Two novel mono- and heptanuclear Ni(II) complexes constructed from new unsymmetric and symmetric Salamo-type bisoximes – Synthetic, structural and spectral studies

Electrochemical sensing of hydrogen peroxide on a carbon paste electrode modified by a silver complex based on the 1,3-bis(1H-benzimidazole-2-yl)propane ligand

A new carbon paste electrode (Ag-CPE) modified with a nitrogen heterocyclic silver(I) complex, [Ag2(BBP)2](pic)2·CH3OH (BBP = 1,3-bis(1H-benzimidazol-2-yl)propane, pic = picrate), was developed as a highly sensitive and simple electrochemical sensor for the determination of hydrogen peroxide. The Ag(I) complex was prepared by an interface reaction and characterized by elemental analysis, IR and UV/Vis spectra and single crystal X-ray diffraction. The Ag(I) complex shows a dinuclear cluster structure, which is formed by two BBP ligands bridging two Ag (I) centers and an Ag–Ag interaction (d Ag–Ag = 3.0875 Å). Cyclic voltammetry and chronoamperometry studies showed that the electrochemical sensing performance of Ag-CPE for H2O2 was improved in 0.2 m phosphate buffer solution (PBS, pH = 6). The electrochemical H2O2 sensor Ag-CPE exhibits a wide linear detection range from 0.5 to 4.0 mm and a lower detection limit of 0.39 μm with a relatively high sensitivity of 6.77 μA mm −1. Moreover, the sensor also shows good anti-interference properties and stability. The results prove that the Ag(I) complex based on the bis(benzimidazole) ligand may be an efficient component of electrode materials.

A 2-D Zn(II) coordination polymer based on 4,5-imidazoledicarboxylate and bis(benzimidazole) ligands: synthesis, crystal structure and fluorescence properties

In this work, a new type of zinc(II) coordination polymer {[Zn(HIDC)(BBM)0.5]·H2O} n (Zn-CP) was synthesized using 4,5-imidazoledicarboxylic acid (H3IDC) and 2,2-(1,4-butanediyl)bis-1,3-benzimidazole (BBM) under hydrothermal conditions. Its structure has been characterized by infrared spectroscopy, elemental analysis and single crystal X-ray diffraction analysis. The Zn(II) ion is linked by the HIDC2− ligand to form a zigzag chain by chelating and bridging, and then linked by BBM to form a layered network structure. Adjacent layers are further connected by hydrogen bond interaction to form a 3-D supramolecular framework. The solid-state fluorescence performance of Zn-CP shows that compared with free H3IDC ligand, its fluorescence intensity is significantly enhanced.

Synthesis and crystal structure of bis{2-((E)-((4-((E)-1-(methoxyimino)ethyl)phenyl)imino)methyl) phenolato-κ2 N,O}cobalt(II) — ethanol (1/1), C34H36CoN4O5

C34H36CoN4O5, triclinic, P1̅ (no. 2), a = 8.7040(5) Å, b = 12.7375(9) Å, c = 14.2626(9) Å, α = 99.054(2)°, β = 95.727(2)°, γ = 92.477(2)° V = 1550.96(17) Å3, Z = 2, R gt(F) = 0.0554, wR ref(F 2) = 0.1369, T = 296(2) K.

Homo- and heterometallic Cu(II)-M(II) (M = Ca, Sr and Ba) bis(salamo)-based complexes: Syntheses, structures and fluorescent properties

Four homo/heterometallic complexes [Cu₃(L)(μ₂-OAc)₉(CH₃OH) ₉]·3CHCl₃ (1), [Cu₂(L)Ca(μ₂-NO₃)₉] (9), [{Cu₂(L)Sr(μ₂-NO₃)₉}₉]·CH₃CH₂OH (11) and [Cu₂(L)Ba(μ₂-OAc)₉(OAc)] (14), containing an acyclic naphthalenediol-based ligand H₄L, were synthesized and characterized by elemental analyses, IR, UV-Vis, fluorescence spectra, TG-DTA and X-ray crystallography. The complex 1 was obtained by the reaction of H₄L with 11 equivalents of Cu(OAc) ₉·2H₂O. The heterometallic complexes 9, 11, 14 were acquired by the reaction of H₄L with 9 equivalents of Cu(OAc)₉·2H₂O or Cu(NO₃)₉·2H₂O and 1 equivalent of M(OAc)₉ (M = Ca, Sr and Ba). Owing to the different coordination cavities of the N₂O₂ and O₆ of the completely deprotonated (L)^14- unit, the crystal structures showed the N₂O₂ sites were occupied by Cu(II) atoms, alkaline earth metal(II) atoms occupied the O₆ site of the ligand (L)^14- unit, respectively. Furthermore, the fluorescence properties and TG-DTA analyses were discussed.

