Synthesis and structure of a novel tetranuclear 32-membered macrocycle of triphenyltin complex with pyridine-4-carboxylic acid N-oxide

The 32-membered stereoregular triphenyltin macrocycle: [Ph₃Sn (OCOC₅H₄NO)]₄·3(CH₂Cl₂) has been synthesized by the reaction of triphenyltin chloride with pyridine-4-carboxylic acid N-oxide. The complex was characterized by elemental analysis, FT-IR, NMR (¹H, ¹¹⁹Sn) spectra and X-ray crystallography. Single crystal X-ray diffraction data reveal that the complex is highly symmetrical tetranuclear cyclic complex with the ligand pyridine-4-carboxylic acid N-oxide bridging the adjacent tin atoms. All four tin atoms are five-coordinated resulting in trigonal bipyramidal geometry. And the complex showed good thermal stability and high antitumor activity.     

A novel 3D double helix cobalt(II) coordination polymer: Synthesis, crystal structures and third-order non-linear optical properties

One new metal-organic complex formulated as {[Co(bipy)₃][Co₂(μ₂–ox)₃]}_n 1 (bipy = 2,2′-bipyridyl; ox = oxalate) has been synthesized by low-temperature solid-state reaction and characterized by single-crystal X-ray diffraction, elemental analyses, IR spectra and UV–visible spectra. The complex 1 contains helical chains composed of left-handed and right-handed helices interlaced in pairs. The third-order non-linear optical (NLO) properties of the 1 were also investigated and they exhibit the reverse saturable absorption and self-defocusing performance with modulus of the hyperpolarizability (γ) 5.75 × 10⁻³⁰ esu for 1 in a 2.36 × 10⁻⁴ mol dm⁻³ DMF solution.     

Cadmium(II) chloride complexes of imidazole-based ligands: Solvothermal syntheses,crystal structures and luminescent properties

Presented are the solvothermal syntheses, structures, characterizations, and luminescent properties of four novel organic-modified cadmium chloride complexes constructed from CdCl₂ and imidazole (or its derivatives), namely [CdCl₂(Im)₄] (1, Im = imidazole), [CdCl₄(HAPI)₂] (2, API = N-(3-Aminopropyl)-imidazole), [Cd(μ-Cl)₂(1-Mim)₂]_∞ (3, 1-Mim = 1-methyl imidazole) and [CdCl₃(HAPI)]_∞ (4). 1 and 2 feature a zero dimensional (0D) mononuclear structure with different mole ratios of Cd: Cl: ligand, while compound 3 and 4 bear infinite chains constructed from different subunits and connection modes. Worthy of note is that 4 represents a new structural type in the family of organic modified cadmium halides. The fluorescence spectra showed that compounds 1–4 exhibited emission peaks around 450 nm with the quantum yields of 23.01%, 5.84%, 27.31%, 5.71%, respectively.     

Polymer crystal silverware: a fast method for the prediction of polymer crystal structures

Summary A method is presented for the fast prediction of polymer crystal structures. From a stable helical conformation of the polymer chain well packed three dimensional periodic starting structures are generated using an adapted version of M. Blanco's Molecular Silverware algorithm. These structures are then energy-minimised using classical molecular mechanics methods. The method only requires a rough estimate of the crystalline density. No information about crystal class, space group or cell parameters is necessary. Using this method, possible crystal structures of poly(ethylene ketone), Nylon-6,6 and poly(ethylene terephthalate) are calculated. Both the - and -structures of poly(ethylene ketone) are correctly predicted. For Nylon-6,6 the lowest-energy structure obtained corresponds to the experimental -structure. For poly(ethylene terephthalate) a large number of structures are generated using the algorithm. Besides the experimental structure four structures are found with a lower energy than the experimental structure.     

Hydrothermal syntheses,characterizations and crystal structures of two new lead(II) diphosphonates with a layered and a microporous structure

Hydrothermal reactions of lead(II) salts with N-isobutylimino-bis(methylene-phosphonic acid), C₄H₉N(CH₂PO₃H₂)₂ (H₄L), under different conditions lead to two new lead(II) diphosphonates, namely, a layered Pb₁₀L₂(HL)₄ 1, and Pb₂L 2 with a microporous network structure.     

