3-((5-(3-吡啶基)-2-(1,3,4-噁二唑基))硫代)-2,4-戊二酮Cu(Ⅱ)/Zn(Ⅱ)/Mn(Ⅱ)配合物的合成及其晶体结构

将配体3-((5-(3-吡啶基)-2-(1,3,4-噁二唑基))硫代)-2,4-戊二酮(HL)与Cu(OAc)_2·H_2O、Zn(OAc)_2·2H_2O和Mn(OAc)_2·4H_2O分别进行配位反应,得到3个配位聚合物{[Cu_2(L)_4]·CHCl_3}_n(1)、{[Zn(L)_2]·4CHCl_3}_n(2)和{[Mn(L)_2]·4CHCl_3}_n(3),并通过元素分析、红外光谱、粉末X射线衍射、单晶X射线衍射等对配合物的结构进行了表征。在固体状态下,配位聚合物1形成1D螺旋链状结构,配位聚合物2和3形成2D网状结构。     

Metal complexes with thioether containing unsymmetrical N2S donor Schiff base ligand: Crystal and molecular structure of nickel(II) complex

Abstract

A thioether unsymmetrical N₂S donor Schiff base ligand, N-2-((2-nitrophenyl)thio)phenyl)-1-(pyrrole-2-yl)methanimine (HL) and its five complexes [NiL₂], [CuL₂], [ZnHL(H₂O)₂(OAc)₂], [CdHL(H₂O)₂(OAc)₂]·2H₂O and [MnHL(H₂O)₂(OAc)₂]·2H₂O were synthesized. The ligand and metal complexes were characterized by spectroscopic methods (FT-IR, ¹H and ¹³C NMR, UV–Vis), elemental analyses, mass spectrometry, and conductance measurements. Of these complexes, [NiL₂] was structurally characterized by single-crystal X-ray crystallography. In this complex, two ligands function as monobasic N₂S tridentate and coordinate through pyrrole-N, thioether-S, and azomethine-N, and the nickel(II) is in distorted octahedral environments.     

Synthesis,structural characterization,molecular docking,and urease inhibition studies of dinuclear cobalt(II) complexes derived from 3,5-bis(pyridin-2-yl)-4-amino-1,2,4-triazole

Two dinuclear Co(II) complexes, [Co₂(L)₂(EtOH)₄]·4ClO₄ (1) and [Co₂(L)₂(H₂O)₂(NO₃)₂]·2NO₃ (2) (L?=?4-amino-3,5-bis(pyridin-2-yl)-1,2,4-triazole), have been obtained and characterized by IR, elemental analysis, and single-crystal X-ray diffraction analysis. The stabilization of their crystal lattices is maintained by strong H-bonds between counterions and host framework, which lead to various supramolecular architectures. The urease inhibitory properties of 1, 2, and L were investigated, where the two complexes revealed strong urease inhibition activities. Docking simulations of 2 have been performed with H. pylori urease (PDB code: 1E9Z) to rationalize their binding models.     

New platinum(II) and palladium(II) quinoline-imine-pyridine, quinoline-imine-thiazole and quinoline-imine-imidazole complexes by metal-assisted condensation reactions

Pt(II) and Pd(II) methyl- and chloro-complexes with the tridentate N-donor ligands ((pyridin-2-yl)methylene)quinolin-8-amine (NNPy), ((pyridin-2-yl)ethylidene)quinolin-8-yl-amine (NNMePy), (phenyl(pyridin-2-yl)methylene)quinolin-8-yl-amine (NNPhPy), ((thiazol-2-yl)methylene)quinolin-8-amine (NNTh) and ((imidazol-4-yl)methylene)quinolin-8-amine (NNImH) were prepared by metal-assisted condensation of 8-aminoquinoline and an ortho-substituted aldehydo- or keto- N-heterocycle. Preliminary reactivity studies involving the coordinated tridentate N-donors, the chloro-ligand and the M-CH₃ bond were carried out, leading to the synthesis of several new complexes. During these studies, the formation of a novel five-coordinate Pt(II) carbonyl-complex was observed.     