Structurally Characterized Solvent-Induced Homotrinuclear Cobalt(II) N2O2-Donor Bisoxime-Type Complexes

Four new solvent-induced Co(II) complexes with chemical formulae [{CoL(μ2-OAc)(MeOH)}2Co] (1), [{CoL(μ2-OAc)(EtOH)}2Co] (2), [{CoL(μ2-OAc)(Py)}2Co] (3) and [{CoL(μ2-OAc)(DMF)}2Co] (4) (H2L = 4-nitro-4′-chloro-2,2′-[(1,3-propylene)dioxybis(nitrilomethylidyne)]diphenol) have been synthesized and characterized by elemental analyses, FT–IR, UV–Vis spectra and single-crystal X-ray diffraction. Each of the prepared complexes, crystallizing in the space groups P–1 (1 and 4), P21/n (2) and P21/c (3), consists of three Co(II) atoms, two completely deprotonated (L)2− units, two μ2-acetato ligands and two coordinated solvent molecules. Although the four complexes 1–4 were synthesized in different solvents, it is worthwhile that the Co(II) atoms in the four complexes 1–4 adopt hexa–coordinated with slightly distorted octahedral coordination geometries, and the ratio of the ligand H2L to Co(II) atoms is 2:3. The complexes 2–4 possess a self-assembled infinite 1D, 2D and 1D supramolecular structures via the intermolecular hydrogen bonds, respectively. Magnetic measurement was performed in the complex 3.

Synthesis, crystal structure, luminescence and electrochemical properties of a Salamo-type trinuclear cobalt(II) complex

A trinuclear Co(II) complex, [{CoL(C4H9OH)}2-(OAc)2Co]·C3H7NO, was synthesized by the reaction of a Salamo-type chelating ligand (H2L=4,42′-dinitro-2,2′-[1,2-ethylenedioxybis(nitrilomethylidyne)]diphenol) with cobalt(II) acetate tetrahydrate in n-butanol, and characterized by elemental analyses, X-ray crystallography, FT-IR and UV/Vis spectra. In the Co(II) complex, there are two ligand L2− units, two μ 2-acetate ions, two coordinated n-butanol molecules and one non-coordinated N,N-dimethylformamide molecule. The Co(II) atoms in the structure of the Co(II) complex adopt slightly distorted octahedra geometries. Furthermore, through intermolecular C–H···O, O–H···O and C–H···π interactions, infinite layer-like, plane-like and 3D supramolecular structures are constructed. The fluorescence and electrochemical properties of the Co(II) complex have also been investigated.

Crystal structure of diaqua-bis(N,N-dimethylformamide-κ1 O)-bis{3-((5-chloro-2-oxidobenzylidene)amino)-2-oxo-2H-chromen-4-olato-κ4 N,O,O′:O′}dinickel(II), C38H34Ni2Cl2N4O12

C38H34Ni2Cl2N4O12, monoclinic, C2/c (no. 15), a = 17.867(3) Å, b = 9.170(6) Å, c = 24.651(5) Å, β = 110.837(2)°, Z = 4, V = 3775(3) Å3, R gt(F) = 0.0323, wR ref(F 2) = 0.1078, T = 293(2) K.

Crystal structure of bis((1-(((4-(((benzyloxy)imino)methyl)phenyl)imino)methyl)naphthalen-2-yl)oxy-κ2 O,N)copper(II), C52H42CuN4O4

C52H42CuN4O4, monoclinic, I12/c1 (no. 15), a = 21.8573(13) Å, b = 5.8605(4) Å, c = 33.683(2) Å, β = 97.428(5)°, Z = 4, V = 4278.4(5) Å3, R gt(F) = 0.0554, wR ref(F 2) = 0.1255, T = 293(2) K.

