Supramolecular Framework Based on Pyridiniodiketone Ligand via Non-classic Hydrogen Bonding

A novel ligand L, 4-(1-hydroxy-3-oxo-3-phenylpropenyl)-1-methylpyridinium was synthesized and identified by NMR spectra and X-ray single crystal structure analysis from L · CH₃SO₄ (1L). Through self-assembling reactions, two new Cu^II/La^III-organic complexes, [CuL₂(SCN)][SCN] · H₂O (2Cu) and [LaL₂(SO₄)Cl₂] · (toluene) (3La), have been synthesized and characterized by X-ray crystallography. Structural analysis of 1L revealed that L and HSO₄ ⁻ coexist in a unit cell. For 2Cu, Cu(II) ion show a five-coordinated structure with a highly compressed square pyramid configuration; For 3La, each La(III) ion has an eight-coordinated structure with a distorted capped pentagonal bipyramidal geometry. It should be mentioned that supramolecular framework was formed via a number of hydrogen bonding interactions. Here, intramolecular C–H···O hydrogen bonding interactions stabilized and restricted the distortion between different rings. On the contrary, intermolecular hydrogen bond, e.g. C–H···O dual hydrogen bond interactions (1L), O5-involving triple C–H···O/O–H···O(N) hydrogen bond (2Cu) and triple C–H···Cl hydrogen bonding(3La), greatly affect geometric distortion between rings from ligand. Finally, we believe that the cooperative effect plays more important roles in supramolecular self-assembly.     

Self‐Activated Vanadate Compounds Toward Realization of Rare‐Earth‐Free Full‐Color Phosphors

Rare‐earth‐free phosphors based on vanadate compounds were investigated, where the vanadates included chloride vanadates (M^II₂VO₄Cl), pyrovanadates (M^II₂V₂O₇), orthovanadates (M^II₃(VO₄)₂) with divalent cations M^II of Mg, Sr, Ba, and Zn, and oxofluorovanadates (A^IVOF₄) with an alkali metal A^I. A chloride pyrolysis method and a liquid phase precipitation method were proposed for preparing the chloride vanadates and pyro‐ and orthovanadates, respectively. These vanadate compounds showed self‐activated photoluminescence (PL) based on the VO₄ clusters against the ultraviolet (UV) light irradiation. The colors of PL covered almost the whole visible‐light region from blue to yellow as Sr₂VO₄Cl (deep blue), Ca₂VO₄Cl (sky blue), Ba₂V₂O₇ (green), Sr₂V₂O₇ (yellowish green), Zn₃(VO₄)₂ (yellow), and Mg₃(VO₄)₂ (yellow). A correlation was suggested from these compounds between the luminescent colors and the structural feature as the longer V–O distances in the VO₄ tetrahedra in the crystal structures led to the longer wavelength in PL. This seemed to be also applicable for the oxofluorovanadates A^IVOF₄ (A^I = K and Cs) which contain the VOF₄ polyhedra with one O^2? ion and four F^‐ ions as the ligands, as they exhibited the reddish PL.     

One-pot syntheses,structures and properties of two novel 1-D copper complexes: [CuII2(Hbpdc)2Cl2]2·2H2O and CuI(H2bpdc)Cl (H2bpdc = 2,2′-bipyridyl-5,5′-dicarboxylic acid)

Two novel 1-D copper complexes {[Cu^II₂(Hbpdc)₂]Cl₂}₂·2H₂O (1) and Cu^I(H₂bpdc)Cl (2) (H₂bpdc = 2,2′- bipyridyl-5,5′-dicarboxylic acid) have been one-pot hydrothermally synthesized by reaction of H₂bpdc, CuCl₂·2H₂O, PrCl₃ and glacial acetic acid and structurally characterized by IR spectroscopy, X-ray photoelectron spectroscopy and single-crystal X-ray diffraction. Single-crystal structural analyses show that 1 is a novel 1-D stair-like chain constructed from centric tetra-copper clusters {[Cu^II₂(Hbpdc)₂]Cl₂}₂ by means of Cu–O weak coordination interactions whereas 2 displays a 1-D comb-like chain built by [Cu^I(H₂bpdc)Cl] units through Cl^? bridges. More interestingly, 1 and 2 were one-pot hydrothermally synthesized, which is very rare in synthetic chemistry. The photofluorescence properties of 1 and 2 have been investigated.     