Structure of zinc complexes with 3-(pyridin-2-yl)-5-(arylideneiminophenyl)-1H-1,2,4-triazoles in different tautomeric forms: DFT and QTAIM study

On the basis of X-ray crystallographic data on molecular crystals of zinc complexes with 3-(pyridin-2-yl)-5-(arylideneiminophenyl)-1H-1,2,4-triazoles, quantum-chemical analysis of the electron density distribution function for these complexes has been performed by Bader’s atoms in molecules method. Topological parameters of electron density at the critical points of coordination and noncovalent bonds have been interpreted, and the bond energies have been estimated using the Espinosa equation. For the solvated complex Zn[(L3)(OAc)₂] · i-PrOH (L3 = 3-(pyridin-2-yl)-5-(benzylideneiminophenyl)-1H-1,2,4-triazole), a variable coordination number of the Zn²⁺ ion has been predicted as a result of dynamic dissociation/formation of an unstable Zn-O coordination bond. For the binuclear [Zn₂(L2)₂] complex (L2 = 3-(pyridin-2-yl)-5-(salicylideneiminophenyl)-1H-1,2,4-triazole), an orbital interpretation of the decrease in the fluorescence quantum yield in tetrahydrofuran and dimethyl sulfoxide as compared with free L2 ligand is presented.     

Preparations,IR spectra and crystal structures of cyano-bridged bimetallic complexes of zinc(II) and cadmium(II) with tetracyanopalladate(II)

The novel heteronuclear compounds [Zn(hydet-en)₂Pd(CN)₄] (1) and [Cd(hydet-en)₂Pd(CN)₄] (2) {hydet-en: N-(2-hydroxyethyl-ethylenediamine)} have been synthesized and characterized by elemental analyses and IR spectra. The crystal structures of 1 and 2 have been determined by X-ray diffraction. Structural analysis shows that both compounds have shown a polymeric chain, in which the Zn(II)/Pd(II) and Cd(II)/Pd(II) centres are linked by two CN groups. Both zinc and cadmium atoms are six coordinate with two trans cyanide–nitrogen and four hydet-en N atoms in a distorted octahedron arrangement; the palladium atoms in 1 and 2 are four coordinate with four cyanide-C atoms in a square planar arrangement. The chains in both compounds are connected through weak interchain hydrogen bonds, N–H?···?O, N–H?···?N and O–H?···?N, thereby forming a three-dimensional network.     

A series of 1-D zinc(II) coordination polymers with 3-D supramolecular networks: synthesis,structural investigation,and NBO analysis

Abstract

N,N′-Bis(pyridin-4-ylmethylene)naphthalene-1,5-diamine (L) acts as a bipyridine analogue linker ligand towards {Zn₇(μ₄-O)₂(OAc)₁₀}, {Zn₂(NCS)₂(OAc)₂}, and {Zn(N₃)₂} nodes and allows construction of three new 1-D coordination polymers, the linear chain [Zn₇(μ₄-O)₂(OAc)₁₀(L)]_n (1), [Zn(NCS)(OAc)(L)]_n (2) in ladder-type geometry and the zigzag chain [Zn(N₃)₂(L)]_n (3). Structural characterization reveals that in 1 acetate anionic ligands connect seven Zn(II) ions through the bridging coordination modes μ₃-η¹,η² and μ₂-η¹,η¹. The resulting heptanuclear node is located on an inversion center and therefore consists of four crystallographically distinct cations; their coordination spheres correspond to distorted octahedra or tetrahedra. The Zn(II) ions in polymer 2 exhibit distorted trigonal bipyramidal {ZnN₃O₂} coordination; μ₂-η¹,η¹ coordinated acetate and terminal thiocyanate ligands lead to inversion-symmetric [Zn₂(NCS)₂(OAc)₂] secondary building units (SBU), which are further linked by the N,N′-bipyridine analogue L. Terminal coordination of two anionic azide ligands and the bridging bipyridine L result in coordination polymer 3, in which the cations adopt distorted tetrahedral {ZnN₄} coordination. In all crystalline solids 1–3, adjacent 1-D chains interact through π–π stacking and non-classical (C???H···O, C???H···π) hydrogen bonds, leading to 3-D supramolecular architectures. Differences in their 3-D arrangement are due to variations in the anionic co-ligands, subtle conformational differences in the semi-rigid linker and the variable coordination sphere about the zinc cations. Thermogravimetric investigations indicate differences in both thermal stability and decomposition mode. Natural bond orbital (NBO) analysis provides a convenient basis for investigating the intramolecular bonding interactions and delocalization effects in these molecular systems. Finally, solids 1–3 exhibit intense luminescence at room temperature.     

