Polymeric Chain Structure Research Articles

Azido derivatives of dinuclear copper(II) and 1D polynuclear nickel(II) complexes containing an unsymmetrical bidentate amine: synthesis, crystalline architecture, and magnetic behavior

Dinuclear copper(II) complex [Cu2(L)2(μ2-1,1-N3)2(N3)2] (1) with double μ1,1-azido bridges and polynuclear nickel(II) complex [Ni(L)(μ2-1,1-N3)(μ2-1,3-N3)]n (2) with alternate double μ1,1-azido and μ1,3-azido bridges [L = 1-amino-2-(dimethylamino)ethane, N 3 − = azide ion] have been synthesized and were characterized by physicochemical and spectroscopic methods. X-ray structural analysis revealed that each Cu(II) center of 1 adopts a distorted square-pyramidal geometry with a CuN5 chromophore ligated through two N atoms of L, two N atoms of double bridging (μ1,1-N3), and one N atom of terminal azide ion. On the other hand, each Ni(II) center around the asymmetric unit of 2 adopts a distorted octahedral geometry with a NiN6 chromophore ligated through two N atoms of L, two N atoms of double μ1,1-N3, and two N atoms of double μ1,3-N3 bridges. The adjacent nickel centers are connected to alternate double μ1,1-N3 and double μ1,3-N3 bridges, affording a one-dimensional (1D) polymeric chain structure. Temperature-dependent magnetic susceptibility measurements evidenced a dominant antiferromagnetic interaction between the metal centers of both complexes 1 and 2.

A nitrate bridged one-dimensional copper(II) coordination polymer with a tridentate (NNO) Schiff base: synthesis, X-ray structure and catalytic efficacy

A one-dimensional Cu(II) coordination polymer of [Cu(L)(μ-ONO2)]n (1) (HL = 4-methoxy-2-[1-(methylaminoethylimino)methyl]-phenol) with bidentate bridging nitrate has been isolated and characterized by X-ray diffraction analysis and spectroscopic studies. Single crystal X-ray analysis revealed that each copper(II) center in the asymmetric unit of complex 1 adopts a distorted square pyramidal geometry with a CuN2O3 chromophore ligated through a tridentate Schiff base (L) with (NNO) donor sets and two O atoms of bridging nitrate ion. The adjacent copper atoms are connected by bridging nitrate (μ-ONO2) in bidentate fashion affording a 1D coordination polymeric chain structure along the crystallographic b-axis. In the polymeric framework, the Cu…Cu separation is 4.3749(4) A. The catalytic efficacy of complex 1 was studied in a series of solvents for the epoxidation of cyclooctene using tert-butyl-hydroperoxide (TBHP) as an efficient oxidant under mild conditions. The catalytic reaction mixture was analyzed by gas chromatography and the data indicated that the yield of the epoxidation reaction and its selectivity is maximum in acetonitrile medium.

Polymeric layer framework and chain structure of two three-component cadmium and copper phosphonates embedded with pyrazine

Two metal phosphonate coordination polymers, [Cd2(H4tpmm)2(pz)2]n (1) and {[Cu2(H4tpmm)2(pz)2(H2O)4]·5H2O}n (2), have been synthesized from the self-assembly reactions of 2,4,6-tris(phosphorylmethyl)mesitylene (H6tpmm) with Cd(ClO4)2·6H2O or Cu(NO3)2·3H2O by introducing pyrazine (pz) as ancillary ligand. Cadmium phosphonate 1 possesses a layer framework, in which the two crystallographic distinct Cd(II) centers show two different coordination environments, one of which has a {CdO4N2} octahedral geometry in an approximately regular manner and the other suits a {CdO3N2} square pyramidal geometry. Copper phosphonate 2 displays a chain structure, in which the two crystallographic distinct Cu(II) centers both have the same {CuO4N2} octahedrons but distort in different ways; one is in a Jahn–Teller distortion while the other is in a rhombic distortion. For both Cd(II) and Cu(II) complexes, the pz ligand can be regarded to be embedded into the extended metal phosphonate architectures and form remarkable C–H … π interactions with the phenyl rings of the H4tpmm2− ligands, which cooperate with O–H⋯O hydrogen-bonding interactions in providing supports for stabilization. Thermogravimetric analysis reveals that 1 and 2 both are highly thermally stable with a decomposition process occurred at a temperature approaching 375 and 405 ​°C, respectively. The luminescence properties of 1 have also been studied.

