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Two new binuclear complexes, [Ni2L(OAc)2(H2O)]ClO4·H2O·CH2Cl2 (1) and [Zn2L(OAc)2]ClO4·CHCl3·0.5C6H12 (2), have been synthesized by using 2-[N,N-di(2-pyridylmethyl)aminomethyl]-6-(2-imidazolylmethyl)aminomethyl-4-methylphenol (HL) as a ligand. Complexes 1 and 2 have been characterized by FT-IR, powder X-ray diffraction, elemental analysis and single-crystal X-ray diffraction. X-ray crystallographic analyses show that 1 crystallizes in the triclinic P-1 space group, while 2 in the monoclinic C2/c space group. Both Ni1 and Ni2 in 1 are six-coordinate octahedra with a [Ni1O3N3] and [Ni2O4N2] configuration. In 2, the six-coordinate Zn1 cation displays a distorted octahedral [Zn1O3N3] configuration, while the five-coordinate Zn2 cation has a trigonal bipyramidal [Zn2O2N3] geometry. The intermolecular interactions in 1 and 2 have been investigated by 3D Hirshfeld surface analyses and 2D fingerprint plots to show that the prominent interactions are H···H and O···H/H···O contacts in 1 and H···H and Cl···H/H···Cl contacts in 2. Notably, the fluorescence emission of 2 has larger intensity than that of the free HL.

Metal–organic frameworks (MOFs) as proton-conductive materials have attracted increasing attention due to their applications in proton-exchange membrane fuel cells. While the majority of the MOFs are based on transition metals, group II metals with unusual configurations have received relatively less attention. In this work, we selected three tetrazole-based acetic acids, N,N-di(2-carboxymethyltetrazol-5-yl)amine (H2L1), 1,3,5-tri(2-carboxymethyltetrazol-5-yl)benzene (H3L2), and 4,5-di(tetrazol-5-yl)imidazolylacetic acid (H3L3), as ligands and prepared three MOFs with barium(II) ions: [Ba2(L1)2(H2O)5]·2H2O (1), (Me2NH2)[Ba(L2)(H2O)]·3H2O (2), and [Ba3(μ2-H2O)(L3)2(H2O)3]·2H2O (3). Ba-MOFs have been unambiguously characterized by elemental, FT-IR spectroscopy and single-crystal X-ray diffraction analyses. In the solid state, 2D MOF 1 with two nine-coordinated Ba(II) centers shows a rare hula hoop-like geometry at the Ba1 atom and a distorted tricapped trigonal prismatic geometry around the Ba2 one. Unusual sphenocorona geometry is also found in MOF 2 with a ten-coordinated Ba(II) ion. In MOF 3, three different Ba(II) ions coexist with two nine-coordinated Ba1 and Ba2 displaying a muffin-like configuration and a distorted tricapped trigonal prism geometry, respectively, and an eight-coordinated Ba3 having a distorted biaugmented trigonal prism geometry. In addition, MOF 2 exhibits an unprecedented trinodal 3,7,7-connected 3D network with the Schlafli symbol (37·46·52·62·74)(37·46·52·63·73)2(63) and MOF 3 displays a novel trinodal 4,5,9-connected 3D framework with the Schlafli symbol (421·615)(45·6)(48·62). Due to the presence of extensive hydrogen bonded networks consisting of dimethyl ammonium and water molecules in the 1D channels, MOF 2 shows a high proton conductivity of 4.47 × 10−3 S cm−1 at 85 °C and 98% relative humidity (RH).

The rational design and synthesis of an efficient bielectrocatalyst for the oxygen reduction reaction (ORR) and oxygen evolution reaction (OER) by tuning the chemical composition, structure and the catalytic sites of the hybrid materials is always of a great challenge. In this work, an innovative strategy based on the highly active N,N′-carbonyldiimidazole (CDI) is described to one-pot synthesis of a novel precursor for bifunctional O2-electrocatalyst. The coordination of Co2+ with the in situ generated ligands imidazole and carbonate results in ultrafine cobalt carbonate (CoCO3)-involved cobalt-based zeolitic imidazole framework (CoCO3/Co-ZIF). Owing to the presence of ultrafine CoCO3, carbonization of CoCO3/Co-ZIF at 800 °C under N2 atmosphere endows the pyrolysis product with a special skeleton of carbon nanotube (CNT)-tipped end CoOx, multivalent CoOx wrapped in graphitic carbon layers. Thus, the resulting CoOx/Co-N-C exhibits the enhanced and durable ORR/OER performance in alkaline media, due to the fast electron and mass transfers. For ORR, a large limiting current density of 4.59 mA cm−2 can be obtained by CoOx/Co-N-C, which is comparable to that of Pt/C. For OER, it only needs an over potential of 1.65 V to achieve a current density of 10 mA cm−2, merely 30 mV behind IrO2 (1.62 V).

