Synthesis and Crystal Structure of a New Nickel（II） Complex with 2,4-Pyridinedicarboxylic Acid and 1,4-Bis（imidazol-1-ylmethyl）-benzene） Ligands

A metal-organic coordination polymer [Ni(PDC)(bix)(H2O)]n (H2PDC = 2,4-pyri- dinedicarboxylic acid, bix = 1,4-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. Blue crystals crystallize in the monoclinic system, space group C2/c with a = 25.1475(18), b = 13.1621(9), c = 14.2739(10), β = 118.4150(10)o, V = 4155.4(5) 3, C21H19N5NiO5, Mr = 480.12, Dc = 1.535 g/cm3, F(000) = 1984, Z = 8, μ(MoKα) = 0.979 mm-1, the final R = 0.0478 and wR = 0.1004 for 3727 observed reflections (I > 2σ(I)). The structure of 1 exhibits a one-dimensional chain-like structure.     

Synthesis, Crystal Structure and Photoluminescent Property of a Three-dimensional Zinc（Ⅱ） Coordination Polymer: [Zn1.5（PDB）（bix）0.5（μ2-OH）]2n

A new metal-organic coordination polymer [Zn1.5(PDB)(bix)0.5(μ2-OH)]2n 1 (H2PDB = pyridine-3,4-dicarboxylic acid, bix = 1,4-bis(imidazol-1-ylmethyl)-benzene) has been hydrothermally synthesized and structurally characterized by elemental analysis, IR, TG and single-crystal X-ray diffraction. The title compound crystallizes in the monoclinic system, space group P2/c with a = 7.411(2), b = 7.848(3), c = 25.048(8), V = 1451.8(8)3, C28H22N6O10Zn3, Mr = 798.63, Dc = 1.827 g/cm3, μ(MoKα) = 2.529 mm-1, F(000) = 804, Z = 2, the final R = 0.0440 and wR = 0.1035 for 1952 observed reflections (I > 2σ(I)). It exhibits a three-dimensional framework structure. Moreover, its luminescent property has been investigated in the solid state.     

Hydrothermal Synthesis and Crystal Structure of a Three-dimensional Cadmium（II） Complex

A metal-organic coordination polymer [Cd2(PDC)2(bix)(H2O)2]n ·nH2O(H2PDC=2,4-pyridinedicarboxylic acid, bix=1,4-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Brown crystals crystallize in the orthorhombic system, space group P2 12 12 1 with a=11.741(3), b=14.190(4), c=18.963(5) , V=3159.4(14) 3 , C28H26Cd2N6O11, Mr=847.35, Dc=1.781 g/cm3 , F(000)=1680, Z=4, μ(MoKα)=1.415 mm 1 , the final R=0.0381 and wR=0.0882 for 5472 observed reflections (I >2σ(I)). The structure of 1 exhibits a threedimensional network structure.     

Synthesis and Crystal Structure of a New Cadmium（Ⅱ） Complex with 3,4-Pyridinedicarboxylic Acid and 1,4-Bis（imidazol-1-ylmethyl）-butane Ligands

A metal-organic coordination polymer [Cd(PDB)(bimb)]n (H2PDB=3,4-pyridine- dicarboxylic acid, bimb=1,4-bis(imidazol-1-ylmethyl)-butane) 1 has been hydrothermally synthesi- zed and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Yellow crystals crystallize in the monoclinic system, space group Cc with a=19.001(5), b=7.948(2), c=13.392(4) , β=120.803(3)o, V=1737.0(8)3, C17H17CdN5O4, Mr=467.76, Dc=1.789 g/cm3, F(000)=936, Z=4, μ(MoKα)=1.293 mm-1, the final R=0.0266 and wR=0.0534 for 2707 observed reflections (I > 2?(I)). The structure of 1 exhibits a three-dimensional network structure.     

Hydrothermal Synthesis and Crystal Structure of a One-dimensional Cadmium（Ⅱ） Complex

A metal-organic coordination polymer [Cd2(cbba)4(bix)2] n·nH2O (Hcbba=2-(4′-chlorine-benzoyl)-benzoic acid, bix=1,4-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and characterized by elemental analysis, IR, TG, fluorescence spectrum and single-crystal X-ray diffraction. Colorless crystals crystallize in the triclinic system, space group Pī with a=12.9891(15), b=15.3211(19), c=21.154(3), α=108.476(3), β=90.148(2), γ=105.429(3)°, V=3831.5(8)3 , C84H60Cd2Cl4N8O13 , Mr=1756.00, Dc=1.522g/cm3 , F(000)=1776, Z=2, μ(MoKα)=0.765 mm-1 , the final R=0.0724 and wR=0.1208 for 6916 observed reflections (I > 2σ(I)). The structure of 1 exhibits a one-dimensional infinite chain-like structure.     