Crystal Structures and Phosphorescent Properties of Group 14 Dipyridinometalloles and Their Copper Complexes.

We recently reported dipyridinosilole (DPyS) and dipyridinogermole (DPyG) as π-conjugated units that show low-temperature phosphorescence. A copper complex of DPG shows solid-state phosphorescence at room temperature. In this work, we prepared diphenyldipyridinostannole (DPySn1). Its optical and electrochemical properties were investigated and compared with those of DPyS1 and DPyG1 with the same phenyl substituents. DPySn1 showed the most red-shifted phosphorescence at 520 nm at 77 K in the solid-state, which is likely due to the intermolecular Sn-pyridine interaction that was confirmed by single-crystal X-ray diffraction. Copper complexes of DPyS1 and DPySn1 were also prepared and it was found that the phosphorescence of these dipyridinometallole-copper complex solids was red-shifted in the order of DPySn1-Cu (617 nm)<DPyG1-Cu (624 nm)<DPyS1-Cu (645 nm). Single-crystal X-ray diffraction studies were performed for DPyS1-Cu and DPySn1-Cu complexes. DPyS1-Cu showed a double-chained polymeric ladder-like structure with Cu4 I4 cluster units and DPySn1-Cu possessed a single chain polymeric structure with Cu2 I2 units, analogous to DPyG1-Cu.

Amorphous molybdenum sulfide monolayer nanosheets for highly efficient electrocatalytic hydrogen evolution

Monolayer amorphous molybdenum sulfide (ML-a-MoSx) nanosheets were synthesized via a space-confined strategy, and their electrocatalytic activity was evaluated towards the hydrogen evolution reaction. The so-obtained ML-a-MoSx, with a quite high monolayer ratio of ~ 93%, shows a polymeric chain or network structure consisting of trinuclear [Mo3] clusters, with abundant Mo defects. ML-a-MoSx exhibits much higher activity in comparison with bulk a-MoSx (B-a-MoSx), and is superior among the Mo-S electrocatalysts reported to date. In particular, ML-a-MoSx can deliver a high current density of 400 mA cm−2 at an overpotential of 230 mV vs. RHE, which is similar to the state-of-the-art catalyst commercial 20% Pt/C. The Tafel slope of ML-a-MoSx remains almost unchanged with an increase in overpotential, very conducive to practical applications. The higher electrocatalytic activity of ML-a-MoSx than B-a-MoSx results from its larger specific surface area, higher active site density, stronger conductivity, and faster turnover frequency. The active sites of ML-a-MoSx are identified as Mo defects. This is the first report on the fabrication and catalytic activity of ML-a-MoSx. This work provides an effective route for large-scale fabrication of ML-a-MoSx and contributes to the understanding of the origin of its excellent electrocatalytic activity.

Feasibility of Fuel Synthesized from Solid Plastic Wastage

The growing human population is increasing the consumption of fuels day by day in order to fulfill the requirement of human activities. This demand is also resulted in hiking the fuel prices. Also, the electric vehicles have not so far able to impress the market since their prices are comparatively higher than their counterparts that is motor fuel vehicles and hence isn't the first choice for people. Also, the rapid growing human population has introduced other problems like pollution and waste produced by humans from different activities like construction, household, industrial, etc. One of the most common waste produced in a large quantity is plastic which is nonbiodegradable. Existing way to deal with the plastic is to recycle it which itself produces toxic wastes. As an alternative pyrolysis method can be applied by treating the solid plastic wastage thermally which will break the long polymeric chain structure of the plastic. This will result in the conversion of plastic into hydrocarbon fuels like jet fuel, kerosene, gasoline, auto-gas and other inflammable products which can be used in aerospace industries, general transportation sector, thermal power plants and other industrial sectors. Different types of fuels with different properties can be obtained from different grades of plastics.