Synthesis and crystal structures of three new complexes derived from 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole

Three new coordination complexes, [Cd₂(ppt)₂(cpba)]?·?(H₂O)₂ (1), [Zn(ppt)₂]?·?(H₂O) (2), and [Zn(MoO₄)(Hppt)] (3) (H₂cpba: 3-(2′-carboxy-phenoxy)-benzoic acid; Hppt: 3-(pyridin-3′-yl)-5-(pyridin-2′′-yl)-1,2,4-triazole), were synthesized under hydrothermal conditions. Their structures have been determined by single crystal X-ray diffraction analyses and further characterized by elemental analyses, IR spectra, and thermogravimetric analyses. X-ray diffraction analyses revealed that Cd(II) ions are linked by ppt^? to form a ladder-shaped structure along the a-axis and further displays a 2-D supramolecular architecture with cpba^2? along the c-axis. In 2, each Zn(ppt)₂ fragment is linked by the nitrogen of pyridin-3′-yl from the neighboring Zn(ppt)₂ forming a V-shaped chain. Compound 3 consists of a ladder structure, in which each {MoO₄} unit is a bridge linking three Zn(Hppt)²⁺ fragments.     

Cd(II) complexes based on a tricarboxylate: synthesis,structural characterization and properties

Reactions of cadmium(II) with 5-(4-carboxybenzylamino)isophthalic acid (H₃L) in the presence of 2-(pyridin-2-yl)-1H-benzo[d]imidazole (pybim) and 2,2′-bipyridine (bpy) by hydrothermal method lead to two complexes, [Cd(HL)(pybim)]·H₂O (1) and [Cd₂(L)(HCOO)(bpy)₂(H₂O)]·H₂O (2). Complexes 1 and 2 have been characterized by single-crystal and powder X-ray diffraction, Infrared spectra, and elemental and thermogravimetric analyses. 1 has a double-chain structure while 2 consists of uninodal 3-connected 2-D hcb networks with (6³) topology. Luminescence and sorption properties of 1 and 2 were also investigated.     

Anion-driven Ag(I) coordination architectures: structural diversity and photoluminescence behaviors

To observe anion impact on structural diversity of coordination architectures, three 1-D Ag(I) complexes with distinct features have been prepared, {[Ag(bpbib)₂(NO₃)]·C₃NH₉O)}_n (1), [Ag₂(bpbib)₂·(BF₄)₂]_n (2), and [Ag₂(bpbib)₂·(ClO₄)₂]_n (3), by the reactions of 4,4′-bis((2-(pyridin-2-yl)-¹H-benzo[d]imidazol-1-yl)methyl)biphenyl (bpbib) with Ag(I) salts. Complex 1 is a 1-D helical chain, whereas 2 and 3 bear ligand-unsupported Ag(I)···Ag(I) interaction-directed 1-D structural motif, with synergetic working of flexible organic linker and anions. All complexes exhibit strong triplet state emission at cryogenic temperatures, which profits from the reduction of nonradiative transitions.     

Synthesis,structures, photoluminescence,and theoretical investigations on two new Zn(II)/Mn(II) complexes with pyridine-2-amidoxine and carboxylate ligands

Abstract  

Two new neutral mononuclear Zn(II) and Mn(II) complexes with pyridine-2-amidoxine and carboxylate ligands, [Zn(paH)₂(OAc)₂]·2CH₃OH (paH = pyridine-2-amidoxine, HOAc = acetic acid) (1), and [Mn(paH)₂(OAc)₂]·C₂H₅OH·2H₂O (2), have been prepared and characterized structurally by X-ray crystallography. 1 and free paH exhibit photoluminescence at room temperature in solid state, which is rare so fare for metal complexes with oxime-based ligand. The emissions of 1 and free paH arise from the metal-perturbed paH-based π → π* ligand-to-ligand charge transfer transition (LLCT) and π → π* charge transfer transition in nature, respectively, in terms of the density functional theory level calculations and molecular orbital analyses.     

