Search

Management of CO2 has been attracting great attention in this century. Reaction of CO2 with 2-haloanilines and isocyanides is an attractive way for both converting CO2 and producing quinazolinones, which are key intermediates for the synthesis of various biologically active products. However, the heterogeneous and relatively inert nature of CO2 with 2-haloaniline and isocyanide reactants limits the types of suitable catalysts. Herein, we use metal–organic frameworks (MOFs) as a "microreactor", in which Pd(PPh3)2Cl2 is well-dispersed as a single-molecular catalyst, and the reactants react in the molecular level through a "quasi-homogeneous" way to convert CO2 into quinazolinones under mild conditions with both promising yields over homogeneous catalysts and good recyclability as a heterogeneous reaction. The MOF-assisted single-molecular catalysis strategy should contribute to CO2 conversion, production of quinazolinone-type bioactive intermediates, and the epochal development of "homo-and-heterogeneous" catalysis. [ABSTRACT FROM AUTHOR]

Green and economical synthetic approaches for metal–organic frameworks (MOFs) and incorporating multiple functionalities into MOF matrixes are of great interest for wide applications. Herein, we developed a rapid, high-throughput and universal centrifuge tube grinding (CTG) synthetic strategy for the synthesis of a series of popular MOFs in centrifuge tubes. Significantly, a variety of catalytic and optically active organic, biological and complex molecules were incorporated into the in situ formed defects of MOF skeletons by one-pot CTG synthesis to achieve various novel MOF-encapsulated composite materials. Types of MOFs as well as different composites can be rapidly and greenly synthesized simultaneously in centrifuge tubes with different sizes on a single vortex mixer even on a gram scale. Our strategy provides a facile route for the incorporation of multiple functionalities, especially large active molecules, into MOFs and for greenly affording various MOF-based materials towards various applications in diverse areas. [ABSTRACT FROM AUTHOR]

Abstract: The integration of metal/metal oxide nanoparticles (NPs) into metal–organic frameworks (MOFs) to form composite materials has attracted great interest due to the broad range of applications. However, to date, it has not been possible to encapsulate metastable NPs with high catalytic activity into MOFs, due to their instability during the preparation process. For the first time, we have successfully developed a template protection–sacrifice (TPS) method to encapsulate metastable NPs such as Cu2O into MOFs. SiO2 was used as both a protective shell for Cu2O nanocubes and a sacrificial template for forming a yolk–shell structure. The obtained Cu2O@ZIF‐8 composite exhibits excellent cycle stability in the catalytic hydrogenation of 4‐nitrophenol with high activity. This is the first report of a Cu2O@MOF‐type composite material. The TPS method provides an efficient strategy for encapsulating unstable active metal/metal oxide NPs into MOFs or maybe other porous materials. [ABSTRACT FROM AUTHOR]

Abstract: The integration of metal/metal oxide nanoparticles (NPs) into metal–organic frameworks (MOFs) to form composite materials has attracted great interest due to the broad range of applications. However, to date, it has not been possible to encapsulate metastable NPs with high catalytic activity into MOFs, due to their instability during the preparation process. For the first time, we have successfully developed a template protection–sacrifice (TPS) method to encapsulate metastable NPs such as Cu2O into MOFs. SiO2 was used as both a protective shell for Cu2O nanocubes and a sacrificial template for forming a yolk–shell structure. The obtained Cu2O@ZIF‐8 composite exhibits excellent cycle stability in the catalytic hydrogenation of 4‐nitrophenol with high activity. This is the first report of a Cu2O@MOF‐type composite material. The TPS method provides an efficient strategy for encapsulating unstable active metal/metal oxide NPs into MOFs or maybe other porous materials. [ABSTRACT FROM AUTHOR]

A water-stable copper metal–organic framework (MOF), {[Cu2(HL)2(μ2-OH)2(H2O)5]·H2O}n (1, H2L = 2,5-dicarboxylic acid-3,4-ethylene dioxythiophene), was applied for the electrochemical detection of ascorbic acid (AA) without further post-modification. A glass carbon electrode covered with 1 was used as a biosensor for the simultaneous detection of AA and l-tryptophan (l-Trp) from both a single-component solution and a bio-mimic environment. [ABSTRACT FROM AUTHOR]