Effect of side branch on gas separation performance of triptycene based PIM membrane: A molecular simulation study

In this study ab initio calculations, molecular dynamics (MD) and Monte Carlo (MC) simulation techniques are used to investigate the structural properties of triptycene based polymers of intrinsic microporosity (PIMs), consisting of polyimide branched with the side groups: C4H9, C3H7, CH3 and CF3, to evaluate their performance as polymeric membrane for separation of gases, O2, N2, CO2, CH4 and H2S, which are the constituents of natural gas and their separation is of high industrial interest. In the course of MD simulation, initially, the branched polyimide membranes are built to obtain the PIMs' model. Then the low-density membrane models undergo a consecutive simulation procedure of compression and relaxation to achieve the experimental density of equilibrated membrane. The structure of the constructed membranes is analyzed by calculating: dihedral angles, radius of gyration, fractional free volume, accessible free volume, cavity size distribution, and surface area. The behavior of the membranes against penetration and permeation of the studied gases is determined by evaluating the diffusion and solubility coefficients of the gases and by employing MD and MC simulation techniques, respectively. Comparison of the structural properties of the membranes shows that the PIM membranes with larger side branch groups in their polymeric chain structure are more rigid and therefore, due to restriction in chain packing and cavity formation between polymer chains, the free volume in the membrane's structure increases which as a result would promote the diffusion and permeation of gases into the membrane, where, the obtained results indicate that the membrane with C4H9, as the largest side branch in its polymer chain, has the greatest diffusivity and permeation. Also, the highest selectivity for all studied binary gas mixtures is manifested by the PIM membrane with C4H9 at its side branch, however, for (CO2/CH4) and (H2S/CH4) binary mixtures CF3 as the side branch of PIM membrane represents an acceptable selectivity. The obtained results illustrate that in addition to the membrane free volume, other parameters are influential in gas separation by these polymeric membranes which require further consideration. These parameters include gas adsorption, specific surface area of the membrane for adsorption, the size of gas molecules and their interaction with the PIM membranes which need to be investigated and discussed in the light of the obtained results. To the best of knowledge, based on a thorough investigation of the literature, no similar work can be cited which includes detailed properties of PIM membranes at the atomic scale by using quantum mechanical and simulation techniques in order to elucidate the behavior of PIMs for gas separation.

Synthesis and Structural Characterization of a New Two-Dimensional Polymeric Hybrid Material {[Cu&amp;lt;SUB&amp;gt;3&amp;lt;/SUB&amp;gt;(&amp;lt;i&amp;gt;μ&amp;lt;/i&amp;gt;&amp;lt;SUB&amp;gt;3&amp;lt;/SUB&amp;gt;-1,2,3-BTC)(&amp;lt;i&amp;gt;μ&amp;lt;/i&amp;gt;&amp;lt;SUB&amp;gt;2&amp;lt;/SUB&amp;gt;-1,2,3-BTC)(en)&amp;lt;SUB&amp;gt;3&amp;lt;/SUB&amp;gt;(OH&amp;lt;SUB&amp;gt;2&amp;lt;/SUB&amp;gt;)&amp;lt;SUB&amp;gt;2&amp;lt;/SUB&amp;gt;(OH)(&amp;lt;i&amp;gt;μ&amp;lt;/i&amp;gt;&amp;lt;SUB&amp;gt;2&amp;lt;/SUB&amp;gt;-OH&amp;lt;SUB&amp;gt;2&amp;lt;/SUB&amp;gt;)]&amp;lt;SUB&amp;gt;2&amp;lt;/SUB&amp;gt;&amp;#183;5H&amp;lt;SUB&amp;gt;2&amp;lt;/SUB&amp;gt;O&amp;#183;O}&amp;lt;SUB&amp;gt;n&amp;lt;/SUB&amp;gt;

The reaction of benzene-1,2,3-tricarboxylate copper(II) trihydrate (Cu3(1,2,3-BTC)2·3H2O) and ethylenediamine (en) gave after recrystallization from methanol at room temperature violet crystalline solid of the polymeric two dimensional material {[Cu3(μ3-1,2,3-BTC)(μ2-1,2,3-BTC)(en)3(OH2)2(OH)(μ2-OH2)]2·5H2O·O}n (1) as identified by single crystal X-ray diffraction analysis. The compound was also characterized by elemental analysis, FT-IR spectroscopy, UV-vis spectroscopy, thermogravimetric analysis (TGA) and magnetic susceptibility. The molecular structure indicates crystallization in the triclinic space group P-1 with the unit cell parameters a = 12.1205(3) Å, b = 12.7026(3) Å, c = 13.9890(3) Å, α = 75.034(1)°, β = 74.957(1)°, γ = 68.415(1)°. Structural analysis also revealed that the dimeric compound is connected by Cu-O-Cu bridges and the dimer is further converted into a polymeric chain structure through bridging of one benzene-1,2,3-tricarboxylate ligand. Different coordination modes are observed at the copper atom. The Cu atom at the center is octahedral while the two other ones are pentacoordinated. Thermal analysis of the compound showed decomposition processes, while magnetic studies indicated a magnetic susceptibility μ of 3.21 BM.

