Hydrothermal synthesis of organic-inorganic hybrid materials: network structures of the bimetallic oxides [M(Hdpa)2V4O12] (M = Co, Ni, dpa = 4,4'-dipyridylamine)

The hydrothermal reactions of MCl(2).6H2O (M = Co, Ni) NaVO3, 4,4'-dipyridylamine (dpa), and H2O yield materials of the type [M(Hdpa)2V4O12] (M = Co (1), Ni (2)). The two-dimensional structures of 1 and 2 are constructed from bimetallic oxide networks (MV4O12)n2n- with monodentate Hdpa projecting the protonated ring into the interlamellar region. The oxide network may be described as ruffled chains of corner-sharing (VO4) tetrahedra linked by (NiO4N2) octahedra into the two-dimensional assembly. Crystal data: C10H10Co0.5N3O6V2(1), monoclinic P2(1)/c, a = 10.388(1) A, b = 7.6749(7) A, c = 16.702(2) A, beta = 102.516(1) degrees, Z = 4. C10H10N3Ni0.5O6V2 (2), monoclinic, P2(1)/c, c = 10.3815(2) A, b = 7.7044(2) A, c = 16.6638(4) A, beta = 102.573(1) degrees, Z = 4.     

Oxamidate-bridged dinuclear five-coordinate nickel(II) complexes: a magneto-structural study

The preparation, spectroscopic characterization, and magnetic study of three new oxamidate-bridged nickel(II) dinuclear complexes of formulas ([Ni(Me3[12]aneN3)]2(mu-oa))(PF6)2 (1), ([Ni(Me3[12]aneN3)]2(mu-dmoa))(PF6)2 (2), and ([Ni(Me3[12]aneN3)]2(mu-dpoa))(PF6)2 (3) (Me3[12]aneN3 = 2,4,4-trimethyl-1,5,9-triazacyclododec-1-ene, oa = oxamidate, dmoa = N,N'-dimethyloxamidate, and dpoa = N,N'-diphenyloxamidate) are reported. The crystal structures of two of them (1 and 3) have been determined. 1 and 3 crystallize in the monoclinic system, space group P2(1)/c, with Z = 2 and a = 7.901(4) A, b = 13.597(6) A, c = 17.565(10) A, and beta = 96.46(4) degrees for 1 and a = 13.854(3) A, b = 17.469(4) A, c = 12.543(3) A, and beta = 116.22(3) degrees for 3. The structures of 1 and 3 consist of dinuclear ([Ni(Me3[12]aneN3)]2(mu-oa))2+ and ([Ni(Me3[12]aneN3)]2(mu-dpoa))2+ cations and hexafluorophosphate anions. Each nickel in 1-3 is five-coordinate, and the substitution of the hydrogen atom of the amidate nitrogen of 1 by a methyl (2) or a phenyl (3) group causes a significant modification of the stereochemistry of the nickel(II) ions from square pyramidal toward trigonal bipyramidal (tau values of 0.12 and 0.48 for 1 and 3, respectively). The NOESY spectrum of 3 has allowed us to achieve the assignment of the phenyl protons of the N,N'-diphenyloxamidate. The value of magnetic coupling between the two nickel(II) ions across the oxamidate bridge [J = -57.0 (oa, 1), -38.0 (dmoa, 2) and -30.5 cm(-1) (dpoa, 3)] is very sensitive to this stereochemical change, and its variation is explained on the basis of orbital considerations. DFT type calculations have been performed to analyze and substantiate the trend of the magnetic coupling in 1-3.     

