Synthesis and characterization of new coordination polymers generated from oxadiazole-containing ligands and IIB metal ions

The coordination chemistry of the oxadiazole-containing rigid bidentate ligands 2,5-bis(4-pyridyl)-1,3,4-oxadiazole (L1) and 2,5-bis(3-pyridyl)-1,3,4-oxadiazole (L2) with inorganic IIB metal salts have been investigated. Five new coordination polymers (1-5) were prepared by solution reactions and fully characterized by infrared spectroscopy, elemental analysis, and single-crystal X-ray diffraction. Cd(L1)₂(CH₃CN)₂](ClO₄)₂ · (CH₃CN)₂ (1) crystallized in the monoclinic space group P2₁/c, a = 8.4028(5) Å, b = 21.3726(13) Å, c = 10.5617(7) Å, β = 95.1200(10)°, and Z = 2. In the solid state, it adopts an infinite two-dimensional polymeric structural motif with effective cross section of ca. 14.31 × 14.31 Å. Cd(L2)(H₂O)(NO₃)₂ (2) crystallized in the monoclinic space group Ia, a = 7.1203(5) Å, b = 22.2475(15) Å, c = 20.2652(16) Å, β = 90.6080(10)°, and Z = 8. In the solid state, the two Cd(II) centers are connected to each other by L2 ligands and bridging nitrates into a two-dimensional network. [ZnCl₂(L1)] (3) and [HgI₂(L1)] · CH₃CN (4) crystallized in the monoclinic crystal system (3: P2₁/c, a = 5.3702(3) Å, b = 20.4800(11) Å, c = 12.4093(7) Å, β = 94.7930(10)°, and Z = 4; 4: P2/n, a = 17.2733(11) Å, b = 5.2173(3) Å, c = 20.4069(13) Å, β = 102.8690(10)°, and Z = 4). In the solid state, Zn(II) and Hg(II) metal centers are connected to each other by L1 ligands into a zigzag chain motif. Compound 5 (HgBr₂(L2) is different from 3 and 4, monoclinic, P2(1)/n, a = 5.470(4) Å, b = 16.271(13) Å, c = 16.486(12) Å, β = 93.197(15)°, and Z = 4) adopts a novel one-dimensional helical chain motif which resulted from the relative different coordinated orientation of the two N-donors on L2 ligand.     

Structures from powders: Diflorasone diacetate

Diflorasone diacetate, a steroid anti-inflammatory drug (marketed as Diacort^® or Florone^® by Pfizer) and used in the treatment of skin disorders, can be prepared as anhydrous form, DD1 (as deposited in the US pharmacopoeia), or as a monohydrated phase, DDW. Heating the DDW form above 90 °C, a mixture of DD1 and of a new anhydrous polymorph, DD2 is obtained. Further heating of this mixture, or of pure DD1, up to 230 °C (only a few degrees before melting!), generates an elusive anhydrous DD3 polymorph. Their crystal structures, determined uniquely from laboratory powder diffraction data, show the isomorphous character of the DDW and DD1 forms, while the DD2 and DD3 polymorphs crystallize with markedly different unit cells. Crystals of the DD1, DD2 and DDW forms are orthorhombic, P2₁2₁2₁, a = 29.386(1) Å; b = 10.4310(9) Å, c = 8.1422(7) Å, V = 2495.8(3) Å³ for DD1; a = 15.2639(10) Å; b = 11.7506(7) Å, c = 13.8931(11) Å, V = 2491.9(3) Å³ for DD2; a = 30.311(2) Å; b = 10.6150(9) Å, c = 7.9337(7) Å, V = 2552.7(4) Å³ for DDW; while the lattice parameters for the monoclinic P2₁DD3 species are a = 11.5276(10) Å; b = 13.8135(11) Å, c = 7.8973(7) Å, β = 103.053(6)°, V = 1225.0(2) Å³. These compounds have also been fully characterized by thermo analytical methods, as well by ¹³C, ¹⁹F, and ¹H NMR spectroscopy.     

