Synthesis and Characterization of New Cobalt(II)–Pyrazine Coordination Polymer as Precursor for Preparation of Co(II) Oxide Nanoparticles: Surprising Coordination,DFT Calculation and Spectroscopic Studies

The new 2-D cobalt(II) coordination polymer with pyrazine was synthesized surprisingly from reaction of CoCl₂ and tetrapyrido[3,2-a:2′,3′-c:3″,2″-h:2?,3?-j]phenazine (tpphz) in methanol as medium and characterized by means of Fourier transform infrared spectroscopy (FT-IR), UV–Vis spectroscopy and X-ray single crystal analysis. The results showed that coordination polymer consist of cobalt(II) chain with pyrazine-bridged which crystallizes in orthorhombic unit cell (a?=?10.1307, b?=?10.1310, c?=?10.6838 Å) and space group Pban. Density functional theory (DFT) calculations were also done to figure out the electronic structure of the compound from theoretical aspect. The electronic spectrum of coordination polymer was investigated and the DFT/TDDFT procedures were employed to assign the absorption bands. The thermal decomposition of the title compound resulted in formation of cobalt(II) oxide nanoparticles with average size of 50 nm.     

Coordination Behaviors and Supramolecular Interactions of 2-(2′-Pyridyl) Imidazoline: Crystal Structure of Its Two Cu(II) Complexes

Two new copper coordination complexes, [Cu(PI)(OX)(H₂O)]·H₂O (1) and [Cu(PI)(fum)(H₂O)]·H₂O (2) [PI = 2-(2′-pyridyl) imidazoline, OX^2? = dianion of oxalic acid and fum^2? = dianion of fumaric acid], were synthesized by interface diffusion method based on Cu(II) ions, PI ligands and aliphatic dicarboxylic acids. Complex 1 is a mononuclear complex which spreads into a 3D (4,9)-connected supramolecular network via hydrogen bond interactions, while complex 2 features a 1D zigzag chain with two different orientations. These two compounds are characterized by single crystal X-ray diffraction, powder X-ray diffraction, elemental analyses, infrared spectra, and thermogravimetric analyses.     

Synthesis and Characterization of New Metal–Organic Frameworks Based on Tetracyanoplatinate(II) and N,N′-bis(2-hydroxyethyl)ethylenediamine: Single Crystal Structures of ZnII and CdII Complexes Along with Magnetic Properties of NiII and CuII Complexes

Characterization and synthesis of novel cyano bridged coordination compounds [Ni(bishydeten)Pt(CN)₄] (1), [Cu(bishydeten)Pt(CN)₄] (2), [Zn(bishydeten)Pt(CN)₄] (3), [Cd(bishydeten)Pt(CN)₄] (4) [bishydeten = N,N′-bis(2-hydroxyethyl)ethylenediamine (C₆H₁₆N₂O₂)] were reported herein. The IR spectra of these coordination compounds verified the formation of aforementioned complexes. The ground state of the paramagnetic electron in the Cu^II located in tetragonal distorted octahedral sites (D _4h ) was found to be d_x2−y2 for complex 2. As for complex 1, an EPR signal was not observed because of diamagnetic property of the Pt^II and momentary relaxation times of the Ni^II. All complexes followed identical decomposition mechanism in thermal analysis and thermal stabilities of complexes changed in the order of 1 > 4 > 3 > 2. Both 3 and 4 exhibit polymeric structure according to X-ray single structure analysis. While bishydeten coordinated with three donor atoms (N,N′, and O) in complex 3, it acts as a bidentate ligand (N, and N′) in complex 4. Magnetic properties of complexes 1–2 at 15–300 K temperature range were determined as antiferromagnetic with Weiss constants = −2.619 and −0.847 K respectively.     

Metal-Ion Type Effect on the Crystal Structure and Optical Properties of 2,2′-bipyridine Complexes of Pb(II) and Cd(II)

To investigate the effect of metal ion type on the crystal structure and optical and thermal behaviors of coordination compounds, two homometal and one heterometal 2,2′-bipyridine complexes of Pb(II) and Cd(II) have been synthesized and characterized by elemental analysis, PXRD, FT-IR and single crystal X-ray diffraction. Crystal structure analysis of heterometal coordination polymer, [Pb₂Cd(2,2′-bipy)₄(NO₃)₆]_n, displays the attendance of a centrosymmetric 1D coordination polymer that crystallizes in the triclinic system with the space group of \({\text{p}}_{1}^{ - }\). Thermal behavior of prepared coordination compounds was examined under air atmosphere by thermogravimetric analysis. The study of optical properties of compounds showed that metal ion type of coordination compounds is influential on their photophysical properties. Moreover, heterometal coordination polymer was doped into a PVK:PBD blend in two different concentrations as a light emitting material in the fabrication of two organic light-emitting diodes.     

