Assembly of a New Cyano‐bridged 4f‐3d Dimer Sm(DMSO)4‐ (H2O)3Cr(CN)6 and Crystal Structure of [K3(18‐crown‐6)3‐(H2O)4]Cr(CN)6·3H2O

A new cyano‐bridged binuclear 4f‐3d complex Sm(DMSO)₄‐(H₂O)₃Cr(CN)₆ was synthesized and characterized by single crystal structure analysis. It crystallizes in monoclinic, space group P2₁ with a=0.9367(2) nm, b = 1.3917(3) nm, c = 1.1212(2) run, β = 99.88(3)° and Z = 2. In this binuclear complex, Sm atom is eight coordinated and linked to the Cr atom by a cyano bridge. The molecules packs to form 3D structure due to the hydrogen bonds among them. [K₃(18‐C‐6)₃(H₂O)₄]Cr(CN)₆·3H₂O (18‐C‐6 represents 18‐crown‐6‐ether) that was synthesized as a byproduct in the preparation of a Gd—Cr complex is also structurally characterized. Crystal data: triclinic, space group P‐l with a = 1.0496(7) nm, b= 1.1567(14) nm, c = 1.3530(13) nm, a = 94.15(9)°, β = 96.04(8)°, γ = 95.25(9)° and Z = l. [K₃(18‐C‐6)₃(H₂O)₄]‐Cr(CN)₆·3H₂O consists of ionic [K₃(18‐C‐6)₃(H₂O)₄]³⁺ and [Cr(CN)₆]^3‐ pairs, of which the [K₃(18‐C‐6)₃(H₂O)₄]³⁺ ion is a trinuclear duster connected by water, and K atoms are eight coordinated by eight oxygen atoms of one 18‐C‐6 and two water molecules.     

Structure and Thermal Stability of a Novel 2‐D Layered Copper(II) Coordination Polymer with the Bidentate Ligand 1, 2, 4‐Triazol‐5‐one

Single crystals of {[Cu(TO)₂(H₂O)₂](NO₃)₂}_n (TO: 1, 2, 4‐triazol‐5‐one) were grown by slow evaporation from aqueous solution. It crystallizes in the orthorhombic space group Pbca, with a = 7.082(1), b = 10.285(1), c = 17.911(3)Å, V = 1304.6(3)ų, Z = 4. The Cu^II distorted octahedra are bridged by bidentate TO ligands into infinite 2‐D interlaced rhombic grid‐like network planes, {[Cu(TO)₂(H₂O)₂]²⁺}_n. Hydrogen bonds, electrostatic interactions, and weak van der Waals' forces assemble these planes and the NO₃^— anions to a layered structure. The title compound decomposes at 153.4 °C to the final products, Cu(CN)₂ and CuO.     

Synthesis and crystal structure of polymer cobalt(II) complex, 1,2,4,5-benzenetetracarboxylate hexaimidazole tetraaqua cobalt (II) tetrahydrate

The crystal structure of the title complex {[Co(TCB)2/2-(IMI)2(H2O)2][Co(IMI)4(H2O)2] } (H2O)4 (where TCB = 1,2,4,5-benzenetetracarboxylic anion; IMI = imidazole) has been determined by X-ray diffraction method. Crystal data for {[Co(TCB)2/2(IMI)2(H2O)2][Co(IMI)4(H2O)2]}-(H2O)4: triclinic, space group P 1, a = 1.0647(2) nm, b = 1.1165(1)nm,c = 1.00361(1)nm,α = 91.56(1)°,β = 111.34(1)°, γ = 115.642(10)°, V = 0.9772(3) nm5, Z = 1. The polymer cobalt (II) complex has a novel three-dimension network structure. Co(1) atom and Co(2) atom both are coordinated in an octahedral arrangement and located in the center of the coordination anion and the center of the coordination cation, respectively. Moreover four carboxyl groups of TCB are divided into two types, two para-carboxyl groups bridge Co(1) atom in monodentate fashion and other two para-carboxyl groups are in free.     