From solid state to in vitro anticancer activity of copper(II) compounds with electronically-modulated NNO Schiff base ligands.

The copper(ii) complexes of general formula [Cu(GL)(Cl)] (1-3, G = OMe, H and NO2, respectively), bearing tridentate Schiff base ligands (GL-) and a chloride as a fourth labile one, are here reported. The Schiff bases derive from the monocondensation of ethylenediamine and substituted salicylaldehyde, where the electronic properties are modulated by the releasing or withdrawing power of the G group. The compounds were structurally characterized through single crystal Synchrotron X-ray diffraction experiments in the solid state, revealing that 1 (OMe) and 2 (H) adopt a dimeric assembly [Cu(μ-Cl)(GL)]2 through apical interaction of the chloride ions of two monomeric units, while 3 embraces a 1D polymeric chain structure [Cu(μ-Cl)(NO2L)]n with a similar bridging fashion, all supported by extended intramolecular or intrachain hydrogen bonds. The redox properties of the complexes were also studied by cyclic voltammetry with no marked effect of the substituent on the potential of the CuII/CuI redox system. UV/Vis spectroscopic studies in mimicked physiological conditions highlighted the intactness and stability of the coordinated NNO tridentate ligand in 1-3 and the lability of the coordinated chloride ion with the formation of the aquo-complexes [Cu(GL)(H2O)]+ in aqueous solution, as confirmed by conductance measurements with a 1 : 1 electrolyte molar conductivity. In vitro tests on cell viability were conducted on malignant cell lines typical for their poor prognosis and curability, revealing time-dependent and differential cytotoxicity given by the substituent G. All compounds were capable of formation of intracellular reactive oxygen species and DNA intercalation, acting as nuclease and producing double-strand DNA breaks. This is especially effective for 3 (NO2), which revealed the highest anticancer activity against malignant triple-negative breast cancer MDA-MB-231 cells, with a two-to-four-fold cytotoxicity enhancement with respect to 1 (OMe) and 2 (H), and, most important, substantial differentiation of cytotoxicity with respect to healthy endothelial HUVEC cell line.

Characterization and Thermal Behavior of the Iron Dietary Supplement Ferrous Glycine Sulfate Pentahydrate

Ferrous glycine sulfate pentahydrate [Fe(glycine)(SO4)·5H2O with glycine = C2H5NO2], contained in the supplement for treating iron deficiency anaemia, commercially known as ferro sanol duodenal®, was characterized by laboratory X‐ray powder diffraction (XRPD), scanning electron microscope (SEM), and infrared spectroscopy (IR). The thermal behavior was investigated by thermal analysis (TGA and DTA) and temperature‐dependent in situ XRPD measurements. Furthermore, the phase transitions to a less hydrated form [Fe(glycine)(SO4)·3H2O] and successively to the anhydrous form were demonstrated to occur in the crystalline solid state. Compared to the crystal structure of the pentahydrate, the trihydrate exhibits a different coordination environment of the iron sites where glycine ligands bridge iron forming a 1D polymeric chain structure. From detailed structural comparison, the mechanism of the phase transitions can be concluded.

Complexation of Cobalt(II), Nickel(II), Copper(II), and Zinc(II) Hexafluorosilicates with Nicotinamide in Aqueous Solution