The design and synthesis of metal–organic frameworks (MOFs) have attracted much interest due to the intriguing diversity of their architectures and topologies. However, building MOFs with different topological structures from the same ligand is still a challenge. Using 3-nitro-4-(pyridin-4-yl)benzoic acid (HL) as a new ligand, three novel MOFs, namely poly[[(N,N-dimethylformamide-κO)bis[μ2-3-nitro-4-(pyridin-4-yl)benzoato-κ3 O,O′:N]cadmium(II)] N,N-dimethylformamide monosolvate methanol monosolvate], {[Cd(C12H7N2O4)2(C3H7NO)]·C3H7NO·CH3OH} n , (1), poly[[(μ2-acetato-κ2 O:O′)[μ3-3-nitro-4-(pyridin-4-yl)benzoato-κ3 O:O′:N]bis[μ3-3-nitro-4-(pyridin-4-yl)benzoato-κ4 O,O′:O′:N]dicadmium(II)] N,N-dimethylacetamide disolvate monohydrate], {[Cd2(C12H7N2O4)3(CH3CO2)]·2C4H9NO·H2O} n , (2), and catena-poly[[[diaquanickel(II)]-bis[μ2-3-nitro-4-(pyridin-4-yl)benzoato-κ2 O:N]] N,N-dimethylacetamide disolvate], {[Ni(C12H7N2O4)2(H2O)2]·2C4H9NO} n , (3), have been prepared. Single-crystal structure analysis shows that the CdII atom in MOF (1) has a distorted pentagonal bipyramidal [CdN2O5] coordination geometry. The [CdN2O5] units as 4-connected nodes are interconnected by L − ligands to form a fourfold interpenetrating three-dimensional (3D) framework with a dia topology. In MOF (2), there are two crystallographically different CdII ions showing a distorted pentagonal bipyramidal [CdNO6] and a distorted octahedral [CdN2O4] coordination geometry, respectively. Two CdII ions are connected by three carboxylate groups to form a binuclear [Cd2(COO)3] cluster. Each binuclear cluster as a 6-connected node is further linked by acetate groups and L − ligands to produce a non-interpenetrating 3D framework with a pcu topology. MOF (3) contains two crystallographically distinct NiII ions on special positions. Each NiII ion adopts an elongated octahedral [NiN2O4] geometry. Each NiII ion as a 4-connected node is linked by L − ligands to generate a two-dimensional network with an sql topology, which is further stabilized by two types of intermolecular OW—HW...O hydrogen bonds to form a 3D supramolecular framework. MOFs (1)–(3) were also characterized by powder X-ray diffraction, IR spectroscopy and thermogravimetic analysis. Furthermore, the solid-state photoluminescence of HL and MOFs (1) and (2) have been investigated. The photoluminescence of MOFs (1) and (2) are enhanced and red-shifted with respect to free HL. The gas adsorption investigation of MOF (2) indicates a good separation selectivity (71) of CO2/N2 at 273 K (i.e. the amount of CO2 adsorption is 71 times higher than N2 at the same pressure).

A series of three-dimensional (3D) lanthanide metal–organic frameworks (LnMOFs), (Me2NH2)[LnL(H2O)] (Ln = Eu (1), Gd (2), Tb (3), Dy (4); H4L = 2,2′-disulfonyl-4,4′-biphenyldicarboxylic acid) have been successfully synthesized from H4L and Ln(NO3)3·6H2O under solvothermal conditions. Single crystal X-ray diffraction (SCXRD) shows that all LnMOFs 1–4 are isomorphous and isostructural with a hepta-coordinated Ln(III) being connected through the carboxylate groups of the L4– ligands, resulting in the formation of an one-dimensional (1D) inorganic rod-like [Ln(−COO)2)]+n chain along the c axis. The infinite 1D chains are further linked by the sulfonate and biphenyl groups, leading to formation of a uninodal 5-connected 3D network with bnn topology. The present LnMOFs are the first example of anionic 3D bnn-net constructed on Ln–O–C rods with channels being filled with (Me2NH2)+ cations. The L4– ligand shows a pentadentate coordination mode with two bound sulfonate groups. All the LnMOFs are insoluble in water...

A novel secondary building unit, a Russian nesting doll [Ln4@Ln4] tetrahedron, was developed for building metal–organic frameworks with an unprecedented binodal (3,20)-connected 3D network by using a linear bridge-linking ligand.

