Structural diversity of a series of chlorocadmate(II) and chlorocuprate(II) complexes based on benzylamine and its N-methylated derivatives

Protonated benzylamine and its N-methylated derivatives, [C₆H₅CH₂NH_3?n(CH₃)_n]⁺ (n?=?0?3), have been adopted as cations in chlorocadmate(II) and chlorocuprate(II) complexes, showing inorganic–organic hybrid architectures. For the Cd(II) compounds, the anionic structures vary from perovskite-type layers (n?=?0) to chains (n?=?1–3). For Cu(II) compounds, the anionic structures range from perovskite-type layers (n?=?0), chains (n?=?1) to mononuclear species (n?=?2–3). Coordination geometries of the metal ions and intermolecular interactions have been analyzed. Their dielectric properties have been measured.     

A cyanide-containing cobalt(III) complex [Co(phen)2(CN)2][Co(phen)(CN)4]·4.5H2O: hydrothermal synthesis,crystal structure and spectroscopic properties

A cyanide-containing cobalt(III) complex, [Co(phen)₂(CN)₂][Co(phen)(CN)₄]?·?4.5H₂O (1: phen?=?1,10-phenanthroline) has been synthesized by hydrothermal techniques and characterized by elemental analyses, IR spectroscopy, UV–vis spectroscopy and single-crystal X-ray diffraction methods. The complex is triclinic, space group P 1 , with a?=?11.0047(16), b?=?12.9587(19), c?=?15.076(2)?Å, α?=?100.060(2), β?=?102.061(2), γ?=?91.803(2)°, V?=?2065.0(5)?ų, Z?=?2, and R ₁ [I?>?2σ(I)]?=?0.0481. The molecular unit of 1 consists of a cation/anion pair with interstitial water molecules in the crystal lattice. The combination of coordinative, hydrogen bonding and π–π stacking interactions results in the stabilization of a supramolecular solid-state architecture.     

One-pot synthesis of cis-bis(2,2′-bipyridine)carbonylruthenium(II) complexes from a carbonato precursor: X-ray crystal structures and electron transfer processes of the series complexes

The reaction of Brønsted acids with cis-[Ru(bpy)₂(CO₃)] (bpy?=?2,2′-bipyridine) under CO results in cleavage of the carbonato ligand and formation of cationic cis-[Ru(bpy)₂(CO)L] ^{n +} complexes [L?=?ONO₂ (1 ⁺), OH₂ (2 ²⁺), Cl (3 ⁺), OCOH (4 ⁺), and OCOCH₃ (5 ⁺)]. The structures of 1 ⁺ and 2 ²⁺ were confirmed by single-crystal X-ray diffraction. Crystal data for 1(PF₆): monoclinic, P2₁/c, a?=?10.5242(3), b?=?15.4727(3), c?=?14.6571(3) Å, β?=?92.3219(9)°, V?=?2384.77(9) ų, Z?=?4, D _calcd?=?1.806?g cm^?3, 5460 unique reflections (R _int?=?0.032), R ₁?=?0.0540 [I?>?2σ(I)], wR ₂?=?0.1642 (all reflections); crystal data for 2(ClO₄)₂?·?H₂O: monoclinic, C2/c, a?=?20.4247(7), b?=?10.0777(3), c?=?15.6039(5) Å, β?=?127.7569(8)°, V?=?2539.31(14) ų, Z?=?4, D _calcd?=?1.769?g cm^?3, 2895 unique reflections (R _int?=?0.036), R ₁?=?0.0343 [I?>?2σ(I)], wR ₂?=?0.0907 (all reflections). Except for 2(PF₆)₂ the complexes exhibit oxidation at 1.02–1.30?V versus Fc⁺/Fc in acetonitrile. Bipyridine-centered reductions are also observed; these redox potentials depend on the nature of L. This convenient synthesis will be useful for producing cis-[Ru(bpy)₂(CO)L] ^{n +}-type complexes in high yield.     