The role of auxiliary solvents in the formation of metal–organic frameworks (MOFs) has been studied for a series of copper-based framework systems. Herein we show the formation of three different 3D ordered frameworks with the formulae {[Cu4(cpt)4Cl4]·2DMF·dioxane·3H2O}n (1), {[Cu8(cpt)4(Hcpt)2Cl7(μ3-OH)2(H2O)4]Cl3·4CH3CN}n (2), and {[Cu8(cpt)4Cl4(μ3-OH)2(μ4-O)2]Cl2·4H2O·2CH3CN·3MeOH}n (3) [Hcpt = 4-(4-carboxyphenyl)-1,2,4-triazole], respectively, from the same reaction mixture through varying auxiliary solvents of the medium. These MOFs were fully characterized by single-crystal X-ray diffraction, showing interesting secondary building unit (SBU) variations. The varied SBUs not only bring different framework architectures to these MOFs, but also affect their framework stability. Gas sorption studies of MOF 3 reveal high CO2–N2 selectivity at 298 K and 0.16 bar (a typical partial pressure of CO2 in an industrial flue gas). A high isosteric heat of adsorption (Qst) at zero loading (53 kJ mol−1) was also observed in MOF 3. [ABSTRACT FROM AUTHOR]

Silver nanoparticles were successfully supported on the zeolite-type metal-organic framework MIL-101 to yield Ag@MIL-101 by a simple liquid impregnation method. For the first time, the conversion of terminal alkynes into propiolic acids with CO2 was achieved by the use of the Ag@MIL-101 catalysts. Owing to the excellent catalytic activity, the reaction proceeded at atmospheric pressure and low temperature (50 °C). The Ag@MIL-101 porous material is of outstanding bifunctional character as it is capable of simultaneously capturing and converting CO2 with low energy consumption and can be recovered easily by centrifugation. [ABSTRACT FROM AUTHOR]

Silver nanoparticles were successfully supported on the zeolite-type metal-organic framework MIL-101 to yield Ag@MIL-101 by a simple liquid impregnation method. For the first time, the conversion of terminal alkynes into propiolic acids with CO2 was achieved by the use of the Ag@MIL-101 catalysts. Owing to the excellent catalytic activity, the reaction proceeded at atmospheric pressure and low temperature (50 °C). The Ag@MIL-101 porous material is of outstanding bifunctional character as it is capable of simultaneously capturing and converting CO2 with low energy consumption and can be recovered easily by centrifugation. [ABSTRACT FROM AUTHOR]

Two new Ni(II) complexes, namely [NiL(bpy)0.5(H2O)2]·2H2O (1) and [NiL(bpy)0.5]n (2), respectively, were constructed from the same initial materials thiazolidine-2,4-dicarboxylic acid (H2L), 4,4′-bipyridine and NiCl2·6H2O, exhibiting varying architectures from 0D to 3D by changing reaction temperature. The transformation was confirmed by powder X-ray diffraction, infrared spectra and elemental analysis. The magnetic behaviors of 1 and 2 were investigated as well. [ABSTRACT FROM AUTHOR]

Heterobimetallic drive and cooperativity lead to a striking scenario for C–H bond activation and heteroaggregation involving MoIIIdimers. Reaction of (RO)3MoMo(OR)3with molar excess of ZnMe2at–78 °C affords the novel mixed Zn, Mo oxo clusters [Mo2(MeZn)6(μ2-Me)(μ3-CH2)2(OR)7] 1(R = neopentyl) and 2(R = cyclohexyl) preserving the MoMo triple bond, while the same reaction performed at ambient temperature gives rise to the related cluster [Mo2(MeZn)6(μ2-CH2)(μ3-CH2)2(OR)6] 3. These complexes represent the first examples of heterobimetallic MoMo complexes with bridging methyl and methylene groups and agostic C–H→Mo interactions, as well as penta-coordinate carbon. The complexes 1–3were characterized by elemental analyses, multinuclear NMR and single-crystal X-ray diffraction analysis. [ABSTRACT FROM AUTHOR]