The development of cost-effective proton-conducting materials with high conductivity and water stability is currently of great interest in fuel-cell technology. By using a simple aqueous solution method, a water stable 3D Eu-MOF material, [Me2NH2][Eu(ox)2(H2O)]·3H2O (1), can be easily synthesized from oxalic acid (H2ox) and Eu(NO3)3·6H2O on a large scale. 1 possesses a dia net topology and an extensive hydrogen-bonded network consisting of dimethyl ammonium and water molecules in 1D channels. 1 shows a high proton conductivity of 2.73 × 10−3 S cm−1 at 55 °C and 95% relative humidity, and it is used as a sensitive luminescent sensor for Cu2+ ions in aqueous solutions.

The design and preparation of chiral metal–organic frameworks (CMOFs) from achiral ligands are a big challenge. Using 3-nitro-4-(pyridin-4-yl)benzoic acid (HL) as a new linker, a total of eight chiral lanthanide–organic frameworks (LOFs), namely poly[diaquatris[μ2-3-nitro-4-(pyridin-4-yl)benzoato-κ2 O:O′]lanthanide(III)], L- and D-[Ln(C12H7N2O4)3(H2O)2] n [(1), Ln = Eu; (2), Ln = Gd; (3), Ln = Dy; (4), Ln = Tb], were hydrothermally synthesized without chiral reagents and determined by X-ray crystallography. Crystal structure analyses show that L-(1)–(4) crystallize in the hexagonal P65 space group and are isomorphous and isostructural, while the enantiomers D-(1)–(4) crystallize in the hexagonal P61 space group. All LnIII ions are octacoordinated by six carboxyl O atoms of six 3-nitro-4-(pyridin-4-yl)benzoate ligands and two water molecules in a dodecahedral geometry. A one-dimensional neutral helical [Ln2(CO2)3] n chain is observed in (1)–(4) as a chiral origin. These helical chains are further interconnected via directional hydrogen-bonding interactions between pyridyl groups and water molecules to construct a three-dimensional (3D) homochiral network with hex topology. The present CMOF structure is the first chiral 3D hydrogen-bonded hex-net and shows good water stability. Solid-state circular dichroism (CD) signals revealed that (1)–(4) crystallized through spontaneous resolution. Furthermore, (1) and (4) display a strong red and green photoluminescence at room temperature, respectively, but their intensities reduce to almost half at 200 °C. Notably, upon excitation under visible light (463 nm), a circularly polarized luminescence (CPL) of (1) in the solid state is observed for the first time, with a g lum value of 2.61 × 10−2.

Three 3D lanthanide–organic frameworks (LOFs), [LnL(HCO2)(DMF)]n (Ln = Eu (1), Gd (2), Dy (3); H2L = 2,2′-dimethoxy-4,4′-biphenyldicarboxylic acid), have been prepared by the solvothermal reaction of Ln(NO3)3·6H2O and H2L in DMF–H2O mixed solvent. Crystallographic data show that LOFs 1–3 are isomorphous and crystallize in the orthorhombic space group Pna21. Each Ln(III) is eight-coordinated to four O atoms from four L2− ligands, one O atom from the DMF molecule and three O atoms from HCO2−. The adjacent Ln(III) ions are linked by the carboxylate groups of the L2− ligands and HCO2− to form a 1D inorganic rod-shaped [Ln(CO2)2(HCO2)]n chain as a secondary building unit (SBU). The infinite 1D chains are interconnected by the biphenyl groups, giving rise to a 3D framework along the c axis. LOFs 1–3 are the first neutral Ln-carboxylate/HCO2− chain-based sra-nets. 1 exhibits characteristic luminescence of Eu3+ upon 343 nm excitation. The investigation of magnetic properties shows very weak ferromagnetic interactions (J = 0.0092(3) cm−1) between Gd(III) ions in 2 with a Gd–O–Gd bridging angle of 125.6(1)°, and θ = −1.9(2) K in 3 due to thermal depopulation of the Stark levels of Dy(III) ions and/or the possible antiferromagnetic interactions between Dy(III) ions in contrast to the single-ion behavior observed in 1.

Two new asymmetrical 3-(p-R-phenyl)-4-amino-5-(2-pyridyl)-1,2,4-triazoles (3a, R = CH3 and 3b, R = OCH3) were synthesized with a yield of 58% and 69%, respectively. The compounds 3a and 3b were characterized with FT-IR, 1H NMR, ESI-MS spectra, and elemental analysis. Additionally, their molecular and crystal structures were determined by single crystal X-ray analysis.

