Syntheses and characterization of a new nano-structured bismuth(III) bromide coordination polymer; new precursor for preparation of bismuth(III) bromide and bismuth(III) oxide nanostructures

Nanoparticles of a Bi(III) coordination polymer, {[Bi(μ-4,4′-bipy)Br₄] · (4,4′-Hbipy)} _n (1) (4,4′-bipy = 4,4′-bipyridine), were synthesized by a sonochemical method. The new nanoparticles were characterized by scanning electron microscopy, X-ray powder diffraction (XRD), IR spectroscopy, and elemental analyses. Compound 1 was structurally characterized by single-crystal X-ray diffraction. The thermal stabilities of 1 as bulk and at nanosize were studied by thermal gravimetric (TG) and differential thermal analyses (DTA). The Bi₂O₃ and BiBr₃ nanostructures were obtained by calcinations of nanostructure of 1 in air and argon.     

Sonochemical syntheses and characterization of a new nano-sized 2-D lead(II) coordination polymer as precursor for preparation of PbBr(OH) nano-structure

Nano-particles of a new 2-D Pb(II) coordination polymer, [Pb(4-pyc)(Br)(H₂O)] _n (1) (4-Hpyc = 4-pyridinecarboxylic acid), were synthesized by a sonochemical method. Crystal structure of 1 was determined by X-ray crystallography. The nano-particles were characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy, and elemental analyses. PbBr(OH) nano-structure was obtained by the calcination of nano-particles of 1 at 400°C.     

Supramolecular assemblies of two piperazine metal-organic bismuth(III) derivatives: a new precursor for the preparation of bismuth(III) oxide bromide nano-structures

Two BiBr₃ supramolecular complexes, [Bi(2-bpmp)Br_2.06Cl_0.94] (1) and [Bi(4-H₂bpmp)Br_4.29Cl_0.71]·H₂O (2) {2-bpmp = N,N′-bis(2-pyridylmethyl)piperazine and 4-bpmp = N,N′-bis(4-pyridylmethyl)piperazine}, were prepared by reaction of bismuth(III) chloride and potassium bromide with two nitrogen donor ligands under thermal gradient conditions using the branched tube method. Compounds 1 and 2 were structurally characterized by single-crystal X-ray diffraction. In monomeric 1, bismuth is coordinated by two pyridyl and piperazine nitrogens of 2-bpmp, and by three halides. Compound 2 is also monomeric but is bonded to only one pyridyl nitrogen. In both compounds, extensive hydrogen-bonding interactions lead to supramolecular networks; in 2, the hydrogen bonds are augmented by π–π stacking interactions. Thermal stabilities of both compounds were studied by thermal gravimetric and differential thermal analyses. Thermal decomposition of nanosized 1 and 2 in air produced BiOBr nanoparticles.     

Synthesis and crystal structure of a mixed-ligand bismuth(III) complex, [Bi2(phen)2Br5(NO3)] n (phen = 1,10-phenanthroline)

Complex [Bi₂(phen)₂Br₅(NO₃)] _n has been synthesized by reaction of Bi(NO₃)₃ with potassium bromide and 1,10-phenanthroline. The complex has been isolated and characterized by IR-, ¹H NMR-, ¹³C NMR spectrum and elemental analysis. The structure of the [Bi₂(phen)₂Br₅(NO₃)] _n was confirmed by X-ray crystallography which shows the complex to be a one-dimensional polymer as a result of bridging bromides. The two Bi atoms have different environments, six and seven coordinate.     

Ultrasonic-assisted synthesis of two new nano-structured 3D lead(II) coordination polymers: Precursors for preparation of PbO nano-structures

Nano-structures of two new Pb(II) three-dimensional coordination polymers, [Pb₂(4-pyc)₂I₂(H₂O)]_n (1), {4-Hpyc = 4-pyridinecarboxilic acid} and [Pb(3-pyc)I]_n (2), {3-Hpyc = 3-pyridinecarboxilic acid} were synthesized by sonochemical method. The new nano-structures were characterized by scanning electron microscopy, X-ray powder diffraction, IR spectroscopy and elemental analyses. Compounds 1 and 2 were structurally characterized by single crystal X-ray diffraction and are three-dimensional coordination polymers. The thermal stability of compounds 1 and 2 both their bulk and nano-size were studied by thermal gravimetric and differential thermal analyses and compared. PbO block-structures were obtained by calcination of the nano-structures of compounds 1 and 2 at 400 °C.     

