Synthesis,crystal structure and magnetic properties of a new binuclear copper(II)-copper(II) complex of a macrocyclic oxamide

The binuclear metal complex [Cu(μ-exoO₂)cyclamCu(bpy)](ClO₄)₂·H₂O (bpy?=?2,2′-bipyridine and (exoO₂)cyclam?=?1,4,8,11-tetraazacyclotradecanne-2,3-dione) has been synthesized and characterized by single-crystal X-ray analysis and spectroscopic and magnetic measurements. The structure consists of homobinuclear [Cu(μ-exoO₂)cyclamCu(bpy)]²⁺ cations, a weakly coordinated water molecule and perchlorate ions. In each binuclear unit, Cu1, coordinated by four nitrogen atoms of the macrocyclic organic ligand is connected to Cu2 via the exo-cis oxygen atoms of the macrocyclic ligand with Cu···Cu separations of 5.151?Å; Cu2 assumes square-pyramidal geometry. Magnetic properties measured at 2–300?K show antiferromagnetic exchange between adjacent copper(II) ions.     

Structural and spectral studies of a new copper(II) complex with a tridentate thiosemicarbazone ligand

The reaction of copper(II) chloride dihydrate with 2-hydroxy-3-methoxybenzaldehydethiosemicarbazone (HL) ligand in a 1:1 ratio forms the complex [Cu(L)(Cl)] · H₂O. The complex is characterized by spectroscopic, electrochemical, and thermal analysis. X-ray crystallographic analysis reveals that the central copper atom displays the distorted square planar geometry. The water molecule present in the lattice participates in a strong hydrogen bonding network, which leads to a 2D supramolecular arrangement.     

Synthesis of a novel copper(II) complex and its crystal structure

One novel chiral copper(II) complex was successfully synthesized from the reaction of chiral 1,3-thiazolidine-2-thione ligand with CuCl₂ in dichloromethane in the presence of Et₃N and DMAP at room temperature. Its unique crystal structure was unambiguously disclosed by X-ray analysis. The crystal is tetragonal, space group I4(1), space group a=15.0875(11), b=15.0875(11), c=19.362(3) Å, =90, β=90, γ=90°, V=4407.4(8) ų, Z=8, ρ_calc=1.639 mg cm⁻³.     

Synergistic effects of a specific metal template and H-bonds in controlling macrocyclization: a simple, selective, and effective cyclization from N,N-bis(2-hydroxybenzyl)alkylamine derivatives

A macrocyclic compound obtained from a simple, selective, and effective reaction between N,N-bis(2-hydroxybenzyl)alkylamine derivatives and 1,3-bis(tosyloxy)propane is a good example of a cyclization controlled by synergistic effects of a metal template and hydrogen bonds.     

Synthesis, crystal structure, spectroscopy and magnetic properties of a dinuclear Cu complex with 3,5-bis(2-pyridyl)pyrazole bridging ligand

A dinuclear Cu^II complex [Cu₂(bpp)₂(H₂O)₂](ClO₄)₂ (1) with 3,5-bis(2-pyridyl)pyrazole (Hbpp), has been synthesized and characterized by elemental analyses, thermal analysis, conductance, UV-vis and IR spectra. The crystal structure of 1, determined by X-ray diffraction technique, reveals that two centrosymmetric Cu^II centers are bridged by a pair of tetradentate anionic bpp ligands, adopting a square-pyramidal environment with the water ligand occupying the axial site. An interesting feature of this structure is the formation of a two-dimensional supramolecular network through O-H?O hydrogen bonds between the water moieties of the cationic [Cu₂(bpp)₂(H₂O)₂]²⁺ subunits and perchlorate anions. The magnetic properties of 1 have been investigated by variable-temperature magnetic susceptibility and EPR measurements. Very strong antiferromagnetic interaction between the Cu^II centers (with H=−JS₁S₂, J=−368.3 cm⁻¹) has been observed, and the magneto-structural correlations was analyzed.     

