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This review highlights the most recent applications of Cd(II)-carboxylate-based coordination polymers (Cd(II)-CBCPs), such as sensors, catalysts, and storage materials, in comparison with those of Zn(II) counterparts. A wide range of species with luminescence properties were designed by using proper organic fluorophores, especially a carboxylate bridging ligand combined with an ancillary N-donor species, both with a rigid structure. These characteristics, combined with the arrangement in Cd(II)-CBCPs' structure and the intermolecular interaction, enable the sensing behavior of a plethora of various inorganic and organic pollutants. In addition, the Lewis acid behavior of Cd(II) was investigated either in developing valuable heterogeneous catalysts in acetalization, cyanosilylation, Henry or Strecker reactions, Knoevenagel condensation, or dyes or drug elimination from wastewater through photocatalysis. Furthermore, the pores structure of such derivatives induced the ability of some species to store gases or toxic dyes. Applications such as in herbicides, antibacterials, and electronic devices are also described together with their ability to generate nano-CdO species. [ABSTRACT FROM AUTHOR]

Recently, scientists have been developing sustainable processes, and in this context, mechanochemistry is commonly associated with green chemistry for its ability to reduce waste generation from chemical reactions. The well-known acetate complex, diacetate bis(triphenylphosphine) ruthenium(II) [Ru(OAc)2(PPh3)2], is a versatile precursor for preparing active complexes for several catalytic reactions. This report presents an efficient and straightforward manual grinding protocol for the sustainable synthesis of ruthenium carboxylate complexes starting from the commercially available [RuCl2(PPh3)3] and metal carboxylates. This work represents a novel and preliminary investigation into carboxylate precursors' alternative solventless synthesis route based on manual grinding. To our knowledge, this is the first time [Ru(OAc)2(PPh3)2] has been prepared via a mechanochemical procedure. The synthesis method has also been investigated for other alkali metal carboxylates and yields ranging from 30 to 80% were obtained. A comparison of sustainability and environmental impact between conventional solution synthesis and the grinding route has been carried out using the E-factor and Mass Productivity. While for the acetate complex E-factor and MP were only slightly better compared with the solvent method (3 vs. 4 for E-factor and ~6 vs. 5 for MP), for benzoate higher results were found (1 vs. ~4 for E-factor and 10 vs. 5 for MP). [ABSTRACT FROM AUTHOR]

The crystal structure of [Cu3(C7H5O3)4(C20H20NO5)2(H2O)2]·2(H2O) (1) and analysis of temperature and field dependence of magnetic susceptibility is reported in this work. The structure of 1 is composed of trinuclear complex units and water molecules. The middle copper atom occupies the center of symmetry. N, O-bonded (6,7-dimethoxy-isoquinolin-1-yl)-(3,4-di-methoxy-phenyl)-methanolato ligands, 2-hydroxybenzoates with bridging carboxylic groups, and oxo-bridged water molecules connect the middle Cu(II) atom with the terminal copper atoms. Two 2-hydroxybenzoates coordinate the terminal copper atoms via one carboxylic oxygen and an O atom of the hydroxyl group. The analysis of copper coordination by bond-valence sum approach and relevant structural correlation is consistent with hexacoordinated Cu(II) centers. Cu···Cu separation is 3.0269(3) Å. The magnetism of 1 shows a strong ferromagnetic interaction between the neighboring metallic centers accompanied by very weak antiferromagnetic intermolecular interactions. The complex units are mutually held by π···π stack interactions of 2-hydroxybenzoates and hydrogen bonds. A new N,O bonded ligands, (R, S)-[(6,7-dimethoxy-isoquinolin-1-yl)-(3,4-dimethoxy-phenyl)-methanolate] coordinate the terminal atoms of the trinuclear copper(II) complex. [ABSTRACT FROM AUTHOR]

A reaction between copper(II) nitrate and trans-1,4-cyclohexanedicarboxylic acid (H2chdc) carried out under hydrothermal conditions led to a new metal-organic coordination polymer [Cu2(Hchdc)2(chdc)]n. According to single-crystal XRD data, the compound is based on bi-nuclear paddlewheel-type carboxylate blocks that are joined with polymeric chains due to the (μ3-κ1:κ2) coordination of carboxylate groups. The chains are interconnected by chdc2− bridging ligands into layers containing free COOH groups of terminal Hchdc−. The neighboring layers adopt a RCOOH···OOCR hydrogen bond-assisted arrangement into a dense-packed structure. Magnetization measurements showed the presence of a strong antiferromagnetic exchange interaction (J/kB = −495 K) inside the bi-nuclear blocks. At the same time, no significant interaction was found between the {-Cu2(OOCR)4-} units in spite of their polymeric in-chain packing. Patterns of magnetic behavior of [Cu2(Hchdc)2(chdc)]n were thoroughly analyzed and explained from a structural point of view. [ABSTRACT FROM AUTHOR]

By reaction of sodium electride or NaC2H with the anhydrous sodium salt of propiolic acid, Na(OOC−C≡C−H), in liquid ammonia crystalline powders of Na2C3O2 were obtained. The structure analysis based on synchrotron powder diffraction data revealed that Na2C3O2 crystallizes in a monoclinic unit cell (I2/a, Z=4) exhibiting the elusive Y‐shaped −C≡C−COO− anion, which is unprecedented in a crystalline compound up to now. IR/Raman and solid‐state NMR spectroscopic investigations with assignments supported by DFT‐based ab initio calculations confirm this finding. Reaction with sodium electride led to a higher crystallinity of the product, but additionally a by‐product apparently due to decomposition and polymerization of Na2C3O2 was formed. No such by‐product was observed in the reaction with NaC2H, which turned out to be a milder metalation route. However, the product of the latter reaction is less crystalline. [ABSTRACT FROM AUTHOR]