Two cadmium-thiocyanate coordination polymers with organic cations: Synthesis, crystal structures and luminescent properties

Two new inorganic-organic hybrid polymers [ClBzQl]₂[Cd(SCN)_3.5Br_0.5]·0.25H₂O (1) and [ClBzMePy][Cd(SCN)₃] (2) (ClBzQl = 1-(4′-Cl-benzyl)quinolinium cation and ClBzMePy = 1-(4′-Cl-benzyl)-2-methylpyridinium cation) have been synthesized and characterized by IR, UV, elemental analysis and X-ray crystallography. Crystal structure analyses show that two polymers belong to the monoclinic space group P2/n (1) and P2₁/c (2) with a = 18.548(2) Å, b = 9.526(1) Å, c = 20.689(2) Å, β = 94.008(1)°, V = 3646.6(5) Å³ for 1, and a = 11.195(2) Å, b = 16.415(3) Å, c = 10.751(2) Å, β = 102.930(3)°, V = 1925.7(7) Å³ for 2. The Cd atom exhibits a distorted octahedral coordination geometry for 1 and 2. For 1, a pair of 1,1-μ-SCN⁻ anions and a pair of 1,3-μ-SCN⁻ anions are alternately bridge adjacent Cd centers to form infinite polymeric chains. For 2, adjacent Cd atoms are linked by three 1,3-μ-SCN⁻ anions to form infinite [Cd(SCN)₃⁻]_∞ polymeric chains. The luminescent properties of the two polymers in the solid state at room temperature were investigated.     

Homochiral metal-organic coordination networks from l-typtophan

Three homochiral metal-organic coordination networks [Co₂(l-Trp)₂(Py)₆] · Py · (ClO₄)₂ (1), [Ni(l-Trp)(Py)₃] · H₂O · ClO₄ (2) and [Co₂(l-Trp)(INT)₂(H₂O)₂(ClO₄)] (3), all containing natural amino acid l-HTrp (l-typtophan), were hydrothermally synthesized and structurally characterized. The compounds 1 and 2 crystallize in the orthorhombic space group C222₁, with a = 10.731(2) Å, b = 19.709(4) Å, c = 27.365(6) Å and Z = 4 for 1 and a = 10.710(10) Å, b = 20.088(18) Å, c = 27.63(3) Å and Z = 8 for 2, respectively. The compound 3 has the monoclinic space group P2₁, with a = 8.1934(14) Å, b = 13.209(2) Å, c = 12.464(2) Å, β = 104.107(3)° and Z = 2. Both 1 and 2 consist of 1D helical chains. Compound 3 is composed of 2D networks, which further assemble into a 3D supramolecular structure via weak interlayer interactions. The optically pure amino acid l-HTrp plays an important role leading to homochiral structures reported here.     

Synthesis, crystal structure, magnetic properties and electrochemical behaviour of the mixed valence compound [Cu(CN)3Cu(C3H10N2)2]

The binuclear mixed valence copper(I/II) compound [Cu^I(CN)₃Cu^II(tn)₂] (1) (tn = propane-1,3-diamine) and its acetonitrile adduct [Cu^I(CN)₃Cu^II(tn)₂] · 2MeCN (2) have been synthesized. Complex 1 crystallizes triclinic, space group , a = 8.117(2) Å, b = 8.389(2) Å, c = 11.920(2) Å, α = 108.728(3)°, β = 100.024(3)°, γ = 104.888(4)°, Z = 2, and compound 2 monoclinic, space group P2₁/m, a = 8.752(2) Å, b = 13.243(3) Å, c = 9.549(2) Å, β = 114.678(4)°, Z = 2. In both crystal structures, the binuclear [Cu^I(CN)₃Cu^II(tn)₂] complex with slightly different bonding geometries is formed. One of the three nitrogen atoms of a Cu^I(CN)₃ moiety is coordinated to Cu(II) at the apex of a square-pyramid with two chelating ligands tn on its base. The shortest intramolecular Cu^II?Cu^II distance in 1 is 5.640(7) Å. The EPR behaviour of 1 has been investigated at room temperature and at 77 K. The magnetic properties were measured in the temperature range 1.8-300 K.     