A novel Cd(II) complex with 1,3-bis(4-Pyridyl)propane: Synthesis,crystal structure,and interaction with DNA

The complex [Cd(Bpp)₃Cl₂] _n · 2H₂O (Bpp = 1,3-bis(4-pyridyl)propane) has been synthesized and characterized by elementary analysis, IR spectrum and singel-crystal X-ray diffraction. The crystal belongs to monoclinic system, space group C2/c with the crystal cell parameters of a = 31.05(3), b = 17.556(13), c = 16.281(13) Åβ = 121.402(7)°, V = 7574(10) ų, and Z = 8. The compound has formed a 1D surface shape structure through these coordinate modes with the ligand. The 2D layers are further aggregated by hydrogen bonding with octameric subunits.     

Novel supramolecular compounds with three-dimensional hydrogen-bonded network [M(H2O)6][H2L] (H4L=1,2,4,5-benzenetetracarboxylic acid, M=Mn and Co): syntheses, characterization and crystal structures

Two hydrogen-bonded supramolecular compounds having the general formula [M(H₂O)₆][H₂L] (M=Mn^II or Co^II and H₄L=1,2,4,5-benzenetetracarboxylic acid), have been newly prepared by the reaction of [M(H₂O)₆](ClO₄)₂ and [C₆H₂(COOH)₄] (H₄L), and structurally characterized by X-ray diffraction. The metal center in each compound is six-coordinated, forming an ideal octahedral geometry. Both neutral formula units make unique three-dimensional supramolecular architectures through hydrogen bonds and stabilized by electrostatic force.     

NMR, FTIR, ESI-MS and semiempirical study of a new 2-(2-hydroxyethoxy)ethyl ester of monensin A and its complexes with alkali metal cations

A new 2-(2-hydroxyethoxy)ethyl ester of monensin A (MON6) has been synthesized and its ability to form complexes with Li⁺, Na⁺ and K⁺ cations has been studied by ESI-MS, ¹H and ¹³C NMR, FTIR, and PM5 semiempirical methods. It is demonstrated that MON6 has been able to form stable complexes of 1:1 stoichiometry with monovalent metal cations. The structures of the complexes are stabilized by intramolecular hydrogen bonds in which the OH groups are always involved. In the structure of MON6 the oxygen atom of the CO ester group is involved in very weak bifurcated intramolecular hydrogen bonds with two hydroxyl groups whereas in the complexes of MON6 with monovalent metal cations the CO ester group is not engaged in any intramolecular hydrogen bonds. The structures of the MON6 and its complexes with Li⁺, Na⁺ and K⁺ cations are visualized.     

A novel five-coordinated silver complex {[Ag(HPPz)4(NO3)](NO3)4} [PPz=trans-2-(2-phenylethenyl)pyrazine]: Self-assembly of supramolecular architecture based on anions

The title complex {[Ag(HPPz)₄(NO₃)](NO₃)₄}, 1, has been prepared from the reaction of trans-2-(2-phenylethenyl)pyrazine (PPz) with AgNO₃ at room temperature in 10% HNO₃ and structurally determined by single-crystal X-ray diffraction analysis. The result shows that the Ag^I center is five-coordinated with one anion and four mono-protonated HPPz⁺ ligands. The anions display versatility not only participating in coordination, but also linking the HPPz⁺ ligands by electrostatic and hydrogen bond interactions. The final framework can be considered as a 3D supramolecular architecture built up by the self-assembly of the building blocks ([Ag(HPPz)₄(NO₃)]³⁺, ), driven by diverse interactions based on the anions.     