Hydrothermal Synthesis and Crystal Structure of a Lead(Ⅱ) Polymer with a Two-dimensional Network Structure:[Pb_2(PDB)_2(phen)]_n·nH_2O

A new metal-organic complex [Pb2(PDB)2(phen)]n·nH2O (H2PDB=pyridine-3,4-dicarboxylic acid,phen=1,10-phenanthroline) 1 has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,TG and single-crystal X-ray diffraction.The compound crystallizes in triclinic,space group P1 with a=7.2472(5),b=10.6966(8),c=16.2376(12),α=98.2960(10),β=91.6430(10),γ=97.4810(10)o,V=1233.53(16)3,C26H16O9N4Pb2,Mr=942.81,Dc=2.538 g/cm3,μ(MoKα)=13.697 mm-1,F(000)=872,Z=2,the final R=0.0247 and wR=0.0654 for 3886 observed reflections (I 2σ(I)).In the crystal structure,the Pb(1) atom is six-coordinated with four carboxylate oxygen atoms from three different PDB ligands and two nitrogen atoms from phen ligand,showing a distorted octahedral geometry;the Pb(2) atom is four-coordinated with four carboxylate oxygen atoms from four different PDB ligands,showing a distorted tetrahedral geometry.It exhibits a three-dimensional supramolecular network structure formed by hydrogen bonds and π-π interactions.     

Hydrothermal Synthesis and Crystal Structure of a Nickel（Ⅱ） Polymer with a One-dimensional Chain Structure：[Ni（cbba）_2（bipy）（H_2O）_2]_n

A metal-organic coordination polymer formulated as [Ni(cbba) 2 (bipy)(H 2 O) 2 ] n 1 (H 2 cbba=2-(4-chlorine-benzoyl)benzoic acid,bipy=4,4-bipyridine) has been hydrothermally synthesized and structurally characterized by elemental analysis,IR spectrum,TG and single-crystal X-ray diffraction.The title compound crystallizes in the triclinic system,space group P1 with a=5.4550(4),b=11.4099(8),c=15.3135(11),α=68.7680(10),β=81.3470(10),γ=79.3450(10)o,V=869.48(11) 3,C 38 H 28 Cl 2 N 2 NiO 8,M r=770.23,D c=1.471 g/cm 3,μ(MoKα)=0.768 mm 1,F(000)=396,Z=1,the final R=0.0456 and wR=0.1171 for 2477 observed reflections (I > 2σ(Ⅰ)).It exhibits a one-dimensional chain-like structure.     

Synthesis and Crystal Structure of [Cd（NBA）（μ3-OH）（4,4＇-bipy）1/2]n

A new cadmium polymer [Cd(NBA)(μ3-OH)(4,4'-bipy)1/2]n 1 (NBA=m-nitrobenzoic acid and 4,4'-bipy=4,4-bipyridine) has been synthesized by hydrothermal reaction. Its structure was determined by single-crystal X-ray diffraction method, and characterized by elemental analysis and IR spectrum. The crystal is of monoclinic, space group C2/c, with a=15.6912(9), b=25.9394(15), c=6.7332(4)(A), β=114.7700(10)°, V=2488.4(3)(A)3, C12H9CdN2O5, Mr=373.61, Z=8, Dc=1.995 g/cm3,μ=1.776 mm-1, F(000)=1464, R=0.0411 and wR=0.1128 for 2130 observed reflections (I ＞ 2σ(I)).X-ray diffraction studies reveal that the compound features a layered structure, in which 4,4'-bipy ligands bridge Z type of double chains [Cd(μ3-OH)]n and NBA ligands locate at the two sides of the layer. The π-π interactions between the benzene rings of NBA ligands of two adjacent layers lead to the 3D framework.     

Syntheses, Crystal Structures and Magnetism of Two New Coordination Polymers [Ni（bix）2Cl2]n and [Co（bix）Cl2]n

The self-assembly reactions of MIICl2 (M = Ni, Co) with the flexible bix ligand [bix = 1,4-bis(imidazole-1-ylmethyl)benzene] yielded a 2D network [NiII(bix)2Cl2]n 1 and a 1D chain [CoII(bix)Cl2]n 2. Their crystal structures have been determined by X-ray single-crystal diffraction analysis. Complex 1 characters a two-dimensional grid-type structure and crystallizes in monoclinic, space group P21/c with a = 7.7231(7), b = 12.7787(9), c = 13.9374(13) , β = 105.419(4)o, C28H28Cl2N8Ni, Mr = 606.19, Ζ = 2, V = 1326.0(2) 3, Dc = 1.518 g/cm3, μ = 0.969 mm-1, F(000) = 628, R = 0.0429 and wR = 0.0783 for 2503 observed reflections (I > 2σ(I)). Compound 2 is a one-dimensional chain and crystallizes in orthorhombic, space group Pbca with a = 11.3696(6), b = 10.2128(6), c = 14.4943(9) , C14H14Cl2CoN4, Mr = 368.12, Z = 4, V = 1683.01(17) 3, Dc = 1.453 g/cm3, μ = 1.334 mm-1, F(000) = 748, R = 0.0317 and wR = 0.0800 for 1778 observed reflections (I > 2σ(I)). Magnetic properties of the title complexes were also investigated.     

