Hydrothermal Synthesis, Crystal Structure and Properties of a Novel 2-D Grid-like Cd^Ⅱ Metal-organic Framework

A novel Cd（Ⅱ） coordination polymer, {[Cd3（tzo）2（suc）（H2O）6-（suc）}n （Htzo = 1,2, 4-triazole, H2suc = succinic acid）, has been synthesized from the reaction of aqueous solution of Cd（NO3）2·4H2O with a 1：1 mixture ofdisodium succinate, and 1,2,4-triazole by hydrothermal techniques, and structurally characterized by X-ray analysis and spectral techniques. To the best of our knowledge, among the few documented triazole-cadmium coordination polymers, this complex presents a novel configuration. The deprotonated 1,2,4-triazole is in tridentate and succinate in bis-chelate modes to link the Cd（ll） centers, generating a 2-D grid-like network topology. Thermogravimetric analysis results show that the framework architecture is a stable porous material. The fluorescent emission has also been discussed.

Synthesis,Structure and Luminescent Property of a New Cd(Ⅱ) Complex Containing 2-Propyl-imidazole-4,5-dicarboxylate

A new Cd（Ⅱ） complex（[Cd（H2PIDC）2]n） with singly deprotonated 2-propyl-imidazole-4,5-dicarboxylate as bridging ligand was synthesized and characterized by X-ray diffraction method.Crystal data：monoclinic,space group P21/c,with a=8.2547（11）,b=10.7071（15）,c=13.9131（14）A,β=126.164（5）o,V=992.8（2）A^3,C16H18N4O8Cd,Mr=506.74,Z=2,Dc=1.695g/cm^3,F（000）=508,μ=1.151 mm^-1,R=0.0296 and wR=0.0812 for 1581 observed reflections.Singly deprotonated ligands（H2PIDC-） act as μ3-bridge and join the Cd（Ⅱ） atoms into a 2-D layer structure.The 2-D layers are further linked by intermolecular hydrogen bonds into a 3D network.The luminescent property of the complex was also investigated.

Synthesis and Crystal Structure of [{Cd(hmbdc)(H_2O)_3}·2H_2O]_n

A novel coordination polymer [{Cd（hmbdc）（H20）3}-2H20],, （hmbdc = 5-hydroxyisophthalic acid） has been synthesized and characterized by elemental analysis, IR spectra and single-crystal X-ray diffraction. The crystal belongs to monoclinic, space group P2Jc, with a = 9.599（3）, b = 18.699（5）, c = 7.557（2） A, r= 108.198（4）°, V= 1288.6（6） A3, Z= 4, M,.= 382.60, Dc = 1.972 g/cm^, F（000） = 760, p = 1.740, the final R =0.0555 and wR = 0.0995 for 1732 observed reflections with 1 〉 2σ（I）. The structural analysis shows that the intermolecular hydrogen bonds and π-π interactions result in a three-dimensional supramolecular framework.

A New Cd(Ⅱ) Coordination Polymer Constructed by 3-(2-Pyridyl)pyrazole and 5-Nitroisophthalic Acid：Synthesis, Crystal Structure and Theoretical Calculations

A new coordination polymer, [Cd2（NIPH）（L）2（H2O）]n（1, HL = 3-（2-pyridyl）pyrazole and H2NIPH = 5-nitroisophthalic acid）, has been synthesized. The structure of complex 1 has been characterized by X-ray single-crystal diffraction, elemental analysis, IR spectrum analysis, thermogravimetric analysis and fluorescence spectrum analysis. Complex 1 belongs to the triclinic system, space group P1 with a = 8.9539（6）, b = 11.6252（8）, c = 12.2472（8） A^°, α = 80.011（2）, β = 80.3850（10）, γ = 86.773（2）°, V = 1237.37（14） A^°3, Z = 2, Dc = 1.987 g/cm^3, μ = 1.780 mm^-1, Mr = 740.25, F（000） = 724, the final R = 0.0295 and wR = 0.1015 with I 〉 2σ（I）. Two H2NIPH as monodentate and bidentate ligands and two L ligands link four Cd（Ⅱ） ions to form a tetranuclear subunit. Each pair of the tetranuclear subunits is bridged by NIPH ligands to yield a one-dimensional double-chain structure. Furthermore, the 1D chains are linked into a 3D supramolecular framework with hydrogen bonds and π-π interactions. In addition, we analyzed Natural Bond Orbital（NBO） in using the PBE0/LANL2DZ method built in Gaussian 03 Program. The calculation results indicated the obvious covalent interaction between the coordinated atoms and Cd（Ⅱ） ion.