Spectroscopic, mass spectrometry, and semiempirical investigations of a new 2-(2-methoxyethoxy)ethyl ester of Monensin A and its complexes with monovalent cations

A new 2-(2-methoxyethoxy)ethyl ester of Monensin A (MON7) has been synthesized and its capability of complex formation with Li⁺, Na⁺, and K⁺ cations has been studied by ESI MS, ¹H and ¹³C NMR, FT-IR, and PM5 semiempirical methods. ESI mass spectrometry indicates that MON7 forms complexes with Li⁺, Na⁺, and K⁺ of exclusively 1:1 stoichiometry which are stable up to cv = 70 V. The formation of complexes between MON7 and Na⁺ cations is strongly favored. Starting from about cv = 90 V fragmentation of the respective complexes is observed, primarily characterized by several dehydration steps. The structures of the MON7 complexes with Li⁺, Na⁺, and K⁺ cations are stabilized by intramolecular hydrogen bonds in which the OH groups are always involved. The structures are visualized and discussed in detail. It has been proved that the formation of a pseudo crown ring structure formed by MON7 is preferred in complexes with Na⁺ cations.     

A tetradentate bisoxime and its supramolecular nickel(II) cluster: synthesis,crystal structure,and spectral properties

Salen-type bisoxime 5,5′-dimethoxy-2,2′-[(ethylenedioxy)bis(nitrilomethylidyne)]diphenol (H₂L) and its trinuclear Ni(II) cluster {[(NiL)(n-BuOH)]₂(μ-OAc)₂Ni}?·?n-BuOH have been synthesized and structurally characterized. The structure of H₂L adopts an L-shape conformation where the two salicylaldoxime moieties are well separated. In the trinuclear Ni(II) cluster, two acetates coordinate to three Ni(II)'s through Ni–O–C–O–Ni bridges, four μ-phenoxos from two [NiL(n-BuOH)] units also coordinate to Ni(II), and two n-butanols coordinate to two terminal Ni(II)'s forming a distorted octahedral geometry. The Ni–O–C–O–Ni and μ-phenoxo bridges play important roles in assembling Ni(II) and the ligands. H₂L forms a rectangle-like large cave structure through O–H?···?N, C–H?···?O, and C–H?···?π hydrogen-bond interactions, whereas its trinuclear Ni(II) cluster exhibits a 3-D supramolecular network structure through intermolecular O–H?···?O, C–H?···?O, and C–H?···?π hydrogen-bond interactions.     

Bis-(bis-(1,3-diaminopropane)-copper(II) Tetracyanonickellate(II)) Tetrahydrate: Preparation, Characterization, and Crystal Structure of a Novel Molecular Tetracyanonickellate

Summary.  [Cu(tn)₂Ni(CN)₄]₂ċ4H₂O and Cu(tn)₂Ni(CN)₄ (tn = 1,3-diaminopropane) were prepared and characterized. The hydrate is unstable on air and readily dehydrates to Cu(tn)₂Ni(CN)₄. Crystal structure analysis of the hydrate at 150 K revealed a novel tetranuclear molecular structure of the tetracyanonickellate. The building elements are two [Cu(tn)₂]²⁺ cations (coordination numbers of Cu: 5 and 6, respectively), two [Ni(CN)₄)²⁻ anions, and crystal water. The two cations are linked by one tetracyanonickellate anion via bridging cyano groups placed in cis positions. The second anion is bound weakly (Cu-N = 2.82 ?) via one μ₂-bridging cyano ligand. The tetranuclear molecules and pairs of solvate water molecules are linked by strong hydrogen bonds, thus forming infinite planes which are linked in the third dimension by considerably weaker hydrogen bonds. Received May 9, 2000. Accepted (revised) August 21, 2000     

Vibrational spectra and structure of some oxalic acid/substituted pyridine (methyl-, amino-, and dihalogeno-) complexes: Hydrogen bond features