Hydrothermal Synthesis and Crystal Structure of a One-dimensional Cobalt（Ⅱ） Complex

A metal-organic coordination polymer [Co2(cbba)4(bix)2]n(Hcbba = 2-(4'-chlorine-benzoyl)-benzoic acid,bix = 1,4-bis(imidazol-1-ylmethyl)-benzene) 1 has been hydrothermally synthesized and characterized by elemental analysis,IR,TG,and single-crystal X-ray diffraction.Pink crystals crystallize in the monoclinic system,space group P21/n with a = 21.148(4),b = 15.728(3),c = 23.879(4) ,β = 102.148(3)°,V = 7764(2)3,C316H232Cl15Co8N32O48,Mr = 6248.53,Dc = 1.336 g/cm3,F(000) = 3207,Z = 1,μ(MoKα) = 0.621 mm-1,the final R = 0.0567 and wR = 0.1280 for 8510 observed reflections(I > 2σ(I)).The structure of 1 exhibits a one-dimensional chain-like structure.     

OH(3) (-) and O(2)H(5) (-) double Rydberg anions: predictions and comparisons with NH(4) (-) and N(2)H(7) (-)

A low barrier in the reaction pathway between the double Rydberg isomer of OH(3) (-) and a hydride-water complex indicates that the former species is more difficult to isolate and characterize through anion photoelectron spectroscopy than the well known double Rydberg anion (DRA), tetrahedral NH(4) (-). Electron propagator calculations of vertical electron detachment energies (VEDEs) and isosurface plots of the electron localization function disclose that the transition state's electronic structure more closely resembles that of the DRA than that of the hydride-water complex. Possible stabilization of the OH(3) (-) DRA through hydrogen bonding or ion-dipole interactions is examined through calculations on O(2)H(5) (-) species. Three O(2)H(5) (-) minima with H(-)(H(2)O)(2), hydrogen-bridged, and DRA-molecule structures resemble previously discovered N(2)H(7) (-) species and have well separated VEDEs that may be observable in anion photoelectron spectra.     

An Efficient Synthesis of Optically Pure (R)- and (S)-2-(aminomethyl)alanine ((R)- and (S)-ama) and (R)- and (S)-2-(aminomethyl)leucine ((R)- and (S)-aml)

An efficient synthesis of enantiomerically pure (R)- and (S)-2-(aminomethyl)alanine ((R)- and (S)-Ama) 1a and (R)- and (S)-2-(aminomethyl)leucine ((R)- and (S)-Aml) 1b is described (Schemes 1 and 2). Resolution of the racemic amino acids was achieved using L -phenylalanine cyclohexylamide ( 2 ) as chiral auxiliary. The free amino acids 1a, b were converted to the N^α-Boc,N^γ-Z-protected derivatives 11a, b (Scheme 3) ready for incorporation into peptides. Based on the three crystal structures of the diastereoisomeric peptides 8a, 8b , and 9b , the absolute configurations in both series were determined. β-Turn type-I geometries were observed for structures 8b and 9b , whereas 8a crystallized in an extended backbone conformation.     

Hexaaquacobalt(II) bis(hypophosphite) and hexaaquacobalt(II)/nickel(II) bis(hypophosphite)

The title compounds, hexa­aqua­cobalt(II) bis­(hypophosphite), [Co(H₂O)₆](H₂­PO₂)₂, and hexa­aqua­cobalt(II)/nickel(II) bis(hypophosphite), [Co_0.5Ni_0.5(H₂O)₆](H₂PO₂)₂, are shown to adopt the same structure as hexa­aqua­magnesium(II) bis­(hypophosphite). The packing of the Co(Ni) and P atoms is the same as in the structure of CaF₂. The Co^II(Ni^II) atoms have a pseudo‐face‐centred cubic cell, with a = b～ 10.3 Å, and the P atoms occupy the tetrahedral cavities. The central metal cation has a slightly distorted octahedral coordination sphere. The geometry of the hypophosphite anion in the structure is very close to ideal, with point symmetry mm2. Each O atom of the hypophosphite anion is hydrogen bonded to three water mol­ecules from different cation complexes, and each H atom of the hypophosphite anion is surrounded by three water mol­ecules from further different cation complexes.