The new complexes [M(NA)2(H2O)4]SiF6 ⋅ 2H2O, where M2+ = Co, Ni, Zn (complexes I, II, and III, respectively), and NA = C6H6N2O is nicotinamide, [Cu(NA)2(SiF6)(H2O)2] ⋅ 2H2O (IV), and (HNA)2SiF6 (V) have been synthesized from aqueous solutions and studied by chemical, IR spectroscopic, and X-ray diffraction analyses. Their unit cell parameters are a = 16.2448(18) A, b = 6.8834(8) A, c = 10.0767(11) A, β = 102.765(3)°, V = 1098.92 A3, space group C2 for I; a = 16.1591(7) A, b = 6.8777(3) A, c = 10.0314(5) A, β = 102.410(1)°, V = 1088.82 A3, space group C2 for II; a = 16.2265(6) A, b = 6.8965(3) A, c = 10.0696(5) A, β = 102.390(1)°, V = 1100.60 A3, space group C2 for III; a = 6.5915(4) A, b = 7.7670(4) A, c = 10.1506(5) A, α = 110.7390(10)°, β = 105.824(2)°, γ = 95.448(2)°, V = 456.868 A3, space group P $$\overline{1}$$ for IV; and a = 14.1904(7) A, b = 9.0468(4) A, c = 11.8160(7) A, β = 106.277(2)°, V = 1456.1 A3, space group C2/c for V. Complexes I–III are isostructural and represent ionic compounds formed by hexafluorosilicate anions and complex cations. The coordination polyhedron of the metal is a slightly distorted octahedron built of the O atoms of four coordinated water molecules and the two N atoms of two pyridine rings of two nicotinamide molecules in trans positions of the polyhedron. Complex IV has a polymeric chain structure. The coordination polyhedron of the copper cation represents an octahedron, which is elongated along its axis and built of the two N atoms of two pyridine rings of two nicotinamide molecules, the two O atoms of coordinated water molecules, and the two F atoms of hexafluorosilicate anions acting as bridges between neighboring cations. In the structure of complex V, the nitrogen atom of the pyridine ring HNA+ is protonated. The geometry of hexafluorosilicate anions is identical in all the five complexes. The structures have branched networks of hydrogen bonds.

The Optical Band-Gap Evolution in Perovskite-Like Hybrid Iodobismuthates Effected by Nuclearity and Dimension: An Experimental and DFT Calculation Study

Three new perovskite-like hybrid iodobismuthates with two quaternary ammonium cations, namely (BnNEt3)3(Bi2I9) (1) (BnNEt3)4(Bi4I16) (2) and (n-Bu4N)2n(Bi4I14)n (3) (Bn = benzyl, n-Bu = n-butyl), have been synthesized by reacting BiI3 with the quaternary ammonium iodide in molar ratio 2:3 (1), 1:1(2), and 2:1 (3), respectively. All hybrids were characterized by elemental analysis, X-ray diffraction and UV–Vis spectroscopic analysis. Single-crystal X-ray diffraction revealed that hybrids 1 and 2 are di-nuclear and tetra-nuclear cluster structures respectively, while 3 is a polymeric chain structure based on a (Bi4I14) tetra-nuclear cluster unit. Their optical band-gaps have been determined as 2.19 eV(1), 2.16 eV(2), 2.02 eV(3), respectively. The optical band gaps exhibit a structure-related decrease from 1 to 3, in agreement with their color changes and the density functional theory (DFT) calculation results. The DFT calculations also reveal that there is a inversely proportional relationship between the optical Eg and the aggregation degree of the BiI6 octahedra in the hybrid iodobismuthate clusters.

Spectroscopic and single‐crystal X‐ray diffraction studies of enantiomeric copper(II) Schiff base one‐dimensional coordination polymers with 4‐(2‐aminoethyl)benzenesulfonamide appendage: Comprehensive biological evaluation (DNA binding, cleavage, superoxide dismutase mimetic activity, topoisomerase I inhibition and cytotoxicity)

New chiral Cu(II)‐based one‐dimensional coordination polymers [l‐C25H27CuN3O6S] (1a) and [d‐C25H27CuN3O6S] (1b) were designed and synthesized by in situ reaction of Schiff base (o‐vanillin and l‐/d‐phenylalanine) and appended ligand 4‐(2‐aminoethyl)benzenesulfonamide incorporated with Cu(II) ion. The enantiomeric complexes 1a and 1b were fully characterized using various spectroscopic techniques and single‐crystal X‐ray diffraction studies. The enantiomeric analogues 1a and 1b crystallized in chiral monoclinic P21 space group with z = 2 exhibiting a distorted square pyramidal environment around Cu(II) metal centre coordinated to N2O3 donor atoms with apical position occupied by adjacent bridging carboxylate oxygen, resulting in one‐dimensional polymeric chain structures. Comprehensive biological studies of 1a and 1b (DNA binding, superoxide dismutase (SOD), topoisomerase I and cytotoxic activity) were performed which revealed that 1a showed better prospects as a therapeutic drug candidate as compared to 1b as quantified by their comparative DNA binding (Kb, K and Ksv values), SOD mimetic activity (IC50 values of 0.160 and 0.198, respectively) and anticancer properties.