Synthesis and structural determination of the first eight-coordinate rare earth metal complex with a six-member ring, (NH4)[EuIII(pdta)(H2O)] · H2O

(NH₄)[Eu^III(pdta)(H₂O)]?·?H₂O has been synthesized and characterized by infrared spectrum, fluorescence spectrum, elemental analyses and single-crystal X-ray diffraction techniques. It crystallizes in the monoclinic system with space group P2₁/n, a?=?12.7700(15)?Å, b?=?9.3885(11)?Å, c?=?14.4070(18)?Å, α?=?90°, β?=?95.950(2)°, γ?=?90°, V?=?1718.0(4)?ų, Z?=?4, M?=?508.28, D _c?=?1.965?g?cm^?3, μ?=?3.708?mm^?1, F(000)?=?1108. The structure was refined to R ₁?=?0.0238 for 3469 observed reflections (I?>?2σ(I)). The Eu^IIIN₂O₆ part in the [Eu^III(pdta)(H₂O)]^? complex anion has an eight-coordinate structure with a distorted square anti-prismatic conformation, in which six coordination positions, two nitrogen atoms and four oxygen atoms are from one pdta (=propylenediaminetetraacetic acid) ligand, the seventh position is an oxygen (O(8A)) from another pdta and the eighth coordination site is occupied by a water molecule. (NH₄)[Eu^III(pdta)(H₂O)]?·?H₂O is the first eight-coordinate complex with a six-member ring in the rare earth metal complexes with aminopolycarboxylic acid ligands.     

Solid state structure of a rhenium bibenzimidazole complex

Re(CO)₅Br readily forms a complex with 2,2′-bibenzimidazole (bbimH₂) of the general composition (bbimH₂)Re(CO)₃Br, 1. The complex was characterized by NMR, IR, electronic and emission spectroscopy. The orange-brown compound is sparingly soluble in apolar solvents but could be crystallized from a DMF/toluene mixture. An X-ray structural investigation shows that the rhenium ion has a distorted octahedral geometry. Nitrogen atoms of the bibenzimidazole are trans to two carbonyl ligands. The secondary amine protons of the bibenzimidazole ligand form a hydrogen bond to the amide oxygen of a DMF molecule; N3–O4 2.725(7)?Å, N4–O4 2.761(7)?Å. The bending angle of the two benzimidazole units is 168°; the greatest deviation from planarity within the ligand is 0.14?Å. Crystal data: monoclinic, space group P2₁/n, a?=?10.9743(2), b?=?12.9182(2), c?=?15.1864(3)?Å, β?=?91.647(1)°, V?=?2152.06(7)?ų, T?=??90°C, Z?=?4, R ₁?=?0.025, wR ₂?=?0.062 for 4296 reflections with F _o?> 4σ(F _o) out of 4886 independent reflections.     

Synthesis,electrochemical and antimicrobial studies of mono and binuclear iron(III) and oxovanadium(IV) complexes of [ONO] donor tridentate Schiff-base ligands

Tridentate Schiff bases (H₂L¹ or H₂L²) were derived from condensation of acetylacetone and 2-aminophenol or 2-aminobenzoic acid. Binuclear square pyramidal complexes of the type [M₂(L¹)₂]?·?nH₂O (M?=?Fe–Cl, n?=?0; M?=?VO, n?=?1) were accessed from interaction of H₂L¹ with anhydrous FeCl₃ and VOSO₄?·?5H₂O, respectively. A similar reaction with H₂L², however, produced mononuclear complexes [ML²(H₂O) _x ]?·?nH₂O (M=Fe–Cl, x?=?0, n?=?0; M=VO, x?=?1, n?=?1). The compounds were characterized using elemental analysis, FT-IR, UV-Vis, and NMR (for ligand only), and mass spectroscopies and solution electrical conductivity studies. Magnetic susceptibility measurements suggest antiferromagnetic exchange in binuclear Fe(III) and VO(IV) complexes. Thermo gravimetric analysis (TGA) provided unambiguous evidence for the presence of coordinated as well as lattice water in [VOL²(H₂O)]?·?H₂O. Cyclic voltammetric studies showed well-defined redox processes corresponding to Fe(III)/Fe(II) and VO(V)/VO(IV). In vitro antimicrobial activities of the compounds were investigated against Klebsiella pneumoniae, Staphylococcus aureus, Pseudomonas aeroginosa, Escherichia coli, Bacillus subtilis, and Proteus vulgaris. H₂L¹ and its binuclear complexes exhibited pronounced activity against all the microorganisms tested.     

