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Earth-abundant, cheap and non-toxic zinc-based coordination compounds are drawing research attention as promising candidates for various applications, such as photoluminescent materials and anticancer agents. In this paper we report six zinc complexes (1–3-NO3 and 1–3-Cl) with pyridyl-based thiazolyl–hydrazone ligands, which differ in the nature of substituents at the ligands' periphery, anion type, and geometry around the metal ion. The complexes were characterized by single-crystal and powder X-ray diffraction analysis, as well as IR and NMR spectroscopy. The symmetrical complexes 2-Cl and 3-Cl, where zinc atoms are located at a two-fold axis, do not exhibit photophysical properties, unlike their asymmetrical analogs 2-NO3 and 3-NO3 with the same complex cation. Asymmetrical pentacoordinated 1-Cl and hexacoordinated 1-NO3 complexes exhibit photophysical properties. An admixture of allowed intra-ligand (1IL) and chloro (X)-to-ligand charge-transfer (1XLCT) electronic transitions is responsible for the fluorescence of the 1-Cl complex. The origin of the emission of the 1-NO3 complex is ascribed to an admixture of 3IL and ligand-to-ligand charge-transfer (3LLCT) forbidden electronic transitions, while for 3-NO3 most electronic excitations are of LLCT character. The thermal stability of the complexes is in accord with the strength of respective intermolecular interactions. The antiproliferative activity of the complexes was in the nanomolar range on some of the investigated cancer cell lines. Contrary to the increase of antiproliferative activity of the complexes in comparison to the free ligands in cancer cell lines, an acute toxicity determined in the brine shrimp assay follows the opposite trend. The overall results suggest that Zn(II) thiazoyl–hydrazone complexes have considerable potential as multifunctional materials. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have garnered significant interest owing to their tunable structures and versatile properties. In this study, the construction of MOF-74 analogues based on pre-installation of functional ligands has been investigated. Five distinct ligands and their corresponding complexes are synthesized and characterized. The ligands are strategically designed to impart specific functional groups, enabling enhanced reactivity and tailored properties. Building upon the previously synthesized compounds, an efficient method for the directional functionalization of MOF-74 analogues under moderate conditions has been outlined. This method involves pre-installation through directive substitution of the ligands with suitable functional groups viz. –F, –Br, –I, –CH3 and –CN, allowing precise control over the resulting MOF's properties and functionalities. The study presents the characteristics and properties of [Cu(L1)]n (1), [Cu(L3)]n (2), [Cu(L4)]n (3), [Cu(L5)]n (4) and [Cu(L6)]n (5) complexes, highlighting their distinct features and potential applications. The findings from this research contribute to the fundamental understanding of MOF-74 analogues' synthesis and the efficient functionalization of these materials. The outlined methodology opens new avenues for the tailored design of MOFs with desired properties, enabling their potential utilization in diverse applications, such as catalysis, gas storage and luminescence sensing properties. [ABSTRACT FROM AUTHOR]

trans-9,10-Dihydro-9,10-ethanoanthracene-11,12-dicarboxylic acid (deadcH2), in its racemic or R,R enantiomeric forms, has been used to synthesize eight uranyl ion complexes under solvo-hydrothermal conditions. [UO2(deadc)]·1.5CH3CN (1) and [H2NMe2]2[(UO2)2(deadc)3]·2H2O (2) crystallize as monoperiodic coordination polymers in which deadc2− forms both 4- and 7-membered chelate rings. Although synthesized in the same conditions as 2, the enantiomerically pure complex [H2NMe2]4[(UO2)2(O)(R,R-deadc)2]2 (3) is a discrete tetranuclear complex containing two μ3-oxo anions. Association with the zwitterion Ni(tpyc)2, where tpyc− is 2,2′:6′,2′′-terpyridine-4′-carboxylate, gives [(UO2)2(deadc)(deadcH)(NO3)Ni(tpyc)2]·CH3CN·2H2O (4), a rake-shaped monoperiodic assembly. [UO2(deadc)(DMA)] (5), [UO2(deadc)] (6) and [PPh4]2[(UO2)2(R,R-deadc)3] (7) crystallize as diperiodic networks with the fes, sql and hcb topologies, respectively, the thick layers formed being coated on both sides by protruding, hydrophobic dibenzobarrelene groups. Finally, [(UO2)2Ag2(deadc)3(CH3CN)2]·0.5H2O (8) contains monoperiodic uranyl–deadc2− subunits which are assembled into a triperiodic framework by bridging silver(I) cations, the latter interacting with both carboxylate groups and aromatic rings. Except for 6, all these complexes are emissive with photoluminescence quantum yields of 2–26%, and most spectra display the usual vibronic fine structure of uranyl emission. [ABSTRACT FROM AUTHOR]

In this paper, we present four Co-MOFs using R-substituted isophthalic acid (R-H2BDC, R = H, OH and COOH) along with trigonal n-TBT (n = 3 or 4) as organic ligands. These Co-MOFs are formulated as {[Co(1,3-BDC)(4-TBT)2/3]·(H2O)(DMF)1.5}n (Co-MOF-1), {[Co(HO-BDC)(4-TBT)]·(EtOH)2(DMF)2}n (Co-MOF-2), {[Co(HO-BDC)(4-TBT)2/3]·(H2O)3(MeOH)3(DMA)}n (Co-MOF-3) and {[Co3(BTC)2(3-TBT)2(H2O)2]·(H2O)2(EtOH)5(DMA)1.5}n (Co-MOF-4), where H2BDC = isophthalic acid, OH–H2BDC = 5-hydroxyisophthalic acid and H3BTC = 1,3,5-tricarboxybenzene, 4-TBT = 1,3,5- tris(4-pyridyl)benzene and 3-TBT = 1,3,5-tris(3-pyridyl)benzene. Co-MOF-1, 2 and 3 are constructed from the dimeric Co2(COO)2 unit and exhibit 3D frameworks. In Co-MOF-4, the dimeric Co2(COO)2 unit and single nuclear CoII center are connected by BTC3− and 3-TBT ligands into a 3D network. The catalytic experiments revealed that four Co-MOFs can catalyze the oxidative coupling reaction of benzyl alcohols and aniline to imines with good to excellent conversions under solvent-free conditions and an air atmosphere. Co-MOF-4 exhibited the best catalytic performance and the catalyst could be reused for at least five cycles without losing its structural integrity and catalytic activity. [ABSTRACT FROM AUTHOR]

Four Ni, Co, Cu, Zn-containing coordination polymers incorporating 4,4′,4′′,4′′′-tetrakiscarboxyphenylsilane (H4tcps) and 1,3,5-tris(2-methyl-1H-imidazol-1-yl)benzene (tmib) ligands, namely [Ni6(tcps)3(tmib)4(H2O)2] (1), [Co6(tcps)3(tmib)4] (2), [Cu2(tcps)(tmib)(H2O)] (3) and [Zn2(tcps)(tmib)] (4), were synthesized by the solvothermal method. Compounds 1 and 2 were isostructural with three-dimensional (3D) (3,4)-connected frameworks. Compounds 3 and 4 possessed (3,4)-connected 3D networks with (6·82)(6·85)(62·82·102)(62·8) and (4·6·8)(4·63·82)(66)(67·83) topology, respectively. The thermal derivatives of compounds 1 and 2, Co-800 and Ni-700, exhibited low OER overpotentials of 338 and 388 mV to achieve a current density of 10 mA cm−2 and hold their electrocatalytic activity for at least 9 hours in 1 M KOH. [ABSTRACT FROM AUTHOR]

The crystal structures and crystallisation behaviours of MII–TbIII–MII heterotrinuclear complexes, [(L)MTbM(L)]NO3 (M = Mn and Zn; L3− stands for a conjugated base of H3L = 1,1,1-tris[(3-methoxysalicylideneamino)methyl]ethane), obtained from various organic solvents (MeOH, EtOH, CH2Cl2 and CHCl3) were investigated. The trinuclear complex cation has two asymmetric centres (Δ or Λ) at two MII sites as a result of the twisted tripodal arms of L3−. Single-crystal X-ray diffraction analysis revealed that all the analysed Zn–Tb–Zn complexes had homochiral structures (Δ,Δ- or Λ,Λ-enantiomers) in each single crystal; however, the type of crystallisation behaviour showed clear differences depending on the type of solvent molecule. Specifically, crystallisation from MeOH or CH2Cl2 resulted in the exclusive formation of the Λ-conglomerates with the Λ,Λ-enantiomers—a phenomenon we recently termed 'absolute spontaneous resolution'. The analogous Mn–Tb–Mn complex crystallised from MeOH also resulted in the same phenomenon as that of Zn–Tb–Zn. In contrast, the meso-type (Δ,Λ) achiral isomer of the Mn–Tb–Mn complex was deposited for the first time in a series of MII–LnIII–MII trinuclear complexes from a CH2Cl2 or EtOH solution. Density functional theory calculations were performed to compare the thermodynamic stability of homochiral (Λ,Λ) and meso-type (Δ,Λ) complex cations of [(L)MnTbMn(L)]+ in MeOH and EtOH. Results were consistent with the molecular structures observed in the crystallographic analysis of the compounds deposited from these solvents. [ABSTRACT FROM AUTHOR]