Indirect Spectrophotometric Determination of Sulphide with the Complex of Cd(Ⅱ)-5-Br-PADAP-CPB

By the use of CPB, Cd(Ⅲ) forms a highly sensitive complex with 5-Br-PADAP in aqueous solution, molar absorptivity εis 1. 21 ×105 1. mol-1. cm-1.Trace amount of sulphide can be determined from its effect on the complex of Cd (Ⅲ)-5-Br-PADAP-CPB, sulphide in the range 0~3. 2 ×10-6mol dm-3 causes a decrease in absorption, that is a linear function of the concentration, For 13ng cm-3 sulphide, common metal ions such as Na+, K+, Ca2+, Mg2+, Al3+ and anions such as CO (24μg cm-3). S2O (22μg cm-3). PO (20μg cm-3) etc. do not interfere. A method for the indirect determination of sulphide in beer and in dustrial waste water with good selectivity and accuracy is described.

Syntheses and Crystal Structures of Two New Hg(Ⅱ) and Cd(Ⅱ) Complexes with 2,3,5,6-Tetrakis-(2-pyridyl)Pyrazine

Under thermal gradient in solution phase, the reaction of Hg（Ⅱ） and Cd（Ⅱ） salts with 2,3,5,6-tetrakis-（2-pyddyl）pyrazine （tppz） in 1：1 molar ratio afforded dinuclear [{HgI2}2}- tppz）] （1） and mononuclear [CdI2（tppz）] （2） complexes. Single-crystal X-ray diffraction structural analysis reveals that the tppz acts as bis-tridentate and tridentate chelating ligands in 1 and 2, respectively. Metal（Ⅱ） ions adopt a distorted square pyramidal geometry and have the same coor- dination environment in both complexes. Based on the 1H NMR spectroscopy measurements, both complexes decompose in solution and release free tppz.

Coordination Assemblies of Cd^(Ⅱ)with 5-(Ethylthio)-1H-tetrazole and Halide Ions:Synthesis,Structure,and Luminescent Properties

Three cadmium（II）-halide complexes with 5-（ethylthio）-1H-tetrazole（Hett） as ligand, namely [Cd_7Cl_2（ett）_（12）（H_2O）_2]_n（1）, [Cd_2（OH）Br（ett）_2]_n（2） and [Cd_2（OH）I（ett）_2]_n（3）, have been hydrothermally synthesized and characterized. Complex 1 was synthesized at pH = 7 and exhibits a 3D supramolecular framework, where the adjacent Cd ions form a tetrahedron unit by ett ligands bridge and the tetrahedron units share vertices to connect each other by ett bridges to form a 2D layer architecture, which is further interlinked by μ_2-Cl to form 3D structures. Complexes 2 and 3 are isostructural, generated at pH = 8.0~9.0, displaying similar 2D networks via ett ligands and different halide ions（Br-in 2, I-in 3, respectively）. In addition, thermal stabilities and luminescent properties of new complexes 1~3 have been studied.

Syntheses,Structures and Photoluminescent Properties of Cd(Ⅱ)Polymeric Complexes Based on 5-Aminoisophthalic Acid and Bipyridine Co-ligands

Two novel complexes, namely {[Cd（AIP）（4,4＇-bpy）]·1.3DMF}n（1） and [Cd（AIP）（2,2＇- bpy）]n（2）, have been synthesized through solvothermal reaction（H2AIP = 5-aminoisophthalic acid, 2,2＇-bpy = 2,2＇-bipyridine, 4,4＇-bpy = 4,4＇-bipyridine, and DMF = N,N＇-dimethylformamide） and structurally determined by single-crystal X-ray diffraction. Complex 1 shows a three-dimensional（3D） layer-pillar framework with rectangular channels, while complex 2 displays a two-dimensional（2D） wave net architecture. Furthermore, 1 and 2 were characterized by elemental analysis, infrared spectra（IR）, thermal gravimetric analyses（TGA） and fluorescence measurements. The luminescent properties of 1 dispersed in various organic solvents have been investigated systematically, demonstrating high selectivity for acetone via the fluorescence quenching effect.