Hydrothermal Synthesis, Crystal Structure and Characterization of New Coordination Polymer [Co2(pydc)2(H2O)6] n ·2nH2O

A coordination polymer of cobalt(II) containing the pyridine-2,5-dicarboxylate (pydc) ligand and having the composition [Co₂(pydc)₂(H₂O)₆] _n ·2nH₂O was prepared by the hydrothermal method. The coordination polymer was characterised by FTIR, single crystal XRD, SEM, TGA–DTA, and N₂ Temperature Programmed Desorption, Brunauer, Emmett and Teller surface area. The polymer contains two cobalt(II) ions with slightly distorted octahedral geometry. The carboxylate group at the 2-position of pyridine acts as a bridging ligand between two cobalt metal ions and this expansion leads to formation of a 1-D chain-like coordination polymer. The coordination polymer chains are packed together by well-directed hydrogen bonds to generate a three dimensional mesoporous network. The N₂ TPD study shows that the polymer is mesoporous in nature and possesses slit-shaped mesopores with average pore size diameter of 17.78 nm. SEM micrographs show well-defined channels in the solid crystals confirming the porosity of polymer. Thermogravimetric studies indicate the robust nature of the polymer. The polymer undergoes thermal decomposition in well-defined steps leading to the formation of cobaltous oxide as the end-product.     

Hydrothermal Synthesis,Crystal Structure and Electrochemical Property of Two Inorganic–Organic Hybrid Frameworks via Hydrogen Bonding

Two inorganic–organic hybrid frameworks, namely [Cu₂(pdca)₂(bibp)(H₂O)₂]·H₂O (1) and [Fe(pdca)(pyco)(H₂O)]·H₂O (2) (H₂pdca = pyridine-2,6-dicarboxylic acid, bibp = 4,4′-bisimidazolylbiphenyl, pyco = picolinate N-oxide) were synthesized via hydrothermal reactions. Both compounds have been characterized by elemental analysis, spectroscopic analysis, thermogravimetric analysis (TGA) and the single crystal diffraction. Complex 1 is dinuclear and five-coordinated copper(II) complex, while complex 2 displays mono-nuclear and six-coordinated iron(III) complex. In the crystal structures of both complexes, the coordinated and crystalline water molecules and H₂pdca ligands contribute to the formation of O–H···O and C–H···O hydrogen bonds, which link the molecules into layers parallel. Cyclic voltammetry (CV) analysis shows one reversible reduction potential at 0.14 V (E_pc) in complex 1, whereas in complex 2 shows a reduction potential at 0.15 V (E_pc) in the cathodic region.     

Architectural View of Flexible Aliphatic –OH Group Coordinated Hemi-Directed Pb(II)-Salen Coordination Polymer: Synthesis,Crystal Structure,Spectroscopic Insights,Supramolecular Topographies,and DFT Perspective

Journal of Inorganic and Organometallic Polymers and Materials - We serendipitously designed one novel 1D hetero-binuclear Zn(II)-Pb(II) coordination polymer, namely...     

Synthesis, Structural Investigation and DFT Calculations of Cadmium (II) Fluorine-Substituted β-Diketonate: A Precursor to Producing Pure Phase Nano-Sized Cadmium (II) Oxide

A novel aza-aromatic base adduct of a cadmium(II) fluorine-substituted β-diketonate, [Cd(dmp)(ttfa)₂]_n(1), (“dmp” is an abbreviation for 2,9-dimethyl-1,10-phenanthroline and “ttfa” is an abbreviation for thenoyltrifluoroacetonate) was synthesised and characterised by elemental analysis and IR, ¹H NMR and ¹³C NMR spectroscopy and studied by thermal as well as X-ray crystallography. The single-crystal structure of this complex shows that the coordination number of the Cd²⁺ ion is six with two N-donor atoms from the dmp ligand and four O-donors from ttfa. Self-assembly of this complex was mediated by CH···F–C and π–π stacking interactions. The supramolecular features of these complexes are controlled by weak directional intermolecular interactions. The structural energy of the title complex was determined by density functional theory calculations. The calculated HOMO–LUMO gap is 0.131 a.u. (3.474?eV). The CdO nano-particles were obtained by thermolysis of 1 at 180?°C with oleic acid as the surfactant. Scanning electron microscopy showed that the size of the CdO particles is ~35?nm.     