Bis(2-Amino-5-bromopyrimidinium) Tetrahalometallates: Crystal structures of (2-amino-5-bromopyrimidinium)2 MCl4 (M = Co,Zn)

The reactions of metal(II) chlorides and bromides with 2-amino-5-bromopyrimidine (2-abpm) in neutral and acidic solution were investigated. The reaction with ZnCl₂, ZnBr₂, CoCl₂, CoBr₂ and MnCl₂ in acidic nitromethane solution gave complexes of the formula (2-abpmH)₂MX₄ (1, M?=?Zn, X?=?Cl; 2, M?=?Zn, X?=?Br; 3, M?=?Co, X?=?Cl; 4, M?=?Co, X?=?Br; 5, M?=?Mn, X?=?Cl). Crystals of 1 and 3 suitable for single crystal X-ray diffraction were obtained. Crystal data: For (1): triclinic, P-1, a?=?6.2485(13), b?=?9.0520(14), c?=?15.334(4)?Å, α?=?94.81(2), β?=?95.224(17), γ?=?98.027(17)°, V?=?851.1(3)?ų, Z?=?2, R?=?0.0596 for [|I|?≥?2σ(I)]. For (3): triclinic, P-1, a?=?6.2438(13), b?=?9.0597(15), c?=?15.318(3)?Å, α?=?94.749(18), β?=?95.343(15), γ?=?98.021(17)°, V?=?850.2(3)?ų, Z?=?2, R?=?0.0452 for [|I|?≥?2σ(I) ]. Variable temperature magnetic susceptibility data indicates weak antiferromagnetic interactions in the cobalt and manganese complexes.     

Synthesis,characterization and crystal structure of a 1D heteropolytungstate [4,4′-bipyH2]2[4,4′-bipyH][PCoW11O39]·H2O

A chain-like structure compound [4,4′-bipyH₂]₂[4,4′-bipyH][PCoW₁₁O₃₉]?·?H₂O, in which lacunary polyoxoanions are joined by a Co–O–W bridge, was prepared through the hydrothermal method and characterized by IR, and X-ray crystallography. The title compound crystallizes in a monoclinic lattice, P2₁/n space group, with a?=?13.643 (3), b?=?27.052(5), c?=?15.180(3)?Å, β?=?100.63(3)°, V?=?5506.2(19)?ų, Z?=?4, R ₁?=?0.0792, wR ₂?=?0.1532. Cobalt-substituted Keggin-type subunits are connected via Co–O–W bridges to form a 1D, chainlike, polymolecular Keggin POM. TG-DTA analysis indicates the title compound decomposes at 553°C.     

Synthesis,crystal structure and magnetic properties of a three-dimensional cyano-bridged heterometallic complex of manganese(II) and molybdenum(IV)

A bimetallic cyano-bridged complex {[Mn(ImH)(H₂O)₂]₂[Mo(CN)₈]·4H₂O} _n (ImH?=?imidazole) has been prepared and characterized. Single-crystal X-ray analysis reveals that the complex crystallizes in space group C2/c with a?=?15.665(2), b?=?14.616(2), c?=?12.307(2)?Å, α?=?90, β?=?108.31(1), γ?=?90°. The structure of the complex demonstrates a three-dimensional network through cyano-bridges. Each Mo(IV) atom has six –CN–Mn linkages and two terminal cyano ligands arranged in a square antiprismatic arrangement. The Mn(II) atom is in a distorted octahedral environment formed by three MoCN?→?Mn linkages along with one imidazole and two water molecules in cis configuration. Variable temperature magnetic susceptibility shows an antiferromagnetic coupling between Mn²⁺ ions through the NC–Mo^IV–CN diamagnetic bridges within the three-dimensional network. The IR spectra have also been investigated.     