Organolanthanide constrained geometry complexes modified for catalysis: synthesis, structure, and aminoalkene hydroamination properties of a pyrrolidine-substituted constrained geometry organolutetium complex

The reaction of the organolutetium complex (CGC′)LuCl₃Li₂(THF), (1; CGC′ = [Me₂Si(3-pyrrolidinyl-1-η⁵-indenyl)(^tBuN)]²⁻) with NaN(TMS)₂ provides a straightforward route to the halide-free organolutetium amido complex, (CGC′)LuN(TMS)₂(THF) (2). These new complexes were characterized by standard analytical methodology. The monomeric complex 2 crystallizes in the monoclinic space group P2₁/c with four molecules in a cell of dimensions a = 11.1566(6) Å, b = 14.9805(8) Å, c = 22.18007(12) Å, and β = 90.0620(10)°. Complex 2 is an active precatalyst for the intramolecular hydroamination/cyclization of representative aminoalkenes with turnover frequencies as high as 205 h⁻¹ at room temperature.     

One-dimensional azido-bridged chiral copper(II) coordination polymers: Syntheses, structures and magnetic studies

Two new one-dimensional azido-bridged chiral copper(II) coordination polymers, [(μ-1,1,3-N₃)₂{Cu₂(R-L)₂(N₃)₂}]_n (1) (R-L = R-2-(N-(2-hydroxybutyl)carbaldimino) pyridine) and [(μ-1,1,3-N₃)₂{Cu₂(S-L)₂(N₃)₂}]_n (2) (S-L = S-2-(N-(2-hydroxybutyl)carbaldimino)pyridine) have been synthesized and structurally characterized. Complexes 1 and 2 crystallize in the monoclinic chiral space group P2₁. For 1, with a = 6.9565(17) Å, b = 20.675(5) Å, c = 9.859(2) Å, β = 105.944(5)° and Z = 2. In the case of compound 2, a = 6.9650(17) Å, b = 20.705(5) Å, c = 9.878(2) Å, β = 105.941(4)° and Z = 2. Both complexes consist of one-dimensional chiral structures in which the copper(II) ions with a distorted octahedral geometry are interlinked by the unusual μ-1,1,3 azido ligands. Circular dichroism spectra demonstrate that 1 and 2 are a pair of enantiomers. Their magnetic properties have been studied. Fitting of the susceptibility data for 1 and 2 using the Bleany-Bowers expression derived from the isotropic spin-exchange Hamiltonian H = −2JS₁S₂ leads to the parameters g = 2.21, J = −2.06 cm⁻¹, zJ′ = −0.0309 cm⁻¹ and R = 4.0 × 10⁻⁴.     

Syntheses, structures, and magnetic properties of two new μ-alkoxo-μ-pyrazolato bridged dicopper(II) complexes

The syntheses, structures, and magnetic properties of two new μ-alkoxo-μ-pyrazolato heterobridged compounds, [Cu ^II₂(L¹-F)(μ-prz)] (1) and [Cu ^II₂(L¹-2OMe) (μ-prz)] · 0.5 CH₃CN (2) (prz=pyrazolato; H₂L¹-F=1,3-bis(3-fluorosalicylideneamino)-2-propanol; H₂L¹-2OMe=1,3-bis(4,6-dimethoxy salicylideneamino)-2-propanol) have been reported. Compound 1 crystallizes in triclinic space group with a=8.6392(10) Å, b=10.6431(9) Å, c=11.6809(13) Å, α=85.972(8)°, β=71.492(9)°, and γ=72.221(9)°, while the unit cell parameters of 2 are as follows: space group: monoclinic C2/c, a=28.2948(5) Å, b=7.3033(2) Å, c=26.3933(5) Å, and β=96.243(1)°. The variable-temperature magnetic susceptibility measurements reveal that the metal centers in both the compounds are antiferromagnetically coupled with J=−200 cm⁻¹ for 1 and J=−175 cm⁻¹ for 2. The magnetic behaviors have been explained on the basis of two opposing factors, complementarity and countercomplementarity of magnetic orbitals.     