Ni(II) and Co(III) complexes of 5-methyl-1,3,4-thiadiazole-2-thiol: syntheses,spectral, structural,thermal analysis,and DFT calculation

Two new complexes, [Ni(en)₂(mtt)₂] (1) and [Co(en)₂(mtt)₂](mtt) (2) (Hmtt = 5-methyl-1,3,4-thiadiazole-2-thiol and en = ethylenediamine), have been synthesized and characterized by various physicochemical techniques. Complexes 1 and 2 crystallize in monoclinic and orthorhombic system with space groups P 21/n and P 21 21 21, respectively. The molecular structures of 1 and 2 show that the metal ions are six-coordinate bonded through four equatorial nitrogens of two en and two axial nitrogens of mtt ligands. The crystal structures of the complexes reveal that mtt is present in thione form and bound to the metal ion through the thiadiazole nitrogen. The crystal structures of the complexes are stabilized by various intermolecular hydrogen bonding providing supramolecular architecture. Complex 2 is also stabilized by weak π···π interactions occurring between two thiadiazole rings. The bioefficacies of the ligand and complexes have been examined against the growth of bacteria to evaluate their antimicrobial potential. The biological results suggest that 2 is more active than the ligand and 1 against the tested bacteria. The geometries of the ligand and the complexes have been optimized by the DFT method and the results are compared with the X-ray diffraction data. The Co(III) complex exhibits an irreversible Co(III)/Co(II) process while the Ni(II) complex displays quasi-reversible Ni(II)/Ni(III) redox processes with large peak separation as compared to that expected for a one electron process which is thought to be coupled with some chemical reaction.     

A comparative study of coordination architectures constructed by di[4-(pyridin-3-yl)pyrimidinyl]disulfide and different metal salts: crystal structures and luminescence properties

Assembly of di[4-(pyridin-3-yl)pyrimidinyl]disulfide (3-ppds) with different metal salts resulted in a variety of coordination polymers that were structurally elucidated. For MnCl₂, a 1-D repeated rhomboidal chain structure [MnCl₂(3-ppds)₂] _n (1) was obtained, whereas a 1-D helical chain structure [Zn(NO₃)₂(3-ppds)] _n (2) was built from Zn(NO₃)₂. A 1-D zigzag chain structure [Cu₂(OAc)₄(3-ppds)] _n (3) was produced from Cu(OAc)₂. In all three complexes, the 3-ppds ligand plays the same role as a bis(monodentate) bridging linker but with variations in both C–S–S–C torsion angles and dihedral angles defined by its conjugated heteroaromatic rings (pyrimidine and pyridine). The luminescence properties of the complexes have been evaluated in the solid state.     

Syntheses,structures, and fluorescent properties of three Zn(II) and Cu(II) complexes of different ligands derived from 3,6-bis(2-pyridyl)-1,2-dihydro-1,2,4,5-tetrazine

Three supramolecular complexes [Zn(HL₁ )₂(H₂O)₂(ZnCl₄)₂] (1), [Cu(L₂ )₂Cl₂] (2), and [Zn(L₃ )Cl₂] (3) have been synthesized and characterized by single crystal X-ray diffraction analysis (L₁ = 3,5-di(2-pyridyl)-4-amino-1,2,4-triazole, L₂ = 3,5-di(2-pyridyl)-1,2,4-triazole, and L₃ = 2-pyridinecarboxylic acid (pyridin-2-ylmethylene)-hydrazide). In 1, anion–π interactions between Cl^? and the π-systems of L₁ are observed and anion–π, hydrogen bonding and π–π stacking interactions link the two complex units of [Zn(HL₁ )₂(H₂O)₂]⁴⁺ and [ZnCl₄]^2? to form a 3-D supramolecular network. In 2, π–π stacking interactions between aromatic rings of 1,2,4-triazole and pyridine rings are observed; in 3, hydrogen bonding of Cl ··· H–N and π–π stacking interactions between parallel pyridine rings of L ₃ are observed. The mechanisms of rearrangement reactions of L to L₁ –L₃ are discussed. The fluorescent properties for solid 1 and 3 are also investigated.     