Direct reductive amination using triethylsilane and catalytic bismuth(III) chloride

Direct reductive amination (DRA) using triethylsilane (TESH) and catalytic bismuth(III) chloride (BiCl₃) is described for the first time. The use of TESH and BiCl₃ provides easy handling, low cost, non-toxicity, and a mild Lewis acid activity, thereby meeting the demand for green and sustainable chemistry. The developed DRA is highly chemoselective and applicable to less-basic amines. The experimental results of this study revealed that the developed DRA could be catalyzed by BiCl₃, which was gradually reduced to Bi(0) or bismuth with a low valency by TESH, but TESCl, Bi(0), and Bi(0) with TESCl catalyzed the DRA to some extent.     

Ketiminate supported aluminum(III) complexes: Synthesis, characterization and reactivity

The reaction of LLi, (L = [RNC(Me)CHC(Me) = O] (R = C₂H₄NEt₂)), with AlCl₃ at −78 °C forms the mono-ketiminate product, LAlCl₂, 1, while the same reaction at 0 °C affords the bis-ketiminate complex, [{(LH)₂AlCl}(Cl₂)], 2, Reduction of 1 with Li^o, K^o or Mg^o yielded an unusual dimeric aluminum(III) species, [L′AlCl]₂, 3, where C-C coupling of the ligand backbone is observed.     

Synthesis and crystal structure of two new Bi(III) complexes {(Me2NCS2)3Bi}2 and {[(CH2)5NCS2]2BiI}2

Six bismuth(III) complexes containing dithio-ligands formulated as (R₂NCS₂)₃Bi [R₂NCS₂M?=?Me₂NCS₂Na, C₄H₈NCS₂Na, Bz₂NCS₂Na] and [(R₂NCS₂)₂BiI]₂ [R₂NCS₂M?= C₅H₁₀NCS₂Na, ⁿ Bu₂NCS₂Na, OC₄H₈NCS₂Na] have been obtained by reactions of bismuth(III) halides with dithiocarbamate ligands in 1?:?2 or 1?:?3 stoichiometry. All compounds were characterized by elemental and IR analyses. The crystal structures of complexes 1 and 4 have been determined by X-ray single crystal diffraction. The structure analyses reveal that Bi^III in complex 1 adopts a distorted pentagonal–pyramidal coordination, due to its stereochemically active lone pair of electrons. A long Bi?·?S contact of 3.218 (3)?Å leads to dimeric associations of molecules in the crystal structure. The structure of complex 4 is six-coordination with a distorted octahedral configuration. Intramolecular S?·?S weak interactions contribute to the stability and lead to a one-dimensional chain structure.     

Synthesis,spectra and X-ray crystal structure of a new type of macrocyclic hexanuclear iron(III) cluster

A macrocyclic iron(III) 18-azametallacrown-6 compound, [Fe₆(5-Brashz)₆(H₂O)₆]?·?20H₂O(5-Brashz?=?N-acetyl-(5-bromosalicylhydrazide)), where the pentadentate ligands bridge the metal ions, was synthesized and characterized. Due to the meridional coordination of the ligand to the metal ion, the ligand is not only bridging the ring metal ions using a hydrazide N–N group, but also enforcing the stereochemistry of the metal ions as a propeller shape with alternating Λ/Δ configuration. The disc-shaped hexanuclear cluster is about 14.5?Å in diameter, 16.8?Å in thickness and has a vacant cavity in the center of the cluster.     

Synthesis and Physicochemical Characteristics of New Tetrachloroferrates(III) with Dimethylammonium Cation: X‐ray Crystal Structure of Bis(dimethylammonium) Chloride Tetrachloroferrate(III)

Two new tetrachloroferrates(III) have been synthesized of molecular formulas [(CH₃)₂NH₂][FeCl₄] and [(CH₃)₂NH₂]₂FeCl₅. The differences in their physicochemical properties have been highlighted using thermal analysis (TG‐MS) and differential scanning calorimetry (DSC). The crystal and molecular structure of [(CH₃)₂NH]₂FeCl₅ was determined. The iron(III) cation is four coordinated by chloride ions, and it adopts a slightly distorted tetrahedral coordination with three angles smaller and three larger than the tetrahedral one. In the structure four intermolecular N‐H···Cl hydrogen bonds link the [(CH₃)₂NH₂]⁺ cations to dimers via a Cl^? bridge.     