Studies on syntheses and permeabilities of special polymer membranes: 24. Permeation characteristics of poly(vinylidene fluoride) membranes

The permeation characteristics of poly(vinylidene fluoride) membranes were investigated by changing the preparation conditions of the membranes, the composition of the casting solution, membrane thickness, time of heat treatment and temperature, etc.; and by changing the permeation conditions, operating temperature, the feed concentration, and the feed solute, etc. Aqueous solutions of poly(vinyl alcohol) and poly(ethylene glycol) were used as feed. The permeation characteristics were influenced significantly by the change of the above conditions and were dependent on the structure of resulting membrane, the viscosity of feed, the form of polymer molecules in aqueous solution, and the concentration polarization of polymer solute molecules onto the membrane surface. The permeation through very swollen membranes (ca. 85% in water content) followed the viscous flow.     

Synthesis,crystal structure and photoluminescent properties of a 3D Zn(II) coordination polymer

A new 3D coordination polymer [NH₂(CH₃)₂]₂[Zn₇L₄(DMF)₂(H₂O)₃]·19H₂O (1) (L = 2,3′,5,5′-biphenyl tetracarboxylic acid) has been solvothermally synthesized and structurally characterized by IR, elemental analysis and single-crystal X-ray diffraction. Single-crystal X-ray diffraction studies indicate that 1 exhibits 3D framework with a one-dimensional (1D) channel. The luminescence properties have been studied, and the results showed that 1 displays strong fluorescent emissions both in the solid state and in methanol suspension at room temperature. More interesting, the addition of Fe^3 + causes the fluorescence intensity of 1 to be weakened, which implies that it may be used as luminescent probes of Fe^3 +.     

Solvothermal synthesis and crystal structure of a luminescent 2D copper(I) coordination polymer with a (3,4)-connected net

A novel copper(I) coordination polymer, {[Cu(tpt)(MeCN)](ClO₄)}_∞ (1) (tpt = 2,4,6-tris(4-pyridyl)-1,3,5-triazine), was synthesized by solvothermal synthesis method and structurally characterized. Single crystal X-ray diffraction showed that 1 consists of a 2D (3,4)-connected network with a unique (5³)₂(5⁴8²) topology. The luminescent properties of 1 in the solid state at ambient temperature were investigated.     

Synthesis and crystal structure of a mononuclear Ni(II) complex with tetraazadiphenol macrocycle bearing cyclohexanes

The mononuclear tetraazadiphenol macrocyclic nickel(II) complex [Ni(H₂[20]-DCHDC)](ClO₄)₂ (II) {H₂[20]-DCHDC = 14,29-dimethyl-3,10,18,25-tetraazapentacyclo-[25,3,1,0^4,9,1^12,16,0^19,24] ditriacontane-2,10,12,14,16(32),17,27(31),28,30-decane-31,32-diol} has been synthesized by self-assembly and characterized by elemental analysis, conductance, IR and FAB-MS spectrum, and single crystal X-ray diffraction. In the mononuclear complex, the Ni(II) ion is coordinated with a square planar conformation by two phenolate groups and two iminic sites on one side of the macrocycle. The bond angles of O–Ni–O {85.37(19)°} and N–Ni–N {88.0(2)°} are smaller than 90°.     

Self-assembly of a 1D helical manganese coordination polymer and a tetranuclear lanthanum complex with 1,10-phenanthroline and 3,5-dinitrosalicylato dianion

The hydrothermal reaction of manganese chloride and lanthanum nitrate with 3,5-dinitrosalicylic acid (3,5-(NO₂)₂sal) and 1,10-phenanthroline (phen) yielded two compounds [Mn(phen){3,5-(NO₂)₂sal²⁻}]_n (1) and La₂(phen)₃{3,5-(NO₂)₂sal²⁻}₂ (NO₃)(OH) (2). Magnetic susceptibility measurements show weak antiferromagnetic interactions in (1).     

Solvothermal synthesis,crystal structures and characterization of open-framework metal (CoII and MnII) phosphites with helical channels and 16-membered rings

Two new 3D open-framework metal phosphites [(CH₃)₂NH₂]₂Co₃(HPO₃)₄ (1) and [(CH₃)₂NH₂]₂Mn₃(HPO₃)₄ (2) have been solvothermally synthesized. Single-crystal X-ray diffraction analysis shows that complexes 1 and 2 are isomorphic structures, with left/right-handed helical channels and 16-membered ring channels. Complex 2 represents the first monometallic four-coordinate manganese phosphite. These two phosphite complexes 1 and 2 display antiferromagnetic behavior.     