As a biodegradable and biocompatible polymer material, polyglycolic acid is attracting more and more attention in the field of polymeric and biomedical materials. Consequently, the study of the transformation between different crystal forms of glycolide, the monomer of polyglycolic acid, is of great importance, because crystal forms of glycolide determine the stabilities and properties of polyglycolic acid products polymerized under different conditions in industry. Herein, this article reports the synthesis and crystallization of α‐ and β‐glycolide controlled by the type of organic solvents and/or temperatures, during which an intermediate crystal form of β′‐glycolide is newly observed. The transformation between α‐, β‐, and β′‐glycolide is investigated in detail, and the stabilities of different crystal forms are illustrated via the controlled experiments under different relative humidity (RH) as well as the theoretical calculations, which should provide fundamental concepts and guidance for the industrial production of glycolide and optimization of polyglycolic acid products. [ABSTRACT FROM AUTHOR]

The glucose derivative 3-O-methyl-D-glucose (OMG) is used as a cryoprotectant in freezing cells. However, its protective role and the related mechanism in static cold storage (CS) of organs are unknown. The present study aimed to investigate the effect of OMG on cod ischemia damage in cold preservation of donor kidney. Pretreatment of OMG on kidney was performed in an isolated renal cold storage model in rats. LDH activity in renal efflux was used to evaluate the cellular damage. Indicators including iron levels, mitochondrial damage, MDA level, and cellular apoptosis were measured. Kidney quality was assessed via a kidney transplantation (KTx) model in rats. The grafted animals were followed up for 7 days. Ischemia reperfusion (I/R) injury and inflammatory response were assessed by biochemical and histological analyses. OMG pretreatment alleviated prolonged CS-induced renal damage as evidenced by reduced LDH activities and tubular apoptosis. Kidney with pCS has significantly increased iron, MDA, and TUNEL+ cells, implying the increased ferroptosis, which has been partly inhibited by OMG. OMG pretreatment has improved the renal function (p <0.05) and prolonged the 7-day survival of the grafting recipients after KTx, as compared to the control group. OMG has significantly decreased inflammation and tubular damage after KTx, as evidenced by CD3-positive cells and TUNEL-positive cells. Our study demonstrated that OMG protected kidney against the prolonged cold ischemia-caused injuries through inhibiting ferroptosis. Our results suggested that OMG might have potential clinical application in cold preservation of donor kidney. [Display omitted] [ABSTRACT FROM AUTHOR]

A single-crystal to single-crystal (SC–SC) transformation process driven by water molecules has been exhibited by a multi-metallic coordination polymer. The in situ heating single crystal X-ray diffraction technique was applied to study the control of metal ion movement in the reversible SC–SC transformation process. [ABSTRACT FROM AUTHOR]

In the surroundings of carbon neutrality, nano‐Cu2O is considered a promising catalyst for the electrochemical CO2 reduction reaction (ECO2RR), whose improvements in product selectivity still require considerable efforts. Here, we present an efficient strategy for controlling the ECO2RR product by modifying the surface of nano‐Cu2O, i.e. by controlling the exposed facets via a reductant‐controlled method to achieve the highest C2H4 selectivity (Faradic efficiency=74.1 %) for Cu2O‐based catalysts in neutral electrolytes, and introducing a well‐suited metal–organic framework (MOF) coating on the surface of nano‐Cu2O to obtain syngas completely with an appropriate H2:CO ratio. Detailed mechanism and key intermediate have been illustrated by DFT calculations. Our systematic strategy is expected to control the ECO2RR product, improve the selectivity, and provide a reliable method for CO2 management and the green production of important carbon resources. [ABSTRACT FROM AUTHOR]

In the surroundings of carbon neutrality, nano‐Cu2O is considered a promising catalyst for the electrochemical CO2 reduction reaction (ECO2RR), whose improvements in product selectivity still require considerable efforts. Here, we present an efficient strategy for controlling the ECO2RR product by modifying the surface of nano‐Cu2O, i.e. by controlling the exposed facets via a reductant‐controlled method to achieve the highest C2H4 selectivity (Faradic efficiency=74.1 %) for Cu2O‐based catalysts in neutral electrolytes, and introducing a well‐suited metal–organic framework (MOF) coating on the surface of nano‐Cu2O to obtain syngas completely with an appropriate H2:CO ratio. Detailed mechanism and key intermediate have been illustrated by DFT calculations. Our systematic strategy is expected to control the ECO2RR product, improve the selectivity, and provide a reliable method for CO2 management and the green production of important carbon resources. [ABSTRACT FROM AUTHOR]