Synthesis, Crystal Structure and Properties of a New 3D Supramolecular Metal–Organic Framework with Stable Tunnels

A flexible polycarboxyl ligand of tetrahydrofuran-2,3,4,5-tetracarboxylic acid (H₄THFTCA) and a common rigid aromatic ligand of 1,10-phenanthroline (phen) have been successfully co-assembled with Cu(NO₃)₂·3H₂O to give out a novel 3D supramolecular metal–organic framework (MOF) compound, [Cu₂(THFTCA)(phen)(H₂O)₂·CH₃CH₂OH·3H₂O] _n (1), by a solution self-assembly process. Compound 1 has been characterized as a 2D layered coordination polymer constructed by THFTCA^4? and Cu²⁺ ions, and the layer present a novel (3.5²)(3².5³.6⁴.7) topological network. Interestingly, the layers are fused each other via strong π–π stacking interactions among adjacent ligands of the terminal phen, so that a 3D supramolecular MOF with 1D rhomboidal tunnels array is formed. The thermogravimetric analysis and corresponding powder X-ray diffraction analysis have revealed that the tunnels structure of 1 could be retained after all guest molecules are removed, and the framework could resist the collapse even heating up to 210?°C. An opinion has also been proposed that the larger accessible volume of the guests means the larger stress on the backbone of the MOF after the guests are removed, and the stress is harmful to the stability of the supramolecular porous structure. Finally, the application properties based on the porous structure have also been primarily evaluated.     

Sonochemical Synthesis and Characterization of the New Plate-Shaped Lead(II)–Iodo Coordination Polymer: A Precursor to Produce a Pure Phase Nano-Sized Lead(II) Oxide

Preparation of plate-shaped nanostructures of a new 1D polymeric lead(II) complex containing the Pb₂-(μ-I)₂ motif, [Pb(neo)I₂] _n ,(1) where neo is the abbreviation of neocuproine, using a sonochemical method is described. The new coordination polymer is characterized by scanning electron microscopy, X-ray diffraction (XRD), elemental analysis and infrared spectroscopy. The single crystalline material is obtained using a heat gradient applied to a solution of the reagents. Single-crystal XRD analysis indicates that a coordination number of six for Pb^II ions, (i.e., PbN₂I₄) with an asymmetrical coordination sphere and “stereo-chemically active” electron lone pairs. They also show that the chains interact with each other through π–π stacking interactions creating a 3D framework. PbO nanoparticles are obtained by thermolysis of 1 at 180?°C with oleic acid as a surfactant. Scanning electron microscopy confirms formation of PbO particles with a size of ~25?nm.     

Correction to: Preparation and Characterization of Amino‑Functionalized Zeolite/SiO2 Materials for Trypsin–Chymotrypsin Co‑immobilization

Catalysis Letters - A correction to this paper has been published: https://doi.org/10.1007/s10562-021-03665-x     

Synthesis,Characterization, Crystal Structures and Thermal and Fluorescence Studies of Dinuclear and Polymeric Silver(I) Complexes of 5,5-Diethylbarbiturate with 2,5-Dimethylpyrazine and Piperazine Involving Ag–Ag Interactions

Two silver(I) complexes, [Ag(dmpyz)₂][Ag(barb)₂] (1) and {[Ag(ppz)][Ag(barb)₂]·H₂O} _n (2) (barb = 5,5-diethylbarbiturate, dmpyz = 2,5-dimethylpyrazine and ppz = piperazine), have been synthesized and characterized by elemental analyses, IR, thermal analysis (TG-DTA) and single-crystal X-ray diffraction. Complex 1 consists of [Ag(dmpyz)₂]⁺ and [Ag(barb)₂]^? ions in which the silver(I) ions are linearly coordinated by two dmpyz or two barb ligands. These two ions are connected by strong Ag–Ag interactions (Ag–Ag = 2.896 (1) Å). Complex 2 is a 1D coordination polymer in which the silver(I) ions are bridged by the ppz ligands in a linear fashion, leading to a zigzag chain of [Ag(ppz)] _n ⁺ , which interacts with the [Ag(barb)₂]^? units by Ag–Ag interactions of 3.183 (1) Å. The 1D chains are further assembled to form 3D networks by strong N–H···O and OW–H···O hydrogen bonds. IR spectra and TG-DTA data are in agreement with the crystal structures. The fluorescent properties of 1 were also evaluated.     