One Dimensional Coordination Polymer Constructed by1,2—Bis（4—pyridinecarboxamido）ethane and Copper（Ⅱ）

The ligand [1,2‐bis(4‐pyridinecarboxamido)ethane] (L) and the coordination polymer |[Cu(L)₂(H₂O)]‐(NO₃)₂·6H₂O|·(1) haw been synthesized and characterized by ER and ¹H NMR spectra. Their molecular structures and the packing of 1 have been determined by single‐crystal X‐ray diffraction analysis. The Cu(n) in 1 is bridged by two ligands forming an infinite one‐dimensional chain like structure and L in 1 adopts a different conformation from its free state. 1 belongs to monoclinic, space group P2₁/n, a = 1.2896(3) nm, b = 1.2552(8) nm, c = 2.2903(19) nm, β = 93.04(5)°, Z = 4, V = 3.702(4) nm³. The TG and DTG experiments showed that the uncoordinated H₂O can be removed at low temperature by heating, and it does not decompose until 250 °C.     

Synthesis,Crystal Structure,and Magnetic Properties of {[Cu(phen)]2(C4H2O4)2} · 4.5H2O with C4H4O4 = Maleic Acid

Reaction of CuCl₂ · 2H₂O, phenanthroline, maleic acid and NaOH in CH₃OH/H₂O (1:1 v/v) at pH = 7.0 yielded blue {[Cu(phen)]₂(C₄H₂O₄)₂} · 4.5H₂O, which crystallizes in the monoclinic space group C2/c (no. 15) with cell dimensions: a = 18.127(2)Å, b = 12.482(2)Å, c = 14.602(2)Å, β = 103.43(1)°, U = 3213.5(8)ų, Z = 4. The crystal structure consists of the centrosymmetric dinuclear {[Cu(phen)]₂(C₄H₂O₄)₂} complex molecules and hydrogen bonded H₂O molecules. The Cu atoms are each square‐pyramidally coordinated by two N atoms of one phen ligand and three carboxyl O atoms of two maleato ligands with one carboxyl O atom at the apical position (d(Cu‐N) = 2.008, 2.012Å, equatorial d(Cu‐O) = 1.933, 1.969Å, axial d(Cu‐O) = 2.306Å). Two square‐pyramids are condensed via two apical carboxyl O atoms with a relatively larger Cu···Cu separation of 3.346(1)Å. The dinuclear complex molecules are assembled via the intermolecular π—π stacking interactions into 1D ribbons. Crossover of the resulting ribbons via interribbon π—π stacking interactions forms a 3D network with the tunnels occupied by H₂O molecules. The title complex behaves paramagnetically between 5—300 K, following the Curie‐Weiss law _χm(T—θ) = 0.435 cm³ · mol^—1 · K with θ = 1.59 K.     

Four Discrete Transition Metal Complexes Involving Pyridyl‐substituted Nitronyl Nitroxide: Syntheses,Crystal Structures,and Magnetic Properties

Four discrete metal‐radical complexes, [Cu(p‐MePh‐COO)₂(NITpPy)₂] ( 1 ), [Ni(m‐MePhCOO)₂(NITpPy)₂(H₂O)₂] · (CH₃‐OH)₂ ( 2 ), [Mn(p‐MePhCOO)₂(NITpPy)₂(H₂O)₂] ( 3 ), and [Mn(m‐MePhCOO)₂(NITpPy)₂(H₂O)₂] ( 4 ) [NITpPy = 2‐(4‐pyridyl)‐4,4,5,5‐tetramethyl‐4,5‐dihydro‐1H‐imidazolyl‐1‐oxyl‐3‐oxide] were synthesized and characterized by elemental analyses, IR spectroscopy, PXRD, single‐crystal X‐ray diffraction, and magnetic susceptibility. For the four complexes, the crystal structural analyses indicate that the two radical ligands coordinated to the metal ions by the nitrogen atoms of the pyridine rings form three spin complexes, where toluates act as co‐ligands. Weak antiferromagnetic interactions [J_Cu–Rad = –6.75 cm^–1 ( 1 ), J_Co–Rad = –4.15 cm^–1 ( 2 ), J_Mn–Rad = –0.22 cm^–1 ( 3 ), and J_Mn–Rad = –3.74 cm^–1 ( 4 )] were observed, spin polarization mechanism and orbital symmetry are used to explain the magnetic coupling in these complexes.     

