Synthesis and crystal structure of cobalt(III) α-dioximates with pyrazine

A series of new coordination compounds of cobalt(III) trans-dioximates with pyrazine [CoCl(DH)₂Pz] · H₂O (I), [CoBr(DH)₂Pz] · H₂O (II), [Co(DH)₂Pz₂]NO₃ · H₂O (III), [Co(DH)₂Pz₂][BF₄] (IV), [Co(MgH)₂Pz₂][BF₄] (V), and [Co(NioxH)₂Pz₂][BF₄] (VI), where DH, MgH, and NioxH are dimethylglyoxime, methylglyoxime, and 1,2-cyclohexanedionedioxime monoanions, respectively, Pz is a pyrazine molecule were synthesized. The structures of compounds I, II, and VI were determined by X-ray diffraction. The Co(III) environment in these compounds is octahedral and the pseudomacrocyclic (DioxH⁻)₂ fragment occurs in the equatorial plane. This fragment is stabilized by O-H…O hydrogen bonds. The neutral Pz ligand is monodentate in all three compounds.     

Synthesis and x-ray crystal structure of a stable α-chlorooxetane

The Barton modification of the Hunsdiecker reaction is the key step in the preparation of 3,5-anhydro-5R-chloro-1,2-O-isopropylidenexylofuranose (1), a stable α-chlorooxetane.     

Synthesis,crystal structure,and photocatalytic property of heterometallic calcium‒titanium oxo cluster with high aqueous stability

Transition Metal Chemistry - A new heterometallic calcium?titanium oxo cluster formulated as [Ca2Ti8(μ3-O)8(AcO)2(OiPr)2(BA)16]·4H2O (BA?=?benzoate) was synthesized and...     

Synthesis,crystal structure,spectroscopic and thermal investigations of neodymium(III) biphenyl-4,4′-dicarboxylate framework

The three-dimensional complex {[Nd(bpdc)_1.5(DMF)]·1.4DMF}_n (DMF=N,N′-dimethylformamide, bpdc=biphenyl-4,4′-dicarboxylate) was synthesized using the solvothermal method. The crystal structure of the neodymium(III) complex has been determined by single-crystal X-ray diffraction method at 100(2) K. The polymeric structure consists of neodymium polyhedra bridged by bpdc ligands. Eight-coordinated Nd(III) atoms are surrounded by seven oxygen atoms from six bpdc moieties and one oxygen atom from the DMF molecule. The 3D structure of the complex contains two types of channels occupied by DMF molecules. Thermal analysis revealed that DMF molecules are lost in a stepwise manner. The infrared spectrum confirmed full deprotonation of acid and presence of DMF molecules in the structure.      

Synthesis and structure of cobalt α-dioximate complexes with isonicotinamide

New cobalt trans-dioximate complexes with isoniconinamide have been synthesized: [Co^II(DmgH)₂(Inia)₂] (I), [Co^III(DmgH)₂(Inia)₂][PF₆] · 1.5H₂O (II), [Co^III(NioxH)₂ (Inia)₂][PF₆] · H₂O · CH₃OH (III), and [CoIIICl(DmgH)₂(Inia)] · H₂O (IV), where DmgH⁻ and NioxH⁻ are the dimeth-ylglyoxime and 1,2-cyclohexanedionedioxime monoanions, respectively; Inia is the isonicotinamide molecule. The structures of compounds I–IV have been determined by X-ray crystallography. In I–IV, Co(II) or Co(III) has an octahedral environment with the pseudomacrocyclic (DioxH⁻)₂ moiety (DioxH⁻ is the dioximate monoanion) in the equatorial plane. The latter is stabilized by O-H…O hydrogen bonds. The isonicotinamide molecules in all four complexes are monodentately bound to the metal ion through the heterocyclic nitrogen atom.     