Syntheses, structures, and properties of novel one dimensional copper cyanide coordination polymers

Three new one-dimensional copper coordination polymers have been prepared and fully characterized by single-crystal X-ray diffraction, IR spectroscopy, thermogravimetric analysis, and magnetic susceptibility measurements. The structure of [Cu(CN)₂(bpy)] (1) (bpy = 2,2-bipyridyl) (monoclinic P2₁/c, a = 8.9761(7) Å, b = 16.731(1) Å, c = 8.0224(6) Å, β = 114.437(1)°) consists of Cu(II) metal centers coordinated by three cyanide ligands and chelated by one bpy to form the monomers Cu(CN)₃(bpy) with distorted square pyramidal geometry. Each monomer shares two cyanide ligands with two adjacent monomers to form infinite -Cu(II)-CN-Cu(II)-CN-Cu zigzag chains along the c-axis. The one-dimensional structure of [Cu(CN)(bpy)] (2) (hexagonal P3₂, a = 14.4883(6) Å, b = 12.921(1) Å) is built of tetrahedral Cu(CN)₂bpy metal complexes in which Cu(I) metal centers are coordinated by one nitrogen and one carbon from two different CN ligands, and two nitrogens from one bpy. The two CN ligands act as bridging ligands between adjacent monomers to form helical chains along the 3₂ screw axis. The crystal structure of [Cu₂Cl(CN)(bpy)] (3) (orthorhombic Pbca, a = 17.853(2) Å, b = 6.9724 (9) Å, c = 18.7357 (9) Å) consists of two monomers, CuCl₂(CN) and Cu(bpy)(CN) that share a cyanide ligand to form Cu₂Cl₂(CN)(bpy) dimers. The dimers link to each other by sharing Cl ligands leading to the formation of infinite Cu-Cl-Cu chain decorated by the complex Cu(CN)(bpy). Variable-temperature magnetic measurement shows an overall ferromagnetic behavior for compound 1. The magnetic pathway of compound 1 is through the cyanide bridge connecting apical and equatorial positions of adjacent copper (II) ions.     

Formation and molecular structure of novel Ru(III) dimers of a symmetric antitumor drug analogue

The symmetrical anionic and neutral dimers [H(TMSO)₂]₂trans-[{RuCl₄(TMSO)}₂](μ-pyz) (1), and mer-[{RuCl₃(TMSO)₂}₂](μ-pyz) (2) were isolated by the reaction of [H(TMSO)] trans-[RuCl₄(TMSO)₂] and mer-[RuCl₃(TMSO)₃] with heterocyclic nitrogen donor ligand pyrazine (pyz) at room temperature. These complexes can be regarded as unprecedented examples in the general Creutz-Taube family of ruthenium dimers. Each ruthenium center in 1 and 2 has a coordination environment akin to that of known anionic and neutral monomeric Ru(III) complexes. Crystals of 1 · acetone are orange, needle like, space group , a=10.419(3) Å, b=10.539(3) Å, c=12.595(5) Å, α=69.837(16)°, β=69.968(15)°, γ=74.330(15)° and crystals of 2 · 4TMSO are orange prisms, trigonal, space group , a=33.971(5) Å, b=33.971(5) Å, c=12.210(2) Å, α=90°, β=90° and γ=120°.     