The self-assembly of a new class of bis-tridentate ligands has led to the spontaneous formation of polymeric complexes with transition metal ions (M = Fe2+, Zn2+, Co2+, Cu2+, Ni2+, Mn2+). A straightforward synthetic route to prepare a series of 2,5-bis(1,2,3-triazol-4-yl) pyrazine (tzopz) ligands containing two N,O,N-tridentate chelation pockets, through a double Cu(I) catalysed azide–alkyne cycloaddition reaction of 2,5-bis((prop-2-yn-1-yloxy)methyl)pyrazine with a functionalised azido group is described. Complexes of the tzopz ligand have been investigated by UV-vis spectroscopy and single crystal X-ray crystallography. Complexes using this ligand motif consistently self-assemble into 1D zig-zag polymers, from which secondary interactions allow for the solid-state assembly of 2D sheets, providing an avenue for future functionalised materials. [ABSTRACT FROM AUTHOR]

To investigate the effect of conformationally flexible molecules on the crystal packing of coordination compounds, eleven mercury(II) complexes containing N-(3-halophenyl)-2-pyridinecarboxamide ligands, carrying different halogen atoms in the ortho-position of the phenyl ring, have been synthesized, molecularly characterized and structurally compared. In this contribution, three various sets of isostructural compounds were obtained by manipulating the proportions of the different solvents and the crystallization temperatures. By varying the reaction conditions three different compositions were observed, and from each composition, independent isostructural series could be observed by halogen replacements. Due to the simultaneous presence of competitive halogen atoms and the flexibility of ligands, conformational preference and altering the kind of halo-atom of ligands can change the nature and type of intermolecular interactions. Despite the presence of isostructurality in the studied compounds, structural diversity is also observed. The structural similarities of these isostructural compounds were interpreted via Hirshfeld surface fingerprint plots, Xpac, and unit cell similarity comparison. Synthon crossover of halogen interaction in coordination compounds of HgX2 was observed, and systematic investigation of halogen⋯halogen interactions utilizing energy calculation was performed. Halogen⋯halogen synthon crossover in coordination compounds has been investigated. [ABSTRACT FROM AUTHOR]

Reactions of N,N′,N′′-tris(3-methylpyridyl)trimesic amide (L) and Cd(OAc)2·2H2O with various polycarboxylic acids afforded {[Cd2(L)(1,4-BDC)2(H2O)2]·2H2O}n (1,4-H2BDC = benzene-1,4-dicarboxylic acid), 1, {[Cd(L)(4,4′-BDC)(H2O)]·H2O}n (4,4′-H2BDC = biphenyl-4,4′-dicarboxylic acid), 2, and {[Cd3(L)2(1,3,5-BTC)2(H2O)6]·15H2O}n (1,3,5-H3BTC = benzene-1,3,5-tricarboxylic acid), 3, which have been structurally determined by using single-crystal X-ray diffraction. Complexes 1–3 display 2D layers with (3·82)2(32·4)2(36·44·52·84·96·105·11), (44·62)-sql and (42·124)3(43)4-3,4L129 topologies, respectively, indicating that the identities of the polycarboxylate ligands involving length and shape play important roles in determining the structural diversity. Complexes 1 and 2 show stabilities in various solvents and display high selectivity toward sensing of Fe3+ ions with low detection limits and good reusability of up to five cycles. [ABSTRACT FROM AUTHOR]

Two organic ligands, one rigid and one flexible, were designed and used to construct two cobalt-based metal–organic frameworks (MOFs) with coligands to obtain 3D and 2D structures, respectively. Both the Co-based MOFs were pyrolyzed at different temperatures to obtain the derived materials, and their electrocatalytic hydrogen evolution properties were studied. The results show that the electrocatalytic hydrogen evolution performance of MOF derivatives based on the rigid ligand was better than that of MOF derivatives based on the flexible organic ligand. [ABSTRACT FROM AUTHOR]

Two new manganese(II) coordination polymers (CPs) have been synthesized using Mn(SO4)2·6H2O, 2,4-[6-(4-carboxyphenyl)pyrazin-2-yl]benzoic acid (H2L) and two auxiliary N-donor linkers, 1,10-phenanthroline (phen) and 1,4-bis(1H-imidazol-1-yl)benzene (dib) to assist in the self-assembly process. The resulting compounds were identified as [Mn(L)(phen)]n (1) and {[Mn(L)(H2O)]·0.5dib}n (2). 1 displays a one-dimensional (1D) structure, which is further assembled to form a 2D structure through weak interactions between adjacent L2− ligands. In contrast, 2 shows a 2D network, which can further form a 3D supramolecular network via packing interactions between the 2D networks. Focusing on the structure around manganese(II) ions, both 1 and 2 have bis(μ-carboxylate-κO:κO′)dimanganese(II) structures. The cryomagnetic behavior for 1 and 2 was complicated, suggesting the temperature-induced structural change due to the flexibility of the Mn(II) compounds. The unique magnetic behaviors exhibited by the two complexes also provide a new perspective for the subsequent study of magnetic materials. [ABSTRACT FROM AUTHOR]

Two new isostructural 2D coordination polymers, denoted 1(Mn) and 2(Fe), have been synthesized using the layer diffusion method. These polymers, {[Mn(PDA)(4-bpdb)(H2O)2]·4-bpdb}n and {[Fe(PDA)(4-bpdb)(H2O)2]·4-bpdb}n, incorporated 1,4-phenylenediacetate (PDA) and 1,4-bis(4-pyridyl)-2,3-diaza-1,3-butadiene (4-bpdb) ligands. Structural analysis through the single-crystal X-ray study revealed that compound 1(Mn) and compound 2(Fe) exhibited a one-dimensional connectivity along the a-axis between metal ions (Mn(II)/Fe(II)) and 1,4-phenylenediacetate ligands and formed a 2D layered structure interconnected with 4-bpdb. These layers are arranged in an AAA... pattern along the b-axis, forming a three-dimensional supramolecular structure. Non-bonded 4-bpdb molecules occupy voids within this arrangement, stabilized by hydrogen bonds and π⋯π interactions. The redox-active metal centers (Mn2+/Fe2+) present in the coordination polymers hold promise for electrochemical studies. Supercapacitor assessment revealed an intriguing discrepancy: compound 1(Mn) demonstrated nearly 2.5 times greater specific capacitance than compound 2(Fe) in a 1 M H2SO4 medium, despite their isostructural nature. However, cyclic stability testing showed a reverse trend, with compound 2(Fe) exhibiting excellent stability, retaining 98% capacity after 5000 cycles compared to 1(Mn)'s 78%. Conductivity measurements indicated that compound 1(Mn) possesses conductivity 10 times superior to that of compound 2(Fe). Notably, both compounds exhibited potential for Schottky diode fabrication. Overall, this study highlights the influence of specific metal ions on distinctive supercapacitor characteristics and conductivity within isostructural coordination polymers. [ABSTRACT FROM AUTHOR]

Networking of molecular hosts via non-covalent interactions has become one of the central topics in crystal engineering. We herein report the self-assembly of silver(I) coordination polymers with an NS4-macrocycle (L) whose connectivity patterns depend on anion types. First, a one-pot reaction of L with AgPF6 yielded an endo/exocyclic one-dimensional (1D) coordination polymer {[Ag3L2](PF6)3·2CH2Cl2}n (1) in which two silver(I) atoms (endoAg)2 are sandwiched by two L ligands to form an L(endoAg)2L unit. Further, the disilver(I) sandwich units are linked by one exocyclic silver(I) atom (exoAg), giving rise to a polymeric loop chain array of 1 without anion coordination. When L was reacted with AgCF3SO3 and AgCF3CO2, again, endo/exocyclic 1D coordination polymers {[Ag4L2(CF3SO3)2](CF3SO3)2·CH2Cl2}n (2) and {[Ag4L2(CF3CO2)2](CF3CO2)2·4CH3OH}n (3) with a similar connectivity pattern were obtained, respectively. In both 2 and 3, one endoAg atom and one exoAg atom link three L ligands to form a double-stranded array with one anion coordinated to the exoAg atom. In the anion exchange experiments, the formation of 2 (CF3SO3− form) is relatively favourable over 1 (PF6− form) or 3 (CF3CO2− form) mainly due to the anion access-friendly conformation and moderate binding affinity of CF3SO3− which can easily gain entry. [ABSTRACT FROM AUTHOR]

