Synthesis,Crystal and Molecular Structure of Mono- and Diaquadi(acetato-O)-Bis(2,4′-Bipyridyl) Copper(II)

The title compound has been synthesized and characterized by elemental analysis and conductivity studies. The crystal and molecular structure has been determined. There are two different types of molecules in the crystal: mono- and diaquadi(acetato-O)-bis(2,4'-bipyridyl) copper (II). Both copper atoms occupy special positions. The copper atoms show almost ideal square pyramidal (4 + 1) and square bipyramidal (4 + 2) coordination. Due to the Jahn-Teller effect, the axial Cu-O(water) bond distances are longer than respective equatorial Cu-O(acetate) bond distances. The bond valences of the copper were computed. An intramolecular strong hydrogen bond linking O(water) and O(acetate) atoms exists in the molecule. The differences of geometrical environment for copper in mono- and diaquadi(acetato-O)-bis(2,4'-bipyridyl) copper(II) are imposed by strong intermolecular hydrogen bonds creating a linear infinite chain structure along crystallographic x axis. Also weak intramolecular hydrogen bonds are present in the molecule.     

Synthesis,structures and properties of two carboxylate-bridged coordination polymers with linear and ladder chain motifs

Two cadmium(II) compounds, [Cd(nip)(phen)₂] _n (1) and [Cd₂(nip)₂(phen)₂] _n (2) [nip = 5-nitroisophthalate, phen = 1,10-phenanthroline], have been synthesized under hydro (or solvo) thermal conditions and characterized by single-crystal X-ray diffraction. Compound 1 exhibits a 1-D linear chain structure adopting the coordination mode in which one Cd is coordinated to two phen ligands. The formation of 1 was favored by selecting Cd(phen)₂(NO₃)₂ as metal source in ethanol-water. Compound 2 displays a 1-D ladder-like chain structure featuring di-cadmium units. Both 1 and 2 are further assembled into 3-D supramolecular frameworks through interchain hydrogen bonding.     

Some Calculus Rules for Contingent Epiderivatives

This article presents some calculus rules for contingent epiderivatives of set-valued maps. Among other results the main emphasis is focused on a formula for scalar multiplication, sum formulae and chain rules. The calculus of contingent cones and some inversion theorems are used as a tool. Some applications are also given.     

Metal phosphonates containing pyridyl N-oxide groups: Syntheses of Cd{(2-C5H4NO)CH(OH)PO3}(H2O)2 and Zn{(4-C5H4NO)CH(OH)PO3} with chain and layer structures

This paper reports the syntheses and characterization of two phosphonate compounds Cd{(2-C₅H₄NO)CH(OH)PO₃}(H₂O)₂ (1) and Zn{(4-C₅H₄NO)CH(OH)PO₃} (2) based on hydroxy(2-pyridyl N-oxide)methylphosphonic and hydroxy(4-pyridyl N-oxide)methylphosphonic acids. Compound 1 has a chain structure in which dimers of edge-shared {CdO₆} octahedra are linked by {CPO₃} tetrahedra through corner-sharing. The pyridyl rings reside on the two sides of the inorganic chain. Compound 2 has a layer structure where the inorganic chains made up of corner-sharing {ZnO₄} and {CPO₃} tetrahedra are covalently connected by pyridyl N-oxide groups. Crystal data for 1: triclinic, space group , a=6.834(1) Å, b=7.539(1) Å, c=10.595(2) Å, α=84.628(3)°, β=74.975(4)°, γ=69.953(4)°. For 2: triclinic, space group , a=5.219(1) Å, b=8.808(2) Å, c=9.270(2) Å, α=105.618(5)°, β=95.179(4)°, γ=94.699(4)°.     

Synthesis of poly(methyl methacrylate-co-styrene)-block-polysulfide-block-poly(methyl methacrylate-co-styrene) copolymers by free radical polymerization combined with oxidative coupling

Poly(methyl methacrylate-co-styrene)-block-polysulfide-block-poly(methyl methacrylate-co-styrene) triblock copolymers were synthesized for the first time by the free radical copolymerization of methyl methacrylate (MMA) and styrene (St) in the presence of a thiocol oligomer as a chain transfer agent, followed by chemical oxidation of the remaining SH-end groups. The apparent chain transfer constant of the thiocol SH groups in the copolymerization reaction was estimated from the rate of consumption of the thiol groups versus the overall rate of consumption of the monomers (C_T = 1.28). Based on this value, the chain transfer constant of the thiocol SH groups in St polymerization was calculated . The triblock copolymers synthesized were characterized by SEC and ¹H NMR measurements.     

A Chain Rule for Upper Semicontinuous (CF)-Mappings

A chain rule for calculating convexificators of composite functions of the type f = h∘g, with the inner factor g being a transformation of , is proposed. The proof is based on a double application of a mean value theorem for (CF)-mappings due to V.F. Demyanov and V. Jeyakumar (see [4]), along with a stability property for the support of a certain ɛ-perturbation of (CF)-mappings.     

Solvothermal Synthesis,Crystal Structures,and Magnetic Properties of Two Organically Templated Iron Sulfates with Chain Structures

Two new one‐dimensional (1D) organically templated iron(III) sulfates [C₂NH₈]₃ [Fe₃(μ₃‐O)₂(SO₄)₄] ( 1 ) and [C₂N₂H₁₀][C₂NH₇]_0.5[FeF(SO₄)₂] ( 2 ) were synthesized under solvothermal conditions and characterized by single‐crystal X‐ray diffraction, powder X‐ray diffraction (XRD), FT‐IR spectroscopy, elemental analyses, ICP analyses, and thermogravimetric analyses. Single‐crystal structure analysis reveals that both compounds show linear‐chain structures, involving FeO₆ (FeF₂O₄) octahedra and SO₄ tetrahedra. The magnetic properties of the two compounds have also been investigated.     

Different crystallinity of poly(d,l-lactide-co-p-dioxanone) copolymers acquired by control of chain microstructure

Poly(d,l-lactide-co-p-dioxanone)(P(LA-co-PDO)) copolymers with different chain microstructures were synthesized by one-step or two-step bulk ring-opening polymerizations of d,l-lactide(LA) and p-dioxanone(PDO) monomers using stannous octoate [Sn(Oct)_2]/n-dodecanol as the initiating system.The average sequence lengths of the lactidyl(L_(LA)) and dioxanyl(L_(PDO)) units were calculated from the ~1H NMR spectra.It was found that both L_(LA) and L_(PDO) values from the two-step syntheses were significantly ...     

On minor-minimally 3-connected binary matroids

A matroid M is called minor-minimally 3-connected if M is 3-connected and, for each e∈E(M), either M?e or M/e is not 3-connected. In this paper, we prove a chain theorem for the class of minor-minimally 3-connected binary matroids. As a consequence, we obtain a chain theorem for the class of minor-minimally 3-connected graphs.