Carboxylate molecules are distinguished as potential compounds in the largely emergent chemical world of heterocyclic compounds showing alike pharmacological characteristics. The knowledge of a mixture of synthetic pathways and different physicochemical parameters of such compounds are of special interest to medicinal chemists to produce combinatorial collections and carry out in-depth searches of lead molecules. Among various groups of the compounds studied, carboxylate moieties stand out as unique in features due to their biological, pharmacological, and medicinal properties. The synthesis, crystal structure, conformation, and density functional theory study of the (4-(4-nitrophenyl)-9-(phenylsulfonyl)-9H-carbazole-2,3-diyl)bis(p-tolylmethanone) derivative are reported in detail. The carboxylate moiety is in the planar conformation with C–H⋯O hydrogen bonds and Van der Waals forces. Density functional theory is utilised to investigate the carboxylate derivative. Similar to co-crystal ligands, carboxylate compounds exhibit potent interactions with the target protein. The supramolecular properties are measured and validated using Hirshfeld surface studies. [ABSTRACT FROM AUTHOR]

Two new copper dimers, namely, bis(dimethyl sulfoxide)tetrakis(μ-pyrene-1-carboxylato)dicopper(Cu—Cu), [Cu2(C17H9O2)4(C2H6OS)2] or [Cu2(pyr-COO−)4(DMSO)2] (1), and bis(dimethylformamide)tetrakis(μ-pyrene-1-carboxylato)dicopper(Cu—Cu), [Cu2(C17H9O2)4(C3H7NO)2] or [Cu2(pyr-COO−)4(DMF)2] (2) (pyr = pyrene), were synthesized from the reaction of pyrene-1-carboxylic acid, copper(II) nitrate and triethylamine from solvents DMSO and DMF, respectively. While 1 crystallized in the space group P\overline{1}, the crystal structure of 2 is in space group P21/n. The Cu atoms have octahedral geometries, with four oxygen atoms from carboxylate pyrene ligands occupying the equatorial positions, a solvent molecule coordinating at one of the axial positions, and a Cu...Cu contact in the opposite position. The packing in the crystal structures exhibits π–π stacking interactions and short contacts through the solvent molecules. The Hirshfeld surfaces and two-dimensional fingerprint plots were generated for both compounds to better understand the intermolecular interactions and the contribution of heteroatoms from the solvent ligands to the crystal packing. In addition, a Cu2+/Cu1+ quasi-reversible redox process was identified for compound 2 using cyclic voltammetry that accounts for a diffusion-controlled electron-donation process to the Cu dimer.

Minerals are the chief constituents of rocks and have varied properties, such as the surface area, surface charge, site density, etc. Hence, numerous interactions are bound to occur in a reservoir during rock–fluid (i.e., rock, crude oil and brine) interactions. This study seeks to assess the role of the mineralogical composition in the wettability of sandstone rocks (SRs) and mineral mixture (MM) using both surface complexation modeling (SCM) and a flotation test. From the considered sandstone rocks, both the experimental results and the simulated counterparts revealed that the SRs were preferentially hydrophilic. For the MM, when the mass fraction of the hydrophobic mineral was increased, the affinity of the MM became slightly hydrophobic, and vice versa. For the dominant sandstone reservoir rock minerals with predominantly negatively charged surfaces, negligible oil adsorption took place due to the interfacial repulsive forces at the oil–brine and mineral–brine interfaces. For the MM with low calcite content, the wetting preference was influenced by the mineral with a prominent surface area. Our developed model portrayed that the main mechanism of oil adhesion onto sandstone minerals was divalent cation bridging. Nonetheless, adhesion of carboxylate (>COO−) onto the illite, montmorillonite and calcite sites also took place, with the latter being more pronounced. [ABSTRACT FROM AUTHOR]

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

Two new copper dimers, namely, bis(dimethyl sulfoxide)tetrakis(κ-pyrene-1-carboxylato)dicopper(Cu--Cu), [Cu2(C17H9O2)4(C2H6OS)2] or [Cu2(pyr-COO-)4(DMSO)2] (1), and bis(dimethylformamide)tetrakis(κ-pyrene-1-carboxylato)dicopper(Cu--Cu), [Cu2(C17H9O2)4(C3H7NO)2] or [Cu2(pyr-COO- )4(DMF)2] (2) (pyr = pyrene), were synthesized from the reaction of pyrene-1-carboxylic acid, copper(II) nitrate and triethylamine from solvents DMSO and DMF, respectively. While 1 crystallized in the space group P1, the crystal structure of 2 is in space group P21/n. The Cu atoms have octahedral geometries, with four oxygen atoms from carboxylate pyrene ligands occupying the equatorial positions, a solvent molecule coordinating at one of the axial positions, and a Cu. . .Cu contact in the opposite position. The packing in the crystal structures exhibits π-π stacking interactions and short contacts through the solvent molecules. The Hirshfeld surfaces and two-dimensional fingerprint plots were generated for both compounds to better understand the intermolecular interactions and the contribution of heteroatoms from the solvent ligands to the crystal packing. In addition, a Cu2+/Cu1+ quasi-reversible redox process was identified for compound 2 using cyclic voltammetry that accounts for a diffusion-controlled electron-donation process to the Cu dimer. [ABSTRACT FROM AUTHOR]

This review highlights the most recent applications of Cd(II)-carboxylate-based coordination polymers (Cd(II)-CBCPs), such as sensors, catalysts, and storage materials, in comparison with those of Zn(II) counterparts. A wide range of species with luminescence properties were designed by using proper organic fluorophores, especially a carboxylate bridging ligand combined with an ancillary N-donor species, both with a rigid structure. These characteristics, combined with the arrangement in Cd(II)-CBCPs’ structure and the intermolecular interaction, enable the sensing behavior of a plethora of various inorganic and organic pollutants. In addition, the Lewis acid behavior of Cd(II) was investigated either in developing valuable heterogeneous catalysts in acetalization, cyanosilylation, Henry or Strecker reactions, Knoevenagel condensation, or dyes or drug elimination from wastewater through photocatalysis. Furthermore, the pores structure of such derivatives induced the ability of some species to store gases or toxic dyes. Applications such as in herbicides, antibacterials, and electronic devices are also described together with their ability to generate nano-CdO species.