Synthesis and characterization of β-diketiminato complexes of antimony (III) halides

Treatment of SbX₃ (X = Br, Cl) with DippnacnacLi (Dippnacnac = [{N(C₆H₃ⁱPr₂2,6)C(Me)}₂CH]⁻) or Mesnacnac (Mesnacnac = [{N(Mes)C(Me)}₂CH]⁻, Mes = 2,4,6, trimethyl benzene) affords different products that are dependent on the stoichiometry of the reaction and the halide precursor. When DippnacnacLi is reacted with SbBr₃, C-H activation of the ligand backbone is observed and an asymmetric, bridged bromide dimer is isolated. In comparison, the reaction of SbCl₃ with MesnacnacLi affords monomeric MesnacnacSbCl₂. The solid-state structures were determined using X-ray crystallography.     

Syntheses,crystal structures,and antibacterial activities of manganese(III), nickel(II), and copper(II) complexes containing a tetradentate Schiff base

Three new mononuclear Schiff-base complexes, namely [Mn(L)Cl] (1), [Ni(L)] (2), and [Cu(L)] (3), where L?=?anion of [N,N′-bis(2-hydroxybenzophenylidene)]propane-1,2-diamine, have been synthesized by reacting equimolar amounts of the respective metal chloride and the tetradentate Schiff base, H₂L, in methanol. The complexes have been characterized by microanalytical, spectroscopic, single-crystal X-ray diffraction, and other physicochemical studies. Structural studies reveal that 1 adopts a distorted square-pyramidal geometry whereas 2 and 3 are isotypic with distorted square-planar geometries. The antibacterial activities of 1–3 along with their Schiff base have been tested against some Gram(+) and Gram(?) bacteria.     

Disproportionation of rhenium(V). Imidazolate coordination of pyridylbenzimidazole in a rhenium(III) complex

Reaction of trans-[ReOCl₃(PPh₃)₂] with 2-(2′-pyridyl)benzimidazole (pbiH) in methanol led to the isolation of the rhenium(III) compound [ReCl₂(pbi)(PPh₃)₂] (1). Complex 1 could also be prepared in better yield by the reduction of [ReO₄]^? with PPh₃ in the presence of pbiH and hydrochloric acid. An X-ray crystallographic study showed that pbi is coordinated as a bidentate monoanionic chelate, with deprotonation of the imidazolyl NH group. The PPh₃ ligands are trans to each other.     

Ein anionischer Oxohydroxo‐Komplex mit Bismut(III): Na6[Bi2O2(OH)6](OH)2 · 4H2O

An Anionic Oxohydroxo Complex with Bismuth(III): Na₆[Bi₂O₂(OH)₆](OH)₂ · 4H₂O Colourless, plate‐like, air sensitive crystals of Na₆[Bi₂O₂(OH)₆](OH)₂ · 4H₂O are obtained by reaction of Bi₂O₃ or Bi(NO₃)₃ · 5H₂O in conc. NaOH (58 wt %) at 200 °C followed by slow cooling to room temperature. The crystal structure (triclinic, P 1¯, a = 684.0(2), b = 759.8(2), c = 822.7(2) pm, α = 92.45(3)°, ß = 90.40(3)°, γ = 115.60(2)°, Z = 1, R1, wR2 (all data), 0, 042, 0, 076) contains dimeric, anionic complexes [Bi₂O₂(OH)₆]^4— with bismuth in an ψ¹‐octahedral coordination of two oxo‐ and three hydroxo‐ligands. The thermal decomposition was investigated by DSC/TG or DTA/TG and high temperature X‐ray powder diffraction measurements. In the final of three steps the decomposition product is Na₃BiO₃.     

Hydrothermal synthesis and characterization of a novel polyoxometallate-templated three-dimensional supramolecular network

The well-known polyoxomolybdate anion [Mo₈O₂₆]^4? has been used as a noncoordinating anionic template for the construction of a novel three-dimensional (3D) supramolecular network, [Co(phen)₃]₂[Mo₈O₂₆]·?2.5H₂O (1) (phen?=?o-phenanthroline). Compound 1 has been characterized by elemental analyses, IR spectrum, X-ray photoelectron spectroscopy (XPS), TG analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction analysis reveals that [Co(phen)₃]²⁺ coordination complexes are packed together via aromatic?π–π?stacking and hydrogen-bonding interactions, and exhibit an interesting 3D supramolecular network with one-dimensional (1D) box-like channels in which the octamolybdate anions reside.     