Isolation of mixed-ligand compounds has attracted considerable research interest as the synergy between ligands results in species with interesting technological, environmental and biomedical applications. In this study, initial employment of 2-pyridyl oximes or 2-pyridyl alcohols in combination with 2-hydroxyterephthalic acid (H3MHBDC) and 2,5-dihydroxyterephthalic acid (H4DHBDC) has yielded a new family of 1D coordination polymers and a metal cluster, namely [M(H2pyaox)2(H2DHBDC)]n (M = Zn, 1; Mn, 2), [Co3(mpko)4(Hmpko)2](H2DHBDC)2·2DMF (3·2DMF), [M(Hhmp)2(H2DHBDC)]n·DMF (M = Ni, 4·DMF; Zn, 5·DMF), [Ni(H2pyaox)2(HMHBDC)]n·2DMF (6·2DMF), and [Zn(Hmpko)2(HMHBDC)]n·DMF (7·DMF), where H2pyaox = pyridine-2-amidoxime and Hmpko = 2-methyl pyridyl ketoxime. 1–7 are the first compounds bearing a 2-pyridyl oxime or 2-pyridinemethanol (Hhmp) with H3MHBDC or H4DHBDC in their neutral or anionic form. Notably, 4 exhibits a high capacity for Co2+ uptake (900 mg Co2+ g−14), which can be attributed to the presence of free coordination sites in the carboxylate linker. [ABSTRACT FROM AUTHOR]

The modular construction method provides a feasible way to construct pre-designed cyano-bridged {LnIIIMIV/V} systems with more attractive structures and adjustable interactions between 4d/5d and 4f ions. In this work, the pentadentate Schiff-base ligands H2Ln (H2L1: 2,6-diacetylpyridine bis(nicotinoylhydrazone); H2L2: 2,6-diacetylpyridine bis(isonicotinoylhydrazone)) with multiple coordination sites were designed to coordinate with DyIII ions firstly, and then combined with K4M(CN)8·2H2O (M = W, Mo) by a liquid–liquid diffusion method to successfully synthesize two trinuclear structures {Dy[MIV(CN)8]0.5(HL1)(H2O)3}2·8H2O (1: M = W; 2: M = Mo), and two dinuclear structures {[Dy[MIV(CN)8](H3L2)(H2O)3]}·sol (3: M = W, sol = 11.5H2O; 4: M = Mo, sol = 2CH3OH·9.5H2O). Interestingly, deprotonation occurs in ligand H2L1 during the formation of complexes 1 and 2, while deprotonation/protonation processes both occur in ligand H2L2 during the synthesis of complexes 3 and 4. Magnetic analyses reveal that complexes 1–4 are all field-induced single-ion magnets (SIMs). The energy barriers (Ueff/kB) of complexes 1 and 2 are 92.83 K and 101.08 K, respectively, which are nearly three-fold higher than those of complexes 3 (30.19 K) and 4 (32.77 K). Ab initio calculations were performed on these series of {LnIIIMIV} heteronuclear complexes to provide more insights into the magnetic relaxation properties. This work provides another example of improving the SMM behaviors of cyano-bridged {LnIIIMIV} systems by deprotonation/protonation at different sites in the ligands. [ABSTRACT FROM AUTHOR]

Reactions of Co(II) salt and N,N′-di(4-pyridyl)sebacoamide (L1), N,N′-bis(4-pyridylmethyl)bicyclo(2,2,2,)oct-7-ene-2,3,5,6-tetracarboxylic diamide (L2) or N,N′-di(4-pyridyl)adipoamide (L3) with angular dicarboxylate ligands afforded coordination polymers (CPs) {[Co(L1)(OBA)(H2O)]·0.5H2O}n [H2OBA = 4,4′-oxybis(benzoic acid)], 1a, {[Co2(L1)(OBA)2]·3DMF}n, 1b, {[Co(L1)0.5(SDA)]·2H2O}n (H2SDA = 4,4′-sulfonyldibenzoic acid), 2a, {[Co2(L1)2(SDA)2(H2O)]·2H2O}n, 2b, {[Co(L1)0.5(MBA)]·H2O}n (H2MBA = diphenylmethane-4,4′-dicarboxylic acid), 3, {[Co(L2)(OBA)]·solvent}n, 4, {[Co(L2)(SDA)(H2O)]·solvent}n, 5, {[Co(L2)(MBA)(H2O)]·2H2O}n, 6, [Co(L2)(HFIPBB)(H2O)]n [H2HFIPBB = 4,4-(hexafluoroisopropylidene)-bis(benzoic acid)], 7, and {[Co(L3)(MBA)]·2H2O}n, 8. CPs 1a, 1b, 2a and 2b exhibit a 2D layer with an (84·122)(8)-22,4L2 topology, a 3-fold interpenetrated 3D net with a (412·63)-pcu topology, a 2D → 3D inclinedly polycatenated framework with a (42·68·8·104)(4)2-2,6L1 topology and a 2-fold interpenetrated 3D framework with a (48·67)-msw topology, respectively, and 3 displays a 2-fold interpenetrated 2D layer with a (42·68·8·104)(4)2-2,6L1 topology. CPs 4–6 are 2D layers, showing (64·8·10)(6)-2,4L3, (36·46·53)-hxl and (4·82)-fes topologies, respectively, whereas CP 7 displays a 3-fold interpenetrated 3D net with a (45·8)-dmp topology and 8 forms a 1D → 2D polycatenation with a (63·82·10)(6)2-2,2,4C5 topology. A structural comparison of 1–8 indicates that the flexibility of the bis-pyridyl-bis-amide plays an important role in the formation of entangled Co(II) CPs auxiliarily supported by the angular dicarboxylate ligand. [ABSTRACT FROM AUTHOR]

Four Co(II) complexes [CoII2(H2L1)Cl2]·2MeCN (1), [CoII2(H2L2)Cl2] (2), [CoII2(H2L1)(acac)2]·2MeCN (3), and [CoII2(H2L2)(acac)2]2 (4) (acac = acetylacetone, H2L1 = N,N′-bis[(2-hydroxybenzylideneamino)propyl]piperazine, H2L2 = N,N′-bis(2-hydroxy-5-bromobenzyl)-1,4-bis(3-iminopropyl)piperazine) based on symmetric Schiff base ligands were synthesized and charactered. They are all symmetric Co(II) dimers, in which Co(II) ions in complexes 1 and 2 are four-coordinate tetrahedral, and Co(II) ions in complexes 3 and 4 are five-coordinate trigonal bipyramidal. The coordination geometries of the Co(II) ions change from tetrahedral to trigonal bipyramidal by regulating the coordination anions. Furthermore, remote substituents of the aromatic benzene rings in the ligands were fine-tuned. Magnetic studies indicate that remote substituents of the ligands, as well as the coordination geometries, have no significant effect on the magnetic properties of these four Co(II) dimer complexes. [ABSTRACT FROM AUTHOR]

A series of lanthanide dicyanoaurate coordination polymers with 2,2′-bipyridine dioxide (OOBipy) has been created with the formula Ln(OOBipy)2(H2O)x[Au(CN)2]3·yEtOH·zH2O, where x and y = 0–2, and z = 0–4. It is possible to convert between these coordination polymers through the addition of heat (removing water, aqua ligands, or ethanol) or by exposure to water vapour (adding a full complement of aqua ligands and water molecules to a partially or fully dehydrated structure). The coordination polymers containing Sm, Eu, and Tb were emissive, with quantum yields between 0.43–0.66 and 0.09–0.72 for Eu- and Tb-containing materials respectively, depending on the solvation state. Atypically for emissive lanthanide materials, the highest quantum yields were found for the hydrated species, with a substantial drop in quantum yields as aqua units were sequentially removed. Eu/Tb-containing solid-solutions were prepared but only showed Eu-based emission, while Sm/Tb-containing solid-solutions had quantum yields of less than 0.02. [ABSTRACT FROM AUTHOR]

Energetic metal organic frameworks (EMOFs) are increasingly developed and have proven to be candidates for novel high energy density materials (HEDM). Here, two energetic metal complexes based on 3,5-diaminopyrazolone-4-oxime (DAPO) ligands were synthesized by simple steps and fully characterized by NMR and IR spectroscopy, X-ray single-crystal diffraction, and DSC-TG. The detonation performance was calculated using the Kamlet–Jacobs formula. The crystal densities of these complexes (C6H14N12O10Co (2) and C6H14N12O10Cd (3) are as high as 1.945 g cm−3 at 163 K and 2.072 g cm−3 at 298 K, respectively. Thermal analysis by the DSC-TG test shows that they all have good thermal stability with the highest decomposition temperatures of 287 °C and 344 °C, respectively. These two as-synthesized complexes exhibit excellent detonation performance; 2 (D = 8682 m s−1, P = 34.98 GPa) and 3 (D = 8383 m s−1, P = 33.78 GPa) have good detonation velocity and detonation pressure that are superior to those of TNT, which is widely used today. Thus, they show great promise for potential applications as thermally stable energetic materials. [ABSTRACT FROM AUTHOR]