Prediction of acute toxicity of organophosphorus pesticides using topological indices

Topological indices were used in the prediction of the acute toxicity (intraperitoneal and oral LD₅₀) of organophosphorus pesticides on rats. Models with six variables for the prediction of LD₅₀-i.p. (r?=?0.849, Q ²?=?0.613) and eight variables for LD₅₀-oral (r?=?0.906, Q ²?=?0.701) were selected. External group and cross-validation by use of leave-n-out tests were also performed in order to assess the stability and the prediction performance of the selected topological models.     

Hydrothermal synthesis and characterizations of a novel modular europium(III) coordination polymer bridged by biphenyl-2,2′-dicarboxylate dianions and 1,10-phenanthroline

A novel europium(III) coordination polymer, [Eu₂(bpdc)₃(phen)₂(H₂O)₂] _n ·nH₂O (1) (bpdc?= biphenyl-2,2′-dicarboxylate; phen?=?1,10-phenanthroline), has been hydrothermally synthesized and structurally characterized by single-crystal X-ray diffraction methods. Complex 1 is monoclinic, space group C2/c, with a?=?24.3862(6), b?=?12.0792(3), c?=?22.9120(5)?Å, α?=?90.00, β?=?115.160(1), γ?=?90.00°, V?=?6108.8(3)?ų, Z?=?4, final R ₁?=?0.0605 and wR ₂?=?0.1760. Each Eu(III) ion is coordinated by six oxygen atoms from three carboxylate groups of three different bpdc anions, an oxygen atom from one coordinated water molecule and two nitrogen atoms from one phen ligand to complete a deformed monocapped square antiprism. Each pair of bpdc anions acts as a tetradentate ligand to connect two adjacent Eu(III) ions through chelating carboxylate groups, resulting in a centrosymmetric binuclear unit. Each binuclear unit links two adjacent binuclear units through two terminal bpdc anions to produce a one-directional zigzag chain. Two different kinds of hydrogen-bonding interactions link the chains and the lattice water molecules to form a hydrogen-bonding network.     

Complicated weak interactions in a hybrid material containing tetra(isothiocyanate)cobalt(II) and 1,1′-ethylene-2,2′-dipyridinium: synthesis,crystal structure,and magnetic properties

A new inorganic–organic hybrid material, [EtdiPy][Co(NCS)₄] (1) ([EtdiPy]²⁺?=?1,1′-ethylene-2,2′-dipyridinium), was synthesized and characterized by elemental analysis, IR spectrum, UV-Vis spectrum, ESI-MS, and single-crystal X-ray diffraction. Compound 1 is monoclinic, space group P2₁/n, with a?=?21.691(5)?Å, b?=?8.639(2)?Å, c?=?21.748(5)?Å, β?=?90.124(3)°, V?=?4075.1(16)?ų, D _c?=?1.550?g cm^?3, Z?=?8, F(000)?=?1928, and R ₁?=?0.0435. The C–H···S hydrogen bond, short S···C, S···N interactions, p···π, and π···π interactions observed in the solid state of 1 give a 3-D structure. Magnetic measurements from 2 to 300?K have shown weak antiferromagnetic exchange with θ?=??0.892?K in 1.     

Syntheses and structural determinations of the nine-coordinate rare earth metal: Na4[DyIII(dtpa)(H2O)]2·16H2O,Na[DyIII(edta)(H2O)3]·3.25H2O and Na3[DyIII(nta)2(H2O)]·5.5H2O