Hydrothermal synthesis and structure characterization of the first organically templated metal iodates

The first organically templated molybdenum iodates (C₅H₆N)₂Mo₂O₅(IO₃)₄(H₂O)₂ (1), (C₁₀H₈N₂)[MoO₂(IO₃)₃] · H₃O (2), and uranium iodate (C₅H₅N)₂[(UO₂)(IO₃)₃](IO₃) (3), have been successfully synthesized under mild hydrothermal conditions. Compound 1 is simple zero-dimensional units consisting of [(Mo₂O₅(IO₃)₄)]²⁻ anions, which can be described as a tetranuclear unit hanged on either side by two [IO₃] groups. The [Mo₂O₅(IO₃)₄]²⁻ anions are in a close connection through the water molecules and protonated pyridine cations, via hydrogen bonds and intermolecular actions. Compound 2 is built up from [MoO₆] octahedra and [IO₃] pyramids to two-dimensional layers, in which 4,4′-bipy molecules and water cations are located, forming strong hydrogen bonds with the inorganic framework, leading to pseudo three-dimensional structure. Compound 3 is one-dimensional ribbons containing {[(UO₂)(IO₃)₃](IO₃)}²⁻ anions and charge neutrality is achieved by the protonated 4,4′-bipy cations, which reside between two ribbons, forming hydrogen bonds with the inorganic framework and resulting in pseudo two-dimensional structure. Crystal data are as follows: (C₅H₆N)₂Mo₂O₅(IO₃)₄(H₂O)₂ (1), orthorhombic, Pnma, a = 24.097(5) Å, b = 13.532(3) Å, c = 7.836(16) Å, Z = 4, V = 2555.2(9) Å³; (C₁₀H₈N₂)[MoO₂(IO₃)₃] · H₃O (2), monoclinic, C2/c, a = 24.176(5) Å, b = 10.751(2) Å, c = 7.5074(15) Å, β = 107.44(3)°, Z = 8, V = 1861.6(6) Å³; (C₅H₅N)₂[(UO₂)(IO₃)₃](IO₃) (3), monoclinic, P2₁/n, a = 14.430(3) Å, b = 7.3459(15) Å, c = 19.811(4) Å, β = 106.70(3)°, Z = 4, V = 2011.3(7) Å³.     

Synthesis and characterisation of palladium(II) iodo complexes containing water soluble phosphine ligands. Crystal structures of [PdI2(PTA-H)2][PtI3(PTA)]2 · 2H2O and trans-[PdI2(PTA)2]

The aqueous solution behaviour of the equilibrium related cis-[PdCl₂(PTA)₂] and [PdCl(PTA)₃]Cl complexes has been investigated in the presence of acid and iodide ions. Several of the resulting species were identified and a reaction scheme accounting for identified complexes is proposed. The crystal structures of trans-[PdI₂(PTA-H)₂][PdI₃(PTA)]₂ · 2H₂O (1) (PTA-H⁺ = protonated form of PTA) and trans-[PdI₂(PTA)₂] (2) are reported. The geometry around the Pd(II) metal centre in 1 (for both the cation and anion) and 2 is distorted square planar. The PTA ligands occupy a trans orientation in the cation of 1 and in complex 2. Compound 1 represents a rare example of a Pd(II) system wherein the cation:anion pair, in a 1:2 ratio, are both coordination complexes. It is the first d⁸ Ni-triad square planar complex containing only one PTA ligand and only the second platinum group metal complex. For the cation in 1, the bond distances and angles are Pd(1)-P(1) = 2.2864(16) Å, Pd(1)-I(1) = 2.6216(7) Å, P(1)-Pd(1)-P(1)′ = 180.00(7)° and P(1)-Pd(1)-I(1) = 87.62(4)°, while in the anion the bond distances are Pd(2)-P(2) = 2.2377(15) Å, Pd(2)-I(4) = 2.5961(13) Å, Pd(2)-I(2) = 2.6328(13) Å, Pd(2)-I(3) = 2.6513(8) Å, while the angles are P(2)-Pd(2)-I(4) = 90.00(5)°, P(2)-Pd(2)-I(2) = 89.69(5)°, I(4)-Pd(2)-I(2) = 179.57(2)°, P(2)-Pd(2)-I(3) = 175.19(4)°, I(4)-Pd(2)-I(3) = 90.29(4)° and I(2)-Pd(2)-I(3) = 90.05(4)°. Bond distances and angles of the coordination polyhedron in 2 are Pd-P = 2.327(3) Å, Pd-I = 2.5916(10) Å, P-Pd-I = 89.13(7)° and P-Pd-P = 180.00(13)°. The average effective- and Tolman cone angles for the two ligands, calculated from the crystallographic data, are 115° and 117° for PTA and PTA-H, respectively.     