Synthesis,Crystal Structure and Magnetic Properties of a Coordination Polymer [Ni（C10H13NO4）（H2O）2]n

A novel organic polycarboxylate N-cyclohexylaziridines-2R,3S-dicarboxylic acid was synthesized and reacted with Ni2(OH)2CO3.As a result,a coordination polymer was obtained.It crystallizes in orthorhombic,space group Pbca with a = 8.6325(10),b = 10.5414(13),c = 27.644(3) ,Z = 4,V = 2515.5(5) 3,C20H34N2Ni2O12,Mr = 611.91,Dc = 1.616 g/cm3,μ = 1.562 mm-1,F(000) = 1280,the final R = 0.0320 and wR = 0.0677 for 2854 independent reflections with Rint = 0.0390.Crystal structure shows that the coordination environment around the Ni(Ⅱ) ion can be described as a slightly distorted octahedron.The ligands act as a bridge through the carboxyl O atoms and join the Ni atoms into an infinite 1D chain structure.The 1D chain forms a 2D network through intermolecular O-H…O hydrogen bonds.The magnetic susceptibility measurements(2～300 K) agree with a weak antiferronmagnetic interaction between neighboring Ni ions in the chain.     

Synthesis, characterization, and spontaneous resolution of chiral nickel(II) complexes with the tripod ligand tris[2-(((2-phenylimidazol-4-yl)methylidene)amino)ethyl]amine

The chiral nickel(II) complexes of a tripod-type ligand with the chemical formulas [Ni(H3L)](NO3)2.MeOH (1), [Ni(H3L)](ClO4)2.MeOH (2), and [Ni(H3L)](C6H5COO)2.6H2O (3) were synthesized and characterized (H3L = tris[2-(((2-phenylimidazol-4-yl)methylidene)amino)ethyl]amine). The crystal structures of 1-3 were determined by their single-crystal X-ray analyses. 1, C37H40N12O7Ni: orthorhombic, P2(1)2(1)2(1); a = 14.198(2) A, b = 22.422(2) A, c = 12.019(2) A, Z = 4. 2, C37H40N10O9Cl2Ni: orthorhombic, P2(1)2(1)2(1); a = 14.206(2) A, b = 22.735(3) A, c = 12.696(3) A, Z = 4. 3, C50H58N10O10Ni: triclinic, P1; a = 14.191(5) A, b = 16.048(4) A, c = 13.692(4) A, alpha = 115.25(2) degrees, beta = 111.07(3) degrees, gamma = 64.75(2) degrees, Z = 2. Each complex has an octahedral coordination environment for the nickel(II) ion, formed by the six nitrogen donor atoms, and is either a delta (clockwise) or a lambda (anticlockwise) enantiomorph, depending on the screw arrangement of the tripod-type ligand around the nickel(II) ion. The circular dichroism (CD) spectrum of a powdered sample of a crystal of 1 showed a positive and a negative peak at 915 and 630 nm, respectively, and that of another crystal showed an enantiomeric pattern. The observation of the Cotton effect and the crystal structure provided evidence for spontaneous resolution of the chiral complex molecule.     

New two-dimensional metal-organic networks constructed from 1,2,4,5-benzenetetracarboxylate and chelate ligands

Two novel nickel coordination polymers [Ni(2)(2,2'-bipy)(2)(OH)(2)(H(2)btec)](3)(n)(1) and [Ni(2)(1,10'-phen)(2)(H(2)O)(2)(btec)](n)(2) (btec = 1,2,4,5-benzenetetracarboxylate) have been hydrothermally synthesized and characterized by elemental analyses, IR and XPS spectra, TG analysis, X-ray powder diffraction, and single crystal X-ray diffraction. Crystal data for 1: C(90)H(66)N(12)O(30)Ni(6), monoclinic P2(1)/c, a = 10.905(2) A, b = 18.006(4) A, c = 20.551(4) A, beta = 94.91(3) degrees, Z = 2. Crystal data for 2: C(34)H(22)N(4)O(10)Ni(2), monoclinic P2(1)/n, a = 10.122(2) A, b = 9.3106(19) A, c = 15.690(3) A, beta = 92.03(3) degrees, Z = 2. Compound 1 exhibits a novel one-dimensional chainlike structure, in which the dinuclear Ni centers are linked by the btec ligands. Furthermore, the adjacent chains are linked into a 2-D wavelike layer via the strong OH.O hydrogen bonding interactions. Compound 2 possesses an unusual two-dimensional steplike network with interesting rhombic grids. Both compounds exhibit unprecedented metal-organic ligand construction modes in [M/btec/L] (M = transition metal; L = chelate ligands) systems. The magnetic behaviors of compounds 1 and 2 have been studied.     