A reaction between copper(II) nitrate and trans-1,4-cyclohexanedicarboxylic acid (H2chdc) carried out under hydrothermal conditions led to a new metal-organic coordination polymer [Cu2(Hchdc)2(chdc)]n. According to single-crystal XRD data, the compound is based on bi-nuclear paddlewheel-type carboxylate blocks that are joined with polymeric chains due to the (μ3-κ1:κ2) coordination of carboxylate groups. The chains are interconnected by chdc2− bridging ligands into layers containing free COOH groups of terminal Hchdc−. The neighboring layers adopt a RCOOH···OOCR hydrogen bond-assisted arrangement into a dense-packed structure. Magnetization measurements showed the presence of a strong antiferromagnetic exchange interaction (J/kB = −495 K) inside the bi-nuclear blocks. At the same time, no significant interaction was found between the {-Cu2(OOCR)4-} units in spite of their polymeric in-chain packing. Patterns of magnetic behavior of [Cu2(Hchdc)2(chdc)]n were thoroughly analyzed and explained from a structural point of view.

ChemCatChem homepage for more articles in the collection. The mechanism of the low‐temperature water gas shift reaction (LTWGS) on an Au/CeO2 catalyst was investigated by means of in situ diffuse reflectance infrared (DRIFT) spectroscopy. Under steady‐state LTWGS reaction (373–623 K), the catalyst is partially reduced, and signals from carbonate/formate dominates the infrared spectra. Time‐resolved pulse of CO experiment under a constant partial pressure of water at 423 K indicates that Ce4+ can be reduced to Ce3+ and that formate (HCOO) species cannot be directly related to the CO2 production. Further information was obtained by performing modulation excitation spectroscopy (MES) experiments coupled with a phase‐sensitive detection (PSD) method. Under periodic modulation of the CO partial pressure while keeping the H2O concentration constant, most of the intense bands of carbonate and formate remained constant, indicating that these species are only spectators. The same is observed for the concentration of Ce3+. Conversely, signals in‐phase with the conversion of CO to CO2 are observed and assigned to carboxyl [C(O)OH] and carboxylate (CO2δ−) species, while some monodentate formate (m‐HCOO) also changes but at a lower rate. A plausible associative reaction mechanism where carboxyl/carboxylate are key intermediates is postulated. [ABSTRACT FROM AUTHOR]

We designed 0D, 1D, and 2D supramolecular assemblies made of diaryliodonium salts (functioning as double σ-hole donors) and carboxylates (as σ-hole acceptors). The association was based on two charge-supported halogen bonds (XB), which occurred between IIII sites of the iodonium cations and the carboxylate anions. The sequential introduction of the carboxylic groups in the aryl ring of the benzoic acid added a dimension to the 0D supramolecular organization of the benzoate, which furnished 1D-chained and 2D-layered structures when terephthalate and trimesate anions, correspondingly, were applied as XB acceptors. The structure-directing XB were studied using DFT calculations under periodic boundary conditions and were followed by the one-electron-potential analysis and the Bader atoms-in-molecules topological analysis of electron density. These theoretical methods confirmed the existence of the XB and verified the philicities of the interaction partners in the designed solid-state structures. [ABSTRACT FROM AUTHOR]

A mixed-ligand complexation approach implying the reaction of metal carboxylates with the chelating tridendate diethylenetriamine (DETA) ligand has been applied to modify the structure of the layered coordination polymer based on lanthanum propionate (Prop). Lanthanum propionate monohydrate has been synthesized and characterized by a set of analytical methods to determine its crystal structure and chemical composition. The crystal structures of lanthanum propionate and nickel propionate complexes with DETA have additionally been determined. The native lanthanum propionate monohydrate [La2(H2O)2Prop6] has been proven to have a 2D-layered topology, whereas the mixed-ligand complex [La2(DETA)Prop6] ⋅ MeCN (where MeCN stands for acetonitrile) has a chain structure. A chemical solution deposition procedure has been developed to produce phase-pure oriented LaNiO3 thin films. These films exhibit metallic conductivity and can be used as conductive sublayers. [ABSTRACT FROM AUTHOR]

Organic electrode materials based on conjugated dicarboxylate moieties are particularly attractive to develop metal‐ion organic batteries. Exhibiting good stability properties in liquid electrolytes, such organic electrode materials can reversibly store alkali metal ions (Li, Na or K) at low working potential. Although many molecular designs have been investigated in the last decade, conjugated dicarboxylates are impeded by low coulombic efficiencies, especially at the first cycle, and sluggish kinetics in most cases. Herein, a new strategy in the design of conjugated carboxylates by fusing a thiadiazole heterocycle to the terephthalate core is reported. The synthesis and electrochemical performance of dilithium‐2,1,3‐benzothiadiazole‐4,7‐dicarboxylate (Li2‐DCBTZ) as positive electrode material is investigated for the first time. Next to being a new structural design, the presence of the thiadiazole ring enables (i) a better conjugation of π‐n electrons leading to a benefit in terms of rate capability, and (ii) a better stabilizing coordination network for Li ions through both oxygen and nitrogen atoms. In addition, the reduced state in Li4‐DCBTZ is stabilized due to a maintained aromaticity in the heteroaromatic core in comparison to the parent terephthalate. Theoretical calculations on the Li‐ion storage mechanism and bonding character support the experimental work. [ABSTRACT FROM AUTHOR]

Cu(II), Ni(II), Zn(II), Co(II), Fe(II), Mn(II) carboxylates containing a pharmacophoric glycoluril fragment were obtained for the first time. The proposed structure of the complexes was established using elemental analysis, spectral methods, and magnetochemistry. Structure of one of the copper(II) complexes was proved by X-ray diffraction analysis. Antibacterial and fungicidal activity of all the compounds was studied. It was shown that the starting acids are inactive, while some complexes exhibit antibacterial activity. [ABSTRACT FROM AUTHOR]

Bu çalışmada, polikarboksilat-eter esaslı su azaltıcı katkının anyonik monomer içeriğinin kendiliğinden yerleşebilen beton (KYB) karışımlarının çeşitli taze ve sertleşmiş hal özelliklerine etkisi araştırılmıştır. Bu amaçla, anyonik monomeri %100 karboksilat olan kontrol katkısına ilaveten, kontrol katkısının anyonik monomerinin %10 ve %30 oranında sülfonat ve fosfat ile ikame edilmesiylebirbirinden farklı 5 adet su azaltıcı katkı sentezlenmiştir. Elde edilen sonuçlara göre, su azaltıcı katkı anyonik monomerinin sülfonat ile ikame edilmesi, karışımların katkı ihtiyacını artırırken; zamana bağlı yayılma performanslarını olumlu yönde etkilemiştir. Fosfat ikame edilmesi durumunda ise karışımların katkı ihtiyacı azalırken zamana bağlı yayılma performansı olumsuz etkilenmiştir. Tüm karışımlar içerisinde taze hal özellikleri açısından en iyi performans %10 sülfonat ikame edilen katkı ile elde edilmiştir. Anyonik monomer değişimi, KYB karışımlarının basınç dayanımları, su emme oranları, ultrases geçiş hızları (UPV) ve dinamik elastisite modüllerinde önemli bir değişikliğe sebep olmamıştır