Hydrothermal Synthesis and Structure of a New 3D Lanthanide—Carboxylate Framework,[La（btec）1／2（H2btec）1／2（H2O）]n（H4btec=1,2,4,5—Benzeneteracarboxylic acid）

The title complex, [La(btec)_1/2(H₂btec)_1/2 (H₂O)]_n (H₄btec= 1, 2,4,5‐benzenetetracarboxylic acid) (1) was synthesized by the hydrothermal reaction of 1,2,4,5‐benzenetetracarboxylic dianhydride with La(NO₃)₃·6H₂O in H₂O, and crystallizes in the triclinic system, space group P‐1 with a = 0.64403(3) nm, b = 0.94500(4) nm, c = 0.96380(5) nm, a = 88.535(2)°, β = 100.314(2)°, γ = 76.6470(10)°, V = 1.60968(10) nm³, Z = 2, and final R = 0.0274, R_w = 0.0735. In 1, each La(m) ion is coordinated by eight oxygen atoms from six carboxylate groups and one coordinated water molecule. Two different coordination modes of H₄btec were present in the structure, one of which contains two protonated carboxylate groups to balance the charge.     

Molecular and Low‐dimensional Coordination Compounds of Copper(II) and 3, 5‐Dimethylpyrazole — Synthesis,Crystal Structure,and Properties

Three 3, 5‐dimethylpyrazole (pz*) copper(II) complexes, [Cu(pz*)₄(H₂O)](ClO₄)₂ ( 1 ), [Cu(pz*)₂(NCS)₂]·H₂O ( 2 ), and [Cu(pz*)₂(OOCCH=CHCOO)(H₂O)]·1.5H₂O ( 3 ), have been synthesized and characterized with single crystal X‐ray structure analysis. 1 crystallizes in the tetragonal space group, 14/m, with a = 14.027 (3) Å, c = 16.301 (5) Å, and Z = 4. 2 crystallizes in the monoclinic space group, P2₁/c, with a = 8.008 (3) Å, b = 27.139 (9) Å, c = 8.934 (3) Å, β = 106.345 (6)°, and Z = 4. 3 crystallizes in the triclinic space group, P1¯, with a = 7.291 (9) Å, b = 10.891 (13) Å, c = 11.822 (14) Å, α = 80.90 (2)°, β = 79.73(2)°, γ = 70.60(2)°, and Z = 2. In 1 , one water molecule and four pz* ligands are coordinated to Cu^II. Two [Cu(pz*)₄(H₂O)]²⁺ units are connected to ClO₄^— via hydrogen bonds. One lattice water molecule is found in the unit cell of 2 , which forms an one‐dimensional chain via intermolecular hydrogen bonds with the N‐H atom of pz*. In 3 , the oxygen atom of the coordinated water molecule is connected with two C=O groups of two neighbouring maleic acid molecules to form a linear parallelogram structure. Another C=O group of maleic acid forms a hydrogen bond with the N‐H atom of pz* to create a two‐dimensional structure. The spectroscopic and bond properties are also discussed.     

Structure of Bischloro tris (1, 10‐phenanthroline) copper (II) Dichloromethane Solvate Nonahydrate: [Cu(phen)3]Cl2CH2Cl2·9H2O

The crystal and molecular structures of [Cu(phen)₃] Cl₂ · CH₂Cl₂^.9H₂O (PHEN= 1, 10‐pbenanthroline) have been determined by X‐ray crystallography. The complex crystallizes in triclinic system, space group P1, with lattice parameters a = 1.26000(3), b = 1.37525(4), c = 1.42750(3)nm, α = 85.2970(1),β = 66.8400(1), γ= 83.09(1)°, and Z = 2. The coordinated cations contain a six‐coordinated copper atom chelated by three PHEN ligands, and the Jahn‐Teller effect of the Cu(II) ion results in a distorted octahedral arrangement with the six Cu? N distances ranging from 0.2112(6) to 0.2265(7) nm. In addition to the copper coordinated cation, there are two chloride ions, one dichloromethane solvate and nine water molecules in its asymmetric unit. In the solid state, the title compound forms three dimensional network structures through hydrogen bonds. The intermolecular hydrogen bonds connect the [Cu(phen)₃]²⁺, chloride ion, dichloromethane solvate and H₂O moieties altogether.     