Structural Transformations and adsorption of fuel-related gases of a structurally responsive nickel phosphonate metal-organic framework, Ni-STA-12

The structure of the nickel N,N'-piperazinebismethylenephosphonate, Ni-STA-12 (St. Andrews porous material-12), has been determined in the hydrated (Ni2L x 8 H2O, L = O3PCH2NC4H8NCH2PO3), partially dehydrated (Ni2L x 2 H2O), and fully dehydrated (Ni2L) forms from high-resolution synchrotron X-ray powder diffraction. The framework structures of Ni2L x 8 H2O and Ni2L x 2 H2O are almost identical (R, a = 27.8342(1) A, c = 6.2421(2) A; R, a = 27.9144(1) A, c = 6.1655(2) A) with additional physisorbed water of the as-prepared Ni-STA-12 present in an ordered hydrogen-bonded network in the channels. Ab initio structure solution of the fully dehydrated solid indicates it has changed symmetry to triclinic (P1, a = 6.03475(5) A, b = 14.9157(2) A, c = 16.1572(2) A, alpha = 112.5721(7) degrees, beta = 95.7025(11) degrees, gamma = 96.4950(11) degrees) as a result of a topotactic structural rearrangement. The fully dehydrated solid possesses permanent porosity with elliptical channels 8 A x 9 A in free diameter. The structural change results from the loss of water coordinated to the nickel cations, so that the nickel coordination changes from edge-sharing octahedral NiO5N to edge- and corner-sharing five-fold NiO4N. During this change, two out of three phosphonate groups rotate to become fully coordinated to nickel cations, leaving the remainder of the phosphonate groups coordinated to nickel cations by two oxygen atoms and with a P=O bond projecting into the channels. This transformation, which is completely reversible, causes substantial changes in both vibrational and electronic properties as shown by IR, Raman, and UV-visible spectroscopies. Complementary adsorption, calorimetric, and infrared studies of the probe adsorbates H2, CO, and CO2 reveal the presence of several distinct adsorption sites in the solid, which are attributed to their interactions with nickel cations which are weak Lewis acid sites, as well as with P=O groups that project into the pores. At 304 K, the adsorption isotherms and enthalpies of adsorption on dehydrated Ni-STA-12 have been measured for CO2 and CH4: Ni-STA-12 gives adsorption uptakes of CO2 of 2.5 mmol g(-1) at 1 bar, an uptake ca. 10 times that of CH4.     

Crystal Structure of Tris(2,2'-bipyridine)nickel (Ⅱ) Tetrachlorozincate

A bimetallic complex Ni[C10H8N2]3[ZnCl4] has been synthesized and its crystal structure determined at room temperature. The complex crystallizes in the trigonal system, space group R3c, with a = 13.343(2), b = 13.343(2), c =58. 932(12) A, V= 9087(3) A 3, Z = 12, NiZnC30N6CI14H24, Mr=734.30, Dc=1.611 g/cm3, μ= 1. 799 mm-1, F(000)=4464. Least-squares refinement of the structure leads to the agreement factors R1=0. 0278 and wR2=0. 0741 for the observable reflections. The complex consists of discrete tris (2, 2'-bipyridine) nickel (Ⅱ)cation, [Ni-(bipy)3]2+, and tetrachlorozincate anion, [ZnCl4]2-. Each nickel (Ⅱ)atom is six coordinated in an octahedron with six nitrogen atoms of three 2,2'-bipyridine ligands. The mean Ni(Ⅱ)-N bond length is 2. 089(2) A. The zinc(Ⅱ) atom is coordinated with four chloride atoms in tetrahedral geometry. The mean Zn (Ⅱ)- Cl bond length is 2. 264(1) A.     