Nickel(II) complexes of 5-phenyl and 5-furan-1,3,4-oxadiazole-2-thiones containing ethylenediamine: synthesis,spectral and X-ray characterization

The products obtained by the reactions of Ni(OAc)₂·4H₂O with Hpot (Hpot = 5-phenyl-1,3,4-oxadiazole-2-thione) and [K(H₂fchc)] (potassium N′-(furan-2-carbonyl) hydrazine carbodithioate), on treatment with excess of ethylenediamine (en), gave mixed ligand complexes [Ni(pot)₂(en)₂] (1) and [Ni(fot)₂(en)₂] (2) (fot = 5-furan-(1,3,4)-oxadiazole-2-thione). These complexes have been characterized with the aid of elemental analyses, IR, magnetic susceptibility and single crystal X-ray studies. In both complexes, the heterocyclic ligand coordinates through oxadiazole nitrogen, and the ligand exists as the thione form. The complexes 1 and 2 have distorted octahedral geometries around the centrosymmetric Ni(II) center with trans oxadiazole ligands. Both complexes show extended hydrogen bonding to give a supramolecular framework.     

A new luminescent 3-D metal-organic framework of diamond-like network possessing 8-fold interpenetration

A new 3-D coordination polymer [Zn(L)₂] (1) (HL?=?4-(pyridin-4-ylmethoxy)benzolic acid) was synthesized under hydrothermal conditions with Zn(OAc)₂?·?2H₂O and HL and characterized by single crystal X-ray diffraction (XRD). Compound 1 displays a 3-D 8-fold interpenetrating structure with diamondoid framework containing large adamantanoid cages. Meanwhile, it exhibits intense fluorescence at 402?nm in the solid state. In addition, powder XRD and thermogravimetric (TG) analysis for 1 are also reported.     

Coordination of ZnII,CdII, and HgII by 2‐Pyridineformamide‐3‐piperidyl‐thiosemicarbazone

Sodium in dry methanol reduces 2‐cyanopyridine in the presence of 3‐piperidylthiosemicarbazide and produces 2‐pyridine‐formamide‐3‐piperidylthiosemicarbazone, HAmpip. Complexes with zinc(II), cadmium(II), and mercury(II) have been prepared and characterized by elemental analyses and spectroscopic techniques. In addition, the crystal structures of [Zn(Ampip)₂], [Zn(Ampip)(Oac)]₂, [Cd(HAmpip)Cl₂]·(CH₃)₂SO, [Cd(HAm‐pip)Br₂] · (CH₃)₂SO, [Cd(HAmpip)I₂]·(CH₃)₂SO, [Cd(Ampip)₂] and [Hg(HAmpip)Br₂]·(CH₃)₂SO have been solved. Coordination of the anionic and neutral thiosemicarbazone ligand is via the pyridyl nitrogen, imine nitrogen and thiolato/thione sulfur atom, respectively. In [Zn(Ampip)(OAc)]₂ one of the bridging acetato ligands has monodentate coordination and the other bridges in a bidentate manner. ¹¹³Cd NMR studies were carried out on the [Cd(HAmpip)X₂](X = Cl, Br or I) and [Cd(Ampip)(OAc)]₂ complexes. The ¹¹³Cd chemical shifts are affected by the halogen and range from 411 to 301 ppm, and the spectrum of [Cd(Ampip)(OAc)]₂ shows two signals at 450 and 251 ppm. The ¹⁹⁹Hg NMR spectrum of [Hg(HAmpip)Cl₂] also is discussed.     