Based on a cationic layered Zn-MOF (1⊃NO3−) with free NO3− anions located in the interlayer channels, two anion-exchanged compounds (1⊃ClO4− and 1⊃BF4−) were achieved by replacing free NO3− anions with ClO4− or BF4− anions. However, an anion-induced structural transformation occurred during the Cl− anion exchange with coordinated NO3− anions replaced by Cl−anions, resulting in the formation of a 2D hcb layered structure (2) and a 3D ths framework (3). The transformation process is fully investigated by means of FT-IR, PXRD and SC-XRD, revealing anion-dependent structural dynamism of the framework. More interestingly, these MOFs demonstrated anion-dependent tunable luminescence evidenced by different fluorescence intensities in the solid state as well as highly sensitive but varied detection capabilities for nitroaromatics. Thus, the MOFs presented here can be used as an ideal platform to deeply explore the possible transformation mechanism, and various tunable luminescent behavior related to the nature of anions, including sizes/shapes, geometries, their coordinating tendencies to metal, and their different hydrogen-bonding abilities with the framework. [ABSTRACT FROM AUTHOR]

The two triple-armed species tris(2-carboxyethyl)nitromethane (H3tcenm) and tris(2-carboxyethyl)phosphine (H3tcep) have been used to synthesize seven uranyl ion complexes under (solvo)-hydrothermal conditions and in the presence of various structure-directing cations. The three carboxylate groups chelate three different cations and the nitro group is uncoordinated in [H2NMe2][UO2(tcenm)]·3H2O (1), [C(NH2)3][UO2(tcenm)]·0.5H2O (2) and [PPh3Me][UO2(tcenm)] (3), which crystallize as diperiodic coordination polymers with the hcb topology and minor variations in shape depending on the counterion. The two isomorphous complexes [UO2(tcenm)M(bipy)2][UO2(tcenm)]·3H2O, with M = Ni (4) or Cu (5) and bipy = 2,2′-bipyridine, display the same arrangement, with a M(bipy)22+ group bridging two adjoining carboxylate donors in one uranyl equatorial plane. [(UO2)2(tcenm)2Cu(R,S-Me6cyclam)]·2H2O (6), where R,S-Me6cyclam = 7(R),14(S)-5,5,7,12,12,14-hexamethyl-1,4,8,11-tetraazacyclotetradecane, is the only triperiodic framework in the series, with the tcs topology resulting from CuII pillaring diperiodic, uranyl-based sql networks. H3tcep is oxidized in situ to give the phosphine oxide H3tcepo, which is partially deprotonated in [UO2(Htcepo)] (7); the phosphine oxide and the two carboxylate groups are coordinated, and the diperiodic, three-dimensional network formed has the point symbol {66} and the vertex symbol 62·62·63·66·64·64, with the rings involved in Hopf links formation. Only complexes 3 and 7 are significantly emissive in the solid state, with photoluminescence quantum yields of 9%, and the emission maxima positions are in agreement with the number of uranyl equatorial donors. [ABSTRACT FROM AUTHOR]

Compounds [Ag(5NO2Qu)2]BF4 (1) and [Ag(Qu3CN)(H2O)]BF4 (2) were prepared and studied from a structural perspective and screened for antimicrobial activity. The Ag(I) in the monomeric complex 1 is coordinated to two 5-nitroquinoline (5NO2Qu) ligands via the N-atoms of the quinoline rings with equidistant Ag–N bonds (2.146(2) Å) and a N–Ag–N# bond angle of 171.42(8)°. The 2D coordination polymer 2 contains tetracoordinated Ag(I) with two N-atoms (N1 and N2#1) from two quinoline-3-carbonitrile (Qu3CN) ligands and two O-atoms (O1 and O1#1) from two water molecules. The Qu3CN ligand acts as a connector between the Ag(I) sites along the b-direction via two short Ag1–N1 (2.185(4) Å) and Ag1–N2#1 (2.204(4) Å) bonds. In addition, the Ag(I) is coordinated with two symmetry related water molecules which are also acting as connectors between the Ag(I) sites along the a-direction via two longer Ag1–O1 (2.470(4) Å) and Ag1–O1#2 (2.546(4) Å) bonds. Hirshfeld surface analysis confirmed the significance of the polar F⋯H contacts in the molecular packing of 1 (25.9%) and 2 (39.9%). In addition, the crystal packing of 1 showed a significant amount of polar O⋯H (23.5%) contacts. Also, both complexes displayed π–π stacking interactions. The Ag(I) complexes and the free ligand were assessed for their antimicrobial activities. It was found that 1 (MIC = 7.8 μg mL−1) and 2 (MIC = 31.25 μg mL−1) have higher antifungal potency against C. albicans than their free ligands (MIC = 125 μg mL−1). Interestingly, 1 has better antifungal activity than the standard nystatin (15.6 μg mL−1). Also, both Ag(I) complexes and the free ligands as well have better activity against P. mirabilis than the common antibiotic amoxicillin. [ABSTRACT FROM AUTHOR]

In this study, we report four coordination polymers based on di-9,10-(pyridine-4-yl)-anthracene (dpa). 1 and 2 are similar 2-fold interpenetrating pcu networks built by Co2+, dpa and dicarboxylate ligands of different lengths, and the porosities and pore sizes of the interpenetrated frameworks were adjusted. 1 contains 1D channels of a cross-section of 3.7 × 3.7 Å and exhibits very high selectivity in adsorbing CO2 over N2. The channels in 2 are larger (5.1 × 5.1 Å) but unstable upon removing solvent guests. 3, [Cd(dpa)2(Cl)2]n·2nDMF, contains layer structures constructed by dpa, Cd2+ and Cl− atoms. 4, [Cd(dpa)(Cl)2(H2O)2]n, contains polymeric chains with Cd2+ atoms linked by dpa ligands. 3 and 4 showed strong fluorescent emissions, and mixed matrix membranes prepared based on 3 or 4 showed very high sensitivity and selectivity for detecting Cr2O72− in water. [ABSTRACT FROM AUTHOR]

Four Zn(II) metal–organic coordination polymers (Zn-MCPs), [Zn2(O-cpia)(2,2′-bpy)·OH] (1), Zn2(O-cpia)(4,4′-bpy)0.5·OH (2), Zn3(O-cpia)2(bpp)2·H2O (3) and [Zn4(O-cpia)2(phen)2·(OH)2] (4), were synthesized by using the mixed ligand approach, namely 5-(2-carboxyl-phenoxy)-1,3-benzenedicarboxylic acid (O-cpiaH3) and different auxiliary N-donor ligands 2,2′-bipyridine (2,2′-bpy), 4,4′-bipyridine (4,4′-bpy), 1,3-di(4-pyridyl)propane (bpp), and 1,10-phenanthroline (phen). The four Zn-MCPs exhibited different architectures based on different secondary building units (SBUs) and different ligand bridging modes. Four adjacent Zn2+ ions and two μ3-OH groups formed [Zn4(μ3-OH)2] tetranuclear SBUs in 1, 2, and 4, further linking together to build different frameworks by different ligand bridging modes. Moreover, the [Zn4(μ3-OH)2] units are composed of Zn(II) ions in different coordination environments. 3D (1) is composed of [Zn4(μ3-OH)2] containing [Zn1O5] and [Zn2O4N2] units by an O-cpia linker. 3D (2) consists of [Zn4(μ3-OH)2] with [Zn1O4N1] and [Zn2O4] units via O-cpia/4,4′-bpy mixed ligands. 3D (3) comes from [Zn2(COO)4] ([Zn2O4N1]) and [Zn1O2N2] by O-cpia/bpp mixed ligands. 2D network (4) is composed of [Zn4(μ3-OH)2] with [Zn1O4N2], [Zn2O5], [Zn3O5], and [Zn4O4N2] units by O-cpia ligands. Luminescence sensing studies revealed that 1 detected 2,2-bis(4,4′-hydroxyphenyl)-propane (BPA) and imipramine hydrochloride (IMH) with detection limits of 1.495 × 10−6 M and 9.92 × 10−5 M, respectively. The sensing mechanism is attributed to the absorption of BPA/IMH under excitation. [ABSTRACT FROM AUTHOR]

Five new ZnII/CdII coordination polymers (CPs) based on a flexible bis(imidazole) ligand 9,10-bis((2-methyl-1H-imidazol-1-yl)methyl)anthracene (bmima) with three different aromatic carboxylic acid ligands have been synthesized under solvothermal conditions: {[Cd(bmima)0.5(atp)(H2O)]·DMF·0.5H2O} (CP 1), {[Zn(bmima)(atp)]·DMF} (CP 2), {[Cd(bmima)(bpdc)]·2DMF} (CP 3), and {[M(bmima)0.5(oda)]·DMF·H2O} (M = Zn for CP 4 and Cd for CP 5), (H2atp = 2-aminoterephthalic acid; H2bpdc = [1,1′-biphenyl]-4,4′-dicarboxylic acid and H2oda = 4,4′-oxydibenzoic acid). CP 1 displays a 3,4-connected TiSc topology 3D framework with vertex symbols of {42·6·102·12}{42·6}. CP 2 and CP 3 both feature 2D layer structures with a five-fold interpenetration framework for CP 3. CP 4 and CP 5 both show a 3D "pillar-layer" structure with pcu α-Po topology. The structural differences of the five CPs may be due to the diverse coordination modes of dicarboxylate ligands and the conformation of flexible N-donor ligands. Moreover, CP 1 and CP 3 are two good fluorescent sensors for the detection of Fe3+, Cr2O72− and TNP. The mechanism of the two sensors shows that the fluorescent sensing process toward Fe3+ and Cr2O72− is mainly attributed to the competitive absorption process, while both competitive absorption and the more efficient FRET mechanism for TNP, respectively, which indicates that CP 1 and CP 3 can serve as two fluorescence sensors to sensitively and selectively detect the presence of Fe3+ and Cr2O72− in water. [ABSTRACT FROM AUTHOR]