A series of thioether-functionalised imidazolium salts have been prepared and characterized. Subsequent reaction of the thioether-functionalised imidazolium salts with iodomethane affords imidazolium-sulfonium salts composed of doubly charged cations and two different anions. Imidazolium-sulfonium salts containing a single anion type are obtained either by a solvent extraction method or by anion exchange. The imidazolium-sulfonium salts undergo a methyl-transfer reaction on exposure to water, giving rise to a new, singly charged imidazolium salt with iodide introduced at the 2-position of the imidazolium ring. Crystal structures of some of the imidazolium-sulfonium salts were determined by X-ray crystallography providing the topology of the interactions between the dications and the anions. Electrospray ionization mass spectrometry and quantum-chemical calculations were used to rationalise the relative strength of these interactions.

Four novel metal–organic frameworks, [MnL(DMF)]n (1), [NiL(H2O)2(DMF)]n (2), [Cu2L2(H2O)2]·6H2O·2DMF (3), and Na2(Me2NH2)4[Cd7L10]·9H2O·17Me2NH·2DMF (4), were successfully synthesized in solvothermal conditions using 2,2′-dimethoxy-4,4′-biphenyldicarboxylic acid (H2L) as the ligand. The X-ray crystallography analysis reveals that MOF 1 exhibits a 3D framework with sra topology, while MOF 2 shows a 2D network with sql topology though they possess a similar secondary building unit (SBU) [MO6] (M = Mn for 1 and Ni for 2). MOF 3 reveals an unprecedented 4-fold interpenetrated 3D framework with lvt topology constructed from only planar 4-connected nodes ([Cu2(CO2)4] SBUs) with the rigid dicarboxylic acids. MOF 4 features an unique acentric 3D/3D hetero-interpenetrated framework built from two different nodes (4- and 8-connected), different chemical compositions [Cd(CO2)4 and Cd3(CO2)8], and different topology of networks (66 and 424·64) and contains an inorganic 1D chain consisting of a Na+ and three Cd2+ ions. The solid state 113Cd NMR spectrum indicates that 4 has three 6-, 7-, and 8-coordinated Cd2+ ions with chemical shifts at δ −25.3, −41.2 and −83 ppm, respectively. MOF 3 has two kinds of 1D channels with diameters of 11 A and 7 A and exhibits a selective gas adsorption for CO2–N2 and CH4–N2. MOF 4 shows a selective adsorption for cationic dyes and a nonlinear SHG activity (ca. 0.8 times that of urea).

A novel iron(II) complex, trans-[FeL2(NCS)2][FeL2(CH3OH)2](NCS)2 (1) with 4-amino-3-(p-chlorophenyl)-5-(2-pyridyl)-1,2,4-triazole (L) has been successfully synthesized and characterized. X-ray crystallography analysis shows that 1 is the first example in the mononuclear triazole-based complexes consisting of two distinct molecules: trans-[FeL2(NCS)2] and trans-[FeL2(CH3OH)2](NCS)2 with each octahedral iron(II) center coordinated axial by two NCS− ions in Fe1 but two MeOH molecules in Fe2. Moreover, 1 can lose two MeOH molecules at 220 °C to form trans-[FeL2(NCS)2] (2) which can be transformed to 1 when recrystallizing 2 in methanol. Both 1 and 2 are high-spin species in the range of 1.8–300 K.

Triaryltriazoles are of interest in iron(II) complexes designed to study spin-crossover properties. In this study, three new asymmetrical substituted triaryltriazoles, 3-(p-R-phenyl)-4-(p-chlorophenyl)-5-(2-pyridyl)-1,2,4-triazoles (R = OCH3, 5a; Cl, 5b; Br, 5c), were successfully synthesized from 2-picolinic acid by a three-step reaction through an intermediate N-(p-R-phenylcarbonyl)-N′-(2-pyridylcarbonyl)hydrazine (4a–4c). Yield of 5a–5c is in the range from 74 to 87%. The compounds 5a–5c were characterized by UV, FTIR, 1H-NMR, electrospray ionization mass spectrum spectra, and elemental analysis. Additionally, the absolute configurations of 5a–5c were determined by single crystal X-ray crystallography.

Two linear trinuclear clusters, [Co3(L)6(H2O)6](ClO4)6 (1) and [Ni3(L)6(H2O)6](ClO4)6 · 3H2O (2) (L = 4-(4-hydroxyphenyl)-1,2,4-triazole), obtained by the reactions of M(ClO4)2 · 6H2O and 4-(4-hydroxyphenyl)-1,2,4-triazole have been isolated and structurally characterized. The two isostructural clusters, linear hexapositive trimers, are linked by three N1,N2-1,2,4-triazoles to the divalent central and terminal metal ions. The magnetic behaviors of the clusters were investigated from 1.8 to 300 K. Magnetic susceptibility measurements reveal antiferromagnetic exchange interactions between the metal centers in the clusters. The magnetic data were analyzed by using linear trinuclear modes with S = 3/2 and S = 1 for 1 and 2, respectively. Further studies were performed by accounting spin–orbital coupling for 1 and involving zero-field splitting within the ground state for 2.