Sulfate binding in zinc(II) complexes of a monopyridylurea ligand N-(1-naphthyl)-N′-(3-pyridyl)urea

Two zinc(II) complexes of a urea-functionalized pyridyl ligand, [Zn(SO₄)L₃]·CH₃OH (1) and {[Zn(μ₂-SO₄)L₂]·0.5CH₃OH}_n (2) (L = N-(1-naphthyl)-N′-(3-pyridyl)urea), have been synthesized by the reaction of L with ZnSO₄·7H₂O under different conditions. Complex 1 is a hydrogen-bonded 2D grid structure in which the sulfate anion not only coordinates to the Zn^II ion as a monodentate ligand but also forms multiple hydrogen bonds with the urea groups of adjacent molecules. In complex 2 the sulfate ion serves as a μ₂-bridging ligand, connecting the Zn^II ions to form an infinite 1D organic–inorganic hybrid framework. Meanwhile, the sulfate anion is also bound by neighboring ligands through hydrogen bonds between urea groups and the non-coordinated oxygen atoms. The solid-state emission spectra of 1 and 2 show a red shift of the fluorescence emission of ligand L.     

In situ synthesis and dielectric properties of copper(II) and nickel(II) chiral Schiff base complexes

Two chiral Schiff base-containing complexes, [Cu(L¹)](ClO₄)₂·H₂O (1, L¹ = (S,S)-N1,N2-bis((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) and [Ni(L²)₂](ClO₄)₂ (2, L² = (S,S)-N1-((1H-imidazol-4-yl)methylene)cyclohexane-1,2-diamine) were synthesized from the reaction mixture of 1H-imidazole-4-carbaldehyde, (S,S)-1,2-diaminocyclohexane and Cu(ClO₄)₂·6H₂O or Ni(ClO₄)₂·6H₂O in methanol. Single-crystal X-ray diffraction analyses reveal that the in situ generated chiral Schiff base ligands L¹ and L² are bisubstituted and monosubstituted, respectively, corresponding to the different metal ions Cu^II and Ni^II. Variable-frequency and -temperature dielectric properties of 1 and 2 have been studied.     

Characterization of extracted complexes in liquid–liquid extraction of rhodium with Kelex 100 in the presence of SnCl2

Mixed Rh? Sn complexes found in aqueous and organic solutions involved in the liquid–liquid extraction of Rh(III) from chloride solutions, also containing SnCl₂, with 7-(4-ethyl-1-methyloctyl)-8-hydroxyquinoline (Kelex 100) were characterized through ¹¹⁹Sn NMR and Raman spectroscopy. At Sn: Rh molar ratios of 3:1 and 12:1, it was found that [Rh^IIICl₃(SnCl₃)₃]^3? and [Rh^I(SnCl₃)₅]^4?, respectively, are the dominant complexes in both the aqueous and organic solutions. These complexes can be quantitatively extracted from the aqueous solutions in less than 1 min contact time via ion-pair formation with the protonated 7-substituted 8-hydroxyquinoline reagent such that for both Sn:Rh ratios, the same Rh? Sn complex is found in the aqueous feed and in the fully loaded organic. In addition, it was found that [Rh^I(SnCl₃)₅]^4? is preferentially extracted over excess free Sn(II). Preliminary characterization of the complex stripped from the 12:1 loaded organic using 1·7 M H₂SO₄ shows an Rh? Sn complex having a ratio of 5:1 Sn:Rh.     