New polymer syntheses: 6. Linear and branched poly(3-hydroxy-benzoates)

Synthesis of poly(3-hydroxybenzoate) were conducted in three ways: (a) condensation of the novel monomer, 3-(trimethylsiloxy)benzoyl chloride in bulk and in solution, (b) bulk condensation of 3-acetoxybenzoic acid, (c) condensation of 3-hydroxybenzoic acid by means of phosphorus reagents in solution. The bulk condensation of 3(trimethylsiloxy)benzoyl chloride gave the best results with respect to both yields (89–99%) and molecular weights (Mn = 10 000–14 000). Because amorphous poly(3-hydroxybenzoate) is soluble in various solvents the molar weights could be determined by both vapour pressure osmometry and ¹H n.m.r. endgroup analyses. Crystalline poly(3-hydroxybenzoate) was only obtainable by solvent induced crystallization; yet not by annealing. Glass transition (Tg = 145°C) and melting point (Tm=181°–185°C) were determined by means of differential scanning calorimetry and torsion pendulum. Branched poly(3-hydroxybenzoate) was prepared by condensation of 3-(trimethylsiloxy) benzoyl chloride and 3,5-(bistrimethylsiloxy) benzoyl chloride. Thus, for the first time a branched polycondensate was obtained which did not crosslink regardless of the conversion.     

A new inorganic (carbon-free) chelate ring: SnO2N2. Eight-coordinated tin(IV) in Sn(O2N2Ph)4 and a self-assembled 20-membered macrocycle in [Me3Sn(O2N2Ph)]4

The reaction of cupferron (NH₄L, L=PhN(O)NO⁻) with tin(IV) and trimethyltin(IV) halides yields cupferronato complexes SnL₄ (1) and [Me₃SnL]₄ (2) which were characterised by FT-IR and FT-Raman spectroscopy. The first X-ray diffraction analysis of the complexes reveals a slightly distorted dodecahedral and trigonal-bipyramidal coordination of the central metal atoms in 1 and 2, respectively. The N-nitroso-N-phenylhydroxylaminato [PhN(O)NO⁻] ligand behaves as chelating in 1 and bridging in 2 leading to a novel five-membered chelate ring, SnO₂N₂ in 1 and an unprecedented 20-membered inorganic metallomacrocycle, Sn₄O₈N₈ in 2.     

Laser from the dimer state of a conjugated polymer (PFO) in solution

The spectral and laser properties of the conjugated polymer poly (9,9-dioctylfluorenyl-2, 7-diyl) (PFO) in benzene have been studied and presented in this paper. The absorption spectra of PFO in benzene under low concentration showed that there was only one peak at 390 nm. When the concentration was increased, a new peak at 437 nm appeared additionally, indicating dimer formation at higher concentration of PFO in benzene. The fluorescence spectra for low concentration showed two peaks at 422 nm and 444 nm, which could be attributed to the monomer and the excimer. At the longer wavelength side of these spectra, there was a hump at 465 nm. This hump became dominant for higher concentrations and in low temperatures, while the other peaks became weaker. So, this new peak at 465 nm may be due to the dimer. For still higher concentrations, the peaks at 422 nm and 444 nm vanished and there was a dominant peak only at 465 nm. Under suitable concentration and pump power excitation of Nd: YAG laser (355 nm) the amplified spontaneous emission (ASE) spectra were obtained. It could be seen that there were three ASE peaks at 422, 444 and 470 nm. These peaks could be attributed to the monomer, excimer and dimer respectively. This is perhaps the first report on ASE from dimers of the conjugated polymer, PFO in liquid solution.     