Hydroxo‐bridged Tetranuclear CuII Complexes: {[Cu(bpy)(OH)]4Cl2}Cl2 · 6 H2O and {[Cu(phen)(OH)]4(H2O)2}]Cl4 · 4 H2O

The blue tetranuclear Cu^II complexes {[Cu(bpy)(OH)]₄Cl₂}Cl₂ · 6 H₂O ( 1 ) and {[Cu(phen)(OH)]₄(H₂O)₂}Cl₄ · 4 H₂O ( 2 ) were synthesized and characterized by single crystal X‐ray diffraction. ( 1 ): P 1 (no. 2), a = 9.240(1) Å, b = 10.366(2) Å, c = 12.973(2) Å, α = 85.76(1)°, β = 75.94(1)°, γ = 72.94(1)°, V = 1152.2(4) ų, Z = 1; ( 2 ): P 1 (no. 2), a = 9.770(3) Å, b = 10.118(3) Å, c = 14.258(4) Å, α = 83.72(2)°, β = 70.31(1)°, γ = 70.63(1)°, V = 1252.0(9) ų, Z = 1. The building units are centrosymmetric tetranuclear {[Cu(bpy)(OH)]₄Cl₂}²⁺ and {[Cu(phen)(OH)]₄(H₂O)₂}⁴⁺ complex cations formed by condensation of four elongated square pyramids CuN₂(OH)₂L^ap with the apical ligands L^ap = Cl, H₂O, OH. The resulting [Cu₄(μ₂‐OH)₂(μ₃‐OH)₂] core has the shape of a zigzag band of three Cu₂(OH)₂ squares. The cations exhibit intramolecular and intermolecular π‐π stacking interactions and the latter form 2D layers with the non‐bonded Cl^– anions and H₂O molecules in between (bond lengths: Cu–N = 1.995–2.038 Å; Cu–O = 1.927–1.982 Å; Cu–Cl^ap = 2.563; Cu–O^ap(OH) = 2.334–2.369 Å; Cu–O^ap(H₂O) = 2.256 Å). The Cu…Cu distances of about 2.93 Å do not indicate direct interactions, but the strongly reduced magnetic moment of about 2.74 B.M. corresponds with only two unpaired electrons per formula unit of 1 (1.37 B.M./Cu) and obviously results from intramolecular spin couplings (χ_m(T‐θ) = 0.933 cm³ · mol^–1 · K with θ = –0.7 K).     

Configurational assignment in alkyl‐branched sugars via the geminal C,H coupling constants

The measurement of the magnitude and sign of ²J(C,H) couplings offers a reliable way to determine the absolute configuration at a carbon center in a fixed cyclic system. A decrease of the dihedral angle ? in the O—C_A—C_B—H fragment always leads to a change of the ²J(C_A,H_B) coupling to more negative values, independent of the type and position of substituents at the two carbon centers. The orientations of the two substituents at C‐3 of the epimeric pair 1 and 2 were determined unambiguously through the measurement of the geminal coupling constants between C‐3 and the hydrogen atoms at C‐2 and C‐4. In particular, ²J(C‐3,H‐2ax) with ?1.5 Hz, ? = 174° in 1 and ?6.6 Hz, ? = 47° in 2 , and ²J(C‐3,H‐4) with +1.5 Hz, ? = 175° in 1 and ?4.7 Hz, ? = 49° in 2 showed the greatest differences between the two epimers. Both couplings therefore allow the determination of the absolute configuration at C‐3. It should be noted, however, that the size of the coupling constants can be different for dihedral angles of nearly identical size, when there are different numbers of electronegative substituents on the two coupling pathways, i.e. no O‐substituent at C‐2, but one axial O‐substituent at C‐4. It becomes clear that it is not sufficient to measure the magnitude of ²J coupling constants only, but that the sign of the geminal coupling is needed to identify the absolute configuration at a chiral center. The coupling of C‐3 with H‐2eq is not useful for the determination of the configuration at C‐3, as the similarity of the dihedral angles ? (O—C‐3—C‐2—H‐2eq) (57° in 1 and 70° in 2 ) leads to identical coupling constants (?6.1 Hz) for both epimers. Copyright © 2003 John Wiley & Sons, Ltd.     