An investigation of the coordination chemistry of the ((E)-N′-(4-hydroxybenzylidene)-4-hydroxybenzohydrazide) Schiff-based ligand (HL) towards Ni(II) acetate was performed using single crystal X-ray diffraction. The compounds [Ni(L)2]·H2O (2) and [Ni(HL)2(H2O)2](CH3CO2)2·2CH3CH2OH (1a) were isolated. Also, two solvated complexes of general formula [Ni(L)2]·solvent (2a, 2b) could be obtained as single crystals. Theoretical calculations were performed to evaluate the formation of the square-planar complex 2 from the octahedral 1a and to study the thermodynamic stability of the different compounds. The study of the reactivity of 2 with 1,2-di(4-pyridyl)ethylene (bpe) yielded single crystals of [Ni(L)2(bpe)2]·solvent (3). [ABSTRACT FROM AUTHOR]

Solvothermal reactions between three bis-pyridine-bis-amide ligands containing a fluorene scaffold bearing different substituents on the C9 position (CH2, 1; CMe2, 2; C＝O, 3) with 2,6-naphthalenedicarboxylic acid (H2ndca) and Zn(NO3)2·6H2O led to the isolation of three new microporous mixed-ligand MOFs (PUM310, containing 1; PUM310Me2, containing 2; PUM310CO, containing 3). The structural characterization conducted with X-ray quality single crystals revealed parallel polycatenated frameworks of thick layers in all cases, corresponding to the topological type 5,6L18. The entangled nets contain complete and truncated Zn-paddle wheels. In the truncated paddle wheel, a pyridine of the bis-amide linker has been replaced by a DMF molecule. Solvent removal leads to framework rearrangement, as evidenced by XRPD analysis performed on desolvated PUM310, with consequent framework shrinkage as also evidenced by volumetric adsorption analyses. The three MOFs are fluorescent in the solid state. The optical spectra are indicative of a Förster resonance energy transfer (FRET) involving ndca2− as an excitation energy donor and the bis-pyridine linkers as acceptors, with a FRET efficiency close to 100% in the case of PUM310CO. [ABSTRACT FROM AUTHOR]

Two new dinuclear cobalt(II) complexes, [(H2O)CoIIL1(μ-O2CR1)CoII(NCS)] (1) and [(DMSO)CoIIL2(μ-O2CR2)CoII(NCS)] (2) (H2L1 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-methoxyphenol), H2L2 = (2,2-dimethyl-1,3-propanediyl)bis(iminomethylene)bis(6-ethoxyphenol), R1CO2H = 3-methyl-4-nitrobenzoic acid, and R2CO2H = 4-methyl-3-nitrobenzoic acid), were synthesized using multidentate N,O-donor ligands with two pockets. Each complex was characterized using single crystal X-ray diffraction and spectral analysis. The noncovalent interactions were analyzed using density functional theory (DFT) calculations. In addition, the optical properties of the complexes were studied with a focus on the band gaps. Both complexes were utilized for the fabrication of semiconducting Schottky devices. [ABSTRACT FROM AUTHOR]

A pair of chiral metal–organic frameworks based on enantiomers of chiral Zn(salen) ligands has been successfully obtained by solvothermal subcomponent self-assembly. Both chiral MOFs were characterized by infrared spectroscopy, UV-vis absorption spectroscopy, thermogravimetric analysis, and single-crystal/powder X-ray diffraction. They crystallize in the chiral space group I222 and possess an extended 2D network with a sql topology. Moreover, these MOFs exhibit circularly polarized luminescence (CPL) with a dissymmetry factor of about 3.7 × 10−3. This work provides a simple strategy to make CPL-active MOF materials based on salen ligands. [ABSTRACT FROM AUTHOR]

MOFs with semiconducting behavior exhibit unique optoelectronic properties, and they are hailed as future low-bandgap materials, which are expected to serve as a new generation of functional materials to solve some thorny problems in the field of environment and energy. In this work, eight semiconducting MOFs with chemical formulae, {[Cd(m-bix)(ATP)]}n (1), {[Zn2(m-bix)(ATP)2]·DMF}n (2), {[Cd(m-bix)(BDC)(H2O)]}n (3), {[Co2(m-bix)(BDC)2(H2O)3]·2H2O·CH3OH}n (4), {[Ni2(m-bix)(BDC)2(H2O)3]·2H2O·CH3OH}n (5), {[Cd(m-bix)(Cl)]}n (6), {[Zn(m-bix)(CO3)]}n (7), and {[Cd(FDC)(H2O)3]·2H2O}n (8) (m-bix = m-bis(imidazol-1-ylmethyl)benzene; H2ATP = 2-aminoterephthalic acid; H2BDC = p-phthalic acid; H2FDC = 2,5-furandicarboxylic acid), were successfully synthesized by hydrothermal techniques. Comprehensive characterization of the as-synthesized MOFs showed that they display interesting topologies and fascinating structures (of 6 and 8 being 1D, 1, 2, 3, and 7 being 2D and 4 and 5 being 3D). The incorporation of π-conjugated ligands and abundant intermolecular hydrogen bonds endows these MOFs with higher carrier transport rates, resulting in unique optoelectronic properties. The optical band gaps of MOFs 1–8 obtained by UV reflection spectroscopy were 2.86, 2.59, 3.91, 3.01, 3.69, 3.19, 3.09, and 3.87 eV, respectively, proving that they are all potential semiconductor materials. Electrochemical oxygen evolution reaction (OER) catalysis studies revealed that MOFs 4–5 are efficient catalysts for the OER process with lower overpotentials of 381 and 397 mV at 10 mA cm−2 and lower Tafel slopes of 75.1 and 74.4 mV dec−1. Photoluminescence studies demonstrated that the Cd-based and Zn-based MOFs, especially MOF 2, exhibit strong violet light emission properties in the range of 405–446 nm, which are expected to be used in the development of new luminescent materials. In addition, the photocatalytic performance of these MOFs was evaluated. Among them, the best photocatalytic performance of 4 and 6 was attributed to the combination of the band gap value and luminescence performance, resulting in more photogenerated carriers and thus more catalytically active sites. This work not only provides a certain theoretical and experimental basis for further research on the optoelectronic properties of MOFs, but also affords an advanced strategy for the development of novel multifunctional materials to solve real-life environmental and energy problems. [ABSTRACT FROM AUTHOR]

A systematic structural study of novel complexes formed by aluminium and gallium trihalides with 1,2-bis(4-pyridyl)ethane (bpa) is performed. The complexes were synthesized using a solvent-free melt reaction approach and crystallized by sublimation in vacuum. Ionic coordination polymers (CPs) [MCl2(bpa)2]+[MCl4]−, M = Al (1) or Ga (2), exhibit isostructural one-dimensional networks. Ionic CP 3 [AlBr2(bpa)2]+Br− has a 1 : 2 composition and possesses a cationic part analogous to 1 and 2, featuring a modulated structure, in which the entire polymer chain and/or the positions of the bromido ligands are displaced according to a harmonic law. In the ionic CP [Ga2Br4(bpa)5]2+[GaBr4]2−·bpa (4) featuring a 2 : 3 composition, the [Ga2Br4(bpa)5]2+ cation forms a 2D polymer framework, in which {GaBr2}+ nodes are linked by the μ-bpa spacers forming 1D chains that are further interconnected by μ-bpa ligands of every second metal center. In the case of the 2 : 1 ratio, irrespective of the Lewis acid, molecular complexes [(MX3)2(bpa)] (MX3 = AlCl3 (5), AlBr3 (6), GaCl3 (7), and GaBr3 (8)) were obtained. Solid-state structures of complexes 1–8 were determined for the first time. [ABSTRACT FROM AUTHOR]