Dimethyltin(IV) and palladium(II) complexes derived from 2-benzoylpyridine N(4)-cyclohexylthiosemicarbazone: Synthesis,crystal structures and biological evaluation

Two metal complexes [(Me)₂Sn(L)(OAc)] (1), and [Pd(L)Cl] (2) based on 2-benzoylpyridine N(4)-cyclohexylthiosemicarbazone have been synthesized and structurally characterized. X-ray crystallography reveals that in title compounds, each thiosemicarbazone adopts tridentate NNS manner to coordinate with the metal center, and the metal coordination geometry can be described as a distorted pentagonal bipyramid in 1 and a contorted square-planar in 2, respectively. Growth inhibition assays have indicated that two compounds can effectively inhibit the growth of HepG2 cancer cell lines at micromolar concentrations. In addition, apoptosis mechanisms of 2 on HepG2 cells were further investigated. The results show that 2 can promote the apoptosis of HepG2 cells and the apoptosis is associated with the activation of caspase-3.     

Hydrothermal syntheses and crystal structures of PbII coordination polymers based on a N,O-donor ligand

In this article, four new lead(II) coordination polymers based on a N,O-donor ligand 2′-(1 H-1,3,7,8-tetraaza-cyclopenta[l]phenanthren-2-yl)biphenyl-2-carboxylic acid (HL) have been hydrothermally synthesized, namely, [PbL₂]·2H₂O (1), [PbL₂]·2H₂O·CH₃CH₂OH (2), [Pb₅L₂(m-BDC)₄]·3H₂O (3) and [Pb₂L₂(p-BDC)] (4), where m-BDC = 1,3-benzenedicarboxylate and p-BDC = 1,4-benzenedicarboxylate. Compound 1 shows a 2D bilayer structure, which is further extended into a 3D supramolecular structure through π–π stacking interactions. Compound 2 shows a 3D supramolecular structure based on a zero-dimensional molecule by π–π stacking interactions of neighboring molecules. Compound 3 shows a 2D layer structure. Compound 4 displays a 1D chain-like structure, which is then stacked by π–π interactions to result in a 2D supramolecular structure. Solid-state luminescent spectra of four lead(II) complexes indicate intense fluorescent emissions.     

Hydrothermal syntheses and crystal structures of four novel lanthanide(III) complexes based on two mixed N,O-donor ligands

Four novel polymeric lanthanide(III) complexes [Pr(NCP)(2,5-pydc)]_n·1.5nH₂O (1), [La(NCP)(2,5-pydc)]_n (2), [Nd(NCP)(2,5-pydc)]_n (3) and [Sm(NCP)(2,5-pydc)]_n (4) (HNCP = 2-(4-carboxyphenyl)imidazo(4,5-f)(1,10)phenanthroline, 2,5-H₂pydc = pyridine-2,5-dicarboxylic acid) have been hydrothermally synthesized and characterized via elemental analysis and single crystal X-ray diffraction. Structural analyses revealed that all of these four complexes possess similar two-dimensional sheet structures, which are further linked by the hydrogen bonds to furnish three-dimensional supramolecular structures. Meanwhile, the thermogravimetric analysis and photoluminescent property of complexes 1–4 have also been investigated.     

Synthesis,crystal structure and desulfurization properties of zig-zag 1D coordination polymer of copper(II) containing 4-methoxybenzoic acid ligand

ABSTRACT

Combustion of fuels containing organosulfur compounds has resulted in the emission of sulfur oxides (SO_x) into the atmosphere, therefore, causing serious environmental and health hazards. Herein, slightly distorted octahedral zig-zag 1D coordination polymer of copper(II) [Cu(4-mba)₂(H₂O)₃] was synthesized by reacting copper sulfate pentahydrate with a carboxylate-containing ligand (H-4mba?=?4-methoxybenzoic acid) and employed for sulfur compound uptake. The ligand coordinates to the copper(II) atom via two pairs of deprotonated ligating atoms (carboxylate oxygens) and two water molecules. Structural characterization also reveals that interplay of O–H···O, N–H···O, C-H···O and C–H···π interactions between lattice and coordinated water and ligands significantly contribute to the crystal packing leading to the formation and strengthening of three-dimensional supramolecular assembly. The complex, [Cu(4-mba)₂(H₂O)₃], show potential for desulfurization of fuel with an observed adsorption capacity of 9.6?mg/g at 32°C for 6?h. DFT calculations further revealed a transfer of electron sulfur-containing compounds and the complex, [Cu(4-mba)₂(H₂O)₃], thus leading to a stronger pi–pi interaction.