Preparation and Molecular Structure of Binuclear Nickel (I) Complex Bridged by 1,2,4, 5‐Benzenetetracarboxylato Tetravalent Anion

The title complex [(H₂O)₂(IMI)₃Ni(TCB)Ni(IMI)₃‐(H₂O)₂] H₂O (TCB = 1,2,4,5‐benzenetetracarboxylato te‐travalent anion; IMI = imidazole) has been prepared by the reaction of Ni(IMI)₃(Ac)₂ and TCB in aqueous solution. The crystal structure has been determined by single‐crystal X‐ray diffraction method. It crystallizes in the monoclinic system, space group P2₁/c(# 14), a = 1.2714(4) nm, b = 0.9411 (3) nm, c = 1.5869(4) nm, β= 108.54(2)°, V= 1.8001(9) nm³, Z = 2. The main feature of the crystal structure is a symmetric binuclear unit made up of two slightly distorted coordination octahedrons, which are bridged by TCB in monodentate fashion to each metal ion. Moreover three nitrogen atoms from three imidazoles, three oxygen atoms from two water molecules and one carboxylate group of TCB coordinated to a nickel (I) ion are found on a face of the octahedron respectively, so the octahedron is a facial isomer.     

Synthesis and Structural Characterization of the Helical Coordination Polymers [Co(phen)(oba)(H2O)2] and [Cd3(phen)3(oba)2(Hoba)2(H2O)2] (phen = 1, 10‐phenanthroline; oba = 4, 4′‐oxybis(benzoate)

Two coordination polymers, [Co(phen)(oba)(H₂O)₂] ( 1 ) and [Cd₃(phen)₃(oba)₂(Hoba)₂(H₂O)₂] ( 2 ) (oba = 4, 4′‐oxybis(benzoate), phen = 1, 10‐phenanthroline) have been synthesized under hydrothermal conditions. Complex 1 crystallizes in monoclinic, P2₁/n, a = 7.543(6), b = 33.05(2), c = 9.902(5)Å, β = 103.69(2)°, V = 2398(3)ų, Z = 4; 2 in monoclinic, P2/n, a = 15.11(1), b = 10.069(8), c = 28.02(2)Å, β = 101.83(1)°, V = 4174(5)ų, Z = 2. X‐ray single‐crystal diffraction investigations shows that the complexes 1 and 2 consist of helical chains, which are further assembled into layers and networks via supramolecular interactions such as π—π stacking interactions and hydrogen bonds, respectively. The results indicate that the coordination environment is one of the most important factors for assembly of single‐stranded helical chains into double‐stranded helical chains via supramolecular interactions.     

Synthesis and crystal structure of heteronuclear La( III )‐Cu(II ) complex { [LaCu2(NTA)2(4,4′‐bpy)(H2O)3]NO3·5H2O}n