Exploration of organotin(IV) derivatives for medicinal applications: Synthesis, spectroscopic characterization, structural elucidation and molecular docking study

Organotin (IV) derivatives of carboxylate ligand, 4-(4-methoxyanilino)-4-oxobutanoic acid, have been synthesized and characterized by FTIR, NMR, CHN analysis, mass spectrometry and X-ray crystallography. Single crystal data of four compounds (1–4) displayed a distorted trigonal bipyramidal environment around Sn with the three equatorial positions occupied by alkyl group. In compounds 1–3, carboxylate oxygens of ligand play the role of a bridge between the adjacent tin atoms symmetrically giving a polymeric chain structure. In compound 4, oxygen of the amide carbonyl moiety perform the same function and bridges the adjacent tin atoms [SnO = 2.155 (3) and 2.428 (3) Å, respectively], with the three phenyl ipso-C atoms defining the trigonal plane and the axial positions occupied by O atoms [O1SnO3 = 177.62 (11) Å]. The τ values calculated for complexes 1–4 are 0.78, 0.77, 0.82 and 0.92, respectively, also confirm the trigonal bipyramidal geometry. The antimicrobial results of the synthesized compounds illustrate their use as a potential antimicrobial agent. The DNA interaction study performed by UV–visible spectroscopy as well as by molecular docking suggests the tested compounds interact with DNA through intercalation mode. The compounds were screened for anticancer activity performed against lung carcinoma and Vero cell lines resulting in activity that is almost equivalent to that of the standard, vincristine. The biological significance of these compounds is that there affect on the normal cell line is very small i.e., <27.1%. The compounds also exhibit good inhibition of urease enzyme. A good correlation was observed between the docking scores and biological activities of these compounds.

Crystal Structure of DL-Valinium Tetrafluoroantimonate(III) Monohydrate

The crystal structure of an antimony(III) fluoride complex of the composition (C5H12NO2)SbF4·H2O (I) involving a cation of α-amino isovaleric acid (DL-valine, Val) is determined. Crystals are monoclinic: a = 12.2024(2) A, b = 6.1636(1) A, c = 15.5167(3) A, Z = 4, space group P21/c. The structure is formed of DL-valinium (C5H12NO2)+ cations, complex [SbF4]nn− anions having a polymeric chain structure, and crystallization water molecules. The [SbF4]nn− complex anions consist of trigonal SbF4E bipyramids joined together by asymmetric bridging Sb–F(3)···Sb bonds. The structural units are organized into a threedimensional framework via N–H···F, N–H···O, and O–H···F hydrogen bonds.

Formation and structural characterization of a potassium amidino-guanidinate.

The first potassium amidino-guanidinate complex, catena-poly[[bis-(μ-1-amidinato-N,N',N'',N'''-tetra-iso-propyl-guanidinato-κ5 N 1:N 1,N 2:N 2,N 4)dipotassium]-μ-1,2-di-meth-oxy-ethane-κ2 O:O'], [K2(C14H32N4)2(C4H10O2)] n or [{ i PrN= CHN( i Pr)N(N i Pr)2K}2(μ-DME)] n where DME is 1,2-di-meth-oxy-ethane, has been synthesized and structurally characterized. The title compound was isolated in 76% yield from a reaction of N,N'-diiso-propyl-carbodi-imide with potassium hydride in DME. The single-crystal X-ray structure determination of the title compound revealed a polymeric chain structure comprising cage-like dimeric units, with the amidino-guanidinate ligand displaying a mixed σ-/π-coordination mode.