A zigzag chain structural compound named Ni0.5{[Ni(en)]2[Ni(en)(H2O)]2[H3NiMo6W6O40]}·3H2O 1 (en = ethylenediamine) was hydrothermally synthesized and characterized by IR, TG and X-ray diffraction analysis. Structural analysis indicates that compound 1 exhibits an unusual Mo/W mixed NiII centered Keggin structure, which is tetra-capped by two [Ni(en)]2+ and two [Ni(en)(H2O)]2+ units. Two linkages of M–O–Ni(2) and M–O–Ni(4) connect two adjacent tetra-capping clusters in different directions, and it represents a novel inorganic–organic zigzag chain built on the NiII centered Keggin species. Compound 1 is demonstrated to be a high selectivity for benzaldehyde in the oxidation of styrene, while the magnetic data of complex 1 were fitted to the Curie–Weiss law and show antiferromagnetic interactions.

A new non-planar saddle shaped macrocyclic ligand 4,11-dihydro-5,7,12,14-tetramethyldibenzo[b,i][1,4,8,11]tetraazacyclotetradecine (H2tmtaa) containing a six-coordinate germanium(IV) complex, Ge(tmtaa)(OOCH)2 (1), in which two axial formate ligands are in the trans positions, has been synthesized. IR, UV, mass, NMR spectroscopic study and elemental analysis have been performed to characterize the complex. The single crystal X-ray diffraction analysis shows that in the solid state, molecules of 1 are connected through intermolecular hydrogen-bond weak interactions to form a one-dimensional supramolecular network. The temperature dependence of the electrical conductivity data (240–300 K) for 1 indicates a region of falling dσ/d(1/T), suggesting “semiconductor-like” charge transport in the stacking direction. The conductivity of 1 at room temperature is 6.1 × 10−8 S/cm.

Two new heteroleptic iridium(III) complexes [Ir(4,6-dfppy)2(PPh3)L] (4,6-dfppy = 2-(4,6-difluorophenyl)pyridyl, PPh3 = triphenylphosphine, L = NCS−, 1; NCO−, 2) have been synthesized and fully characterized. By introduction of electron-withdrawing groups such as fluorine atoms on the 4- and 6-positions of 2-phenylpyridyl (ppy) and using strong-field ligands for instance PPh3 and pseudohalogen as ancillary ligands, the HOMO–LUMO electronic energy gaps of 1 and 2 have been increased sufficiently. The photoluminescence (PL) spectra of 1 and 2 in solution show emission maxima at 456 and 458 nm, respectively, corresponding to efficient blue light-emitting. X-ray analyses show that intra- and intermolecular π–π interactions exist in the solid state of 1 and 2. The PL spectra of 1 and 2 in solid state exhibit about 30 nm spectral red shifts compared with those in solution.

The photochemical reaction between three A5-steroids (1–3) and a series of substituted 1,4-benzoquinones and their mechanistic study were reported. The reaction in nitrogen atmosphere led to the formation of three products including the steroid-quinone coupling compound (A), 7-hydroxy derivatives of Δ5-steroids (B) and substituted 1, 4-hydroquinone (C). Both chemical and spectrometric evidences such as UV-Visible spectra, ESR, chemically induced dynamic nuclear polarization (CIDNP) and cyclic voltammetry (CV) verified that the title reaction underwent a predominant photoinduced electron transfer pathway via the triplet quinone.

A new ligand, 3-methyl-4-(p-bromophenyl)-5-(2-pyridyl)-1,2,4-triazole (L) and its complexes, trans-[CuL2(ClO4)2] (1) and cis-[CoL2(H2O)2](ClO4)2·H2O·CH3OH (2), have been synthesized and characterized by UV, IR, electrospray ionization mass spectrum, elemental analyses, and single-crystal X-ray diffraction methods. In the structure, two L ligands are stabilized by intermolecular π···π interactions between the triazole rings. In the complexes, each L ligand adopts a chelating bidentate mode through N atom of pyridyl group and one N atom of the triazole. Both complexes have a similar distorted octahedral [MN4O2] core (M = Cu2+ and Co2+) with two ClO4− ions in the trans position in 1 but two H2O molecules in the cis arrangement in 2.

A novel two-dimensional (2D) copper(II) coordination polymer, [CuL(N3)2]n (1) (L = 2-aminomethylpyridine), has been synthesized and characterized by elemental analysis, IR, X-ray crystallography and magnetic susceptibility. The complex crystallizes in space group P21/c with a = 9.940(3), b = 8.057(2), c = 12.310(4) A, β = 104.119(4)°, V = 956.1(5) A3, Z = 4, with final R = 0.0543. The copper(II) ion in 1 is coordinated through two N atoms of the ligand L and four N atoms from the azido ligands in an elongated octahedron. The polymer consists of (6, 3) layers in which alternate double end-on (EO) and single end-to-end (EE) N 3 - bridging modes are found. The pyridine rings coming from adjacent layers are stacked by π–π interactions. Magnetic measurements reveal a weak antiferromagnetic exchange between copper(II) ions in 1.