A kind of spin crossover-macromolecule polymer composite material, [Fe(NH2trz)3(ClO4)2]-PVP (NH2trz is 4-amino-1,2,4-triazole and PVP is polyvinylpyrrolidone), appears as homogeneous film with a regular structure in nano-scale and shows the spin crossover (SC) phenomenon. [ABSTRACT FROM AUTHOR]

Metal–organic frameworks (MOFs) have risen as a kind of porous materials that are constructed by the coordination of organic ligands to metal centers or clusters, providing compelling potential for various fields of research. In this frontier article, we demonstrate the recent developments in MOF-based materials for electrochemical sensing applications, and the current challenges and some prospects in this field are also discussed. [ABSTRACT FROM AUTHOR]

Catalytic conversion of CO2 into high value‐added chemicals using renewable energy is an attractive strategy for the management of CO2. However, achieving both efficiency and product selectivity remains a great challenge. Herein, a brand‐new family of 1D dual‐channel heterowires, Cu NWs@MOFs are constructed by coating metal–organic frameworks (MOFs) on Cu nanowires (Cu NWs) for electro‐/photocatalytic CO2 reductions, where Cu NWs act as an electron channel to directionally transmit electrons, and the MOF cover acts as a molecule/photon channel to control the products and/or undertake photoelectric conversion. Through changing the type of MOF cover, the 1D heterowire is switched between electrocatalyst and photocatalyst for the reduction of CO2 with excellent selectivity, adjustable products, and the highest stability among the Cu‐based CO2RR catalysts, which leads to heterometallic MOF covered 1D composite, and especially the first 1D/1D‐type Mott–Schottky heterojunction. Considering the diversity of MOF materials, the ultrastable heterowires offer a highly promising and feasible solution for CO2 reduction. [ABSTRACT FROM AUTHOR]

A series of lanthanide metal‐organic frameworks (MOFs) have been assembled with a series of functionalized [1,1′:4′,1′′‐terphenyl]‐4,4′′‐dicarboxylic acid ligands. The relationship between the ligand properties and the corresponding MOF properties has been studied. The structures of the MOFs depend on the solvent‐ligand and ligand‐ligand interactions, as well as the size of the non‐coordinating functional groups of the ligands. The differences in thermal stability among the ligands are inherited and amplified by corresponding lanthanide MOFs. The ligands bearing methyl, ether, and aldehyde functional groups are capable of sensitizing the emission from the lanthanide centers, whereas the ligand with α,β‐unsaturated ketone functional groups are non‐emissive due to the mismatch of the ligand and metal energy levels. [ABSTRACT FROM AUTHOR]

The Co(ii) metal–organic framework (MOF) {[Co(μ3-L)(H2O)]·0.5H2O}n (1, H2L = thiazolidine 2,4-dicarboxylic acid) with rich Lewis acid sites was used as a catalyst for the conversion of CO2 and propylene oxide into propylene carbonate with a yield of up to 98% under 50 °C and 1 atm. 1 exhibited excellent reusability, which could be regenerated easily for at least five runs without a decrease in the yield. Importantly, we synthesized two types of nano-crystals (N1 and N2) of 1 with polyvinylpyrrolidone (PVP) and hexadecyltrimethylammonium bromide (CTAB) as surfactants, respectively, and investigated their catalytic properties in comparison with that of 1 in the powder phase. A significant enhancement in both catalytic efficiency and product yield was observed when 1 was nano-crystallized. This is the first investigation about the relationship between the morphology and the catalytic parameters of MOFs. The results showed a strategy for efficiently applying MOFs as catalysts towards CO2 conversion, which could also be used in other MOF-catalyzed processes. [ABSTRACT FROM AUTHOR]