A novel La( III )‐Cu( II ) heterometallic coordination polymer {[LaCu₂(NTA)₂(4,4′‐bpy)(H₂O)₃]NO₃·5H₂O]_n, where H₃NTA denotes nitrilotriacetic acid and 4,4′‐bpy denotes 4, 4‐bipyridine, was synthesized and characterized by IR spectrum, elemental analysis and X‐ray diffraction. The complex crystallizes in the triclinic space group Pi with cell parameters a = 1.33710(10) nm, b = 1,44530(10) nm, c =1.0949(2) nm, α = 71.905(7)°, β = 74.327(7)°, γ = 64.427(9)°, V = 1.7912(4) nm³and Z = 2. It consists of heterometallic units, in which each La( II ) ion is coordinated in a distorted monocapped square antiprism by three oxygen atoms from water molecules and six carboxyl oxygen atoms from five NTA^3? ions, and each Cu( I ) ion is coordinated by one nitrogen atom from 4,4′‐bpy and one nitrogen atom, three oxygen atoms from NTA^3?. In the title complex, La( I ) ions and Cu( II ) ions are connected by the heterometallic bridging of NTA^3?, constructing a two‐dimensional network structure along the [110]. And it is extended into an infinite three‐dimensional network structure by the formation of homometallic bridging of Cu‐4, 4′‐bpy‐Cu, exhibiting a certain inclusion ability.     

A Novel Cu(Ⅱ） Complex with 2,2′-Bipyridyl and L-Methioninate -synthesis,Characterization,Molecular Structure and Stability

The ternary Cu(II) complex with 2,2′‐bipyridyl (bipy) and L‐methioninate (L‐Met) has been synthesized and characterized by elemental analysis, molar conductivity, UV‐Vis spectra, IR spectra and pH‐potentiometric titration methods. The structure of the complex [Cu(L‐Met) (bipy) (H₂O)]ClO₄ · 3/8H₂O was characterized by the X‐ray diffraction analysis. It crystallizes in the triclinic system, space group P1 with four molecules in a unit cell of dimensions, a = 0.7656(2) nm, b = 1.3142(3) nm, c = 2.0596(4) nm, α = 97.70(3)°, β = 97.96(3)°, γ = 94.33(3)°, V= 2.0244(8) nm³, R₁, = 0.0441 and wR₂ = 0.0678. The crystal contains four crystllographically independent [Cu(L‐Met) (bipy) (H₂O)]⁺ complexes (Cu1—Cu4), having a distorted square‐pyramidal geometry with the same coordinated atoms around each copper center. The base plane is occupied by two nitrogen atoms of one bipy, the amino nitrogen atom and one carboxylate oxygen atom from each independent L‐Met moiety, and one water oxygen at an axial position. Cu1 and Cu3 are essentially enantiomers of Cu2 and Cu4. The four molecules are packed with each other by intermolecular hydrogen‐bonding and aromatic‐ring stacking interactions.     

A Hydrogen Adipato‐bridged Copper(II) Coordination Polymer: [Cu(bpy)(HL)]2L · 6H2O (bpy = 2, 2'‐Bipyridine,H2L = Adipic Acid)

Reaction of a fresh Cu(OH)_2x(CO₃)_1—x · yH₂O precipitate with adipic acid (H₂L) and 2, 2'—bipyridine (bpy) in ethanolic aqueous solution at room temperature afforded the hydrogen adipato bridged Cu^II coordination polymer [Cu(bpy)(HL)]₂L · 6H₂O consisting of double chains according to {[Cu(bpy)(HL)_2/2]₂L} and hydrogen bonded H₂O molecules. The chains result from [Cu(bpy)]²⁺ units bridged by bis—monodentate hydrogen adipato ligands and further crosslinked by bis—monodentate adipato ligands. Through the interchain π—π stacking interactions and interchain C(bpy)—H···O(adipato) hydrogen bonding interactions, the double chains are assembled into layers, between which the crystal H₂O molecules are located. The Cu atoms are square pyramidally coordinated by two N atoms of one bpy ligand and three O atoms of one adipato ligand and two hydrogen adipato ligands. The doubly bonded oxygen atom of the protonated carboxyl group occupies the apical position (Cu—N: 1.997, 2.005 Å; equatorial Cu—O: 1.925, 1.942 Å; apical Cu—O: 2.354 Å). Furthermore, the thermal behavior of the compound will be discussed. Crystal data: triclinic, P1¯ (no. 2), a = 9.618(1) Å, b = 9.933(1) Å, c = 12.782(2) Å, α = 70.88(1)°, β = 73.70(1)°, γ = 75.60(1)°, V = 1090.7(2) ų, Z = 1, R = 0.0453 and wR² = 0.1265 for 4643 observed reflections (F_o² > 2σ(F_o²)) out of 4985 unique reflections.     