Syntheses and Characterization of Two New M(II)-5,5′-dimethyl-2,2′-bipyridine (M = Cd and Pb) Coordination Polymers and Study of Their Thermal and Electrochemical Properties

Two new cadmium(II) and lead(II)-thiocyanato coordination polymers with 5,5′-dimethyl-2,2′-bipyridine (5,5′-dm-2,2′-bpy) as chelating ligands were synthesized and characterized by elemental analysis, IR and ¹H NMR spectroscopy and by X-ray crystallography. Thermal and electrochemical properties were also studied as well. These complexes have formed formula [Cd(5,5′-dm-2,2′-bpy)(NCS)₂]_n (1) and [Pb(5,5′-dm-2,2′-bpy)(CH₃COO)(NCS)]_n (2). The coordination numbers of Cd^II in 1 and Pb^II in 2 are six (CdN₄S₂) and seven (PbN₃O₃S₂), respectively. In 2, “stereo-chemically active” electron lone pairs and the coordination spheres were hemidirected. Bridging properties of thiocyanato anions in 1 and 2 created one- and two-dimensional coordination polymers, respectively. The supramolecular features in these complexes were guided and controlled by weak directional intermolecular interactions.     

Synthesis, Characterization and Antimicrobial Properties of Oligomer and Monomer/Oligomer–Metal Complexes of 2-[(Pyridine-3-yl-methylene)amino]phenol

Oligo-2-[(pyridine-3-yl-methylene)amino]phenol (2-PMAP) is synthesized by the oxidative polycondensation (OP) in aqueous alkaline medium using air as oxidant. At optimum reaction conditions, the yield of products is 71%. The structures of the monomer and oligomer were confirmed by FT-IR, UV–Vis, ¹H-NMR, ¹³C-NMR and elemental analysis. Characterization was made by thermogravimetric analysis-differential thermal analysis (TGA-DTA), size exclusion chromatography (SEC) and solubility. The ¹H-NMR and ¹³C-NMR data show that polymerization proceeds by C–C and C–O coupling of the ortho and para positions (–OH group and oxyphenylene group) of 2-[(pyridine-3-yl-methylene)amino]phenol. The molecular weight distribution of the product was determined by SEC. The number-average molecular weight (M _n ), weight-average molecular weight (M _w ) and polydispersity index (PDI) of O-2-PMAP are 7150, 8000 g mol⁻¹ and 1.119 for air oxidant, respectively. Thermal analysis results of O-2-PMAP indicate stability against thermal decomposition. Thermal analyses of 2-PMAP, 2-PMAP-Cd, 2-PMAP-Co, 2-PMAP-Cu, 2-PMAP-Zn, O-2-PMAP, O-2-PMAP-Cd, O-2-PMAP-Co, O-2-PMAP-Cu and O-2-PMAP-Zn monomer/oligomer–metal complexes were investigated under a N₂ atmosphere between 15 and 1000 °C. Antibacterial and antifungal activity of the synthesized compounds was examined against selected bacteria and fungi.     

Hydrothermal Synthesis,Crystal Structure and Characterization of a Novel 3D Pillared-Layer 3d–4f Lanthanum-Copper Heterometallic Coordination Polymer

A novel three-dimensional (3D) pillared-layer 3d–4f lanthanum-copper heterometallic coordination polymer, {La₂Cu₇I₆(IN)₇(H₂O)₆·2H₂O} _n (1) (HIN = isonicotinic acid), has been synthesized by hydrothermal reaction of La₂O₃, CuI, HIN with HNO₃, and characterized by elemental analyses, IR, PXRD, and single-crystal X-ray diffraction. The structure determination reveals that the 3D framework of 1 is constructed upon [Cu₇I₆] _n ⁿ⁺ inorganic layers linked by dimeric La₂(IN)₆ pillars. Additionally, the thermogravimetric analysis and luminescent property of 1 were investigated and discussed.     

Synthesis, Structures and Luminescent Properties of Two New Cd(II) Coordination Polymers Based on V-Shaped 3,3′,4,4′-Oxidiphthalic Acid

Two new Cd(II) coordination polymers, namely [Cd₂(H₂OA)₂(μ₂-H₂O)(H₂O)₆] _n ·3nH₂O (1) and [Cd₂(H₂OA)(phen)₂] _n ·nH₂O (2) (H₄OA = 3,3′,4,4′-oxidiphthalic acid, phen = 1,10-phenanthroline) have been synthesized by combining H₄OA or H₄OA and phen with Cd(II) salts under hydrothermal conditions. Single-crystal X-ray diffraction analysis reveals that 1 features a hydrogen-bond directed two-dimensional (2D) layered structure constructed from alternating left- and right-handed double strand helical chains, 2 represents a one-dimensional (1D) chain structure with the phen molecules dangling on it, which is further extended into a three-dimensional (3D) supramolecular framework through strong face-to-face π···π interactions. In addition, luminescent properties of these two compounds were also investigated in the solid state at room temperature.