In order to solve the problems of environmental pollution and energy crisis, it is of great significance to develop low-cost, high-efficiency and environmentally friendly multifunctional materials to deal with environmental and energy concerns. Herein, two multifunctional Cu(II) coordination complexes with the formula {[Cu(m-bix)(FDC)(H2O)]·H2O}n (1) and {[Cu2(DAP)4(NIP)2]·DMF}n (2) (m-bix = m-bis(imidazol-1-ylmethyl)benzene; DAP = N-(4-pyridyl)dimethylamine; H2FDC = 2,5-furandicarboxylic acid; H2NIP = 5-nitroisophthalic acid) were successfully constructed by using mixed ligands via a solvothermal method. Structural analyses show that both complexes exhibit a 1D chain structure, extending into a 3D supramolecular network via abundant hydrogen bonding forces. Electrochemical oxygen evolution reaction (OER) catalytic studies reveal that 1 and 2 are efficient electrocatalysts for the OER. In particular, 2 has a lower overpotential of 360 mV at 1 mA cm−2 under alkaline conditions. Furthermore, both complexes exhibit excellent photocatalytic activity due to their narrow band gaps – 2.51 eV (494 nm) for 1 and 2.77 eV (448 nm) for 2. The oxidation system composed of the complex and H2O2 can degrade methyl orange azo dyes (40 mg L−1) to less than 10% in only 150 minutes under sunlight irradiation. This work demonstrates that employing mixed ligands is a promising approach to obtain multifunctional complexes. It also opens up a unique path for the development of high-efficiency, low-cost, and environmentally friendly multifunctional materials to address environmental and energy issues. [ABSTRACT FROM AUTHOR]

The dizwitterionic dicarboxylate ligands 1,1′-[(2,3,5,6-tetramethylbenzene-1,4-diyl)bis(methylene)]bis(pyridin-1-ium-4-carboxylate) (pL) and 1,1′-[(2,3,5,6-tetramethylbenzene-1,4-diyl)bis(methylene)]bis(pyridin-1-ium-3-carboxylate) (mL) have been reacted with uranyl cations under solvo-hydrothermal conditions to generate a series of five complexes containing also additional anionic donors. [UO2(pL)(H2PM)(H2O)2]·DMA·H2O (1), where H4PM is pyromellitic acid and DMA is dimethylacetamide, and [(UO2)2(pL)3(3-SB)2]·8H2O (2), where 3-SB2− is 3-sulfobenzoate, crystallize as monoperiodic coordination polymers, linear or including dinuclear rings, respectively, in which the pL ligands are bridging and the anionic species are merely decorating and involved in hydrogen bonding. pL connects four metal cations in [(UO2)2(pL)(2-SB)2]·1.5H2O (3) and, associated with the chelating and bridging 2-sulfobenzoate (2-SB2−) ligand, it gives a diperiodic network with the kgm topology. [(UO2)3(mL)(O)2(OH)(H2O)](NO3)0.8Cl0.2·3H2O (4) contains oxo- and hydroxo-bridged ribbon-like chains connected by mL linkers to form a cationic diperiodic network. In contrast, two independent, polyanionic and polycationic networks in a 2 : 1 ratio are formed in [(UO2)2(mL)3(H2O)2][(UO2)2(TDC)3]2·10H2O (5), involving either mL or TDC2− (2,5-thiophenedicarboxylate) ligands; both networks have the hcb topological type, albeit with very different cell shapes. [ABSTRACT FROM AUTHOR]

Herein, a series of ionic mononuclear Cu(I) complexes, [Cu(phen)(bdppmapy)]Cl (1a), [Cu(phen)(bdppmapy)]Br (2a), [Cu(phen)(bdppmapy)]I (3a), [Cu(phen)(bdppmapy)]SCN (4a), [Cu(Dpq)(bdppmapy)]Cl (1b), [Cu(Dpq)(bdppmapy)]Br (2b), [Cu(Dpq)(bdppmapy)]I (3b) and [Cu(Dpq)(bdppmapy)]SCN (4b) {phen = [1,10]phenanthroline; Dpq = pyrazino[2,3-f][1,10]-phenanthroline; bdppmapy = N,N-bis((diphenylphosphino)methyl)-2-pyridinamine} have been synthesized and characterized by using IR, NMR, elemental analysis, single crystal X-ray diffraction analysis, fluorescence spectroscopy methods, and UV-vis and terahertz (THz) time-domain absorption spectroscopy. Their crystal structures were elucidated by X-ray crystallography and their photophysical properties were investigated in detail. All the above complexes exhibit a 1D to 3D supramolecular structure which is linked together by intermolecular weak interaction forces and hydrogen bonds. By regulating ligands and anions, the emission wavelengths of these complexes are quite different in the range from 533 nm to 604 nm. Theoretical calculations and photophysical properties indicate that luminescence is derived from metal-to-ligand charge transfer (MLCT) excited states. In the meantime, the results of calculations show that the stabilization of the increased conjugation of the ligand-based π* orbital is ascribed to the observed bathochromic-shift in the MLCT transitions. [ABSTRACT FROM AUTHOR]

The tetratopic 1,4-bis(2-phenylethoxy)-2,5-bis(3,2′:6′,3′′-terpyridin-4′-yl)benzene (1) and 1,4-bis(3-phenylpropoxy)-2,5-bis(3,2′:6′,3′′-terpyridin-4′-yl)benzene (2) ligands have been prepared and fully characterised. Combination of ligand 1 or 2 and [M(hfacac)2]·xH2O (M = Cu, x = 1; M = Zn, x = 2) under conditions of crystal growth by layering led to the formation of [Cu2(hfacac)4(1)]n·3.6n(1,2-Cl2C6H4)·2nCHCl3, [Zn2(hfacac)4(1)]n·nMeC6H5·1.8nCHCl3, [Cu2(hfacac)4(2)]n·nMeC6H5·2nH2O, [Cu2(hfacac)4(2)]n·2.8nC6H5Cl and [Cu2(hfacac)4(2)]n·2n(1,2-Cl2C6H4)·0.4nCHCl3·0.5nH2O. For each compound, single-crystal X-ray analysis revealed the assembly of a planar (4,4)-net in which the tetratopic ligands 1 or 2 define the nodes. The metal centres link two different bis(3,2′:6′,3′′-tpy) ligands via the outer pyridine rings; whereas copper(II) has N-donors in a trans-arrangement, zinc(II) has them in cis. This difference between the copper(II) and zinc(II) coordination polymers modifies the architecture of the assembly without changing the underlying (4,4)-network. [ABSTRACT FROM AUTHOR]

We report the synthesis, crystal structures, and magnetic and theoretical investigations of five erbium complexes based on halogenated ligands with the respective formulas trans-[Er(L1)3(THF)2] (1), trans-[Er(L2)3(Ph3PO)2] (2), fac-[Er(L3)3(THF)3] (3), fac-[Er(L4)3(Ph3PO)3] (4), and [Er(L5)3] (5) (L1 = OCPh2(CF2Cl), L2 = OCPh(CF3)2, L3 = OCH(C6F5)2, L4 = OCHMe(C6F5), L5 = 1,8-dibromo-3,6-di-tert-butylcarbazol-9-ide, THF = tetrahydrofuran). Modulation of the experimental conditions allows controlling the coordination geometry of the resulting complexes. While 1 and 2 adopt a trigonal bipyramidal geometry, 3 and 4 exhibit a distorted octahedral arrangement. In contrast, 5 exhibits a triangular coordination geometry. Magnetic investigations in line with theoretical calculations reveal that only the three-coordinated complex 5 exhibits a zero-field slow relaxation of the magnetization, while compound 1 demonstrates field-induced relaxation dynamics. [ABSTRACT FROM AUTHOR]

Controlled assembly of metal–anthracene complexes is important for the development of smart photoresponsive materials based on [4 + 4] anthracene photocycloaddition reactions. Here, we report three mononuclear complexes containing two anthracene units, namely, [Gd(NO3)3(LR)2(dmpu)] [R = Me (1), Et (2), i-Pr (3)], where LR stands for 9-dialkyl phosphonomethylanthracene, and dmpu is N,N′-dimethylpropyleneurea. For compounds 1 and 3, the anthracene moieties of phosphonate ligands are joined head-to-tail by π–π interactions to form a linear supramolecular chain. Meanwhile for 2, they are almost vertically aligned to create a zigzag supramolecular chain. Both 1 and 2 underwent photodimerization reaction upon 395 nm UV light irradiation and showed a photochromic behaviour, but 3 could not. The reaction rate of 2 is about 40 times that of 1. These results indicate that the alkyl ester group of anthracene–phosphonate ligands can finely regulate the orientation and stacking of anthracene groups, and the onset of the photocycloaddition reaction depends not only on the stacking geometry of the anthracene groups but also on steric hindrance. In addition, thermally induced phase transition was observed for 2 due to the order–disorder transition of nitrate anions, associated with a shift of the emission peak. This work may shed light on the design and synthesis of photoresponsive metal–organic systems containing anthracene ligands. [ABSTRACT FROM AUTHOR]