The Raman and infrared spectra of some polycrystalline substituted pyridine/oxalic acid complexes have been investigated and assignments in terms of group frequencies are given. Various hydrogen bonds (NH?O, OH?O, OH?N) are distinguished and crystal structures are proposed. For the stronger bases (methyl- or aminopyridines with pk_a ≈ 6) proton transfer occurs. The 1/1 complex contains infinite chains of hydrogen oxalate ions linked by strong OH?O hydrogen bonds with vOH between 2000 and 800 cm⁻¹. R_OH?O distances are 2.47–2.62 Å). The substituted pyridinium cations are linked to the chain backbone by medium NH?O hydrogen bonds with NH?O lengths of 2.71–2.81 Å. The 3,5-dichloropyridine forms a 2/1 adduct without proton transfer, in accordance with its pk_a (0.6), and strong OH?N hydrogen bonds occur (vOH about 2000 cm⁻¹ and ). Finally, the 2,6-dihalogenopyridine derivatives do not form complex with oxalic acid, presumably because of steric hindrance.     

新型双肟四核苦味酸铜(Ⅱ)化合物的制备、结构及抗菌性能

室温下,H2L(H2L=6,6'-二甲氧基-2,2'-[(1,4-亚丁基)二氧双(氮次甲基)]二酚)和苦味酸铜在丙酮溶剂中反应,制备了一种新型的四核苦味酸铜(II)化合物[Cu4L2(pic)4(H2O)2]·2H2O(1)。采用红外光谱、元素分析及X射线单晶衍射等手段对化合物的结构进行了确认。结构解析表明,1属单斜晶系,空间群C2/c,晶胞参数为a=3.4376(4)nm,b=1.3750(3)nm,c=2.2418(2)nm,β=106.689(3)0,V=10.150(2)nm3,Z=4,Mr=2011.44,Dc=1.316 g/cm3,μ=0.916 mm-1,F(000)=4096,R1=0.0979,wR2=0.2010。1的对称单元中含有4个Cu(II)原子,2个配位H2L分子,4个配位苦味酸根阴离子,2个配位水分子和2个游离水分子组成。中心4个Cu(II)的配位数均为6,以每个Cu(II)原子为中心均形成了扭曲八面体结构的配位几何构型,分子间氢键和π-π堆积作用形成了三维超分子结构。抗菌性能测试结果表明,化合物1的抑菌活性高于H2L,二者对金黄色葡萄球菌、大肠杆菌和枯草杆菌均有显著的抑菌活性。     

A novel cesium hydroxygallophosphate with a layered structure built up of rutile ribbons: CsGa2(OH)2[(PO4)H(PO4)]

A new cesium gallophosphate, CsGa₂(OH)₂[(PO₄)H(PO₄)], with an original layer structure has been synthesized by hydrothermal route and characterized by single-crystal X-ray diffraction (R=0.0344, R_w=0.0319). Its structure crystallizes in the monoclinic space group P2₁/a with cell parameters , , , β=93.36(4)° and Z=2. It consists of [Ga(OH)PO₄]_∞ layers built up of rutile ribbons interconnected through PO₄ tetrahedra. The structure of CsGa₂(OH)₂[(PO₄)H(PO₄)] is closely related to those of (NH₄)Ga(OH)PO₄ and (en)Ga₂(OH)₂(PO₄)₂ (en=ethylenediamine [H₃N(CH₂)₂NH₃]²⁺). The three structures differ mainly from each other by the relative positions and the spacing of the successive layers, which are governed by different hydrogen bonding modes between [Ga(OH)PO₄]_∞ layers and the interleaved species. The title compound presents strong symmetric hydrogen bonds O---H---O which bridge two PO₄ tetrahedra of two successive layers. As a consequence, the distance between the layers is significantly shorter than in the two other amine compounds.     