Synthesis, characterization and magnetic properties of a novel fluorinated iron phosphite Fe2(HPO3)F2 with infinite -Fe-F-Fe-O-Fe- linkage and -Fe-F-Fe- layer

A novel fluorinated iron phosphite Fe₂(HPO₃)F₂ (1) has been hydrothermally synthesized and characterized by single-crystal X-ray diffraction. Compound 1 crystallizes in the orthorhombic space group Pnma (No. 51) with a = 7.3458(15) Å, b = 10.038(2) Å, c = 5.4947(11) Å, V = 405.16(14) Å³, Z = 4. Its structure is built up from iron(II) oxygen-fluorine FeO₃F₃ octahedra and HPO₃ pseudo-tetrahedra, giving rise to a 3D inorganic framework. The infinite -Fe-O-Fe-F-Fe- linkage and -Fe-F-Fe- layer in the framework are the noteworthy structural features. Mössbauer spectrum shows the presence of Fe²⁺ in the octahedral coordination. Magnetic measurements indicate the existence of antiferromagnetic interactions.     

Octahedral cyanohydroxo cluster complex trans-[Re6Se8(CN)4(OH)2]: Synthesis, crystal structure, and properties

A hexarhenium cyanohydroxo anionic cluster complex [Re₆Se₈(CN)₄(OH)₂]⁴⁻ was synthesized for the first time starting from [Re₆Se₈(OH)₆]⁴⁻, which was crystallized as a salt of the composition Cs_2.75K_1.25[Re₆Se₈(CN)₄(OH)₂]·H₂O (1). The reaction of the complex with Cu²⁺ in an aqueous ammonia or methylamine solutions afforded [Cu(NH₃)₅]₂[Re₆Se₈(CN)₄(OH)₂]·8H₂O (2) or [{Cu(CH₃NH₂)₄}₂Re₆Se₈(CN)₄(OH)₂] (3), respectively. All of these three compounds were characterized by a single-crystal X-ray diffraction method. Compound 1 is crystallized in the tetragonal space group I4/m with eight formula units per cell (a = b = 17.4823(14) Å, c = 19.430(2) Å, V = 5938.3(10) Å³); compound 2 is crystallized in the monoclinic space group P2₁/n with two formula units per cell (a = 12.1845(13) Å, b = 8.6554(9) Å, c = 19.2568(19) Å, β = 91.081(2)°, V = 2030.5(4) Å³); compound 3 is crystallized in the orthorhombic space group Cmcm with four formula units per cell (a = 19.816(4) Å, b = 14.611(3) Å, c = 13.751(3) Å, V = 3981.2(13) Å³). The luminescence properties of 1 were studied in both aqueous solution and solid state. In addition, the electronic structure of [Re₆Se₈(CN)₄(OH)₂]⁴⁻ was elucidated by DFT calculations.     

Synthesis and characterization of tetraphenylporphyrin manganese(III) complexes of phenylcyanamide ligands