This review considers the applications of Zn(II) carboxylate-based coordination polymers (Zn-CBCPs), such as sensors, catalysts, species with potential in infections and cancers treatment, as well as storage and drug-carrier materials. The nature of organic luminophores, especially both the rigid carboxylate and the ancillary N-donor bridging ligand, together with the alignment in Zn-CBCPs and their intermolecular interaction modulate the luminescence properties and allow the sensing of a variety of inorganic and organic pollutants. The ability of Zn(II) to act as a good Lewis acid allowed the involvement of Zn-CBCPs either in dye elimination from wastewater through photocatalysis or in pathogenic microorganism or tumor inhibition. In addition, the pores developed inside of the network provided the possibility for some species to store gaseous or liquid molecules, as well as to deliver some drugs for improved treatment. [ABSTRACT FROM AUTHOR]

The interaction of in situ generated iron(II) complex {Fe(piv)2(bpy)} and gadolinium(III) pivalate [Gd(piv)3]n in the ratio Fe : Gd=1 : 1 leads to new tetranuclear heterometallic complex [Fe2Gd2(piv)10(bpy)2] (1) of the rare {FeII2GdIII2} type (piv is pivalate anion, bpy is 2,2′‐bipyridine). According to X‐ray analysis, a tetranuclear zig‐zag {FeGdGdFe} heterometallic core is formed from two {FeGd} fragments connected by two bridging piv‐anions. The coordination environments of two iron(II) (FeO4N2) can be described as strongly distorted octahedrons, while the environment of the gadolinium(III) (GdO7) – as capped trigonal prisms. The coordination environment of each iron(II) is supported by terminal bpy ligands. The measurements of the temperature dependence of magnetic susceptibility of 1 show avery weak antiferromagnetic exchange between high‐spin Gd3+ (SGd=7/2) and Fe2+ (SFe=2) paramagnetic centers. The alternating current magnetic susceptibility measurements did not reveal any sign of magnetization slow relaxation in complex 1. [ABSTRACT FROM AUTHOR]

We designed 0D, 1D, and 2D supramolecular assemblies made of diaryliodonium salts (functioning as double σ-hole donors) and carboxylates (as σ-hole acceptors). The association was based on two charge-supported halogen bonds (XB), which occurred between IIII sites of the iodonium cations and the carboxylate anions. The sequential introduction of the carboxylic groups in the aryl ring of the benzoic acid added a dimension to the 0D supramolecular organization of the benzoate, which furnished 1D-chained and 2D-layered structures when terephthalate and trimesate anions, correspondingly, were applied as XB acceptors. The structure-directing XB were studied using DFT calculations under periodic boundary conditions and were followed by the one-electron-potential analysis and the Bader atoms-in-molecules topological analysis of electron density. These theoretical methods confirmed the existence of the XB and verified the philicities of the interaction partners in the designed solid-state structures.

This article describes a series of more than 20 new compounds formed by the combination of 2,4,6‐trihydroxybenzoic acid (H4thba) with metal ions in the presence of a base, with structures that include discrete molecular units, chains, and two‐ and three‐dimensional networks. As a result of the presence of two ortho‐hydroxy groups, H4thba is a relatively strong acid (pKa1 = 1.68). The carboxylate group in H3thba− is therefore considerably less basic than most carboxylates with intramolecular hydrogen bonds, conferring a rigid planar geometry upon the anion. These characteristics of H3thba− significantly impact upon the way it interacts with metal ions. In s‐block metal compounds, where the interaction of the metal centres with the carboxylate O atoms is essentially ionic, the anion bonds to up to three metal centres via a variety of binding modes. In cases where the metal ion is able to form directional coordinate bonds, however, the carboxylate group tends to bond in a monodentate mode, interacting with just one metal centre in the syn mode. A dominant influence on the structures of the complexes seems to be the face‐to‐face stacking of the aromatic rings, which creates networks containing layers of metal–oxygen polyhedra that participate in hydrogen bonding. This investigation was undertaken, in part, by a group of secondary school students as an educational exercise designed to introduce school students to the technique of single‐crystal X‐ray diffraction and enhance their understanding of primary and secondary bonding. [ABSTRACT FROM AUTHOR]

As our societal need for materials and energy has grown, so has our need for catalyst processes in hydrogen production. A major function in these applications, for both homogenous and heterogeneous catalysis processes, is the synthesis of an active metal catalyst. It must first be soluble to control the physical properties of the metal being used. Recent work in metal precursors has begun to turn toward these metal carboxylate types of material. Structural models are proposed for bismuth 2-ethylhexanoate and 2,2-dimethyloctanoate and cerium 2-ethylhexanoate. The bismuth compounds have been characterized at different ratios of bismuth to carboxylate as solutions of the free acids. Their structures are most consistent with a Bi 4 (RCO 2) 12 motif where the Bi ions are arranged in a flattened tetrahedron with Bi – Bi distances of about 4.3 Å. There is evidence for Bi – O – Bi linkages at low free acid concentrations. The cerium compound is most consistent with a linear tetracerium molecule where the Ce – Ce distances repeat at about 4.3 Å out to 16.4 Å. The models were generated by analogy with known crystal structures and compared to high-energy x-ray scattering data. To further evaluate the models, DFT calculations were made, and the equilibrium geometries were compared. The vibrational spectra calculated from those geometries are presented and compared to the experimental results. Magnetization vs. temperature data was collected on the cerium compound, and its behavior was consistent with the proposed model. A geometrical approach to determining the dimensionality and relative positions of the metal ions in these structures is presented. [Display omitted] • Molecular elucidation of bismuth and ceria metal carboxylate complex materials. • Designing of highly active catalysts through specific catalytic precursor materials. • Using FTIR, Raman and HEXRD in conjunction with computation studies to propose plausible molecular structures. [ABSTRACT FROM AUTHOR]