Syntheses,Crystal Structures and Thermal Properties of Two Dicadmiun(II) Complexes Cd_2L_2X_2(HL=N-(3-Methoxylsalicylidene)-3-dimethylaminopropylamine,X = Cl(1),NCS(2))

Two Cd（Ⅱ） complexes, Cd2L2Cl2 （1） and Cd2L2（NCS）2 （2） （HL = N-（3-methoxylsalicylidene）-3-dimethylaminopropylamine） were synthesized and determined by EA, IR, TG and single-crystal X-ray diffraction. The crystallographic data are as follows： monoclinic, space group P21/n, a = 9.2710（9）, b = 18.0069（18）, c = 18.5562（19） A^°, β= 99.741（4）°, V = 3053.1（5）, Z = 4,μ = 1.605, F（000） = 1536, R = 0.0264 and wR = 0.0699 for 1; orthorhombic, space group Pca21, a = 16.196（3）, b = 11.506（2）, c = 36.126（7） A^°, V = 6732（2）, Z = 8,μ = 1.428, F（000） = 3264, R = 0.0376 and wR = 0.0877 for 2. There are two geometrically different octahedral Cd（Ⅱ） atoms, with N4O2 and O4Cl2 donor sets for 1 while N4O2 and N2O4 for 2. In the dinuclear Cd（Ⅱ） centers, the Cd（Ⅱ） atoms are held together by two deprotonted phenolate oxygen atoms from tetradentate L^- ligands. The thermal gravity data show two step decompositions with the residues of CdO for two complexes.

Synthesis and Crystal Structure of a Novel Terpyridine-based Cd(Ⅱ) Complex

A novel terpyridine-based complex CdL＇S2 （L＇ = oxide of L; L = 10-hexyl-3-（2,6- di（pyridine-2-yl）pyridine-4-yl）-10H-phenothiazine） has been solvothermally synthesized and characterized by FT-IR spectroscopy, elemental analysis, 1HNMR and X-ray crystallography. The sulfur of phenothiazine moiety was oxidized when the crystal is formed. The complex C36H37CdN5O2S3 crystallizes in triclinic, space group P1 with a = 9.4452（9）, b = 13.0181（14）, c = 14.6721（18） A, a = 73.872（1）, β = 81.531（1）, y = 87.547（2）°, V= 1714.2（3） A3, Mr = 780.29, Dc= 1.512 g.cm-3,μ = 0.861 mm-l, F（000） = 800, Z = 2, the final R = 0.0456 and wR = 0.1059 for I 〉 2σ-（I）. The Cd（II） is coordinated by two terminal sulfur ions and three pyridyl nitrogen atoms in a distorted trigonal bipyramidal geometry. Universal hydrogen bonds between the neighboring molecules have generated a supramolecular arrangement which contributes to the stability of the title complex. Fluorescence property and thermogravimetry of the complex have also been investigated and discussed.

Synthesis,Structure and Characterization of a Cd(Ⅱ) Polymer Based on 6-Hydroxynicotinic Acid

A new 2D layered Cd（Ⅱ） coordination polymer, [Cd（HnicO）（phen）（NOa）]n 1 （H2nicO = 6-hydroxynicotinic acid, phen = 1,10-phenanthroline）, has been hydrothermally synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. It crystallizes in the monoclinic system, space group P21/c with a = 11.1107（2）, b = 13.7639（2）, c = 12.1457（4）A, β = 108.695（1）°, V = 1759.40（7） A^3 Z = 4, Mr= 492.72, F（000） = 976, Dc = 1.860 g/cm^3,μ= 1.289 mm^-1, the final R = 0.0205 and wR = 0.0550 for 3663 observed reflections （I 〉 2σ（I））. X-ray single-crystal structural analyses reveal that in complex 1, the HEnicO ligands and Cd（Ⅱ） nodes define the structure to be （4,4） 2D nets which are further assembled into the final 3D architecture via supramolecular interactions such as hydrogen bonds and aromatic interactions. Moreover, the solid-state luminescent study shows the title polymer possesses intense luminescent property at room temperature.