A dinuclear nickel(II) complex, [Ni2(MOBPT)2(N3)4] · 2H2O (MOBPT = 4-(p-methoxyphenyl)-3,5-bis(pyridine-2-yl)-1,2,4-triazole), has been synthesized and characterized by elemental analysis, UV, IR, ESI-MS, and single crystal X-ray crystallography. The complex crystallizes in triclinic system, space group P 1 with a = 9.877(2) A, b = 10.396(2) A, c = 11.975(3) A, α = 71.638(3)°, β = 74.968(3)°, γ = 64.747(3)°, V = 1044.2(4) A3, Z = 1, R = 0.0371 for 5774 observed reflections. The crystal structure determination shows that the dinuclear Ni2N8 unit is almost planar with each Ni2+ coordinated by four nitrogens from two MOBPT ligands and two axial azides in a distorted octahedral geometry. Magnetic measurements reveal weak antiferromagnetic exchange in the complex.

The dimeric [Cu(bipy)(μ2-OH)]4 [(H2O) (bipy)2HPW11Cu2O39] 2·2EtOH·10H2O Keggin polyoxometalate is prepared by solvothermal reaction of Cu(NO3)2, H3PW12O40, and bipy in H2O/EtOH (2:1) solution (pH 4.6 adjusted with H3PO3, autoclave, 150 °C, 3 d; 38% yield).

A dimeric Keggin polyoxometalate, [Cu(bpy)(μ2-OH)]4[(H2O)(bpy)2HPW11Cu2O39]2·2CH3CH2OH·10H2O (1), constructed from two dicopper(II)-substituted monovacant Keggin polyoxoanions bridged by a Cu4 cluster, has been hydrothermally synthesized. Magnetic analysis indicates predominantly an antiferromagnetic interaction between copper(II) centers. Compound 1 also shows very high catalytic activity for the esterification of phosphoric acid with equimolar lauryl alcohol to monoalkyl phosphate ester.

Triazole (VI) is obtained under solvothermal conditions, whereas triazole (VII) is prepared by a solution method.

Three polynuclear clusters, [Cu4L8](ClO4)4·4H2O (1), [Zn3L6(H2O)6](ClO4)6·6H2O (2), and [Mn3L6(CH3OH)6](ClO4)6·4.5H2O (3) (L = 4-(4-hydroxyphenyl)-1,2,4-triazole), obtained by the reactions of M(ClO4)2·6H2O with L have been isolated and structurally characterized. Complex 1 featured a tetranuclear Cu(I) structure. Both 2 and 3 are linear hexapositive trimers linked by three N1,N2–1,2,4-triazole ligands to the divalent central and terminal metal ions. Furthermore, the luminescence properties of 2 were investigated at room temperature in the solid state.

The molecular structure of a novel manganese(II) complex with 4-(p-methoxyphenyl)-3,5-bis(pyridin-2-yl)-1,2,4-triazole (MOBPT) has been determined by X-ray analysis, FT-IR and by ESI-MS spectroscopy. The manganese atom is in a distorted octahedral environment. Bidentate chelating ligand (MOBPT) and two cis-oriented thiocyanate anions coordinate to the metal center equatorially and two water molecules coordinate axially. MOBPT entity coordinates via one triazole nitrogen and one pyridine nitrogen atom. The molecules are stabilized by intermolecular hydrogen bonds in the crystal lattice. Magnetic measurements show that the complex is high-spin species in the 75‐300 K range. q 2001 Elsevier Science B.V. All rights reserved.

A new complex, [Co2(C25H30N4)3](NO3)4·8H2O, has been synthesized and characterized by single crystal X-ray diffraction, ESI-MS spectroscopy, electronic absorption spectrum, and magnetic measurements. The cation of the complex contains two cobalt(II) atoms and three ligands (L), which twist around the Co(II)–Co(II) axis, leading to a dinuclear triple helix. Each cobalt(II) atom is six-coordinated with three Co–N (pyridyl) and three Co–N (N CH–) of three ligands (L), and attains a pseudo-octahedral coordination geometry. Magnetic measurements show that the complex is a high-spin species in the temperature range of 75–300 K.