Synthesis and Crystal Structure of [Cu2(H2O)2(phen)2(OH)2][Cu2(phen)2(OH)2(CO3)2] · 10 H2O with phen = 1,10‐phenanthroline

The blue copper complex [Cu₂(H₂O)₂(phen)₂(OH)₂][Cu₂(phen)₂(OH)₂(CO₃)₂] · 10 H₂O, which was prepared by reaction of 1,10‐phenanthroline monohydrate, CuCl₂ · 2 H₂O and Na₂CO₃ in the presence of succinic acid in CH3OH/H₂O at pH = 13.0, crystallized in the triclinic space group P1 (no. 2) with cell dimensions: a = 9.515(1) Å, b = 12.039(1) Å, c = 12.412(2) Å, α = 70.16(1)°, β = 85.45(1)°, γ = 81.85(1)°, V = 1323.2(2) ų, Z = 1. The crystal structure consists of dinuclear [Cu₂(H₂O)₂(phen)₂(OH)₂]²⁺ complex cations, dinuclear [Cu₂(phen)₂(OH)₂(CO₃)₂]^2– complex anions and hydrogen bonded H₂O molecules. In both the centrosymmetric dinuclear cation and anion, the Cu atoms are coordinated by two N atoms of one phen ligand, three O atoms of two μ‐OH groups and respectively one H₂O molecule or one CO₃^2– anion to complete distorted [CuN₂O₃] square‐pyramids with the H₂O molecule or the CO₃^2– anion at the apical position (equatorial d(Cu–O) = 1.939–1.961 Å, d(Cu–N) = 2.026–2.051 Å and axial d(Cu–O) = 2.194, 2.252 Å). Two adjacent [CuN₂O₃] square pyramids are condensed via two μ‐OH groups. Through the interionic hydrogen bonds, the dinuclear cations and anions are linked into 1D chains with parallel phen ligands on both sides. Interdigitation of phen ligands of neighboring 1D chains generated 2D layers, between which the hydrogen bonded water molecules are sandwiched.     

Crystal Structures,Magnetic Properties and Catecholase‐Like Activities of μ‐Alkoxo‐μ‐Carboxylato Double Bridged Dinuclear and Tetranuclear Copper(II) Complexes

One μ‐alkoxo‐μ‐carboxylato bridged dinuclear copper(II) complex, [Cu₂(L¹)(μ‐C₆H₅CO₂)] ( 1 )(H₃L¹ = 1,3‐bis(salicylideneamino)‐2‐propanol)), and two μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear copper(II) complexes, [Cu₄(L¹)₂(μ‐C₈H₁₀O₄)(DMF)₂]·H₂O ( 2 ) and [Cu₄(L²)₂(μ‐C₅H₆O₄]·2H₂O·2CH₃CN ( 3 ) (H₃L² = 1,3‐bis(5‐bromo‐salicylideneamino)‐2‐propanol)) have been prepared and characterized. The single crystal X‐ray analysis shows that the structure of complex 1 is dimeric with two adjacent copper(II) atoms bridged by μ‐alkoxo‐μ‐carboxylato ligands where the Cu···Cu distances and Cu‐O(alkoxo)‐Cu angles are 3.5 11 Å and 132.8°, respectively. Complexes 2 and 3 consist of a μ‐alkoxo‐μ‐dicarboxylato doubly‐bridged tetranuclear Cu(II) complex with mean Cu‐Cu distances and Cu‐O‐Cu angles of 3.092 Å and 104.2° for 2 and 3.486 Å and 129.9° for 3 , respectively. Magnetic measurements reveal that 1 is strong antiferromagnetically coupled with 2J =‐210 cm^?1 while 2 and 3 exhibit ferromagnetic coupling with 2J = 126 cm^?1 and 82 cm^?1 (averaged), respectively. The 2J values of 1–3 are correlated to dihedral angles and the Cu‐O‐Cu angles. Dependence of the pH at 25 °C on the reaction rate of oxidation of 3,5‐di‐tert‐butylcatechol (3,5‐DTBC) to the corresponding quinone (3,5‐DTBQ) catalyzed by 1–3 was studied. Complexes 1–3 exhibit catecholase‐like active at above pH 8 and 25 °C for oxidation of 3,5‐di‐tert‐butylcatechol.     