Synthesis,crystal structure and properties of two terbium complexes with 2,2′-bipyridine

Two new complexes {[Tb(2-IBA)₃ · 2,2′-bipy]₂ · C₂H₅OH} (1) and [Tb(2-ClBA)₃ · 2,2′-bipy]₂ (2) (2-IBA = 2-iodobenzoate; 2-ClBA = 2-chlorobenzoate; 2,2′-bipy = 2,2′-bipyridine) were prepared and their crystal structures determined by X-ray diffraction. Complex 1 is composed of two types of binuclear molecules, [Tb(2-IBA)₃ · 2,2′-bipy]₂ (a) and [Tb(2-IBA)₃ · 2,2′-bipy]₂ (b), and an uncoordinated ethanol molecule. In molecule (a), two Tb³⁺ ions are linked by four 2-IBA groups, all bidentate-bridging. In molecule (b), two Tb³⁺ ions are held together by four 2-IBA groups in two coordination modes, bidentate-bridging and chelating-bridging. In the two molecules, each Tb³⁺ ion is further bonded to one chelating 2-IBA group and one chelating 2,2′-bipy molecule, resulting in coordination numbers of eight for (a) and nine for (b). The structural characteristics of 2 are similar to that of molecule (b) in 1. The two complexes, 1 and 2, both emit strong green fluorescence under ultraviolet light with the ⁵D₄ → ⁷F _j (j = 6–3) emission of Tb³⁺ ion observed.     

Synthesis and crystal structure of pyridine and methanol coordinated α-octabutyloxyphthalocyaninatocobalt (II)

Crystal structure of pyridine and methanol axially coordinated 1,4,8,11,15,18,22,25-octabutyloxyphthalocyaninatocobalt(II)(viz. α-octabutyloxyphthalocyaninatocobalt) [(n-BuO)₈Pc]. Co(Py)(MeOH) (1) was determined by X-ray diffraction methods. Crystal data: monoclinic, space group P2₁/n, Z = 4, a = 1.06482(4), b = 3.5487(2), c = 1.79428(9) nm, β=103.246(2)°, V = 6.5792(5) nm³, μ = 0.325 mm^-1. The result shows that the ring skeleton of 1 maintains planar conformation, which is similar to that of unsubstituted phthalocyanine but is remarkably different from the saddle shape conformation of 1,4,8,11,15,18,22,25-octabutyloxyphthalocyaninatocopper (II) [(n-BuO)₈Pc]Cu(2), which has no axial coordination. In the structure of 1, the substituents butyloxy groups of 1 somewhat deviate from the ring plane, while pyridine and methanol are coordinated to the center atom Co from opposite sides of the ring plane. In addition, all molecules are stacked along axis a to form one-dimensional molecule chain, the neighboring molecules in the chain overlap to some extent with a benzene ring and a distance of 0.3565 nm.     

Synthesis and photocatalytic properties of α-Fe2O3 nanoellipsoids

A simple and a novel chemical approach was used for the growth of α-Fe₂O₃ nanostructures. Field emission scanning electron microscopy analysis revealed the monodisperse nanoellipsoid morphology of α-Fe₂O₃ nanostructures. The sizes of the short axis and the long axis of these ellipsoids were in the ranges of 50–60 nm and 40–50 nm, respectively. XRD analysis revealed that the product exhibited α-Fe₂O₃ phase. Comprehensive TEM and HRTEM analysis revealed that α-Fe₂O₃ nanoellipsoids are single crystal in nature. The methylene blue decomposition kinetics was studied for different irradiation time. The methylene blue was totally decomposed by increasing the irradiation time up to 220 min.     

Synthesis, crystal structure and forming mechanism of two novel copper (Ⅱ) α-methacrylate complexes with benzimidazole

Two copper (Ⅱ) a-methacrylate complexes with benzimidazole, Cu [CH_2=C( CH_3)-COO]_2(C_7H_6N_2)_2(1) and Cu_2 [CH_2=C(CH_3)-COO]_4(C_7H_6N_2)_2 (2), have been prepared and characterized by elemental analyses, IR and electronic reflectance spectroscopies. The single crystal X-ray diffraction study of the two complexes shows that complex 1 has a square planar configuration, while complex 2 has a binuclear cage structure. The crystal structural analyses show that both complexes 1 and 2 are monoclinic, with space group P2_1/c, a=0.924 16(8) nm, b=1.233 02(13) nm, c =0.989 1(3) nm, β=91.912(13)°, D_c=1.386 g/cm~3, Z=2, R=0.033 9 for the former; and a=0.905 7(2) nm, b=2.252 1(5) nm, c=1.623 5(4) nm, β=90.11(2)°, D_c =1.411 g/cm~3 , Z=4, R=0.056 8, Cu-Cu=0.266 21 nm for the latter. Different structural types of complexes 1 and 2 were produced simultaneously in the reaction of copper (Ⅱ) α-methacrylate with benzimidazole in methanol solution. The forming mechanism of the complexes has been summarized.     