Three complexes, Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and Na₃[Dy^III (nta)₂(H₂O)]?·?5.5H₂O, have been synthesized in aqueous solution and characterized by FT–IR, elemental analyses, TG–DTA and single-crystal X-ray diffraction. Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O crystallizes in the monoclinic system with P2₁/n space group, a?=?18.158(10)?Å, b?=?14.968(9)?Å, c?=?20.769(12)?Å, β?=?108.552(9)°, V?=?5351(5)?ų, Z?=?4, M?=?1517.87?g?mol^?1, D _c?=?1.879?g?cm^?3, μ?=?2.914?mm^?1, F(000)?=?3032, and its structure is refined to R ₁(F)?=?0.0500 for 9384 observed reflections [I?>?2σ(I)]. Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O crystallizes in the orthorhombic system with Fdd2 space group, a?=?19.338(7)?Å, b?=?35.378(13)?Å, c?=?12.137(5)?Å, β?=?90°, V?=?8303(5)?ų, Z?=?16, M?=?586.31?g?mol^?1, D _c?=?1.876?g?cm^?3, μ?=?3.690?mm^?1, F(000)?=?4632, and its structure is refined to R ₁(F)?=?0.0307 for 4027 observed reflections [I?>?2σ(I)]. Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O crystallizes in the orthorhombic system with Pccn space group, a?=?15.964(12)?Å, b?=?19.665(15)?Å, c?=?14.552(11)?Å, β?=?90°, V?=?4568(6)?ų, Z?=?8, M?=?724.81?g?mol^?1, D _c?=?2.102?g?cm^?3, μ?=?3.422?mm^?1, F(000)?=?2848, and its structure is refined to R ₁(F)?=?0.0449 for 4033 observed reflections [I?>?2?σ(I)]. The coordination polyhedra are tricapped trigonal prism for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O and Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, but monocapped square antiprism for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O. The crystal structures of these three complexes are completely different from one another. The three-dimensional geometries of three polymers are 3-D layer-shaped structure for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 1-D zigzag type structure for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and a 2-D parallelogram for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O. According to thermal analyses, the collapsing temperatures are 356°C for Na₄[Dy^III(dtpa)(H₂O)]₂?·?16H₂O, 371°C for Na[Dy^III(edta)(H₂O)₃]?·?3.25H₂O and 387°C for Na₃[Dy^III(nta)₂(H₂O)]?·?5.5H₂O, which indicates that their crystal structures are very stable.     

Synthesis,crystal structure,and spectral analysis of a 1-D Mn(II) coordination polymer

A manganese(II) coordination polymer [Mn(TMB)₂?·?H₂O] _n (1) (HTMB?=?3,4,5-trimethoxybenzoic acid) has been synthesized under hydrothermal conditions and characterized by single-crystal X-ray diffraction, elemental analysis, powder X-ray diffraction analysis, spectroscopic (IR, solid state UV-Vis), and thermal methods. The crystal belongs to orthorhombic system, space group P2₁2₁2₁, with cell parameters a?=?7.3001(8), b?=?11.4146(13), c?=?27.053(3)?Å, α?=?β?=?γ?=?90°, V?=?2254.3(4)?ų, Z?=?4. In 1, TMB in two different coordination modes bridges six-coordinate manganese(II) centers forming a 1-D infinite chain coordination framework. The spectral and thermal properties of the complexes have also been studied.     

Synthesis of the monosubstituted arylcyanoxime and its Na,Tl(I) and Ag(I) compounds

Nitrosation of 2-chlorophenyl acetonitrile with t-butylnitrite under basic conditions (Meyer reaction) resulted in a high-yield preparation of the first substituted arylcyanoxime, 2-chlorophenyl(oximino)acetonitrile, H(2Cl–PhCO) (HL). The obtained cyanoxime is readily deprotonated in solution by metal hydroxides or carbonates with the formation of yellow sodium, tetrabutylammonium, thallium(I) and silver(I) derivatives. The crystal structure of the Tl(I) complex was determined. Thallium(I) salt (TlL) crystallizes in the monoclinic space group P2₁ n with a?=?3.8382(7), b?=?11.0065(18), c?=?20.901(4)?Å, and β?=?92.447(3)°, V?=?882.2(3) ų, Z?=?4; T?=?193?K (Mo?Kα radiation). The structure was solved by direct methods to a final R of 0.0689 (wR2?=?0.1650) for I?>?2σ(I). The crystal structure of the complex is a one-dimensional coordination polymer that consists of centrosymmetric [TlL]₂ dimers in which Tl₂O₂ rhombohedra are connected to each other at 90.72°. The crystal structure of TlL is an interesting example of the ruffled metal-organic network composed of Tl–O–Tl–O zigzag chains with close (3.838?Å) intermetallic distances comparable to those in metallic thallium (3.42?Å). The cyanoxime anion bridges metal centers and acts as a tridentate ligand where oxygen atoms of the oxime group bond to three different Tl(I) cations with three different bond lengths.