Two C2H6‐selective metal‐organic framework (MOF) adsorbents with ultrahigh stability, high surface areas, and suitable pore size have been designed and synthesized for one‐step separation of ethane/ethylene (C2H6/C2H4) under humid conditions to produce polymer‐grade pure C2H4. Experimental results reveal that these two MOFs not only adsorb a high amount of C2H6 but also display good C2H6/C2H4 selectivity verified by fixed bed column breakthrough experiments. Most importantly, the good water stability and hydrophobic pore environments make these two MOFs capable of efficiently separating C2H6/C2H4 under humid conditions, exhibiting the benchmark performance among all reported adsorbents for separation of C2H6/C2H4 under humid conditions. Moreover, the affinity sites and their static adsorption energies were successfully revealed by single crystal data and computation studies. Adsorbents described in this work can be used to address major chemical industrial challenges. [ABSTRACT FROM AUTHOR]

Two C2H6‐selective metal‐organic framework (MOF) adsorbents with ultrahigh stability, high surface areas, and suitable pore size have been designed and synthesized for one‐step separation of ethane/ethylene (C2H6/C2H4) under humid conditions to produce polymer‐grade pure C2H4. Experimental results reveal that these two MOFs not only adsorb a high amount of C2H6 but also display good C2H6/C2H4 selectivity verified by fixed bed column breakthrough experiments. Most importantly, the good water stability and hydrophobic pore environments make these two MOFs capable of efficiently separating C2H6/C2H4 under humid conditions, exhibiting the benchmark performance among all reported adsorbents for separation of C2H6/C2H4 under humid conditions. Moreover, the affinity sites and their static adsorption energies were successfully revealed by single crystal data and computation studies. Adsorbents described in this work can be used to address major chemical industrial challenges. [ABSTRACT FROM AUTHOR]

Abstract: A series of chromium(III) complexes [Cr(bipy)(HC2O4)2]Cl·3H2O (1), [Cr(phen)(HC2O4)2]Cl·3H2O (2), [Cr(phen)2(C2O4)]ClO4 (3), [Cr2(bipy)4(C2O4)](SO4)·(bipy)0.5·H2O (4) and [Mn(phen)2(H2O)2]2[Cr(phen)(C2O4)2]3ClO4·14H2O (5) were synthesized (bipy=4,4′-bipyridine, phen=1,10-phenanthroline), while the crystal structures of 1 and 3–5 have been determined by X-ray analysis. 1 and 3 are mononuclear complexes, 4 contains binuclear chromium(III) ions and 5 is a 3D supromolecule formed by complicated hydrogen bonding. 1–3 are potential molecular bricks of chromium(III) building blocks for synthesis heterometallic complexes. When we use these molecular bricks as ligands to react with other metal salts, unexpected complexes 4 and 5 are isolated in water solution. The synthesis conditions and reaction results are also discussed. [Copyright &y& Elsevier]

Both bulk crystals and nanocrystals of two helical complexes, [Cu(μ2-L)(H20)]„ (l) and {[Cu(ji2-L)(H20)]-2H20}„ (2) (H2L = thiazolidine-2,4-dicarboxylic acid), have been synthesized with the chiralities of right- j-- handedness (l) and left-handedness (2), respectively. 4- <-- Cyanopyridine and poly(vinylpyrrolidone) (PVP) have been applied to control the synthesis of complexes with different helicities in bulk-crystal and nanocrystal forms, respectively. 2 can be irreversibly transformed to 1 under heating. Associated with the conformation changing, the symmetry alters between nonpolar and polar space groups. [ABSTRACT FROM AUTHOR]

Dissolution-recrystallization structural transformation (DRST) is a powerful tool to unravel unequivocally the mechanism of dynamic conversion processes, based on the structures of the initial reactants, final products and sometimes intermediates isolated from the reaction mixture. Herein, we illustrate the details of the conversion processes of (CuIpz)3 into [CuII(OH)pz]6 (pzH = 4-chloro-3,5-diphenylpyrazole) through DRSTs. Based on crystal structure determination and spectroscopic methods, the most encountered species, (CuIpz)3, is in equilibrium with (CuIpz)4 in solution with the tetramer becoming dominant at low temperature, indicating an entropy-controlled conversion between these two structural isomers. The CuI trimer/tetramer in solution further experiences an oxidation if exposed to the open air, resulting in the formation of a pentanuclear mixed-valence intermediate CuI3CuII2(OMe)2pz5 which can be isolated as single crystals at −20 °C and has been structurally characterized for the first time. The final product isolated from the solution is the fully oxidized hexanuclear [CuII(OMe)pz]6, which is easily transformed into [CuII(OH)pz]6 in the presence of humidity. [ABSTRACT FROM AUTHOR]

