M' = Mg, Co, Zn) and triple metal oxalates MM'M"(C 2 O 4) 3 ⋅6H 2 O (M = Fe, M' = Mg, Mn, Co; M" = Zn) were recorded at room temperature and briefly discussed on the basis of their structural characteristics. No changes in the hyperfine interactions at the 57Fe site were detected because of the presence of the other metal ions. [ABSTRACT FROM AUTHOR]

myo-inositol phosphates are an important group of biomolecules that are present in all eukaryotic cells. The most abundant member of this family in nature is InsP6 (H12L1), which interacts strongly with inorganic and organic cations. This interaction is essential for determining the possible functions of this biomolecule. A few crystal structures containing InsP6, and a divalent cation, have been reported showing a great versatility of this bioligand. Ins(1,2,3)P3 (H6L2) is another important member of the group, usually thought as a safe cellular iron ligand. No crystal structures showing the interaction of L2 with metal ions can be found in the literature. In this work we characterized by X-ray diffraction two polynuclear complexes, [Cu3(H6L1)(phen)5] (phen = 1,10-phenanthroline) (1) and [Cu2(H2L2)(H2O)(terpy)2] (terpy = 2,2′:6′,2′′-terpyridine) (2). The crystal structure of 2 furnishes, for the first time, a picture of the coordination ability of Ins(1,2,3)P3 against a divalent metal ion. In addition, a PDB survey was performed on all InsPs to frame the coordination modes derived from our small-molecule supramolecular approach within a more realistic biological context. [ABSTRACT FROM AUTHOR]