Several complexes of TPPMn-L, where TPP is the dianion of tetraphenylporphyrin and L is monoanion of 4-methylphenylcyanamide (4-Mepcyd) (1), 2,4-dimethylphenylcyanamide (2,4-Me₂pcyd) (2), 3,5-dimethylphenylcyanamide (3,5-Me₂pcyd) (3), 4-methoxyphenylcyanamide (4-MeOpcyd) (4), phenylcyanamide (pcyd) (5), 2-chlorophenylcyanamide (2-Clpcyd) (6), 2,5-dichlorophenylcyanamide (2,5-Cl₂pcyd) (7), 2,6-dichlorophenylcyanamide (2,6-Cl₂pcyd) (8), 4-bromophenylcyanamide (4-Brpcyd) (9), and 2,3,4,5-tetrachlorophenylcyanamide (2,3,4,5-Cl₄pcyd) (10), have been prepared from the reaction of TPPMnCl and thallium salt of related phenylcyanamide. Each of the complexes has been characterized by IR, UV-Vis and ¹H NMR spectroscopies.4-Methylphenylcyanamidotetraphenylporphyrin manganese(III) crystallized with one molecule of solvent CHCl₃ in the triclinic crystal system and space group with the following unit cell parameters of: a = 11.596(6) Å; b = 11.768(9) Å; c = 17.81(2) Å; and α, β, γ are 88.91(9)°, 88.16(7)°, 67.90(5)°, respectively; V = 2251(3) Å³; Z = 2. A total of 4234 reflections with I > 2σ(I) were used to refine the structure to R = 0.0680 and R_w = 0.2297. The Mn(III) shows slightly distorted square pyramidal coordination with the 4-methylphenylcyanamide in the axial position, coordinated from nitrile nitrogen. The reduction of each of the TPPMn-L complexes was also examined in dichloromethane and spectroelectrochemical behavior of (1) was investigated and compared to TPPMnCl.     

Study on synthesis, structure, and DNA-binding of Ni, Zn complexes with 2-phenylquinoline-4-carboylhydrazide

2-Phenylquinoline-4-carboylhydrazide (HL), and its novel nickel(II), zinc(II) complexes [M(HL)₂(L)]·2H₂O·NO₃ (M = Ni (1), M = Zn (2)), have been synthesized and characterized by elemental analysis, molar conductivity, and IR spectra. The crystal structure of [Ni(HL)₂(L)]·2H₂O·NO₃ obtained from ethanol solution was determined by X-ray diffraction analysis, crystallized in the rhombohedral system, space group , Z = 18, a = 31.913(3) Å, b = 31.913(3) Å, c = 27.709(2) Å, α = 90°, β = 90°, γ = 120°, R₁ = 0.0647. The interactions of the complexes and the ligand with calf thymus DNA had been investigated using UV-Vis spectra, fluorescent spectra, CD (circular dichroism) spectra, CV (cyclic voltammetry) and viscosity measurements. These compounds were tested against MFC (mouse forestomach carcinoma) cell lines. The complex 1 showed significant cytotoxic activity against MFC cell lines. The cleavage reaction on plasmid DNA has been monitored by agarose gel electrophoresis. Results suggest that the two complexes bound to DNA via a groove binding mode and the complexes can cleave pBR322 DNA.     

Lewis-base copper(I) formates: Synthesis, reaction chemistry, structural characterization and their use as spin-coating precursors for copper deposition

Consecutive synthesis methodologies for the preparation of a series of copper(I) formates [L_mCuO₂CH] (L = ⁿBu₃P: 4a, m = 1; 4b, m = 2; 5, L = [Ti](CCSiMe₃)₂, m = 1, [Ti] = (η⁵-C₅H₄SiMe₃)₂Ti) and [L_mCuO₂CH·HO₂CR] (L = ⁿBu₃P: 7a, m = 1, R = H; 7b, m = 2, R = H; 7c, m = 2, R = Me; 7d, m = 2, R = CF₃; 7e, m = 2, R = Ph. L = (^cC₆H₁₁)₃P, R = H: 8a, m = 2; 8b, m = 3. L = (CF₃CH₂O)₃P, R = H: 9a, m = 2; 9b, m = 3. L = (CH₃CH₂O)₃P, R = H: 10a, m = 2; 10b, m = 3. L = [Ti](CCSiMe₃)₂; m = 1: 11a, R = H; 11b, R = Ph) is reported using [CuO₂CH] (1) and L (2a, L = ⁿBu₃P; 2b, L (^cC₆H₁₁)₃P; 2c, L = (CF₃CH₂O)₃P; 2d, L = (CH₃CH₂O)₃P; 3, L = [Ti](CCSiMe₃)₂) as key starting materials. Addition of formic acid (6a) or carboxylic acid HO₂CR (6b, R = Me; 6c, R = CF₃; 6d, R = Ph) to the afore itemized copper(I) formates 4 and 5 gave metal-organic or organometallic 7-11. The molecular structures of 8a and 11a in the solid state are reported showing a threefold coordinated copper(I) ion, setup by either two coordinatively-bonded phosphorus atoms and one formate oxygen atom (8a) or two π-bonded alkyne ligands and one oxygen atom (11a). A formic acid molecule is additionally hydrogen-bonded to the CuO₂CH moiety. The use of 7b as suitable precursor for the deposition of copper onto TiN-coated oxidized silicon wafers by the spin-coating process below 300 °C is described. Complex 7b offers an appropriate transformation behavior into metal phase by an elimination-decarboxylation mechanism. The morphology of the copper films strongly depends on the annealing conditions. A closed grain network densified by a post-treatment is obtained (8 °C min⁻¹, N₂/H₂ carrier gas). Hydrogen post-anneal to 420 °C after film deposition gave a copper film showing resistivities from 2.5 to 3.7 μΩ cm. This precursor was also used for gap-filling processes.     