Synthesis,Crystal Structure and Characterization of a new Protonated Magnesium Borophosphate: (H3O)Mg(H2O)2[BP2O8]·H2O

A new protonated borophosphate (H₃O)Mg(H₂O)₂[BP₂O₈]·H₂O ( 1 ) was synthesized under mild hydrothermal conditions and characterized by single‐crystal X‐ray diffraction, FTIR spectroscopy and TG‐DTA. The compound crystallizes in the hexagonal system, space group P6(1)22 (No 178), a = 9.4462(7) Å, c = 15.759(2) Å, V = 1217.8(2) Å³, and Z = 6. There exist infinite helical $^1_\infty$ {[BP₂O₈]^3–} ribbons built up from corner‐sharing PO₄ and BO₄ tetrahedra, which are connected by MgO₄(H₂O)₂ leading to an infinite three‐dimensional open‐framework. The H₃O⁺ ions are located at the free thread of the helical ribbons, whereas crystallized water occupy the channels of the helical ribbons. The dehydration of the compound occurs at a higher temperature which is presumably due to the anisotropic hydrogen bonds in the crystal structure. The luminescent properties of the compound were studied.     

An unexpected dinuclear Cu(II) complex with a bis(Salamo) chelating ligand: synthesis,crystal structure,and photophysical properties

An unexpected dinuclear Cu(II) complex, [Cu₂(L²)₂], has been synthesized via complexation of Cu(II) acetate monohydrate with a bis(Salamo) ligand H₂L¹. Catalysis of Cu(II) ions results in unexpected cleavage of two N–O bonds in H₂L¹, giving a dialkoxo-bridged dinuclear Cu(II) complex. Each Cu(II) complex possesses a Cu–O–Cu–O four-membered ring instead of the usual bis(Salamo) [Cu₂L¹] complex with H₂L¹. The H₂L¹ molecule is stabilized by intramolecular O1–H1?N1 hydrogen bonds and π?π stacking interactions linking adjacent molecules into a 1-D infinite zigzag chain. In the structure of the Cu(II) complex, intermolecular hydrogen bonds have stabilized the Cu(II) complex to form a self-assembling infinite 1-D linear chain. Furthermore, the H₂L¹ ligand shows intense photoluminescence with two emissions at ca. 370 and 464 nm upon excitation at 310 nm. The Cu(II) complex shows photoluminescence with maximum emission at ca. 423 nm upon excitation at 370 nm.     

A ternary copper(II) complex for supramolecular assembly with double helices: synthesis,crystal structure,DNA-binding and DNA-cleavage properties

A ternary Cu(II) complex, [Cu(naph-ser)(bipy)]·0.125CH₂Cl₂ (naph-ser = a Schiff base derived from 2-hydroxy-1-naphthaldehyde and l-serine, bipy = 2, 2′-bipyridine), has been synthesized and structurally characterized. In the crystal structure, a supramolecular assembly with left-handed double helices is formed by O–H···O hydrogen bonding interactions. The DNA-binding properties and DNA-cleavage activity of the Cu(II) complex have been investigated by spectroscopic methods and agarose gel electrophoresis. The results indicate that the Cu(II) complex can bind to CT-DNA via an intercalative mode and shows efficient cleavage activity in the absence and presence of reducer.     

Synthesis,structure, and antioxidative properties of a copper(II) complex with 1,2-bis(benzimidazol-2-yl)ethane ligand

1,2-Bis(benzimidazol-2-yl)ethane (bbe) and its copper(II) complex, {[Cu(bbe)Br₂]₂}·2DMF ( 1 ), have been synthesized and characterized by elemental analysis, ultraviolet–visible, and infrared spectra. The single crystal structure analysis of 1 shows two crystallographically independent but chemically identical [Cu(bbe)Br₂] molecules. The coordination geometry of the copper atoms may best be described as a distorted tetrahedron (τ₄ = 0.740 for Cu1 and 0.696 for Cu2). The cyclic voltammogram of complex 1 represents quasi-reversible Cu²⁺/Cu⁺ pairs. in vitro antioxidant tests showed that complex 1 has significant antioxidant activity against superoxide and hydroxy radicals. Photoluminescence investigations showed that the fluorescence intensity of complex 1 is significantly weaker than that of the ligand. This may be due to the paramagnetic effect of divalent copper to cause quenching of fluorescence.