Synthesis and Crystal Structure of a Novel Heterometallic Complex with 1,2,4,5-Benzenetetracarboxylic Acid and 1,3,5-Tris（imidazol-1-ylmethyl）-2,4,6-trimethylbenzene

A novel heterometallic complex,[Zn4Ni(OH)2(btec)2(titb)2(H2O)2]·2H2O(1)(H4btec=1,2,4,5-benzenetetracarboxylic acid,titb=1,3,5-tris(imidazol-1-ylmethyl)-2,4,6-trime-thylbenzene),has been hydrothermally prepared and characterized by IR spectroscopy,elemental analysis and single-crystal X-ray diffraction.The crystal is of triclinic system,space group P1 with a=10.817(10),b=11.878(11),c=14.569(14),α=71.762(12),β=76.122(13),γ=71.493(13)°,V=1665(3)3,C62H62N12O22Zn4Ni,Mr=1647.43,Dc=1.643 g/cm3,F(000)=842,μ=1.784 mm-1 and Z=1.The final R=0.0531 and wR=0.0890 for 3545 observed reflections(Ⅰ 2σ(Ⅰ)).In the title complex,the btec ligand acts as a five-dentate bridging ligand to link up zinc and nickel atoms into a lamellar framework,which are further interlinked into a 3-D framework via the titb ligands.     

Trinuclear heterobimetallic Ni2Ln complexes [L2Ni2Ln][ClO4] (Ln=La, Ce, Pr, Nd, Sm, Eu, Gd, Tb, Dy, Ho, and Er; LH3=(S)P[N(Me)NCH-C6H3-2-OH-3-OMe]3): from simple paramagnetic complexes to single-molecule magnet behavior

The reaction of LH3 with Ni(ClO4)(2).6H 2O and lanthanide salts in a 2:2:1 ratio in the presence of triethylamine leads to the formation of the trinuclear complexes [L2Ni2Ln][ClO4] (Ln=La (2), Ce (3), Pr (4), Nd (5), Sm (6), Eu (7), Gd (8), Tb (9), Dy (10), Ho (11) and Er (12) and L: (S)P[N(Me)NCH-C6H3-2-O-3-OMe]3). The cationic portion of these complexes consists of three metal ions that are arranged in a linear manner. The two terminal nickel(II) ions are coordinated by imino and phenolate oxygen atoms (3N, 3O), whereas the central lanthanide ion is bound to the phenolate and methoxy oxygen atoms (12O). The Ni-Ni separations in these complexes range from 6.84 to 6.48 A. The Ni-Ni, Ni-Ln and Ln-O phenolate bond distances in 2-12 show a gradual reduction proceeding from 2 to 12 in accordance with lanthanide contraction. Whereas all of the compounds (2-12) are paramagnetic systems, 8 displays a remarkable ST=(11)/2 ground state induced by an intramolecular Ni. . .Gd ferromagnetic interaction, and 10 is a new mixed metal 3d/4f single-molecule magnet generated by the high-spin ground state of the complex and the magnetic anisotropy brought by the dysprosium(III) metal ion.     

Synthesis of 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane(L1) and a spectroscopic and structural study of [Ni(L1)(ClO4)](ClO4) and of the macrobicyclic precursor diamide complex, [Ni(HL2)](ClO4); chloride substitution kinetics of the corresponding [Ni(III)(L1)]3+ species