Synthesis and crystal structure of tetrakis(μ2-methanolato)-dimethanol-bis(μ2-2-acetyl-1,3-bis(3,5-dibromo-2-oxidophenyl)propane-1,3-bis(olato)-κ5O1,O2,O3:O3,O4,O5)tetramanganese(III), C40H40Br8Mn4O16

C40H40Br8Mn4O16, triclinic, P1̅, a = 9.3446(11) Å, b = 11.6799(11) Å, c = 12.5833(16) Å, α = 70.937(10)°, β = 76.049(11)°, γ = 80.984(9)°, V = 1255.2(3) Å3, Z = 1, Rgt(F) = 0.0641, wRref(F2) = 0.1246, T = 293(2) K.

A supramolecular tetranuclear zinc(II) complex constructed from an asymmetrical Salamo-type ligand: synthesis, structure and fluorescence properties

The tetranuclear Zn(II) complex, [{ZnL(μ-OAc)Zn(CH3CH2CH2OH)}2], derived from an asymmetrical Salamo-type chelate ligand H3L (5-methoxy-6′-hydroxy-2,2′-[ethanedioxybis(nitrilomethylidyne)]diphenol) has been synthesized and structurally characterized by elemental analysis, IR spectrum, X-ray crystallography, UV/Vis and fluorescence spectra. The structure is made up of four Zn(II) atoms, μ 2-coordinated acetate ions and two coordinated n-propanol molecules, and forms an infinite one-dimensional supramolecular structure via intermolecular C–H···π interactions. The four Zn(II) atoms are penta-coordinated and show slightly distorted trigonal bipyramidal and tetragonal pyramidal symmetries.

Two Supramolecular Cobalt(II) Complexes: Syntheses, Crystal Structures, Spectroscopic Behaviors, and Counter Anion Effects

Two new Co(II) complexes, [{Co(L)}2{Co(Pic)2(CH3OH)2}] (1) and [{CoL(μ-OAc)}2Co] (2), where H2L = 2,2′-[Ethylenedioxybis(nitrilomethylidyne)]dinaphthol, were designed, synthesized and characterized by elemental analysis, FT-IR spectra, UV-Vis spectra, and X-ray crystallography. Complex 1 consists of two [CoL] and one [Co(Pic)2(CH3OH)2] (Pic = picrate) units and in the [CoL] unit, the Co(II) atom is tetra-coordinated with a slightly distorted square-planar geometry. In the [Co(Pic)2(CH3OH)2] unit, the Co(II) atom is hexa-coordinated with a slightly distorted octahedral geometry. Meanwhile in complex 2, two acetate ions coordinate to three Co(II) atoms through Co-O-C-O-Co bridges and four μ-naphthoxo oxygen atoms from two [CoL] units also coordinated to the central Co(II) atom. Thus, complex 2 has two distorted square pyramidal coordination geometries around the terminal Co(II) atom and an octahedral geometry around the central Co(II) atom. The supramolecular structures of complex 1 is a 3D-network supramolecular structure linked by C-H···O hydrogen bonds and π···π stacking interaction, but complex 2 possesses a self-assembled 2D-layer supramolecular structure linked by C-H···π and π···π stacking interactions. The structure determinations show that the coordination anions are important factors influencing the crystalline array.

Syntheses, Crystal Structures and Thermal Behaviors of Two Supramolecular Salamo-Type Cobalt(II) and Zinc(II) Complexes

This paper reports the syntheses of two new complexes, [Co(L1)(H2O)2] (1) and [{Zn(L2)(μ-OAc)Zn(n-PrOH)}2] (2), from asymmetric halogen-substituted Salamo-type ligands H2L1 and H3L2, respectively. Investigation of the crystal structure of complex 1 reveals that the complex includes one Co(II) ion, one (L1)2− unit and two coordinated water molecules. Complex 1 shows slightly distorted octahedral coordination geometry, forming an infinite 2D supramolecular structure by intermolecular hydrogen bond and π–π stacking interactions. Complex 2 contains four Zn(II)ions, two completely deprotonated (L2)3− moieties, two coordinated μ-OAc− ions and n-propanol molecules. The Zn(II) ions in complex 2 display slightly distorted trigonal bipyramidal or square pyramidal geometries.

Tri- and hexanuclear heterometallic Ni(ii)–M(ii) (M = Ca, Sr and Ba) bis(salamo)-type complexes: synthesis, structure and fluorescence properties

Tri- and hexanuclear Ni(ii)–M(ii) (M = Ca, Sr and Ba) complexes have been synthesized and characterized structurally. Fluorescence titration experiments show that the coordinating capabilities in the central O₆ site are in the order of Ca(ii) > Sr(ii) > Ba(ii).