The design and development of low-cost and efficient photovoltaic materials remain a major challenge for the research and application of polymer solar cells (PSCs). Therefore, developing efficient photovoltaic polymers with simple structure and easy preparation has become an important research topic. Here we report a facilely synthesized electron-donating polymer X1 with a simple chemical structure, which is composed of carboxylated benzo[1,2-b:4,5-b′]dithiophene (BDT) and thiophene unit. The carboxylate substituents on the BDT unit endowed the polymer with appropriate solubility, low-lying highest occupied molecular orbital (HOMO) energy level, and superior absorption. The PSCs based on X1 as donor showed a high power conversion efficiency of 16.6%, with a remarkable short-circuit current density of 27.07 mA cm−2. These results demonstrated that X1 is a highly promising candidate for low-cost and efficient PSCs. Furthermore, this study revealed the potential of carboxylated BDT as an effective building block in the research and development of high-performance photovoltaic materials. [ABSTRACT FROM AUTHOR]

Converting small organic molecules to their lithium salts or polymerization effectively solves the capacity fading caused by the dissolution of small organic molecules in electrolytes. While polymer lithium salts have the characteristics of small molecular lithium salts and polymers and can obtain good cycle stability and rate performance. The 3‐carboxylithium substituted thiophene (3‐TCOOLi) and polymer (P3‐TCOOLi) anode materials for lithium‐ion batteries were synthesized, and their electrochemical properties were compared. Compared with the small‐molecule lithium salt 3‐TCOOLi electrode, the polymer P3‐TCOOLi electrode exhibits superior cycling and rate performance. The P3‐TCOOLi electrode still has a specific capacity of 390 mAh g−1 after 100 cycles at a current density of 50 mA g−1. During the rate charge and discharge process, when the current density increased to 1000 mA g−1, the specific capacity was 305 mAh g−1. It shows that the idea of small molecule lithium salt polymerization is feasible. [ABSTRACT FROM AUTHOR]

Four new {Cr8} rings have been synthesized and characterized; they are all based on the classic [CrF(O2CtBu)2]8 ring 1. Three routes have been studied. The first is direct synthesis, by reacting hydrated chromium(III) fluorides with the acid; this has been used to produce LS[CrF(O2CEt)2]8 3. The second route uses 3 as a precursor and substitute with an incoming carboxylate. This has been used to make [CrF(O2CCCl3)2]8 4 and [CrF(O2CC6F5)2]8 5. The third route uses LSN-ethyl-D-glucamine (H5Etglu) as a template and produces chiral rings [Cr8F4(Etglu)(O2CtBu)15] 6. The single crystal X-ray structures of these new compounds are reported.

Hana Stepankova,1,2 Marcin Swiatkowski,3 Rafal Kruszynski,3 Pavel Svec,1 Hana Michalkova,1 Vendula Smolikova,1,2 Andrea Ridoskova,1,4 Zbynek Splichal,1,2 Petr Michalek,1,2 Lukas Richtera,1,2 Pavel Kopel,5 Vojtech Adam,1,2 Zbynek Heger,1,2 Simona Rex1,2 1Department of Chemistry and Biochemistry, Mendel University in Brno, Brno, Czechia; 2Central European Institute of Technology, Brno University of Technology, Brno, Czechia; 3Institute of General and Ecological Chemistry, Lodz University of Technology, Lodz, Poland; 4Central European Institute of Technology, Mendel University in Brno, Brno, Czechia; 5Department of Inorganic Chemistry, Faculty of Science, Palacky University, Olomouc, CzechiaCorrespondence: Simona RexDepartment of Chemistry and Biochemistry, Mendel University in Brno, Brno, CzechiaTel +420-5-4513-3350Fax +425-5-4521-2044Email simona.rex@mendelu.czPurpose: The present study deals with the in vitro evaluation of the potential use of coordination compound-based zinc oxide (ZnO) nanoparticles (NPs) for the treatment of triple negative breast cancer cells (TNBrCa). As BrCa is one of the most prevalent cancer types and TNBrCa treatment is difficult due to poor prognosis and a high metastasis rate, finding a more reliable treatment option should be of the utmost interest.Methods: Prepared by reacting zinc carboxylates (formate, acetate, propionate, butyrate, isobutyrate, valerate) and hexamethylenetetramine, 4 distinct coordination compounds were further subjected to two modes of conversion into ZnO NPs – ultrasonication with oleic acid or heating of pure precursors in an air atmosphere. After detailed characterization, the resulting ZnO NPs were subjected to in vitro testing of cytotoxicity toward TNBrCa and normal breast epithelial cells. Further, their biocompatibility was evaluated.Results: The resulting ZnO NPs provide distinct morphological features, size, biocompatibility, and selective cytotoxicity toward TNBrCa cells. They internalize into two types of TNBrCa cells and imbalance their redox homeostasis, influencing their metabolism, morphology, and ultimately leading to their death via apoptosis or necrosis.Conclusion: The crucial properties of ZnO NPs seem to be their morphology, size, and zinc content. The ZnO NPs with the most preferential values of all three properties show great promise for a future potential use in the therapy of TNBrCa.Keywords: carboxylate, hexamethylenetetramine, nanoparticles, redox homeostasis imbalance, triple negative breast cancer, zinc oxide coordination compounds

Diorganotin(IV) complexes [(R2Sn)2HL] [where, R = methyl-, butyl- and L = 5-(4-carboxy-phenylazo)-2-hydroxy-benzoic acid] were synthesized by reacting sodium salt of the ligand [Na2HL] with dimethyl or dibutyltin(IV) dichlorides in anhydrous methanol using2:1 metal-ligand ratio. The complexes were characterized by elemental analysis, UV, IR, 1H, 13C, 119Sn NMR spectroscopy, and Mass spectrometry techniques. The coordination geometry of the complexes was determined using 119Sn NMR spectroscopy and was found to be tetrahedral in the solution state. The molecular mass and the proposed structure of the complexes have been predicted by the molecular ion peaks in the EI-MS spectra of the complexes. The antibacterial activity of the complexes was investigated by screening against different bacteria with respect to the standard drug, Gentamycin.