The crystal structure of the polyhydrazone dioxime-containing dimeric copper(II) (polyhydrazone dioxime: HON=CMe[CMe=NN=CMe] n CMe=NOH) complex, [Cu2(Hboa)2(H2O)2] · (ClO4)2 (1) (H2boa = biacetyl oxime azine) has been determined. Complex (1) contains an unusual six-membered ring, which is composed of two oxime groups and two CuII ions. The variable temperature magnetic susceptibility of (1) in the 5–300 K range has been interpreted in terms of a CuII dimer. The magnetic behavior shows that the bridging six-membered ring mediates very strongly in the antiferromagnetic exchange interaction, with the fitting value J = −361(1) cm−1 and the e.p.r. g-value of 2.193.

The chelating properties of 4-(p-methylphenyl)-3,5-bis(pyridin-2-yl)-1,2,4-triazole (MBPT) were investigated through the study of the crystal structures of [Co(MBPT)2(H2O)2](ClO4)2·4H2O (1), [Ni(MBPT)2(H2O)2](ClO4)2 (2) and MBPT and the analysis of IR and ESIMS spectra. The metal atom is in a distorted octahedral environment. Two bidentate chelating ligands (MBPT) coordinate to metal center equatorially and two water molecules coordinate axially. Each MBPT coordinates via one triazole nitrogen atom and one pyridine nitrogen atom. The magnetic measurements show that the complexes are high-spin species in the 75–300 K range.

As the precursors of molecular magnets, three metallacrown analogous complexes, [Cu(II)(12-MCCu(II)N(ahpha)-4)]·(NO3)2·4H2O (1), [Cu(II)(12-(II)N(hbha)-4)]·(NO3)2·8H2O (2) and [Cu(II)(12-MCCu(II)N(mha)-4)]·(OH)2·12H2O (3) (H2ahpha=3-amino-3-hydroximino propanoic hydroximic acid, H2hbha=3-hydroximino butanoic hydroximic acid and H2mha=malonic hydroximic acid) have been prepared and 1 and 2 are characterized structurally. The number of donors on the organic periphery of the molecular sheet is modified with additional hydroxy and R group of ligands for modulating the intermolecular architecture of metallacrown molecules and enhancing intermolecular magnetic interaction. Solid-state magnetic susceptibility studies 5–300 K of 1 and 2 show a strongly antiferromagnetic intramolecular exchange between the five Cu(II) centers and weakly antiferromagnetic intermolecular interaction. The fitting of H=−2J1 ∑4i=1 Si·S5−2J2 ∑4i≠j=1 Si·Sj to the experimental magnetic susceptibilities give g=2.066(3), J1=−119.9(7), J2=−79.0(4), zJ′=−0.69(7) cm−1 for 1 and g=2.089(3), J1=−163(2), J2=−85.1(6), zJ′=−0.61(7) cm−1 for 2.

The crystal structure of a 1D chain complex, [Cu(SCN)(deae)]n (1) (Hdeae N,N-diethylamino ethanol), with mixed bridges was determined. The structure is composed of a dimeric Cu(II) unit with two bridging m 3 -h 2 -aminoethanolato ligands, while the units are bridged by end-to-end thiocyanato groups to form a 1D chain. The variable temperature magnetic susceptibility of 1 and [Cu(SCN)(dmae)]n (2) (HdmaeN,N-dimethylamino ethanol) in the temperature 5‐300 K have been interpreted in terms of simple dimer model approximation (H 2JSA·SB). The magnetic behaviors show that the aminoethanolato bridges mediate a moderately strong antiferromagnetic exchange interaction with the fitting values g 1.96(3), J 175(3) cm 1 for 1 and g2.016(7), J 205.4(7) cm 1 for 2, respectively. © 2000 Elsevier Science Ltd. All rights reserved.

The 4-(p-methoxyphenyl)-3,5-bis(4-pyridyl)-1,2,4-triazole has been synthesized and its crystal structure has been determined by X-ray diffraction methods. It crystallizes in the monoclinic space group P21/n, with a = 12.5832(6) A, b = 7.0512(5) A, c = 18.4669(12) A, β = 96.826(1)°, and Dcalc = 1.345 g cm−1 for Z = 4. In the structure, two pyridyl rings, phenyl ring, and triazole ring do not share a common plane. The most favored orientation of the pyridyl rings in the crystal is that their planes are inclined toward opposite directions with respect to the triazole ring.

The novel cobalt(II) and nickel(II) complexes with 4-(p-methoxyphenyl)-3,5-bis(pyridin-2-yl)-1,2,4-triazole (MOBPT) have been synthesized and their molecular structures determined by X-ray analysis, i.r. and by ESI-MS spectroscopy. The metal atom is in a distorted octahedral environment. Two bidentate chelating ligands (MOBPT) coordinate to the metal center equatorially and two water molecules coordinate axially. Each MOBPT entity coordinates via one triazole nitrogen and one pyridine nitrogen atom. Magnetic measurements show that the complexes are high-spin species in the 75–300 K range.