The pentadentate ligand 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane (L1) has been synthesized by the high dilution cyclization of 1-oxa-4,8-diazacyclododecane ([10]aneN(2)O) (1) with 1,3-bis(alpha-chloroacetamido)propane (2) and subsequent reduction of the diamide intermediate. The structure [Ni(L1)(ClO(4))](ClO(4)) (P2(1)/c (no. 14), a = 8.608(3), b = 16.618(3), c = 14.924(4) A, beta = 91.53(3) degrees converged at R = 0.050 (R(w) = 0.046) for 307 parameters using 2702 reflections with I > 2sigma(I). For the nickel(II) complex of the (monodeprotonated) precursor diamide ligand 14-oxa-1,4,8,11-tetraazabicyclo[9.5.3]nonadecane-3,9-dione (H(2)L2), [Ni(HL2)](ClO(4)) (Pbca (no. 61), a = 15.1590(3), b = 13.235(2), c = 18.0195(6) A), the structure converged at R = 0.045 (R(w) = 0.038) for 265 parameters using 1703 reflections with I > 3sigma(I). In the reduced system, the cyclam-based ligand adopts a trans-III configuration. The [Ni(L1)(ClO(4))](2+) ion is pseudooctahedral with the Ni-O(ether) 2.094(3) A distance shorter than the Ni-O(perchlorate) 2.252(4) A. The nickel(II) and nickel(III) complexes are six-coordinate in solution. Oxidation of [Ni(L1)(OH(2))](2+) with K(2)S(2)O(8) in aqueous media yielded an axial d(7) Ni(III) species (g( perpendicular) = 2.159 and g( perpendicular) = 2.024 at 77 K). The [Ni(L1)(solv)](2+) ion in CH(3)CN showed two redox waves, Ni(II/I) (an irreversible cathodic peak, E(p,c) = -1.53 V) and Ni(III/II) (E(1/2) = 0.85 V (reversible)) vs Ag/Ag(+). The complex [Ni(HL2)](ClO(4)) displays square-planar geometry with monodeprotonation of the ligand. The ether oxygen is not coordinated. Ni-O(3) = 2.651(6) A and Ni-O(3a) = 2.451(12) A, respectively. The Ni(III/II) oxidation at E(1/2) = 0.24 V (quasi-reversible) vs Ag/Ag(+) is considerably lower than the saturated system. The kinetics of Cl(-) substitution at [Ni(L1)(solv)](3+) are pH dependent. Detachment of the ether oxygen atom is proposed, with insertion of a protonated water molecule which deprotonates at a pK(a) more acidic than in the corresponding cyclam complex. Mechanistic implications are discussed.     

Synthesis and Structure of Nickel(II) Compound with Tetradentate Schiff-base Ligand and Diazido Monohydrate

1 INTRODUCTION Complexes of ligands which bind two or more metal centers in close proximity are important as potential catalysts[1], as models for a number of metalloproteins[2], and because of the opportunity they provide for the investigation of magnetic interactions. The structural and magnetic properties of binuclear and polymetallic nickel (II) complexes with various bridging ligands have received considerable attention in the past three decades[3～6]. At present, there is a spectacu…     

Structural Evidence of Anion's Effect on the Ion Packing of [Ni2(teta)3]4+ in the View of H-bonding Interaction

Two dinuclear nickel(II) complexes [Ni2(teta)3]Cl4·2H2O 1 and [Ni2(teta)3](NO3)4 2 (teta = triethylenetetramine) were synthesized by a solvothermal method and structurally characterized. Complex 1: orthorhombic, Pbca, a = 13.791(3), b = 13.078(3), c = 18.323(4) , V = 3304.8(12) 3, Z = 4, Mr = 733.98, Dc = 1.475 g/cm3, μ = 1.500 mm-1, F(000) = 1560, R = 0.0585 (I > 2σ(I)) and wR = 0.1243. Complex 2: orthorhombic, P212121, a = 7.8279(14), b = 14.209(3), c = 31.163(6) , V = 3466.2(11) 3, Z = 4, Mr = 804.19, Dc = 1.541 g/cm3, μ = 1.164 mm-1, F(000) = 1704, R = 0.0401 and wR = 0.0840 for 5950 observed reflections (I > 2σ(I)). Two Ni2+ ions are connected by one linear bridging teta ligand, forming a dinuclear [Ni2(teta)3]4+ cation. Each Ni2+ ion in 1 and 2 takes a distorted octahedral geometry with six coordinated N atoms from two teta ligands. The effect of different anions on the arrangement of [Ni2(teta)3]4+ cations has been discussed in view of H-bonding interactions. Thermal stability of 1 and 2 was also investigated.     