Two new 2D Zn(ii) metal–organic frameworks (MOFs) {[Zn2(L)2(μ2-O)(H2O)3]·3DMA}n (Zn-1) and [Zn2(L)2(2,2′-bipy)(μ2-O)(H2O)2]n (Zn-2) (H2L = 2,5-thiophene dicarboxylic acid, bipy = 2,2′-dipyridyl) were designed and synthesized. Through the strategy of introducing bipy as a “lock”, Zn-1 was transferred to Zn-2via a crystal-to-crystal process, which showed significantly enhanced solvent and air stability compared to that of Zn-1. Without post modification, Zn-2 was used as an electrode modified material to construct sensors for the electrochemical recognition and distinction of S-containing amino acids, including l-cysteine, l-methionine and l-cystine. [ABSTRACT FROM AUTHOR]

Abstract Three Gd(III) complexes containing a polydentate carboxylate ligand were synthesized and characterized, which exhibited excellent stabilities toward thermal and acid/alkaline conditions. The Gd(III) complexes were successfully applied as contrast agent for magnetic resonance imaging (MRI). Through nanocrystallizing the Gd(III) complexes into micro-nano crystals, the relaxivity of their MRI were significantly enhanced. Furthermore, our results show that both coordination water molecules on Gd(III) ions and single electron number of the assistant metal ions affect the relaxivity of MRI as well. Graphical abstract Three Gd(III) complexes containing a polydentate carboxylate ligand were synthesized and characterized, The Gd(III) complexes were successfully applied as contrast agent for magnetic resonance imaging (MRI). Unlabelled Image Highlights • Three 3D framework-structured Gd(III) complexes were constructed. • The complexes show excellent stabilities toward air, thermal, and acid/alkaline. • They exhibited rare examples of 3D Gd(III) contrast reagents for MRI. • The longitudinal relaxivities were highly enhanced by nanocrystallization. • Our results may contribute for the improvement of the MRI property. [ABSTRACT FROM AUTHOR]

The triply bonded dimolybdenum compound, Mo2(OtBu)6 (1), was investigated as a homogeneous catalyst for the conversion of CO2. The compound 1 acted as a rare example of a versatile catalyst with an impressive ability to transform CO2 into various valuable products, including propiolic acids, cyclic carbonates, and benzo[d]thiazole- and benzo[d]oxazolecarboxylic acids, in high yields with short reaction times and excellent selectivity at ambient pressure and low temperatures (25–75 °C). This is the first report of the application of a metal–metal bond-containing species in the catalytic conversion of CO2. [ABSTRACT FROM AUTHOR]

Pinene is a family of bicyclic monoterpenes found in nature, which exhibits important applications in chemical industry and biomedicine; however, the discrimination methods used for pinene enantiomers are still rare. The alpha- and beta-pinene enantiomers were recognized and discriminated via an electrochemical method for the first time based on a cyclodextrin metal–organic framework (CD-MOF) as an electrochemical chiral sensor. [ABSTRACT FROM AUTHOR]

Ni(L)2 (1) and Zn2(μ-OL)2(L)2 (2), (HL=S-benzyl-β-N-(2-bromobenzylidene) dithiocarbazate), were synthesized and characterized by elemental analysis and X-ray single-crystal diffraction analysis. 1 is a mononuclear neutral nickel(II) complex and the center nickel atom is chelated by donors of N2S2 possessing a distorted tetrahedral configuration, while in 2, the adjacent two complex molecules are linked through two O atoms to form a dimer and the center zinc atom is five-coordinate in a distorted trigonal-bipyramidal geometry. The cytotoxic activity study indicated that 2 showed potent cytotoxic activity against the human liver hepatocellular carcinoma (HepG2) cancer cell lines, with IC50 2.4±0.2μg·mL−1, which is slightly weaker than 5-fluoroacil (5-FU) (0.89±0.21μg·mL−1) as reference. A gel electrophoresis assay demonstrated the ability of the complex to cleave the pBR322 plasmid DNA. [ABSTRACT FROM AUTHOR]