Syntheses and Structures of Two Selenite Chloride Hydrates: Co(HSeO3)Cl · 3 H2O and Cu(HSeO3)Cl · 2 H2O

The first selenite chloride hydrates, Co(HSeO₃)Cl · 3 H₂O and Cu(HSeO₃)Cl · 2 H₂O, have been prepared from solution and characterised by single‐crystal X‐ray diffraction. The cobalt phase adopts an unusual “one‐dimensional” structure built up from vertex‐sharing pyramidal [HSeO₃]^2–, and octahedral [CoO₂(H₂O)₄]^2– and [CoO₂(H₂O)₂Cl₂]^4– units. Inter‐chain bonding is by way of hydrogen bonds or van der Waals' interactions. The atomic arrangement of the copper phase involves [HSeO₃]^2– pyramids and Jahn‐Teller distorted [CuCl₂(H₂O)₄] and [CuO₄Cl₂]^8– octahedra, sharing vertices by way of Cu–O–Se and Cu–Cl–Cu bonds. Crystal data: Co(HSeO₃)Cl · 3 H₂O, M_r = 276.40, triclinic, space group P 1 (No. 2), a = 7.1657(5) Å, b = 7.3714(5) Å, c = 7.7064(5) Å, α = 64.934(1)°, β = 68.894(1)°, γ = 71.795(1)°, V = 337.78(7) ų, Z = 2, R(F) = 0.036, wR(F) = 0.049. Cu(HSeO₃)Cl · 2 H₂O, M_r = 263.00, orthorhombic, space group Pnma (No. 62), a = 9.1488(3) Å, b = 17.8351(7) Å, c = 7.2293(3) Å, V = 1179.6(2) ų, Z = 8, R(F) = 0.021, wR(F) = 0.024.     

Syntheses,Structures and Characterizations of Two Vanadium(V) Complexes:[2-MePyH][V^vO2(C14H9N2O3Br)] and [2-EtPyH][V^VO2(C14H9N2O3Br)]

Two new oxovanadium(V) complexes, [2‐MePyH][V^vO₂(L)] (3) and[2‐EtPyH][V^vO₂,(L)] (4) (salicylaldehyde 5‐bromo salicyloylhydrazone is abbreviated as H₂L; 2‐MePyH is protonated 2‐Mepyridine; 2‐EtPyH presents protonated 2‐Et‐pyridine) were obtained from a reaction of VOSO₄ and H₂L in acetonitrile‐methanol with small quantity of 2‐Me‐pyridine or 2‐Et‐pyridine, and characterized by X‐ray diffraction and spectroscopic methods. Crystal data: [2‐MePyH][VO₂(L)] (3), C₂₀H₁₇N₃O₅BrV, M_r = 510.2, monoclinic, P2₁/n, a = 0.7363(1) nm, 6 = 0.9514(1) nm, c = 2.8594(2) nm, β = 95.305(2)°, Z = 4 and V=1.9946(3) nm³, μ(Mo Kα) = 2.539 mm^?1; [2‐EtPyH][VO₂(L)] (4), C₂₁H₁₉N₃ O₃BrV, M_r = 524.2, triclinic, P1 , a = 0.8051(1) nm, b = 0.9413(1) nm, c = 1.4648(2) nm, α=99.1900(10)°, α = 99.4530(10)°, γ = 104.6670(10)°, Z = 2 and V= 1.0355(2) nm³, μ(Mo Kα) = 2.448 mm^?1, X‐Ray analyses revealed that the crystal structures of 3 and 4 have similar packing modes.