A New Metal-organic Framework Constructed from Flexible Polycarboxylate Acid and Rigid Imidazole-based Ligands

A new complex, [Ni3(L)2(BTA)2]·2H2O (1, L=1,4-di(1H-imidazol-4-yl)benzene, H3BTA=benzene-1,3,5-triacetic acid), has been hydrothermally prepared and characterized by single-crystal X-ray diffraction, IR spectroscopy, elemental analysis, TG and PXRD. The complex crystallizes in monoclinic, space group P1 with a=9.0303(12), b=10.0796(13), c=12.7966(17) , α=99.268(2), β=94.490(2), γ=103.722(3)o, V=1108.5(3) 3 , Z=2, C48H38N8O14Ni3 , Mr=1126.99, Dc=1.688 g/cm3 , μ=1.344 mm-1 , S=1.001, F(000)=578, the final R=0.0389 and wR=0.0895 for 3083 observed reflections (I > 2σ(I)). In the title complex, the flexible BTA3- ligands utilize oxygen atoms of carboxylate groups to coordinate with Ni(II) ions to form two-dimensional double-layer networks which are further pillared into a three-dimension framework via the rigid ditopic ligand L. Topological analysis revealed that complex 1 is a typical (3,8)-connected tfz-d 3D network based on the trinuclear [Ni3(CO2)6N4] subunits.     

Synthesis, Crystal Structure and Cytotoxic Activity of a Novel Nickel(Ⅱ) Complex with Schiff Base Derived from Salicylhydrazide

A novel Schiff base complex with π-conjugated system, [Ni(L1)2(py)2] 1 (L1 = (E)-N'-(2,4-dichlorobenzylidene)-2-oxidobenzohydraizide), was synthesized and characterized by elemental analysis and single-crystal X-ray determination. Complex 1 crystallizes in the monoclinic system, space group P21/n with a = 12.8286(10), b = 16.3573(13), c = 19.0206(14) (A), β =108.2920(10)°, V = 3789.6(5) A3, Z = 4, Mr = 833.17, Dc = 1.460 g/cm3, μ = 0.843 mm-1, F(000) = 1704, the final R = 0.0537 and wR = 0.0640 for 3836 observed reflections with Ⅰ> 2σ(Ⅰ). In the molecular structure of 1, the NiⅡ atoms are six-coordinated by two N and two O atoms from two Schiff base ligands (L1) and two N atoms from two pyridine solvent molecules to form a distorted octahedral geometry. The cytotoxic activities of complex 1 have been experimentally studied against a human HeLa cell in vitro.     

Synthesis and Crystal Structure of a Complex Bimetallic Salt [Ni(trans_[14]diene)] [Ni (mnt)_2]

1INTRoDUCTIONMacrocycliccoordinationcomPOundshavebeenwidelyinvestigatedinthepastdecadesbecauseoftheirrelationshiptocomplexesofbiologicalsignificancesuchasthePorphyrinsandcorrins(lJ.Structuresofmanymacrocycliccompoundshavebeenre-ported,especiallythecompoundscontainingN4macrocyclicligands"'.However,toourknowledge,onlyafewcrystalstructuresofcomplexbimetallicsaltscontainingmacrocyclicligandshavebeendeterminedbyX-raydiffractionmethod.Inthispa-per,werePortthesynthesisandstructureofthetit1ecom…     

2-pyrrolylthiones as monoanionic bidentate N,S-chelators: synthesis and molecular structure of 2-pyrrolylthionato complexes of nickel(II), cobalt(III), and mercury(II)