Experimental and theoretical Judd-Ofelt intensity parameters Ω λ , rates of radiative A rad and nonradiative A nrad processes, and quantum efficiency of luminescence were calculated for a series of related aromatic and aliphatic carboxylates [Eu 2 (RCOO) 6 L 2 ] (L - 1,10-phenanthroline or 2,2′-bipyridine) using the LUMPAC software. The behavior of these characteristics in the sequence of europium carboxylates with the gradually changing distortions of the crystal field, which is mainly caused by variation in the bond lengths of the bridging-cyclic COO− groups with Eu3+ ion, was analyzed. A correlation between the changes in the value of the Ω 2 intensity parameter, the radiative rate A rad , and the ratio of metal-ligand bond lengths in the Eu coordination polyhedron was demonstrated. The dependence of the parameter Ω 2 on the distribution of metal-ligand orbital overlap among Eu-ligand bonds of the compound was revealed. The higher Ω 2 values in the set of aromatic carboxylates are associated with a more distorted nearest environment of the Eu3+ ion which is caused by the influence of the bulky R fragments. It is shown that the intensity of f-f transitions of the Eu3+ ion in the compounds under investigation is determined foremost by the dynamic coupling (DC) mechanism. The contribution of this mechanism to the parameters Ω 2 and Ω 4 is close to 100 %, its contribution to the Ω 6 parameter is 85–92 %. The luminescence quantum efficiency for the studied europium carboxylates varies in the range of 52–74 %. • Sequence of Eu carboxylates with gradually changing distortions of the crystal field. • Experimental and theoretical Judd-Ofelt analysis using LUMPAC software package. • Correlation between the values of Ω 2 intensity parameter, the radiative rate, and the distribution of Eu-ligand distances. • The dependence of Ω 2 on the distribution of Eu-ligand overlap among Eu-ligand bonds. • Predominance of the dynamic coupling mechanism. [ABSTRACT FROM AUTHOR]

Two polymorphs of the title tetrakis-substituted pyrazine carboxylic acid, 3,3′,3′′,3′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene))tetrakis(sulfanediyl]}tetrapropionic acid, C20H28N2O8S4, (H4L1), have been obtained, H4L1_A and H4L1_B. Each structure crystallized with half a molecule in the asymmetric unit of a triclinic P\overline{1} unit cell. The whole molecules are generated by inversion symmetry, with the pyrazine rings being located about inversion centers. The crystals of H4L1_B were of poor quality, but the X-ray diffraction analysis does show the change in conformation of the –CH2—S—CH2—CH2– side chains compared to those in polymorph H4L1_A. In the crystal of H4L1_A, molecules are linked by two pairs of O—H...O hydrogen bonds, enclosing R22(8) ring motifs forming layers parallel to plane (100), which are linked by C—H...O hydrogen bonds to form a supramolecular framework. In the crystal of H4L1_B, molecules are also linked by two pairs of O—H...O hydrogen bonds enclosing R22(8) ring motifs, however here, chains are formed propagating in the [001] direction and stacking up the a-axis. Reaction of H4L1 with Hg(NO3)2 in the presence of a potassium acetate buffer did not produce the expected binuclear complex, instead crystals of a potassium–organic framework were obtained, poly[(μ-3-{[(3,5,6-tris{[(2-carboxyethyl)sulfanyl]methyl}pyrazin-2-yl)methyl]sulfanyl}propanoato)potassium], [K(C20H27N2O8S4)]n (KH3L1). The organic mono-anion possesses inversion symmetry with the pyrazine ring being located about an inversion center. A carboxy H atom is disordered by symmetry and the charge is compensated for by a potassium ion. A similar reaction with Zn(NO3)2 resulted in the formation of crystals of a dipotassium-organic framework, poly[(μ-3,3′-{[(3,6-bis{[(2-carboxyethyl)sulfanyl]methyl}pyrazine-2,5-diyl)bis(methylene)]bis(sulfanediyl)}dipropionato)dipotassium], [K2(C20H26N2O8S4)]n (K2H2L1). Here, the organic di-anion possesses inversion symmetry with the pyrazine ring being located about an inversion center. Two symmetry-related acid groups are deprotonated and the charges are compensated for by two potassium ions.

• The thermogravimetric experiments of acid-base pretreated coals were studied. • Acid treatment can observably inhibit coal spontaneous combustion. • Alkali treatment promote CSC at low temperature but inhibit it at high temperature. • The effect of acid-base pretreatment on coal spontaneous combustion was discussed. The effect of inorganic salt ions on coal spontaneous combustion has been well revealed. However, the effect of organic metals on coal self-heating process has been paid little attention, which deserves further study. In this study, coals with different content of carboxylate were prepared by acid treatment, alkali treatment and re-acid treatment. The effect of acid-base pretreatment on the generation and oxidation of active sites was measured by pyrolysis-room temperature oxidation experiments. Thermal analysis and kinetic calculation, SEM-EDX, XPS, ESR were used to analyze the internal mechanism. The results show that the increase of free radicals (ΔNg) for the acid -pretreated coal during pyrolysis is 14.52 × 1018 spins/g, less than that of raw coal. The conversion of carboxylate structures to carboxylic acid structures by acid treatment significantly reduced the production of active sites, thus inhibiting coal self-heating behavior. The activation energy of alkali treated coal was 33.57 kJ/mol lower than that of raw coal, attributing to the conversion of carboxylic structures to carboxylate structures. The carboxylate structures can form coal matrix and Na binding structures (CM-Na) during the thermal decomposition process. The structure was able to constantly break and recombine due to its weak stability at low temperatures, accompanied by the generation of active sites, resulting in higher free radical concentration of 20.66 × 1018 spins/g. The research results have great value for investigating the mechanism of coal spontaneous combustion and providing an effective pathway to restrain the coal self-heating process. [ABSTRACT FROM AUTHOR]

Herein, the design, synthesis, supramolecular interactions and structural analysis of a novel bidentate carboxylate chelating N-heterocylic carbene (NHC) ligand is presented. The NHC structure was modified to strategically incorporate adamantyl moiety for the formation of a supramolecular complex with host molecules such as cucurbiturils. The adamantyl modified NHC ligand could potentially be used in recoverable homogeneous catalysts when Immobilized on a solid support via host–guest chemistry. As a versatile precursor, NHC ligand (8) was synthesized and characterized by 1H-NMR, 13C-NMR, FTIR, single crystal X-ray crystallography and elemental analysis. A proof-ofprinciple non-covalent immobilization of the NHC ligand (8) with a Cucurbit[7]uril (CB7) host was demonstrated using 1H-NMR titration. [ABSTRACT FROM AUTHOR]

Polynuclear coordination clusters can be readily arranged in cluster-based coordination polymers (CCPs) by appropriate bridging linkers. This review provides an overview of our recent developments in exploring structurally well-defined Mn/Fe-oxo pivalate and isobutyrate building blocks in the formation of CCPs assemblies with an emphasis on synthetic strategies and magnetic properties.