Synthesis, crystal structure and forming mechanism of two novel copper (II) α-methacrylate complexes with benzimidazole

Two copper (II) α-Methacrylate complexes with benzimidazole, Cu[CH₂ = C(CH₃)-COO]₂ (C₃H₆N₂)₂(1) and Cu₂[CH₂ = C(CH₁)-COO]₂(C₃H₆N₂)₂(2), have been prepared and characterized by elemental analyses, IR and electronic reflectance spectroscopies. ’The single crystal X-ray diffraction study of the two complexes shows that complex 1 has a square planar configuration, while complex 2 has a binuclear cage structure. The crystal structural analyses show that both complexes 1 and 2 are monoclinic. with space group p2₁/c,a = 0.924 16(8) nm,b = 1.233 02(13) nm,c = 0.989 1(3) nm,β = 91.912 (13),D _c = 1.386 g/cm³,Z=2,R = 0.033 9 for the former; anda = 0.905 7(2) nm,b = 2.252 1(5) nm,c = 1.623 5(4) nm,β = 90.11 (2),D _c = 1.411 g/cm³,Z = 4,R = 0.056 8, Cu-Cu = 0.266 21 nm for tin latter. Different structural types of complexes 1 and 2 were produced simultaneously in the reaction of copper (II) α-methacrylate with benzimidazole in methanol solution. ’The forming mechanism of the complexes has been summanzed. Project supported by the national natural Science Foundation of China (Grant No. 29831010) and the Foundation of the State Key Laboratory of Coordination Chemistry of Nanjing university.     

Synthesis of the anionic fluororeceptors based on thiourea and amide groups and recognition property for α,ω-dicarboxylate

Three new neutral receptors (1, 2 and 3) containing thiourea and amide groups were synthesized by simple steps in good yields. The binding properties for anions of 1, 2 and 3 were examined by UV-vis, fluorescence, and ¹H NMR spectroscopy. Receptors 1, 2 and 3 all had a better adipate anion selectivity by comparison with other dicarboxylate anions. The association constants of 1, 2 and 3 with adipate were higher as compared to other anions (malonate, succinate, glutarate). In particular, a distinct color change was observed from light yellow to orange-red upon addition of adipate to the solution of 1 in DMSO. The UV-vis and fluorescence data indicate that a 1:1 stoichiometry complex is formed between compound 1, 2 or 3 and dicarboxylate anions through hydrogen bonding interactions.     

Synthesis,characterization, and crystal structure of one zinc(II) complex with 4-Hydroxypyridine-2,6-Dicarboxylic acid and 4,4′-bipyridine

A new zinc(II) coordination polymer, {[Zn(HCAM)(4,4′-Bipy)_0.5] · H₂O} _n (I) (H₃CAM = 4-hydroxypyridine-2,6-dicarboxylic acid; 4,4′-Bipy = 4,4′-bipyridine), has been synthesized by hydrothermal reaction of Zn(OAc)₂, H₃CAM and 4,4′-Bipy. It has been structurally characterized by element analysis, IR-spectra. X-ray single-crystal analysis was carried out for I (CIF file CCDC no. 974199), which crystallizes in the orthorhombic system, space group Pbca. The single X-ray diffraction studies reveal that I shows a new 2D wave-like plane with 3-connected net. Furthermore, the thermal stability of compound I was studied.     