In a series of molecular dynamics (MD) runs on (KI)108 clusters, the Born–Mayer–Huggins potential function is employed to study structural, energetic, and kinetic aspects of phase change and the homogeneous nucleation of KI clusters. Melting and freezing are reproducible when clusters are heated and cooled. The melted clusters are not spherical in shape no matter the starting cluster is cubic or spherical. Quenching a melted (KI)108 cluster from 960 K in a bath with temperature range 200–400 K for a time period of 80 ps both nucleation and crystallization are observed. Nucleation rates exceeding 1036 critical nuclei m−3 s−1 are determined at 200, 250, 300, 350, and 400 K. Results are interpreted in terms of the classical theory of nucleation of Turnbull and Fisher and of Buckle. Interfacial free energies of the liquid–solid phase derived from the nucleation rates are 7–10 mJ m−2. This quantity is ∼0.19 of the heat of transition per unit area from solid to liquid, or about two-thirds of the corresponding ratio which Turnbull proposed for freezing transition. The temperature dependence of σsl(T) of (KI)108 clusters can be expressed as σsl(T)∝T0.34.

Two novel quinolyl substituted triazoles, 3-(p-methoxyphenyl)-4-amino-5-(2-quinolyl)-1,2,4-triazole (5) and 3-(p-methoxyphenyl)-4-phenyl-5-(2-quinolyl)-1,2,4-triazole (6), were successfully synthesized. The compound 5 was synthesized under solvothermal conditions, whereas 6 was prepared through a solution method. Both 5 and 6 were characterized with UV–vis, FTIR, 1H-NMR, ESI-MS spectra, and elemental analysis. Additionally, the absolute configurations of 5 and 6 were determined by single-crystal X-ray crystallography.

The honeycomb-like lanthanide sulfates (H2pip)3 [Ln3(OH)(SO4)7] (Ln: Sm, Eu, and Tb; pip: piperazine) are prepared by solvothermal reaction of Ln2O3, H2SO4, and piperazine in a 3:2 glycol/H2O mixed solvent (autoclave, 453 K, 6 d).

Asymmetrical substituted triaryltriazoles (VI) are obtained in three steps starting from readily available 2-picolinic acid (I).

Three novel organic amine templated honeycomb-like lanthanide sulfates, (C4N2H12)3[Ln3(OH)(SO4)7] (Ln = Sm (1), Eu (2), and Tb (3)), with extra-large channels containing 24-membered rings (24MR) have been synthesized by using chair form piperazine as the structure-directing agent under one-pot solvothermal reactions. The three compounds are isostructural, and the open framework of the title compounds is the first lanthanide sulfate example with extra-large channels containing 24MR. It has an acs framework topology. The three compounds are strong luminescent materials that display characteristic Sm(3+), Eu(3+), and Tb(3+) emission bands in the visible region. The observed second-harmonic generation efficiencies of the three compounds are all 0.4 times that of urea. TGA profiles and XRD measurements demonstrate their high thermal stability.

The new compound NH4{ [Zn4(DACH)7(H2O)3] [VIII3VIV18P6 O60(DACH)3]}·19H2O (DACH: 1,2-diaminocyclohexane) is synthesized by hydrothermal reaction of NH4VO3, Zn(OAc)2, DACH, H3PO4, and H2O (autoclave, 160 °C, 6 d).

In the title complex, [Ni(C₃₆H₂₆Cl₄N₄O₂)]·C₃H₆O, two 2,4-dichloro-benzoyl groups are grafted onto the methine groups of the Ni(II) complex Ni(tmtaa) (H₂tmtaa = 5,7,12,14-tetra-methyl-4,11-dihydro-dibenzo[b,i][1,4,8,11]tetra-aza-cyclo-tetra-decine). The complex has the shape of a saddle. The Ni atom is tetra-coordinated by the four N atoms of the macrocycle, forming a slightly tetra-hedrally distorted square-planar geometry. The metal is displaced by 0.0101 (8) Å from the N₄ mean plane. The aromatic rings of the 2,4-dichloro-benzoyl groups form dihedral angles of 87.1 (2) and 82.1 (2)° with the N₄ mean plane.

The novel Mo/W mixed Keggin derivative (IV) is characterized by powder and single crystal XRD, XPS, IR spectroscopy, and magnetic susceptibility measurements.

In the molecule of the title compound, C15H14N4, the triazole ring is oriented at dihedral angles of 30.8 (2) and 67.4 (2)° with respect to the pyridine and benzene rings, respectively. The crystal structure is stabilized by C—H...N hydrogen-bonding interactions, forming chains of molecules along [overline{1}01].