The metal-chelating ability of 2-pyrrolylthiones is described. The readily available ligands di-2-pyrrolyl thione (6), 2-thioacetylpyrrole (10), and 2-thiobenzoylpyrrole (11) constitute examples of monoanionic ligands with N,S-donor atom sets, although di-2-pyrrolyl thione (6) could theoretically also achieve chelation through an N,N-donor set. A square planar Ni(II) complex, 14, an octahedral Co(III) complex, 18, and a tetrahedral Hg(II) complex, 17, with the di-2-pyrrolyl thionato chelate have been prepared, and their structures have been characterized by 1H NMR, UV-vis, MS, IR, elemental analysis, and single-crystal X-ray diffraction. Crystal data for 14: C18H14N4NiS2.0.28H2O, trigonal, R3, a = 18.467(1) A, b = 18.467(1) A, c = 26.404(2) A, V = 7797(1) A3; Z = 18, R = 3.2%. Crystal data for 18-mer: C27H21CoN6S3.C3H6O (acetone), monoclinic, P21/n, a = 9.569(1) A, b = 23.152(1) A, c = 13.659(1) A, beta = 100.882(8) degrees, V = 2971.6(5) A3, Z = 4, R = 4.3%. Crystal data for 17: C18H14HgN4S2, triclinic, P1, a = 8.443(2), b = 14.278(1) A, c = 7.445(1) A, alpha = 90.561(9) degrees, beta = 97.64(1) degrees, gamma = 104.250(9) degrees, V = 861.3(2) A3, Z = 2, R = 4.2%. The bond lengths and angles of these metal complexes are comparable to those of known N,S-chelates. A comparison of the structural parameters of the ligand in the metal complexes with those for the free ligand 6 demonstrates the preorganization of the free ligand for complexation and demonstrates the spectator role of the noncoordinating pyrrolic unit. Chelation of Ni(II) by 2-thioacetylpyrrole (10) and 2-thiobenzoylpyrrole (11) to provide complexes 12 and 13 with structures analogous to complex 14 is also described.     

Cyclic polyvanadates incorporating template transition metal cationic species: synthesis and structures of hexavanadate [PdV6O18]4-, octavanadate [Cu2V8O24]4-, and decavanadate [Ni4V10O30(OH)2(H2O)6]4-

Three types of heteropolyvanadates, [(C2H5)4N]4[PdV6O18] (1), [(C2H5)4N]4[Cu2V8O24] (2), and [(C6H5)4P]4[Ni4V10O30(OH)2(H2O)6] (3), were synthesized through the reaction between the [VO3]- anion and metal template cations of Pd(II), Cu(II), and Ni(II). The X-ray crystal structures of 1 (a = 29.952(4) A, b = 12.911(2) A, and c = 13.678(2) A, orthorhombic, space group Pca2(1) with Z = 4), 2 (a = 13.740(1) A, b = 22.488(2) A, c = 18.505(2) A, and beta= 94.058(2) degrees , monoclinic, space group P2(1)/n with Z = 4), and 3 (a = 12.333(2) A, b = 16.208(4) A, c = 16.516(3) A, alpha = 112.438(3) degrees , beta = 94.735(3) degrees , and gamma = 104.749(3) degrees , triclinic, space group P with Z = 1) demonstrate that the metal cationic species induced cyclic [VO3](n-)n (n = 6, 8, 10) ring formation and the cations are incorporated in the rings themselves. In the metal inclusion products, the cyclic vanadates act as macrocyclic ligands, in which the metal cationic species act as the templates. The cyclic vanadate is composed of tetrahedral VO4 units that share corners and incorporates a metal cationic species in the center of the molecules. The bowl-shaped complex 1 includes a Pd2+ cation that is coordinated by the oxygen donors of a boatlike hexavanadate ring. The diamagnetic complex 1 was characterized via 51V and 17O NMR spectroscopy. Complex 2 involves an octavanadate ring and two Cu2+, which are located on both sides of the mean plane as defined by the eight oxygen atoms that bridge the vanadium atoms. In the case of complex 3, the di-mu-hydroxo-bridged Ni2+ dimer with capped Ni2+ aqua ions is formed by hydrolysis to form the decavanadate ring, in which two of the tetrahedral vanadate units are not bonded to the Ni2+ core but supported by hydrogen bonds through the aqua-ligand in the capped Ni2+ cation. Complexes 1-3 in solution were clearly identified by their characteristic isotope patterns using ESI-MS studies.     