Summary: There is currently considerable interest in the prospects for bioengineering crassulacean acid metabolism (CAM) photosynthesis – or key elements associated with it, such as increased water‐use efficiency – into C3 plants. Resolving how CAM photosynthesis evolved from the ancestral C3 pathway could provide valuable insights into the targets for such bioengineering efforts. It has been proposed that the ability to accumulate organic acids at night may be common among C3 plants, and that the transition to CAM might simply require enhancement of pre‐existing fluxes, without the need for changes in circadian or diurnal regulation. We show, in a survey encompassing 40 families of vascular plants, that nocturnal acidification is a feature entirely restricted to CAM species. Although many C3 species can synthesize malate during the light period, we argue that the switch to night‐time malic acid accumulation requires a fundamental metabolic reprogramming that couples glycolytic breakdown of storage carbohydrate to the process of net dark CO2 fixation. This central element of the CAM pathway, even when expressed at a low level, represents a biochemical capability not seen in C3 plants, and so is better regarded as a discrete evolutionary innovation than as part of a metabolic continuum between C3 and CAM. [ABSTRACT FROM AUTHOR]

Plant root exudates serve pivotal roles in supporting plant development and interactions with the physicochemical and biological factors in the rhizosphere. Under stress conditions, root exudation is involved in enhancing plant resource-use efficiency and facilitating the crosstalk between plant and soil microbes to ameliorate stress. Although there are a large number of root exudates that remain to be characterized, recent technological advancements have allowed for the function of many exudate compounds to be elucidated. In this review, we discuss current knowledge about the key root exudates that modulate plant resource-use efficiency under various abiotic stresses including drought, aluminum toxicity, phosphorus, nitrogen, and iron deficiency. The role that key root exudates play in shaping microbial communities in the rhizosphere under stress conditions is also an important consideration addressed in this review. Root exudation plays important roles in plant interactions with soil chemical factors and belowground microorganisms that impact abiotic stresses. Carboxylate efflux is a key mechanism for plant phosphorus acquisition and tolerance to aluminum. Phenolics are utilized by dicots and non-graminaceous monocots while phytosiderophore exudation is used by grasses to mobilize iron for root uptake. Secondary metabolites such as flavonoids and strigolactones facilitate plant association with mycorrhizal fungi under drought and phosphorus-deficient conditions. Under nitrogen-limited conditions root exudates facilitate plant associations with nitrogen-fixing microbes and may reduce losses of soil nitrogen through inhibition of the bacteria involved in nitrification and denitrification. [ABSTRACT FROM AUTHOR]

Transition metal carboxylates with O- and N-donor ligands are interesting for their structural features. Seven novel isonicotinamide(inic)-based metal complexes of [Cd(inic)2(L1)2(H2O)2] · 2H2O (1) (L1 = 2-chloronicotinate), [Cd(inic)2(L2)2(H2O)2] (2) (L2 = 2,4-dichlorobenzoate), [Cu(inic)2(L3)2] (3) (L3 = 4-chlorophenoxyacetate), [Cu3(inic)6(L4)2(HL4)2(H2O)2] · 2H2O (4) (L4 = azelate), [Zn(inic)2(L1)2(H2O)2] · (inic) · H2O (5), [Zn(inic)(L5)(H2O)4] (6) (L5 = 3-nitrophthalate) and [Zn2(inic)2(L6)2] · 5H2O (7) (L6 = 1,4-cyclohexanedicarboxylate) have been obtained by the introduction of the carboxylates by the common solution method and are structurally featured by different techniques of EA, IR spectra, TG and SCXRD analysis. The X-ray studies told that these complexes display mononuclear to trinuclear structures with octahedral/square-pyramidal geometry around the Zn2+, trigonal bipyramidal/octahedral at the Cu2+ and octahedral for the Cd2+. The inic in 1–7 are coordinated only in monodentate fashion with its ring N, while 5 has the lattice inic. The carboxylates coordinated to the metal in monodentate, chelating bidentate and bridging bidentate fashions. The pair of complementary N-H···O H-bonds from the CONH2 of the inic were found in all compounds except 7. Except 1 and 2, all other compounds bear the CH-O contacts from the pyridine CH of the inic. The intricate intra- and intermolecular classical H-bonds, CH-N, CH-O, CH-Cl, CH2-O, O-N, O-O, Cl-O, Cl-Cl, CH-π, CH2-π, C-π, N-π, Cl-π and π-π associations are elucidated by the X-ray crystallographic studies, which push the discrete complexes into high-dimensional ordered supramolecular structures. [ABSTRACT FROM AUTHOR]

SCMNPs@Uridine/Zn is utilized as an environmental-friendly and efficient heterogeneous nanocatalyst for two one-pot four-component condensation reactions, containing hydrazine hydrate, arylaldehyde, ethyl acetoacetate, and barbituric acid to yield tricyclic fused pyrazolopyranopyrimidine derivatives (5a-q), and hydrazine hydrate, arylaldehyde, malononitrile, and dimethyl acetylenedicarboxylate/diethyl acetylenedicarboxylate to yield 3-methyl carboxylate substituted pyrano[2,3-c]pyrazole derivatives (8a-y) under solvent-free conditions with high to excellent yields. The main advantages of this process are easy work-up, short reaction times, no chromatographic purifications, and recyclability of the catalyst for a minimum of six runs without any significant decrease in yields of the products. Also, the prepared catalyst SCMNPs@Uridine/Zn was synthesized and fully characterized by various techniques including Fourier transform infrared spectroscopy (FT-IR), energy dispersive X-ray (EDX), thermogravimetric analysis (TGA), X-ray diffraction (XRD), vibrating sample magnetometer (VSM) and Raman spectroscopy.