Linear polymer of a copper(II) complex and its supramolecular selectivity

The supramolecular framework [Cu₂(TU)₄?·?(TAA)₄] _n (TU?=?thiourea; TAA?=?2-(2-imino-4-oxo-5-thiazolidinylidene)acetic anion) has been synthesized by reaction of CuCl₂?·?2H₂O with meso-2,3-dibromosuccinic acid and thiourea. The one-dimensional supramolecular structure of the title complex is constructed through bridge-linkage of the S atoms on the thioureas between adjacent Cu(II) atoms, forming an infinite chain with lots of positive charges. Around the infinite chain, there are four groups of negatively charged hydrogen-bond tubes constructed by four TAA anions. The hydrogen-bond and ionic interactions between adjacent metal-organic polymeric chains and hydrogen-bond tubes form the three-dimensional supramolecular structure of the complex. Supramolecular selectivity from isomers of 2-(2-imino-4-oxo-5-thiazolidinylidene)acetic anion (TAA) has been studied by quantum calculation.     

Direct Synthesis of a Dimeric Mixed-Anions Bismuth(III) Complex: Synthesis and Structural Characterization of [Bi2(Phen)4(No3)4.4I0.6]I3 (A New Dimeric Compound)

A direct synthetic method of mixing Bi(NO₃)₃ and NaI with 1,10-phenanthroline yielded red crystals of [Bi₂(phen)₄(NO₃)_4.4I_0.6]I₃. In this complex the cationic part is in fact binuclear and contains two [Bi(phen)(NO₃)_1.7I_0.3] groups linked via a bridging NO^? ₃ anion. The I^? ₃ anion was not coordinated to bismuth(III) and the lone pair of valence electrons of the bismuth(III) ions appears to be stereochemically inactive. There are two independent NO^? ₃ anions, one coordinated to bismuth but another shares a position with I^? anion. The final results of crystallography show that 40% of these positions are occupied by NO^? ₃ anions and 60% by I^? anions that are coordinated to bismuth atom in bidentate fashion (NO^? ₃) and in unidentate fashion (I^?). An interesting point is that the I^? ₃ anion was produced by direct synthetic method (Branched tube method). There is a π-π stacking interaction between the parallel aromatic rings around the Bi(III) ion.     

Syntheses,crystal structures,and antibacterial activities of two cobalt(III) complexes

Syntheses, structures, and antimicrobial activities of cobalt(III) complexes with two tetradentate Schiff-base ligands, (BA)₂en?=?bis(benzoylacetone)ethylenediimine dianion and (acac)₂en?=?bis(acetylacetone)ethylenediimine dianion, and two axial pyridines (py) have been investigated. These complexes were characterized by FT-IR, ¹H-NMR, UV-Vis spectroscopy, and elemental analysis. The crystal structures of the complexes were determined by X-ray crystallography. Single-crystal X-ray diffraction analyses revealed that both complexes have distorted octahedral environments, Schiff-base ligand coordinates cobalt in four equatorial positions, and the two axial positions are occupied by pyridines. The pyridines and Schiff-base ligands are involved in N–H···O hydrogen bonds with perchlorate. Biological activities of the ligands and metal complexes have been studied on Staphylococcus aureus, Escherichia coli, and Bacillus subtilis by the well diffusion method. The activity data show the metal complexes to be more potent than the parent ligand against two bacterial species.     

Syntheses,structures, and properties of supramolecular complexes with bipyridine and amino-Schiff-base derived from salicylaldehyde with glycine

The reactions of stoichiometric amounts of Cu(CH₃COO)₂ · 2H₂O or Ni(CH₃COO)₂ · 2H₂O with KHL (potassium salt of salicylideneglycine) and 4,4′-bipy or 2,2′-bipy ethanol afforded [Cu₂(L)₂(μ-4,4′-bipy)(4,4′-bipy)₂] · 2H₂O (1) (L = salicylideneglycine) and Ni(OAc)₂(2,2′-bipy) (H₂O)₂ (2), respectively. The structure of 1 contains two Cu(II)'s, bridged by 4,4′-bipy; each copper is square pyramidal. Complex 2 contains a Ni(II) in highly distorted octahedral geometry. The two complexes were constructed into 3-D interwoven networks by typical H-bonding (i.e., O?H ··· O and N?H ··· O) and some other intra- or intermolecular weak interactions (i.e., C?H ··· O).