Synthesis and Structural Characterization of a Ni(Ⅱ) Complex [Ni(H2O)4(4,4''-bipy)2](hca)2

The reaction of Ni(CH3COO)2(6H2O, 4-hydroxycinnamic acid (Hhca) and 4,4'-bipyri- dine (bipy) ligand in water-solution afforded a mononuclear complex [Ni(H2O)4(4,4'-bipy)2](hca)2 which was characterized by IR, elemental analysis, TGA and single-crystal X-ray diffraction. X-ray crystallography analysis reveals that the complex is of triclinic, space group P with a = 7.0238(14), b = 7.2934(11), c = 17.186(4) (A), α = 87.073(13), β = 84.354(10), γ = 81.961(12)°, V = 866.9(3) (A)3, Z = 1, Dc = 1.474 g/cm3, F(000) = 402, μ = 62.7 mm-1, R = 0.0411, wR = 0.0862 and GOF = 1.048. In solid state, the cation [Ni(H2O)4(4,4'-bpy)2]2+ connects six nearby hca counter anions via O-H…O hydrogen bonds to form an extended 2D lattice framework and the O-H…N hydrogen bonds finally link the 2D layers into an infinite 3D network.     

Synthetic analogues of the active site of the A-cluster of acetyl coenzyme A synthase/CO dehydrogenase: syntheses, structures, and reactions with CO

Two metallosynthons, namely (Et4N)2[Ni(NpPepS)] (1) and (Et4N)2[Ni(PhPepS)] (2) containing carboxamido-N and thiolato-S as donors have been used to model the bimetallic M(p)-Ni(d) subsite of the A-cluster of the enzyme acetyl coenzyme A synthase/CO dehydrogenase. A series of sulfur-bridged Ni/Cu dinuclear and trinuclear complexes (3-10) have been synthesized to explore their redox properties and affinity of the metal centers toward CO. The structures of (Et4N)2[Ni(PhPepS)] (2), (Et4N)[Cu(neo)Ni(NpPepS)] x 0.5 Et2O x 0.5 H2O (3 x 0.5 Et2O x 0.5 H2O), (Et4N)[Cu(neo)Ni(PhPepS)] x H2O (4 x H2O), (Et4N)2[Ni{Ni(NpPepS)}2] x DMF (5 x DMF), (Et4N)2[Ni(DMF)2{Ni(NpPepS)}2] x 3 DMF (6 x 3 DMF), (Et4N)2[Ni(DMF)2{Ni(PhPepS)}2] (8), and [Ni(dppe)Ni(PhPepS)] x CH2Cl2 (10 x CH2Cl2) have been determined by crystallography. The Ni(d) mimics 1 and 2 resist reduction and exhibit no affinity toward CO. In contrast, the sulfur-bridged Ni center (designated Ni(C)) in the trinuclear models 5-8 are amenable to reduction and binds CO in the Ni(I) state. Also, the sulfur-bridged Ni(C) center can be removed from the trimers (5-8) by treatment with 1,10-phenanthroline much like the "labile Ni" from the enzyme. The dinuclear Ni-Ni models 9 and 10 resemble the Ni(p)-Ni(d) subsite of the A-cluster more closely, and only the modeled Ni(p) site of the dimers can be reduced. The Ni(I)-Ni(II) species display EPR spectra typical of a Ni(I) center in distorted trigonal bipyramidal and distorted tetrahedral geometries for 9(red) and 10(red), respectively. Both species bind CO, and the CO-adducts 9(red)-CO and 10(red)-CO display strong nu(co) at 2044 and 1997 cm(-1), respectively. The reduction of 10 is reversible. The CO-affinity of 10 in the reduced state and the nu(co) value of 10(red)-CO closely resemble the CO-bound reduced A-cluster (nu(co) = 1996 cm(-1)).     

芳香二磺酸的配位化学研究化合物[Ni(cyclam)(1，5nds)]·1/3H2O (1)和[Co(cyclam)(H2O)2](1，5nds)·2H2O (2)的合成与结构

合成了两个二价的过渡金属磺酸化合物，并通过X-射线衍射单晶结构分析进行结构表征。化合物[Ni(cyclam)(1，5nds)]·1/3H₂O (1)以P2(1)/c空间群结晶，晶胞参数为a=8.583(5)，b=10.533(6)，c=12.946(7)?，β=92.433(9)°。 [Ni(cyclam)]²⁺与两个磺酸基团形成弱配位，从而构筑了一维的配聚物。[Ni(cycla