Solvothermal Synthesis and Crystal structure of a Two-dimensional Cd(Ⅱ) Complex Based on a Flexible Carboxylate Ligand

A two-dimensional Cd（Ⅱ） coordination polymer, [Cd（dtb）]n （dtb = 5,5 ＇-dithiobis（2- nitrobenzoic acid）, has been solvothermally synthesized and characterized by elemental analysis, IR, TG analysis and single-crystal X-ray diffraction analysis. The complex crystallizes in the monoclinic P21/c space group, with a = 10.7147（10）, b = 7.4518（7）, c = 22.053（2） A, β = 95.477（2）°, V = 1752.7（3） A3, Z = 4, Mr = 524.74, Dc= 1.989 g/cm3 and F（000） = 1032. The final R = 0.0453 and wR = 0.1201 for 2950 observed reflections with 1 〉 2σ（I）. In the complex, the Cd（Ⅱ） ion is coordinated with six oxygen atoms from four different carboxylate groups of dtb ligands and one lattice water molecule. The adjacent Cd centers are interconnected by the flexible carboxylate ligand to form a two-dimensional （2D） structure.

Synthesis,Structure and Physical Properties of Mn and Cd Complexes with 1,1,2,2-Tetracarboxyl-ethylene Acid

Complex [Mn（tce） 0.5（H2O） 4]（1） was obtained from Mn（OAc） 2 and tce,where tce is 1,1,2,2-tetracarboxyl-ethane. The structure of 1 is a single molecule,in which Mn（II） is a distorted octahedron coordinated to six oxygen atoms. Complex [Cd（tce） 0.5（H2O） 3]（H2O） （2） fea-tures a pillared layer architecture. The Cd（II） atom is in an octahedral environment coordinated by six oxygen donors from water molecules and tce ligands. Cd（II） atoms are interlinked by the tce ligand to generate a 2-D wavelike layer. The layers are strutted by the intermolecular O-H···O hydrogen bonds to form a 3-D open framework. Luminescence property of complex 2 was investigated. Magnetic property of complex 1 was also studied. 1 belongs to triclinic,space group P1 with a = 6.2901（12） ,b = 8.0212（15） ,c = 8.0769（15） A,α = 108.522（3） ,β = 95.068（3） ,γ = 97.086（3） °,V = 379.92（12）A^3,Mr = 456.08,Dc = 1.993 g/cm^3,F（000） = 232,μ = 1.748 mm^-1,Z = 1,the final R = 0.0297 and wR = 0.0731 for 1575 observed reflections with I 〉 2σ（I） . 2 is of monoclinic system,space group P21/c with a = 6.4367（14） ,b = 9.495（2） ,c = 13.907（3）A,β = 117.405（8） °,V = 754.6（3） A^3,Mr = 285.51,Dc = 2.513 g/cm^3,F（000） = 556,μ = 2.905 mm^-1,Z = 4,the final R = 0.0375 and wR = 0.0737 for 1521 observed reflections with I 〉 2σ（I）.

Synthesis,Crystal Structure and Magnetic Property of a New Cd(Ⅱ) Complex with Four Nitronyl Nitroxide Radicals

A new Cd（Ⅱ） complex with four nitronyl nitroxide radicals [Cd（NIT4Py）4Cl2]（NIT4Py = 2-（4＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl-3-oxide） has been synthesized and structurally characterized by X-ray diffraction analysis.It crystallizes in triclinic,space group P1 with a = 7.2441（4）,b = 13.6964（8）,c = 13.7354（8） ,α = 89.8610（10）,β = 77.9180（10）,γ = 87.2250（10）°,V = 1331.01（13） 3,C48H64CdCl2N12O8,Mr = 1120.41,Z = 1,Dc = 1.398 g/cm3,μ（MoKα） = 0.573 mm-1,F（000） = 582,S = 1.043,the final R = 0.0257 and wR = 0.0641 for 4333 observed reflections（I 〉2σ（I））.The title complex exists in the mononuclear-metal structures,in which each Cd（Ⅱ） ion adopts a distorted octahedral geometry and is coordinated by two Cl-anions and four pyridyl-N atoms from four NIT4Py ligands.The magnetic measurements show weak antiferromagnetic interactions between the nitroxide radicals.