Four new coordination polymers [Co(btmtmb)2(SCN)2] (1), [Co(bttmb)2(SCN)2] (2), [Co(btmtmb)2(SeCN)2] (3) and [Co(bttmb)2(SeCN)2] (4), where btmtmb=1,3-bis-(1,2,4-triazol-1-ylmethyl)-5-methoxy-2,4,6-trimethylbenzene and bttmb=1,3-bis-(1,2,4-triazol-1-ylmethyl)-2,4,6-trimethylbenzene, have been synthesized and structurally characterized. The X-ray crystal structures reveal that 1 and 3 are constructed of an infinite 1D chain, 2 and 4 contain a 2D (4,4)-network layer. Magnetic properties of the four complexes are investigated, which show that for all these four complexes the antiferromagnetic interactions occur and strong spin-orbit coupling of Co(II) ions exits as well. [ABSTRACT FROM AUTHOR]

Abstract: Based on 4-substituted mono- and bis-triazole ligands 4-2-pyridyl-1,2,4-triazole (L1) and 2,6-(1,2,4-triazole-4-yl)-pyridine (L2), a series of iron(II)-triazole complexes, namely [Fe2(μ2-L1)3(L1)2(NCS)4] 2H2O (1), [Fe2(μ2-L1)3(L1)2(NCS)4] CH3OH CH3CH2OH (2) and [Fe(μ2-L2)2(NCS)2]n (3) have been isolated. For the Fe(II)-L1 system, though dinuclear complexes were obtained in both aqueous solution and methanol/ethanol solution for 1 and 2, respectively, anti-ferromagnetic interactions were found in 1 while incomplete spin transition phenomenon was found in 2. Low temperature structural analysis (100K) of 2 is consistent with one of the Fe(II) centers within the dinuclear complex at low spin (LS) state and the other at high-spin (HS) state resulting in a [LS:HS] species. When L2 is used under the similar preparation method for 1–2, one-dimensional neutral iron (II) chain complex 3 is isolated. The different substituted groups and solvent effect are both important for self-assembly and different magnetic properties of these crystalline iron(II)-triazole complexes 1–3. [Copyright &y& Elsevier]

Abstract: Two isomeric copper-containing coordination polymers, which are constructed from chiral ligand thiazolidine 2,4-dicarboxylic acid (H2L), have been synthesized with the same formula of [CuL(DMF)]n (1 and 1′). Complex 1 was prepared through the reaction of H2L and Cu(ClO4)2·6H2O in the mixture of N,N-dimethylformamide (DMF) and methanol (V/V=1:1). With the same reactants 1′ was obtained only using DMF as solvent. Single-crystal X-ray diffraction analysis exhibited that 1 is left-handed helical chain and crystallizes in chiral space group P212121, while 1′ is right-handed helix with chiral and polar space group P21. In addition, both coordination polymers show obvious chiral and non-linear optical (NLO) properties, which were characterized by circular dichroism (CD) and second harmonic generation (SHG) measurements. [Copyright &y& Elsevier]

Abstract: Two 2D cadmium coordination polymers {[Cd(pda)(2,2′-bpy)(H2O)]·H2O} n (1) and {[Cd(pda)(4,4′-bpy)(H2O)]·2H2O} n (2) (H2pda=3,4-pyridinedicarboxylic acid; 2,2′-bpy=2,2′-bipyridine; 4,4′-bpy=4,4′-bipyridine) have been synthesized and characterized by elemental analysis, infrared spectroscopy and X-ray single crystal diffraction. The 3D supramolecular structures of both 1 and 2 are constructed by hydrogen bonds between the 2D layers. Importantly, there are intramolecular π⋯π stacking interactions in both of the compounds. Crystallographic data for 1: Orthorhombic, Pbca, a =15.5977(12)Å, b =12.6063(10)Å, c =16.9891(13)Å, Z =8, R 1 =0.0202, wR 2 =0.0504; for 2: Monoclinic, C2/c, a =27.345(4)Å, b =11.2530(16)Å, c =12.1068(16)Å, β =104.197(2)°, Z =8, R 1 =0.0269, wR 2 =0.0625. [Copyright &y& Elsevier]