A bulky oxime for the synthesis of Mn(III) clusters

The reaction between Mn(OAc)₂·4H₂O and Br-saoH₂ (=5-Br-salicylaldoxime) in EtOH in the presence of NMe₄OH led to the formation of the hexanuclear cluster [Mn₆O₂(Br-sao)₆(OAc)₂(H₂O)₂(EtOH)₂]·2.8H₂O·2.2EtOH (1). Switching from Mn(OAc)₂·4H₂O to Mn(ClO₄)₂·6H₂O, the same reaction upon addition of pivH (= trimethyl acetic acid) yielded [Mn₆O₂(Br-sao)₆(piv)₂(H₂O)₂(EtOH)₂]·6EtOH (2 6EtOH), and finally upon changing pivH to NaO₂CPh, we were able to isolate [Mn₆Na₂O₂(Br-sao)₆(O₂CPh)₄(H₂O)₂(EtOH)₄]·6EtOH (3 6EtOH). Clusters 1 and 2 6EtOH describe “typical” [Mn₆/oximate] complexes consisting of two {Mn₃} oxo-centered triangular units bridged by oximate groups, while in 3 6EtOH these triangular motifs are separated by two sodium cations. An investigation into the magnetic properties of all three clusters revealed the presence of dominant antiferromagnetic interactions, leading to ground states of S = 4 and 2 for 1 and 3, respectively. Finally, cluster 2 6EtOH functions as a single-molecule magnet with U_eff = 27.54 K.     

4′-(2-Methylphenyl)-2,2′:6′,2″-terpyridine: coordination chemistry with Ni(II), Cu(II), Zn(II) and Ag(I)

The synthesis of 4′-(2-methylphenyl)-2,2′:6′,2″-terpyridine (L) has been improved. The coordination chemistry of the ligand was explored using Ni(II), Cu(II), Zn(II), and Ag(I) ions. X-ray crystallography, elemental analysis, NMR, and mass spectrometry were used to characterize the 13 new compounds that have been synthesized. Under different reaction conditions, Ni(II), Cu(II), and Zn(II) produced discrete complexes, sometimes containing more than one metal ion, while Ag(I) furnished a polymeric spiral complex in which the central pyridine nitrogen of each terpyridine ligand bridges two Ag(I) ions. Crystallographically characterized complexes are [Ni(L)₂]Cl₂, [Ni₂Cl₄(L)₂], [Ni(L)(OH₂)₃]Cl₂, [Ni(L)₂]Br₂, [Cu(L)(OH₂)(OSO₃)], [Cu₃Cl₆(L)₂], [Cu(L)(OH)(OH₂)₂]PF₆, [Cu(L)₂](OTf)₂, [Cu(L)(OAc)₂], [Zn(L)(OAc)₂], [Zn(L)Cl₂], [Zn(L)₂](NO₃)₂, [{Ag₂(μ-L)₂(μ-NO₃)}_n](NO₃)_n.     

Synthesis and structural characterization of mono- and dinuclear NiII and PdII complexes derived from tetradentate 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene

The reaction of Schiff base 1,7-bis-(pyridin-2-yl)-2,6-diaza-1,6-heptadiene (L) with either NiCl₂·6H₂O or [Pd^IICl₂(CH₃CN)₂]/Na[BF₄] in 1?:?1 stoichiometry yielded mononuclear ionic complexes, trans-[Ni^II(L)(H₂O)₂]Cl₂·3H₂O (1·3H₂O) and [Pd^II(L)][BF₄]₂ (2), respectively; the reaction of L with [Pd^IICl₂(CH₃CN)₂] in 1?:?2 ratio yielded dinuclear cis-[Pd^II ₂(μ-L)Cl₄] (3). Complexes 1–3 were characterized by vibrational spectroscopy and X-ray diffraction; diamagnetic 2 and 3 were also characterized by NMR in solution. The molecular structures of 1 and 2 displayed tetradentate coordination of L with formation of two five-membered and one six-membered chelate rings for both complexes. In 3, L showed bidentate coordination mode for each pyridylimine toward Pd^II. Complex 1 has distorted octahedral geometry around Ni^II and an extended hydrogen-bond network; distorted square planar geometry around Pd^II in 2 and 3 was observed.