A Porous 3D Supramolecular Architecture of Cd(II) Complex with Water Clusters as Pillars

A supramolecular complex of Cd（II） with 1D water tapes as pillars[Cd2（dpa）2（phen）2（H2O）2]·6H2O 1 （H2dpa = diphenic acid, phen = phenanthroline）, has been synthesized and characterized by elemental analysis, IR spectroscopy, and single-crystal X-ray diffraction analysis. The crystal is of triclinic, space group P1^- with a = 9.7029（4）, b = 11.9601（5）, c = 12.1788（4） A, α = 71.6990（10）, β = 71.8740（10）, γ = 74.4680（10）°, V = 1252.39（8） A^3, C52H48Cd2N4O16, Mr = 1209.76, Z= 1, Dc = 1.604 g/cm^3,μ = 0.925 mm^-1, F（000） = 612, R = 0.0679 and wR = 0.2514 for 3870 observed reflections （I 〉 2σ（I））. Two intramolecular Cd（II） centers of this complex are encircled by two dpa^2- ligands forming an 18-membered ring, which is further assembled into a pillared three-dimensional （3D） supramolecular architecture through the synergetic effect of intermolecular face-to-face π…π stacking and weak O-H…O hydrogen-bonding interactions. Moreover, this complex exhibits photoluminescence with the main emission bands located at about 456 nm upon excitation at 355 nm in the solid state at room temperature.

Synthesis and Crystal Structure of a Cadmium(Ⅱ) Coordination Polymer:[Cd_2Cl_4(bpme)]_n·n(2H_2O)

A novel coordination polymer, [Cd2Cl4（bpme）]n·n（H2O） （1, bpme=2,5-bis（be-nzoimidazol-2-yl）pyrazine）, has been synthesized and its crystal structure was determined by single-crystal X-ray diffraction. The crystal of the complex belongs to the triclinic system, space group P , with a=7.0737（9）, b=8.7886（11）, c=9.4561（12） , α=105.3580（10）, β=94.981（2）, γ=96.879（2）°, V=558.46（12） 3, Mr=714.97, Z=1, F（000）=346, Dc=2.126 g/cm3, μ=2.412 mm-1, T=296（2） K, S=1.057, R=0.0533 and wR=0.1480. According to the structural analysis, the Cd（Ⅱ） ion adopts a slightly distorted six-coordinated octahedral geometry. The Cd（Ⅱ） atoms are bridged by four Cl atoms along the a direction, forming infinite straight chains which are further constructed to generate 2D network layer structures through the μ4-N bpme ligand in the b direction, and such 2D network layer structures finally form a novel three-dimensional infinite supramolecular framework through weak π-π stacking between two network layers and hydrogen bonds.

A COMPARISON OF THE DETERMINATION OF STABILITY CONSTANTS OF COMPLEXES OF Cd(Ⅱ)WITH AMINO ACIDS AND SIMPLE PEPTIDES USING MICRO—pH—METRIC TITRATIONS AND CYCLIC VOLTAMMETRY

This paper reports the determination of stability constants for complexes of Cd(Ⅱ)with Gly, Ala,Val,Asp,Gly—Asp,Asp Gly,Gly—Gly and Gly—Gly—Gly using both micro—pH—metric titra- tions and the application of convolution—deconvolution cyclic voltammetry at 25℃ and I=0.10 mol· dm^(-3)(KNO_3).Stability constants were calculated from pH—metric data using the SUPERQUAD com- puter program and cyclic voltammograms were collected,stored and manipulated using the EG and G CONDECON 300 software.A considerably larger ligand:metal ratio(e,g.50:1)was possible using voltammetry.Evaluation of results from the two techniques suggests that stability constants for the species[CdL_2]and[CdL_3]are reliable when calculated fromvoltammetry while those for[CdL]are more reliable when determined by pH-metric titration.