1-D Ln–Ag (Ln = Eu; Tb) heterometallic coordination polymers with pyridine-2,6-dicarboxylate as the single ligand: Synthesis,crystal structures,and luminescence

Two new 4d–4f heterometallic coordination polymers [AgLn(pydc)₂(H₂O)₃] · x(H₂O) [Ln = Eu, x = 1.25 (1); Ln = Tb, x = 1.25 (2); pydc = 2,6-pyridinedicarboxylate] have been synthesized and characterized by elemental analysis, IR spectroscopy, and single crystal X-ray diffraction. Both structures display the same unusual 1-D heterometallic coordination polymer based on Ln building blocks and Ag ions. Thermal stabilities and luminescent properties of 1 and 2 are presented.     

Hydrothermal synthesis, structure and photocatalytic property of nano-TiO_2-MnO_2

TiCI4 and MnSO4.H2O as raw materials are hydrolyzed stiochiometrically, following the intermediate of oxide hydrating reacts at 150℃, 0.5 MPa in high-pressure reactor, after filtering, washing and drying, nanometric TiO2-MnO2 (Ti1-xMnxO2) is prepared. The effects of the reaction temperature and time on nanometric TiO2-MnO2 are also discussed. XRD shows that the product is TiO2-MnO2 with amorphous phase. After being sintered at above 780℃, it transfers into Ti1-xMnxO2 with a rutile structure. TEM shows that TiO2-MnO2 is the spherical particle. And the average diameter of the particles is 20 nm. The optical absorbance was determined by UV-265 spec-trophotometer after dispersing the sample in the mixture of water and glycerol with the ratio of 1 : 1 equably. It is found that the nano-material possesses the advantages of both nano-TiO2 and nano-MnO2, and it has strong absorption in the UV and visible region. Photodegradation of dyes in an aqueous solution is investigated using nanometricTiO2-MnO2 as a pho     

Synthesis,crystal structure and pseudocapacitor electrode properties of γ-Bi2MoO6 nanoplates

Nanoplate-like bismuth molybdates (γ-Bi₂MoO₆) is prepared for the first time by urea assisted solution combustion synthesis (SCS) and studied the structural and electrochemical properties to explore the possibility of using as negative electrodes in pseudocapacitors. The formation of single phase γ-Bi₂MoO₆ and plate-like morphology is revealed from XRD Rietveld refinement and FESEM, respectively. The pseudocapacitive behaviour of γ-Bi₂MoO₆ is analyzed by cyclic voltammetry and galvanostatic charge–discharge techniques. The effect of Na based aqueous electrolytes on capacitance of the Aurvillius type structured Bi₂MoO₆ is investigated. As prepared γ-Bi₂MoO₆ nanoplates provide the high specific capacitance (519 F g⁻¹) compared with the high-temperature monoclinic phase γ(H) Bi₂MoO₆ in 1 M NaOH electrolyte. The obtained high specific capacitance of as prepared Bi₂MoO₆ could be attributed to the decrease in particle size, increase in active sites, and nanoplate-like structure of as prepared γ-Bi₂MoO₆.     

Three-pillared layer metal–organic frameworks assembled by imidazole-4,5-dicarboxylate and rigid bisimidazole ligands: synthesis,crystal structure,and sensing nitroaromatics

Three-pillared layer metal–organic frameworks based on 1H-imidazole-4,5-dicarboxylate and linear bis(imidazole) ligands generally formulated as {[Co₃(idc)₂(bib)₃]·8H₂O}_n (1), {[Cd(Hidc)(bib)_0.5]}_n (2) and {[Cd(Hidc)(bibp)]}_n (3), where H₃idc = 1H-imidazole-4,5-dicarboxylate, bib = 1,4-bis(1-imidazolyl)benzene and bibp = 4,4′-bis(1-imidazolyl)biphenyl, have been solvothermally synthesized and structurally characterized by single-crystal X-ray diffraction. Compound 1 features a 3-D-pillared layer structure with 1-D channels, generated by honeycomb-like 2-D layer linked by bib ligands. Compound 2 consists of 2-D lumpy layers of [Cd₄(Hidc)₄], which are further connected by bridging ligands of bib to generate a pillared layer 3-D framework with 1-D channels. In 3, the 2-D corrugated honeycomb networks, structurally analogous to CFx, are pillared by bibp ligands to form a 3-D architecture with 1-D channels. Through selecting different metal ions and the length of pillared ligands, the pore sizes are adjusted in the three complexes. The potential of 2 and 3 for nitro explosive sensing is investigated through luminescence quenching experiments, which show that 3 can be applied as a fluorescent sensor for nitro compounds.     