Coordination assemblies of CdII/ZnII/CoII with the 3-(pyridin-4-yl) benzoate tecton: Structural diversity and properties

Three novel coordination polymers{[CdL₂(HL)(H₂O)]·(H₂O)}_n (1), [Zn₂(OH)L₃]_n (2) and [CoL₂(H₂O)]_n (3) have been hydrothermally synthesized from M(NO₃)₂·nH₂O (M^II = Cd^II, Zn^II and Co^II) and an unsymmetrical tecton 3-(pyridin-4-yl) benzoic acid (HL). All complexes show interesting structural patterns, namely, unprecedented 1D double-stranded supramolecular clasp for 1, novel (3,5,6)-connected helical tubular double layer for 2, 2-fold interpenetrating cds network for 3. The fluorescent and thermal properties of complexes 1, 2 and/or 3 have also been investigated.     

Anion-responsive luminescent Eu3+ complexes with ring-like rigid quinoline–amide ligands

Two novel ring-like rigid quinoline–amide ligands, 2-[2-(1,3-dioxolan-2-yl)quinolin-8-yloxy]-N-benzylacetamide (L^I) and 3-[2-(1,3-dioxolan-2-yl)quinolin-8-yloxy]-1,1-diphenylpropan-2-one (L^II), were designed to assemble the anion-responsive luminescent europium complexes. Crystallographic studies of the EuL^I(NO₃)₃ and EuL^II(NO₃)₃ revealed that the tetradentate ligands L^I and L^II cooperatively coordinated with Eu³⁺ ion and some available sites around central europium ions for guest anions were reserved in the complexes. The luminescent properties of the Eu(III) nitrate complexes in acetonitrile solutions were investigated. And the lowest triplet state energy levels of the ligands are well placed to allow energy transfer to the resonance level of Eu(III). At the same time, the luminescence titration experiments and the Job's plot analysis demonstrated the formation of 1:1 complexes in the solutions. The luminescence intensities at 616 nm were enhanced by addition of NO₃^? or Cl^? anion to the mixed acetonitrile solutions of Eu(CF₃SO₃)₃ and the ligands.     

Synthesis of Magnetite Nanoparticles with PDLLA Corona

The ring-opening polymerization (ROP) of D,L-lactide (DLLA) initiated by tin(II) 2-ethylhexanoate (Sn(Oct)₂) on the surface-initiated magnetite (Fe₃O₄) nanoparticles was performed at 130 °C. Effects of the polymer molar mass and concentration on the amount of polymer on the surface were investigated. The number average molecular weights, M _n , that we obtained by both nuclear magnetic resonance (NMR) and gel permeation chromatography (GPC) methods fit well within the accuracy of the applied methods, and range from 1,100 g · mol⁻¹ to 4,040 g · mol⁻¹. The surface functionalization density for up to 3,900 initiation sites per particle was obtained. The composition of various particles with poly(D,L-lactide) (PDLLA) corona is by means of thermogravimetric analysis (TGA), and indicates magnetite (Fe₃O₄) content between 17 wt.% and 59 wt.%. An erratum to this article can be found at     

Copper-assisted oxidative coupling of primary alcohol and hydrazone: A novel function model of galactose oxidase

Treatments of the MeOH, EtOH and PrOH solutions of 2-acetylpyridine, hydrazine and Cu^II salts (in molar ratio 2:3:2) afforded respectively the complexes, [Cu^II(HL)(Cl)](SO₃CF₃)H₂O (1), [Cu^II(MeL)(H₂O)](ClO₄)₂ (2) and [Cu^II(EtL)](Cl)](ClO₄) (3) (L = bis-(methyl, 2-pyridyl ketone hydrazonyl)methine), in which the ligands, HL, MeL and EtL are formed in situ from oxidative couplings of alcohols and hydrazones.     