Synthesis,Crystal Structure and Magnetic Behavior of a Novel Cd(Ⅱ) Complex with Four Nitroxide Radicals

A novel diamagnetic-metal Cd（Ⅱ） complex with four nitroxide radicals[Cd（IM4Py）4Cl2]（IM4Py=2-（4＇-pyridinyl）-4,4,5,5-tetramethylimidazoline-1-oxyl） was synthesized and characterized by elemental analyses,IR spectra,UV-Vis spectra and X-ray single crystal diffraction.The complex crystallized in triclinic space group P1 with a=0.93285（14） nm,b=1.16827（18） nm,c=1.3660（2） nm,α=112.759（2）°,β=104.524（2）°,γ=92.008（3）°,V= 1.3143（3） nm3,Z=1,Dc=1.335 g/cm3,the final R1=0.0423 and wR2=0.1009.In the title complex,each Cd（Ⅱ） ion adopting a distorted octahedral geometry is coordinated by two Cl-anions and four pyridyl-N atoms from four IM4Py ligands.The magnetic measurements show the weak antiferromagnetic interactions between the nitroxide radicals.

Concentric Centrifugal Figurate Erythema as an Unusual COVID-19 Evanescent Skin Manifestation in a Patient With CD3^(+)/CD45^(+)Lymphocyte Infiltration:A Case Report

Introduction:Coronavirus disease 2019(COVID-19)may be associated with various skin manifestations.Among them,figurate erythema(FE)is rare;only a few clinical reports have been published.Herein,we reported an unusual concentric FE lesions and their immunohistochemical profile in a patient with COVID-19.Case presentation:A 52-year-old woman was diagnosed with COVID-19.One month later,she developed asymptomatic annular erythematous concentric ring lesions on her inner right thigh.The margin of every ring increased in coloration,and the lesions then completely resolved in 2 weeks.A biopsy revealed vasculitis of small vessels,an increase in the fluorescence intensity of CD3 and CD45,and negativity for COVID-19 RNA.Discussion:The results showed an unusual FE that has a clinical mixed type between erythema annulare centrifugum and erythema gyratum repens;the physiopathological mechanism in the FE due to COVID-19 is unknown;one theory involves rapid viral passage into the cutaneous vascular system that triggers an immune and inflammatory response.Although the results exhibited a negative COVID-19 RNA in the tissue,the CD3^(+)/CD45^(+)lymphocyte infiltration could explain the clinical pattern as a direct inflammatory response in the small vessel or as a delayed immune response.Conclusion:Our findings suggest an immunohistochemical small vessel vasculitis pattern with an unusual clinical FE that differs from other types of COVID-19-associated FE or erythema reported previously.

Synthesis and Crystal Structure of a Zeolite-like Metal-organic Framework Based on the Triazole Ligand

A novel zeolite-like metal-organic framework, [Cd12（trz）12＇F10＇（SiF6）3]·（H3O）4 （Htrz = 1,2,4-triazole）, has been synthesized under solvothermal conditions using 1H-l,2,4-triazole-3- carboxylic acid and CdF2 as the starting materials. The complex has been characterized by elemental analysis, IR, SEM-EDS, gas adsorption, powder and single-crystal X-ray diffraction analyses. The title complex crystallizes in the cubic 1-43m space group, with a = 14.6436（8）, V= 3140.1（3）A3, Z = 2, Mr = 2857.96, D,.= 3.023 g/cm3 and F（000） = 2668. The final R = 0.0653 and wR = 0.1880 for 586 observed reflections with 1 〉 2σ（I）. In the title complex, three adjacent Cd（ll） centers are connected by three p3-bridging triazole ligands to form triagonal secondary building units （SBUs）, which are further interconnected to form a three-dimensional skeleton with tetrahedral cages.