A 1D double chains architecture based on the pyridine-2-sulfonate, 4,4′-Bipyridine and acetate-bridged of Zn(II) complex: Synthesis, spectral, thermal properties, and crystal structure

A new 1D double chains Zn(II) supramolecule framework, {[Zn₂(2-pSO₃)₂(Ac)₂(4,4??-Bipy)₂](4,4??-Bipy)} _n (I) (2-pSO₃H = pyridine-2-sulfonate, 4,4??-Bipy = 4,4??-bipyridine), was synthesized by reaction of Zn(CH₃COO)₂ · 2H₂O in methanol-water mixed solution and characterized by X-ray diffraction, elemental analysis, and IR spectrum. X-ray analysis indicates that I is a coordination polymer in which two deprotonated 2-pSO₃H through the aromatic nitrogens in trans positions, oxygens in cis positions and two N atoms of 4,4??-Bipy and two ??₂-Ac^? ligands, resulting in a ZnN₃O₃ distorted octahedral geometry. The 1D coordination polymer was connected to 2D and 3D supramolecule framework via ??-stacking and weak C-H??O contacts. The complex I also displays strong fluorescence property and good thermal stability.     

Synthesis,crystal structure and characterization of zinc(II) complexes with the tripod ligand tris(2-benzimidazolylmethyl)amine and α,β-unsaturated carboxylates

Four 5-coordinate zinc complexes containing the tripod ligand, tris(2-benzimidazolylmethyl)amine (ntb), and four different ,-unsaturated carboxylates (L^1–4), with compositions [Zn(ntb)(L^1–4)](NO₃)·nH₂O (L¹ = acrylate; L² = -methacrylate; L³ = trans-cinnamate; L⁴ = 2-hydroxycinnamate; n = 1, 1.5 and 2), were synthesized and characterized by means of elemental analyses, electrical conductivities, thermal analyses, i.r., u.v., and ¹H-n.m.r. spectra. The novel crystal structure of [Zn(ntb)(L³)](NO₃)·H₂O·DMF has been determined by a single-crystal X-ray diffraction method, and shows that each zinc ion is linked to a tris(2-benzimidazolymethyl)amine (ntb) unit and a trans-cinnamate. The zinc ion is 5-coordinate with a N₄O ligand set. The coordination geometries of the zinc ion may be best described as a distorted trigonal bipyramid of site symmetry C₃.     

Synthesis,crystal structure and properties of manganese(II) complexes with the tripod ligand tris(2-benzimidazylmethyl)amine and α,β-unsaturated carboxylates

Two new ternary complexes of manganese(II) with tris(2-benzimidazylmethyl)amine (ntb), and two different α,β-unsaturated carboxylates, {[Mn(ntb)(acrylate)](ClO₄)}₂?·?(H₂O)·3(CH₃OH) (1) and {[Mn(ntb)(α-methacrylate)](ClO₄)}₂·(H₂O)·2(CH₃OH) (2), have been synthesized and characterized by means of elemental analyses, thermal analyses, IR, UV and single crystal X-ray diffraction. In the two complexes, ntb functions as a tripodal tetradentate ligand, resulting in trigonal pyramidal geometry. In each complex, an additional ligand, acrylate anion, or α-methacrylate anion, is coordinated at the opened site trans to the apical nitrogen atom of the ntb ligand. The crystal structure of 1 shows two crystallographically independent but chemically identical [Mn(ntb)(acrylate)]⁺ cations. In 2, the crystal structure shows two crystallographically independent and chemically different [Mn(ntb)(a-methacrylate)]⁺ cations. Cyclic voltammograms of the manganese complexes indicate a quasireversible Mn³⁺/Mn²⁺ couple. The X-band EPR spectrum of the complexes exhibits a six-line manganese hyperfine pattern with g?=?2, A?=?97 (1) and 93?G (2). The spectrum confirms that the material is high-spin Mn(II).