Synthesis, Crystal Structures and Fluorescence Properties of Two One-Dimensional Cadmium(II) Coordination Polymers Containing Flexible Bis(benzimidazole) Ligands

Two one-dimensional Cd(II) coordination polymers constructed by ribbon-like molecules, {[Cd(L₁)₂(NO₃)]·NO₃} _n (1) (L₁ = 1,3-bis(5,6-dimethylbenzimidazol-1-yl)benzene) and [Cd(L₂)₂(NO₃)₂] _n (2) (L₂ = 1,3-bis(benzimidazol-1-yl)benzene) have been obtained through assembly of the two structurally similar flexible bis(benzimidazole)-based ligands and cadmium nitrate tetrahydrate. The cadmium(II) centers display different coordination environments with trigonal-bipyramidal geometry in 1, and a octahedral geometry in 2. Weak C–H···O interactions in 1 result in a two-dimensional supramolecular layer; two π–π interactions are present in 2 forming a three-dimensional supramolecular network structure. The solid state fluorescence properties of 1 and 2 were investigated.     

Copper(II) and cadmium(II) complexes with an imide tethered imidazole and a copper(II) coordination polymer through ring opening reaction

The reactions of 2-(3-(1H-imidazol-1-yl)propyl)isoindoline-1,3-dione (L) with copper (II) chloride or copper(II) nitrate resulted in mononuclear complexes [CuL₄Cl₂]·12H₂O (1) or [CuL₄(H₂O)NO₃]NO₃·2H₂O (2) respectively; whereas the copper(II) acetate reacted with L to give a three dimensional coordination polymer {[Cu(L′)₂]·4H₂O}n (3), (where L′ = 2-(3-(1H-imidazol-1-yl)propylcarbamoyl)benzoate). The reaction of cadmium(II) acetate with L led to the formation of a seven-coordinated complex [CdL₃(O₂CCH₃)₂]·2H₂O (4).     

Inorganic anion-induced structural diversity and structural transformation in a metal-negative ligand system containing Cd(II) ion and naphthalene diimide ligand

The coordination of a new 1,4,5,8-naphthalenediimides-based ligand N,N-di-(5-tetrazol)-1,4,5,8-naphthalenetetracarboxydiimide (H₂dtNDI) with CdSO₄ afforded mixtures containing {[Cd(dtNDI)(DMF)_2.5]·DMAc}_n (1) and {[Cd₂(dtNDI)₂(DMAc)₂]·DMAc}_n (2) as components. Whereas the coordination of H₂dtNDI with CdX₂ (x = ClO₄⁻, NO₃⁻ and I⁻) afforded pure coordination polymer, namely, {[Cd(dtNDI)(H₂O)_2.5]·DMAc}_n (3). All the compounds contain binuclear M₂L₂ ring as secondary building block (SBU). Compound 1 is a 1D chain composed of the binuclear SBUs and dimeric Cd(II) MBBs. Compound 2 exhibit a 2D network with (4·8²) topology based on a binuclear SBUs. Compound 3 possess a five-fold interpenetrating 3D dia framework with tetrameric Cd(II) MBBs as nodes and binuclear SBUs as linkers. Although the inorganic anions are not appeared in the final frameworks of compounds 1–3, they play an important role in the structural formation during assembly process. In addition, the mixtures composed of compounds 1–2 can transfer to pure compounds 3 via solvent-mediated process.     

A photoluminescent 3D silver(I) polymer with mixed 2-naphthol-5-carboxylate and hexamethylenetetramine ligands,showing an unusual (3,4)-connected (6·7·8)2(4·6·7)2(4·7·8)2(72·8)2(62·7·83)(62·72·8·10) topology

The reaction of AgClO₄ with 2-naphthol-5-carboxylic acid (HL) and hexamethylenetetramine (hmt) in the presence of 2,6-dimethylpyridine afforded a photoluminescent three-dimensional (3D) Ag^I polymer {[Ag₆(L)(μ₃-hmt)₂(μ₄-hmt)₂(ClO₄)](ClO₄)₄(H₂O)}_∞ (1), which exhibited an unusual (3,4)-connected (6·7·8)₂(4·6·7)₂(4·7·8)₂(7²·8)₂(6²·7·8³)(6²·7²·8·10) topological network (L = 2-naphthol-5-carboxylate). Moreover, the luminescent properties of 1 have been briefly investigated.     