Thermal properties and ion mobility in the antimony(III) fluoride complexes with DL–valine (C5H12NO2)SbF4·H2O and DL–serine (C3H8NO3)Sb2F7. Crystal structure of (C5H12NO2)SbF4·H2O compound

Fluoride complexes of antimony(III) with amino acids (DL–valine and DL–serine) of the compositions (C5H12NO2)SbF4·H2O (I) and (C3H8NO3)Sb2F7 (II) have been synthesized. The crystal structure of the (C5H12NO2)SbF4·H2O compound (monoclinic syngony, Z = 4, space group P21/c) has been determined for the first time. The structure of I is composed of cations of DL-valinium ((C5H12NO2)+), complex [SbF4]nn– anions having a polymeric chain structure, and crystallization water molecules. Thermal properties and ionic mobility in fluoroantimonates I and II were studied by the DSC and NMR (1H, 19F) methods. It has been established that irreversible endo-effects on DSC curves at 351 and 385 K for the compounds I and II, respectively, are related to formation of X-ray-amorphous phases. In the complex I, ionic mobilities in fluoride and proton sublattices with frequencies above 104 Hz are absent in the studied temperature range (150–420 K), whereas the ions diffusion is observed in both sublattices of II at 320 K. The mechanisms of emergence of ions diffusion in sublattices of the compound II were suggested.

Mechanochemical synthesis of binary phosphorus telluride: Short range structure and thermal properties

A binary phosphorus telluride sample (20 at% Te) was synthesized by mechanochemical solid state reaction from elemental powders. The X-ray diffraction pattern and neutron total structure factor show no detectable Bragg peaks, indicating that the sample is amorphous with respect to X-ray and neutron diffraction. The neutron and X-ray total pair distribution functions show correlation peak arising from PTe heteropolar bonds in addition to those arising from PP and TeTe bonds. The TeTe bond length is slightly shorter than that in the crystal structure of trigonal tellurium, suggesting a different environment from a polymeric chain structure. The thermal analysis results show that the binary phosphorus telluride is thermally unstable, that is, it decomposes above 200 °C into trigonal tellurium crystals and gaseous phosphorus, where phosphors begins to gasify at a lower temperature than the sublimation temperature of red phosphors.

H-bond assisted coordination bond formation in the 1D chains based on azido and phenoxido bridged tetranuclear Cu(II) complexes with reduced Schiff base ligands

Two new 1D chains [(CuL1R)2Cu2(N3)2(μ1,1,3-N3)2]n (1) and [{(CuL2R)2Cu2(N3)2(μ1,1,3-N3)2}·(CH3)2CO]n (2) based on rare μ1,1,3-N3 bridged tetranuclear Cu(II) complexes, have been synthesized using [CuL1R] and [CuL2R] as “metalloligands” [where H2L1R = N,N′-bis(2-hydroxybenzyl)-1,3-propanediamine and H2L2R = N,N′-bis(2-hydroxybenzyl)-1,2-ethylenediamine]. Both complexes have been characterized by elemental analysis, spectroscopic methods, single crystal XRD, and magnetic study. In case of chain 1, the basic building block is a centrosymmetric tetranuclear unit whereas for 2, it is an asymmetric tetranuclear unit containing two types of square pyramidal Cu(II) centers (terminal and central). The μ1,1-N3 bridged central copper atoms of one tetranuclear unit are connected weakly to the axial position of the terminal copper atoms of neibouring units via the azide ions forming a rare μ1,1,3-N3 bridged novel 1D polymeric chain structure. Variable temperature magnetic susceptibility measurements show the presence of an overall strong antiferromagnetic exchange interactions mediated through the double phenoxido bridges with J values of −123.8 and −144.6 cm−1 for 1 and 2, respectively.

Synthesis, characterization and catalytic studies of two Ni(II) complexes of pentane-2,4-dionate

Abstract Two nickel(II) complexes, [Ni(acac) 2 (dmpeO 2 )] n ·2CHCl 3 ( 1 ) and [(Ni(acac)(MeO)(MeOH)] 4 ( 2 ) (acac − = pentane-2,4-dionato) have been synthesized and characterized by elemental analysis, FT-IR spectroscopy, and single crystal X-ray diffraction. The geometries around the central nickel(II) ion are distorted octahedral in both complexes. The equatorial plane includes four oxygen donor atoms of two acetylacetonato ligands and the axial positions are occupied by two oxygen atoms of two dmpeO 2 ligands. Complex 1 has a polymeric chain structure in the solid state, while complex 2 has a tetranuclear cubane structure. These complexes are the first reported examples of polymeric and tetranuclear structures of Ni((II) containing acac - ligand. Neither complex is catalytically active for the hydrogenation of CO 2 to formamide, even though a mixture of Ni(acac) 2 and dmpe form a very active in situ catalyst together.