A small series of 2,4-dioxothiazolidinyl acetic acids was prepared from thiourea, chloroacetic acid, aromatic aldehydes, and ethyl-2-bromoacetate. They were assayed for the inhibition of four physiologically relevant carbonic anhydrase (CA, EC 4.2.1.1) isoforms of human (h) origin, the cytosolic hCA I and II, and the transmembrane hCA IX and XII, involved among others in tumorigenesis (hCA IX and XII) and glaucoma (hCA II and XII). The two cytosolic isoforms were not inhibited by these carboxylates, which were also rather ineffective as hCA IX inhibitors. On the other hand, they showed submicromolar hCA XII inhibition, with KIs in the range of 0.30–0.93 µM, making them highly CA XII-selective inhibitors.

The reaction of AgNO3 with the ligand 2,2′,2′′,2′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetraacetic acid in the presence of a potassium acetate buffer lead to the formation of a silver(I)–potassium–organic framework, poly[dipotassium [(μ6-2,2′,2′′,2′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetraacetato)disilver(I)] 5.2-hydrate], {K2[Ag2(C16H16N2O8S4)]·5.2H2O}n, (I). The asymmetric unit is composed of half a binuclear silver complex located about a center of symmetry, a potassium cation and 2.6 disordered water molecules. The whole binuclear silver complex is generated by inversion symmetry with the pyrazine ring being located about an inversion centre. The ligand coordinates in a bis-tetradentate manner. The binuclear silver complex anions are linked via bridging Ag...S...Ag zigzag bonds, forming a network lying parallel to the bc plane. The networks are linked by Ocarboxylate...K+...Ocarboxylate bridging bonds to form a framework. The disordered water molecules are present near to the K+ cations.

This review considers the applications of Zn(II) carboxylate-based coordination polymers (Zn-CBCPs), such as sensors, catalysts, species with potential in infections and cancers treatment, as well as storage and drug-carrier materials. The nature of organic luminophores, especially both the rigid carboxylate and the ancillary N-donor bridging ligand, together with the alignment in Zn-CBCPs and their intermolecular interaction modulate the luminescence properties and allow the sensing of a variety of inorganic and organic pollutants. The ability of Zn(II) to act as a good Lewis acid allowed the involvement of Zn-CBCPs either in dye elimination from wastewater through photocatalysis or in pathogenic microorganism or tumor inhibition. In addition, the pores developed inside of the network provided the possibility for some species to store gaseous or liquid molecules, as well as to deliver some drugs for improved treatment.

Reaction of the ligand 2,2′,2′′,2′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetraacetic acid (H4L1), with NiCl2 leads to the formation of a binuclear complex, (μ-2,2′,2′′,2′′′-{[pyrazine-2,3,5,6-tetrayltetrakis(methylene)]tetrakis(sulfanediyl)}tetraacetato-κ5O,S,N1,S′,O′:κ5O′′,S′′,N4,S′′′,O′′′)bis[aquanickel(II)] heptahydrate, {[Ni2(C16H16N2O8S4)(H2O)2]·7H2O} (I). It crystallizes with two half molecules in the asymmetric unit. The complete molecules are generated by inversion symmetry, with the center of the pyrazine rings being located at crystallographic centres of inversion. The ligand coordinates two NiII ions in a bis-pentadentate manner and the sixfold coordination sphere of each nickel(II) atom (NiS2O3N) is completed by a water molecule. The complex crystallized as a hepta-hydrate. The binuclear complexes are linked by Owater—H...Ocarbonyl hydrogen bonds, forming layers parallel to the (101) plane. This layered structure is additionally stabilized by weak C—H...O hydrogen bonds. Further O—H...O hydrogen bonds involving binuclear complexes and solvent water molecules, together with weak C—H...S hydrogen bonds, link the layers to form a supramolecular framework.

The assembly of hydrogen bonded cages using amidinium...carboxylate hydrogen bonding interactions was investigated. A new tris-amidinium hydrogen bond donor tecton based on a tetraphenylmethane scaffold was prepared and its selfassembly with the terephthalate anion studied, and a new tricarboxylate hydrogen bond acceptor tecton was synthesised and its assembly with the 1,3-benzenebis(amidinium) hydrogen bond donor explored. In both cases, molecular modelling indicated that the formation of the cages was geometrically feasible and 1H NMR spectroscopic evidence was consistent with interactions between the components in competitive d6-DMSO solvent mixtures. DOSY NMR spectroscopy of both systems indicated that both components diffuse at the same rate as each other, and diffusion coefficients were consistent with cage formation, and with the formation of assemblies significantly larger than the individual components. An X-ray crystal structure showed that one of the assemblies did not have the desired cage structure in the solid state. [ABSTRACT FROM AUTHOR]

Coordination compounds of various nickel(II) carboxylates (valerate, benzoate, phthalate, maleate, fumarate) with salicyl hydrazide have been synthesized and studied by IR spectroscopy. The crystal structure of the complex of nickel(II) phthalate with salicyl hydrazide [NiL3]Pht (L is salicyl hydrazide, Pht2– is phthalic acid dianion) has been determined by X-ray diffraction. The structural units of the crystal are complex cations [NiL3]2+ and phthalic acid anions Pht2– joined together by cation–anion N–H...O, O–H...O hydrogen bonds. The nickel atom has distorted octahedron coordination formed by three oxygen and three nitrogen atoms of the three bidentate-chelate ligands L (Ni–O 2.027–2.059, Ni–N 2.067–2.097 Å). [ABSTRACT FROM AUTHOR]

The crystal structure of the product of the neutralization reaction between 3-nitrobenzoic acid and pyridine is reported. The entities that crystallized are a pyridinium cation, a 3-nitrobenzoate anion and a 3-nitrobenzoic acid molecule in a 1:1:1 molar ratio, C5H6N+·C7H4NO4−·C7H5NO4. Distinct sets of hydrogen bonds link the pyridinium and benzoate ions (N—H...O) and the acid and benzoate moieties (O—H...O). The hydrogen bonding along with π–π stacking between the acid and benzoate moieties accounts for the long-range ordering of the crystal.