Structural Characterization of a Cu(I) Coordination Polymer Constructed by Weak Intermolecular Cu–Cl⋯Cl–Ar Interaction

The copper(I) complex [Cu(DPPEO)(L₁)Cl] · CH₃CN (1) (DPPEO = 1,2-bis(diphenylphosphino)ethane monoxide; L₁ = 5,7-dimethyl-2-chloronaphthyridine) was prepared by reacting L₁ with CuCl in the presence of DPPE. The compound has been characterized by X-ray diffraction analysis. Compound 1 is a tri-coordinated mononuclear complex, which forms one-dimensional chain through intermolecular halogen-halogen bonds.     

Structure and magnetism of a trinuclear CuII–GdIII–CuII complex derived from one-pot reaction with 2,6-di(acetoacetyl)pyridine

A unique 3d–4f mixed metal trinuclear compound, [Cu₂Gd(L)₂(NO₃)₂]NO₃ (1; H₂L=2,6-di(acetoacetyl)pyridine), is derived from a ‘one-pot’ reaction with H₂L,Cu(NO₃)₂·3H₂O and Gd(NO₃)₃·5H₂O. Two L²⁻ providing one central 2,6-diacylpyridine site and two terminal 1,3-diketonate sites hold two Cu^II ions and Gd^III ion and form a linear Cu–Gd–Cu trinuclear core. This compound shows ferromagnetic interaction between Cu^II and Gd^III.     

Synthesis and cytotoxicity of a ruthenium nitrosyl nitric oxide donor with isonicotinic acid and a cell penetrating peptide

The syntheses and properties of trans-[Ru(NH₃)₄(L)(NO)](BF₄)₃ (L = isonicotinic acid (inaH) (I) or ina-Tat48–60 (II)) are described. Tat48–60, a cell penetrating peptide fragment of the Tat regulatory protein of the HIV virus, was linked to the ruthenium nitrosyl through inaH. I and II release NO after reduction forming trans-[Ru(NH₃)₄(L)(H₂O)]^3 +. The IC₅₀ values against B16-F10 melanoma cells of I and II (21 μmol L^− 1 and 23 μmol L^− 1, respectively) are close to that of the commercially available cisplatin (33 μmol L^− 1) and smaller than similar complexes. The cytotoxicity is assigned to the NO released from I and II.     

pH-induced coordination assembly of mononuclear and dinuclear copper(II) complexes based on a 4,4′-bipyridinium analogue

Upon controlling coordination sites of a new bipyridinium analogue 4′-(N-carboxybenzyl-4-pyridinio)-2,2′:6′,2″-terpyridine chloride (HL·Cl) with different dosage of perchloric acid, two copper complexes with distinct bridging modes, {[Cu(L)Cl]·ClO₄·3H₂O}_n (1) and [Cu₂(HL)₂Cl₂]·4ClO₄·H₂O (2) have been obtained under hydrothermal condition. Complex 1 features a one-dimensional chain-like structure with mononuclear Cu(II) centers, while 2 is a dichloro-bridged dinuclear Cu(II) complex, which forms one-dimensional supramolecular chain via hydrogen bonding interactions between the carboxylic groups of HL ligands. The magnetic measurement reveals that an antiferromagnetic coupling interaction exists in complex 2.     

Synthesis and characterization of nickel phosphonopropionate hybrid materials

Hydrothermal reaction of nickel acetate with 3-phosphonopropionic acid and 4,4′-bipyridine resulted in two novel phosphonate compounds Ni(HO₃PC₂H₄COO)(4,4′-bpy)(H₂O) · 0.5(4,4′-bpy) (bpy = bipyridine) (I) and Ni(O₃PC₂H₄COOH)(4,4′-bpy)(H₂O)₃ · H₂O (II). Single-crystal X-ray studies reveal that self-assemblies between the ligands and metal ion result in layer (I) and chain (II) structures. Magnetic measurement of I indicate there are ferromagnetic couplings between adjacent Ni²⁺ ions (C = 1.29 cm³ mol⁻¹ K and θ = 2.25 K).