We assembled two new Dy(III) compounds, [Dy4(L1)4(OH)4]·2CH3OH (1) and [Dy2(L2)2(HL2)2(CH3CN)2]N(C2H5)3 (2) (where H2L1 and H2L2 are methyl- and p-tolyl-substituted ligands, respectively) using bis-pyrazolone carbohydrazide-based multi-dentate hydrazone ligands. Structurally, the ligands coordinated with the Dy(III) spin centers in eight coordination environments in two ways. While four deprotonated L1 ligands with carbonyl oxygen (μ2-Ocarbonyl) and four hydroxyl (μ2-OH−) as bridging motifs afforded [2 × 2] grid 1 with un-symmetric adjacent centers, the two partially deprotonated HL2 and two deprotonated L2 ligands, as well as two coordinated solvents, afforded defected helicate-like compound 2 with symmetric adjacent centers. Interestingly, the p-tolyl-substituted ligand generates di-nuclear compound 2 with C2v symmetry, while the methyl-substituted ligand produces tetra-nuclear compound 1 with D2d symmetry. Magnetic analyses revealed that compound 1 exhibited a zero-field single-molecule magnet (SMM) behavior with a temperature-dependent multi-step relaxation of the magnetization consistent with the presence of independent centers with slightly different coordination geometries owing to the asymmetric μ2-Ocarbonyl and μ2-OH− bridging motifs. However, the absence of the above bridging motifs, as well as the involvement of an extra third anionic pyrazolone oxygen (Opyrazolone) and solvents in the coordination environment creating centrosymmetric centers, led to magnetically unfavorable conditions that exhibit slow magnetic relaxation under zero applied field in compound 2. [ABSTRACT FROM AUTHOR]

A series of coordination polymers, namely [Zn(μ3-L)(H2O)2] (1), [Zn(μ2-L)(2,2′-bpy)(H2O)] (2), [Zn(μ3-L)(μ2-4,4′-bpy)0.5] (3), [Cd(μ3-L)(2,2′-bpy)] (4), and [Cd(μ2-L)(phen)(H2O)] (5) (H2L = 3-carboxy-1-(3′-carboxybenzyl)-2-oxidopyridinium, 2,2′-bpy = 2,2′-bipyridine, 4,4′-bpy = 4,4′-bipyridine, phen = 1,10-phenanthroline), have been synthesized under hydrothermal conditions. These coordination polymers have been characterized by single-crystal X-ray diffraction, elemental analyses, infrared spectroscopy, thermogravimetric analyses and powder X-ray diffraction. The structure analysis by single crystal X-ray diffraction reveals that compound 1 shows a 1D double chain which can be expanded to a 2D supramolecular architecture through intermolecular π–π stacking interactions. In compound 2, the 1D wave-like chains are extended to a 3D supramolecular framework by intermolecular hydrogen bonds and π–π stacking interactions. In compound 3, the infinite rod-like metal ion chains are linked with L2− anions and 4,4′-bpy to form a 3D framework. In compound 4, the adjacent 1D loop-like chains are interconnected to a 3D supramolecular framework by intermolecular hydrogen bonds and π–π stacking interactions. Compound 5 displays a 3D supramolecular architecture extended from the 1D zigzag chains by intermolecular hydrogen bonds and π–π stacking interactions. The result reveals that the organic ligand plays a key role in the self-assembly of coordination polymers. The luminescence sensing experiments reveal that compounds 1–5 can effectively detect Fe3+, Cr2O72−, and NB. In particular, compound 1 shows a high quenching constant and a low limit of detection for Fe3+. [ABSTRACT FROM AUTHOR]

Although lead halide perovskite (LHP) nanocrystals (NCs) are considered propitious materials due to their extraordinary optoelectronic properties, the scalability of synthesis and poor ambient stability hinder their commercial applications. Herein, we develop a facile and universal room-temperature (RT) protocol for the synthesis of red-emitting all-inorganic CsPbBr3−xIx perovskite NCs by the mediation of capping ligands. The emission wavelength can be tuned in the range of 598–651 nm by tailoring the PbBr2 : PbI2 precursor ratios and the amounts of ligands. Interestingly, the introduction of ligands such as 3-mercaptopropionic acid (MPA) and thioglycolic acid (TGA) heavily improves the stability of the as-synthesized NCs against water, heat stress and UV irradiation, which is due to surface passivation. This work offers a reliable and scalable reference for tuning red-emissive perovskite NCs with improved environmental stability, which will accelerate their commercial application process in optoelectronic fields. [ABSTRACT FROM AUTHOR]

Three coordination complexes {[Cu(pydco)(pz)0.5(H2O)]·H2O}n (1), [Cu(pydco)(phen)(H2O)]·2H2O (2), and [Zn2(pydco)(phen)2Cl2]·2H2O (3) have been synthesized at room temperature using a mixed-ligand system including pyridine-2,6-dicarboxylic acid N-oxide (H2pydco) as O-donor as well as pyrazine (pz) and 1,10-phenanthroline (phen) as N,N′-bidentate donors. Single-crystal X-ray diffraction (XRD) revealed that 1 forms a 1D-coordination polymer through bridging pz units while 2 and 3 form discrete complexes in which endo-bidentate phen can only connect with one metal centre via a five-membered chelate ring. Also, pydco2− can form a six-membered chelate ring around the metal ion via the N-oxide oxygen and one carboxylate oxygen. However, another carboxylate group of this ligand can also participate in the coordination and create unique structures in 1 and 3. Subsequently, 1–3 can expand their structures into 2D-supramolecular networks through π⋯π stacking or H-bonding interactions. Recurrent π⋯π stacking motifs in all compounds have been further analyzed energetically using DFT calculations and characterized using the quantum theory of "atoms-in-molecules" (QTAIM) and noncovalent interaction plot (NCIPlot) index computational tools. In compound 3, cooperativity effects in π⋯π/π⋯π/π⋯π assemblies have been also analyzed. [ABSTRACT FROM AUTHOR]

Hydro(solvo)thermal reactions of N,N′-di(3-methylpyridyl)oxalamide (L1) and N,N′-di(4-methylpyridyl)oxalamide (L2) with angular dicarboxylic acids and Zn(II) and Co(II) metal salts afforded six coordination polymers (CPs), namely, [Zn(L1)0.5(FIPBB)·H2O]n [H2FIPBB = 4,4′-hexafluoroisopropylidenebis(benzoic acid)] (1), [Zn(L2)(OBA)·CH3OH]n [H2OBA = 4,4′-oxybis(benzoic acid)] (2), [Co(L2)0.5(FIPBB)·0.25CH3OH]n (3), [Co(L1)(OBA)·2H2O]n (4), [Co(L1)0.5(FIPBB)]n (5), and [Co2(L1)2(FIPBB)2(H2O)5·4H2O]n (6), which have been structurally characterized by using single-crystal X-ray diffraction. CPs 1 to 6 form a two-dimensional (2D) net with the bey, a polycatenated 2D net with the sql, a three-dimensional (3D) framework with the 6T9, a 2D net with the 3,5L2, 2D net with the bey and a one-dimensional (1D) looped chain with the 2,2,2,4C10 topologies, respectively. The distinct topological switch between 5 and 6 in the presence and absence of coordinated/cocrystallized water molecules was triggered under various temperatures through coordination and breakage of Co–O bonds. CPs 1 and 2 exhibit sustained porosities indicated by CO2 adsorption and exhibit high selectivity toward detection of pesticides such as 2,6-dichloro-4-nitroaniline (2,6-DCNA) and 4-nitroaniline (4-NA) with low detection limits and good recyclability up to five cycles. Integrating 1-octadecene with a long alkyl chain into 1–5 to modify the surface wettability induces hydrophobicity, which was verified by the measurement of water contact angles. [ABSTRACT FROM AUTHOR]

Several aryl polycarboxylic ligands (pyromellitic acid, 4,4′-azobenzenedicarboxylic acid and 3,3′,5,5′-azobenzenetetracarboxylic acid) have been used to react with the pentavalent ethoxide niobium(V) precursor Nb(OEt)5. Three new crystalline molecular compounds (1 with pyromellitate, 2 with 4,4′-azobenzenedicarboxylate and 3 with 3,3′,5,5′-azobenzenetetracarboxylate) were isolated from slow crystallization at room temperature from the mother liquid containing the precursor Nb(OEt)5. They are composed of one polycarboxylate ligand fully coordinated to mononuclear or dinuclear octahedrally-coordinated niobium(V) units. For the dimers, the two adjacent niobium centers are bridged by one μ-O and one μ-OEt groups and complexed by only one of the syn–syn bidentate carboxylate function arms from the polytopic ligand. Compounds 1–3 were characterized in solid state by single-crystal and powder X-ray diffraction analysis. Insight into the formation of the three compounds was supported by the help of infrared and liquid 1H NMR spectroscopy. [ABSTRACT FROM AUTHOR]