The first examples of benzidinium cations templated low-dimensional molybdates

For the first time, use of benzidine as a structure-directing agent has resulted in the crystallization of two novel organic/inorganic hybrid molybdates under hydrothermal condition (180 °C and autogenous pressure). The presence of monoprotonated benzidinium ions in aqueous molybdate solution appears to engineer two new hybrid solids: one-dimensional chains in [H₂NC₁₂H₈NH₃]₂Mo₂O₇, 1 (a = 5.9686, b = 7.0761 and c = 14.3293 Å, α = 77.17°, β = 85.25° and γ = 88.56°; and Z = 2) and two-dimensional step-wise layered molybdate [H₂NC₁₂H₈NH₃]₂Mo₅O₁₆, 2 (a = 5.6843, b = 14.3024 and c = 19.4787Å, α = 108.1°, β = 98.4° and γ = 90.0°; , Z = 2). 1 is an unusual solid wherein the anionic chains are charge compensated by counter cations which also act as ligands to the metal and 2 is a new layered molybdate built of MoO₅ square pyramids and MoO₆ octahedra.     

Synthesis, structure and magnetic property of a 2D grid-like copper(II) complex with end-on azido and pyrazine bridges

A 2D grid-like copper(II) complex [Cu(N₃)₂(pyz)](pyz = pyrazine) (1) has been synthesized and characterized by single crystal X-ray analysis and magnetic measurements. The 2D grid-like network of 1 consists of 1D chain of Cu-pyz units connected by end-on azido bridge. 1 crystallizes in the monoclinic space group C2 with a = 15.148(6) Å, b = 6.877(2) Å, c = 3.4591(12) Å and Z = 2. The magnetic investigation showed the presence of an antiferromagnetic interaction between the copper(II) ions mainly mediated through pyrazine bridge.     

Novel polynuclear thallium thiolates with cage structures

Yellow thallium(I)-tetra(2-butanethiolato)-thallium(III) Tl[Tl(SC₄H₉)₄] (1) crystallizes from a solution of thallium(I) carbonate and 2-butanethiol in DMF after heating under reflux in air. In the crystal structure (space group: , a = 8.941(3) Å, b = 11.078(4) Å, c = 13.458(4) Å, α = 70.81(3)°, β = 83.65(3)°, γ = 74.78(3)°, Z = 2) regular, TlS₄ tetrahedra are bridged by thallium(I) atoms to an one-dimensional framework. The thallium(I) atoms are in fivefold distorted coordination and are linked to four further TlS₄ tetrahedra. The resulting Tl₄(S-Bu)₈ units consist of two face-sharing Tl₃S₄ defect cubane entities.TlSC₃H₇ (2) was obtained from a solution of thallium(I) carbonate and 2-propanethiol in DMF after heating under reflux in air. The crystal structure (space group C2/c, a = 22.501(5) Å, b = 10.360(2) Å, c = 12.760(3) Å, β = 107.92(2)°, Z = 16) contains novel [Tl₄(SPr)₅]⁻ units which are linked via thallium atoms to one-dimensional molecular chains running parallel to [0 0 1].