One-pot solvothermal reactions of CoCl2·6H2O with the semi-rigid ligand 3-(pyridin-4-yl)-1H-pyrazole-5-carboxylic acid under different reaction temperatures and stoichiometry conditions gave rise to three new complexes: [Co(Hppza)2(H2O)2] (1), [Co(Hppza)2]n (2) and [Co(Hppza)(H2O)Cl]n (3), which were characterized by elemental analysis, FT-IR spectroscopy, UV-vis absorption spectroscopy, thermogravimetric analysis (TGA) and X-ray diffraction methods. A comparative study revealed the marked sensitivity of the structural chemistry of the above-mentioned ligand to the synthesis conditions. Complex 1, which exhibited a zero-dimensional (0D) structure of mononuclear cobalt(II), was formed at 120 °C with a metal-to-ligand molar ratio of 2 : 1. A further increase in the reaction temperature to 130 °C resulted in the two-dimensional (2D) structure of 2. Moreover, the three-dimensional (3D) structure of 3 was formed when the metal-to-ligand molar ratio was changed to 1 : 1 at 130 °C. The magnetic measurements of 3 showed weak ferromagnetic coupling with the decrease in temperature from 8 to 30 K and antiferromagnetic interaction among the CoII ions. In addition, the luminescence and electrogenerated chemiluminescence (ECL) behavior of 1–3 were also studied. [ABSTRACT FROM AUTHOR]

Coordination networks (CNs), which have attracted great interest as electrode materials for supercapacitors (SCs), are generally constructed from Co and Ni ions with excellent redox ability and large rigid ligands with good productivity. There are scarce examples of CNs composed of copper ions and flexible ligands. In this work, a new fresh yellow crystal 2D CN [Cu I2 (L1)Cl2]∞ (1a) is successfully synthesized using CuCl and N,N′-bis(3-pyridyl)adipoamide (L1) with a high degree of flexibility. The fresh yellow [Cu I2 (L1)Cl2]∞ crystals (1a) can be spontaneously oxidized to the green isomorphic CN [Cu II2 (L1)Cl2]∞ (1c) in air, and this structural transformation between 1a and 1c is reversible by treatment with redox reagents, which can be also observed for the isomorphic CNs [Cu I2 (L1)Br2]∞ (2a) and [Cu II2 (L1)Br2]∞ (2c). Moreover, 1a, 1c, 2a and 2c show thermoresponsive properties with different degrees and disparity in electrochemical performance due to the different electronic structures of copper atoms and halogen species. Noticeably, the electrochemical performances of 1a and 1c are better than those of 2a and 2c, respectively. This work explores new strategies, i.e., tuning the electronic structure of metal atoms and coordination halide anions, for boosting the pseudocapacitive performance of CNs. [ABSTRACT FROM AUTHOR]

Three cadmium(II) coordination polymers, namely {[Cd(HLI)(NO3)2]·0.5MeOH}n (1), {[Cd(HLII)(NO3)2]·EtOH}n (2), and [Cd2(LII)2(NO3)2]n (3), have been self-assembled from Cd(NO3)2 and N,N′,O-pincer-type isonicotinoylhydrazone-based ditopic ligands (HLI = N′-(pyridin-2-ylmethylene)isonicotinohydrazide and HLII = N′-(1-(pyridin-2-yl)ethylidene)isonicotinohydrazide) and have been characterized experimentally and by DFT computations. In compounds 1 and 2, the corresponding ligand is coordinated to the metal center in the keto form and acted as a tetradentate chelating–bridging agent in which the nitrogen atom of the 4-pyridine ring is coordinated to the cadmium center of the neighboring unit, yielding 1D zig-zag coordination polymers. In compound 3, the ligand was singly-deprotonated and is coordinated in the enolic form with the nitrate ion further acted as a bridging agent, yielding a 2D network. It is revealed by the extended transition state natural orbital for chemical valence (ETS-NOCV) charge and energy decomposition scheme that typical hydrogen bonds O–H⋯O and N–H⋯O, which constitute the networks of 1 and 2, though dominated by a classic Coulomb term, are characterized by an equally important London dispersion constituent due to extra π⋯π and C–H⋯X contacts (X = O, H–C, H–N). The architecture of 3 is due to ionic and dative-covalent Cd–X (X = N, O) bonds as well as London dispersion-driven homopolar dihydrogen C–H⋯H–C and C–H⋯O interactions. NOCV-based representation allowed us to determine that hydrogen bonds O–H⋯O are twice weaker than the corresponding N–H⋯O in the networks of 1 and 2. [ABSTRACT FROM AUTHOR]

It is an attractive but challenging proposition to develop effective fluorescent sensors for detecting specific organic compounds. In this study, we designed and synthesized three Zn(II) complexes, namely [Zn(3N3PY)2](NO3)2·3.5CH3OH (1), [Zn(3N3PY)(BIN)]·1.5DMF (2) and [Zn(3N3PY)(BIN)0.5(HCOO)] (3) (H2BIN = 2,2′-biisonicotinic acid, HCOO− = formate), using a D–π–A ligand 4′-(4-(1H-1,2,4-triazol-1-yl)phenyl)-2,2′:6′,2′′-terpyridine (3N3PY) with mononuclear, one-dimensional (1D) chain and dinuclear structures, respectively. The three-dimensional (3D) supramolecular assemblies were achieved by the linkage of the Zn(II) complexes through π–π and hydrogen bonding interactions. The assemblies demonstrated intense luminescence and exhibited an excellent ability for sensing specific organic molecules namely 2,4,6-trinitrophenol (TNP), 4-methylbenzaldehyde (4-MB) and decabromodiphenyl oxide (DBDPO). [ABSTRACT FROM AUTHOR]

The design of metal–organic frameworks (MOFs) with high connectivity ligands is a potentially important approach towards enhanced stability materials and presents a powerful incentive in the self-assembly process towards high dimensionality networks, yet the MOF literature is dominated by di- and tri-carboxylate ligands. Herein, we report a new class of tetra-isophthalate "hyper-carboxylate" ligands containing flexible, linear diamine cores (H8L1, containing 1,2-diaminoethane; H8L2, 1,3-diaminopropane; H8L3, 1,4-diaminobutane; H8L4, trans-1,4-diaminocyclohexane). A series of MOFs based around copper(II) paddlewheel SBUs and these ligands has been found to regularly display cage-type cavities, not uncommon in isophthalate systems, that increase in size with longer diamine cores. However, with great flexibility comes great unpredictability, and a number of concomitant products were obtained in several instances. Notably the ligands, whilst all notionally able to connect to eight or more metal ions, are able to adopt a variety of coordination modes (coordinated to 8, 10, 12, or 14 metal ions) and topological connectivities (4-, 6-, and 8-connecting) as a consequence of their variable protonation states, in many instances leaving carboxylic acids directed into the framework channels. A variety of networks with other transition metals and node topologies further emphasise the unpredictability that can arise from having eight carboxylate groups in a single ligand including, somewhat surprisingly, two-dimensional coordination polymers. However, it is clear that despite the large variety of possible coordination modes leading to synthetic challenges in obtaining pure products, the use of highly decorated ligands is a strategy that generally trends towards three-dimensional networks of high connectivity. [ABSTRACT FROM AUTHOR]

2D MOFs or metal–organic layers (MOLs) as a new type of 2D materials have received special attention due to their unique merit of integrating both organic and inorganic components compared to inorganic 2D materials. However, they also suffer from weak stability. Here, we report a new method for the syntheses of MOLs with enhanced stability using azolate derivatives as terminal ligands to construct MOLs. Four MOLs have been synthesized containing numerous N atoms of azolate ligands, which as H-bond sites remarkably imprsove the stability of the final structures. In addition, such uncoordinated N atoms act as active sites promoting catalytic activity for CO2 chemical fixation after exfoliation. [ABSTRACT FROM AUTHOR]

Crystalline titanium-oxo clusters have received extensive attention as the model compounds of TiO2 materials. Functional ligands are one of the most significant factors related to their structural diversity and potential applications. Oximes have been proven to exhibit promising performances in coordination chemistry. However, the oxime-based titanium complexes have received little attention. Herein, five novel oxime-based titanium-oxo clusters, namely, Ti3(L1)6·CH2Cl2 (1, H2L1 = salicylaldoxime), Ti4(OiPr)4(L1)6 (2), Ti3(OCH3)3(BA)2(L1)2 (3, BA = benzoic acid), Ti3(μ3-O)(OiPr)2(BA)2(L1)3 (4), and Ti8(μ2-O)2(μ3-O)2(OiPr)12(L2)4 (5, H3L2 = salicylhydroxamic acid), were successfully synthesized and characterized. The coordination of the oxime ligands can effectively promote the visible light absorption of the obtained oxime-based Ti-oxo clusters. As electrode precursors for photoelectric responses, these obtained Ti-oxo clusters display clear photocurrent responses. Moreover, the salicylhydroxamic acid-based Ti-oxo cluster exhibits higher photoelectric activity than salicylaldoxime-based Ti-oxo clusters. This work not only provides new insights for verifying the effect of functional ligands on light absorption of titanium-oxo materials, but also paves the way for the design of novel titanium-based photoelectrode materials. [ABSTRACT FROM AUTHOR]