Poly[aqua­bis(μ-benzene-1,2-dicarboxyl­ato)ethano­ltetra­lithium]

In the crystal structure of the title compound [Li4(C8H4O4)2(C2H5OH)(H2O)]n, there are four crystallographically independent metal centers each of which is coordinated by four O atoms. The benzene-1,2-dicarboxyl­ate groups act as bidentate–bridging ligands producing a two-dimensional coordination network parallel to the ab plane. The coordination polymer is further stabilized by coordination of water and ethanol mol­ecules by the Li+ ions. Simultaneously, the water and ethanol mol­ecules are involved in O—H⋯O and C—H⋯π inter­actions

Poly[potassium-μ-2-[2-(carboxymethyl)phenyl]acetato]

In the title salt, [K(C10H9O4)]n, the K+ ions are coordinated by six O atoms from three different anions, and there is a cation–π inter­action at ca 3.14 Å. The 2-[2-(carboxymethyl)phenyl]acetate anions are stabilized by intramolecular O—H⋯O hydrogen bonds, and the K+ cations are linked into one-dimensional coordination polymers running along the b axis; these are further inter­connected by weak C—H⋯O hydrogen bonds

Bis{4,4′,6,6′-tetra­chloro-2,2′-[trans-(R,R)-cyclo­hexane-1,2-diylbis(imino­methyl­ene)]diphenolato-κ4 O,N,N′,O′}zirconium(IV)

The title mononuclear complex, [Zr(C20H20Cl4N2O2)2], was obtained by allowing hexane to diffuse into a diethyl ether solution of zirconium(IV) sec-butoxide and the enanti­o­meri­cally pure tetra­dentate ligand N,N′-bis­(3,5-dichloro-2-hy­droxy­benz­yl)-trans-(R,R)-1,2-diamino­cyclo­hexane. The metal centre is eight-coordinate and displays a distorted dodeca­hedral coordination environment with average Zr—O and Zr—N bond lengths of 2.082 (9) and 2.441 (8) Å, respectively. In the crystal structure, complex mol­ecules are linked by inter­molecular C—H⋯Cl hydrogen-bond inter­actions into zigzag chains running parallel to the [101] direction. C—H⋯O and N—H⋯O hydrogen bonds are also present

Organostannoxane-Supported Multiferrocenyl Assemblies: Synthesis, Novel Supramolecular Structures, and Electrochemistry

Organostannoxane-based multiredox assemblies containing ferrocenyl peripheries have been readily synthesized by a simple one-pot synthesis, either by a solution method or by room-temperature solid-state synthesis, in nearly quantitative yields. The number of ferrocenyl units in the multiredox assembly is readily varied by stoichiometric control as well as by the choice of the organotin precursors. Thus, the reaction of the diorganotin oxides, R2SnO (R=Ph, nBu and tBu) with ferrocene carboxylic acid affords tetra-, di-, and mononuclear derivatives [{Ph2Sn[OC(O)Fc]2}2] (1), [{[nBu2SnOC( O)Fc]2O}2] (2), [nBu2Sn{OC(O)Fc}2] (3), [{tBu2Sn(OH)OC(O)Fc}2] (4), and [tBu2Sn{OC(O)Fc}2] (5) ( Fc=h5C5H4- Fe-h5C5H5). The reaction of triorganotin oxides, R3SnOSnR3 (R=nBu and Ph) with ferrocene carboxylic acidleads to the formation of the mono-nuclear derivatives [Ph3SnOC(O)Fc] (6) and [{nBu3SnOC(O)Fc}n] (7). Molecular structures of the compounds 1–4 and 6 have been determined by singlecrystal X-ray analysis. The molecular structure of compound 1 is new among organotin carboxylates. In this compound, ferrocenyl carboxylates are involved in both chelating and bridging coordination modes to the tin atoms to form an eight-membered cyclic structure. In all of these compounds, the acidic protons of the cyclopentadienyl groups are hydrogen bonded to the carboxylate oxygens (CH···O) to formrich supramolecular assemblies. In addition to this, p–p, T-shaped, L-shaped, and side-to-face stacking interactions involving ferrocenyl groups also occur. Compound 6 shows an interesting and novel intermolecular CO2–p stacking interaction. Electrochemical analysis of the compounds 1–4, 6, and 7 shows a single, quasi-reversible oxidation peak corresponding to the simultaneous oxidation of four, two, and one ferrocenyl substituents, respectively. Compound 5 shows two quasi-reversible oxidation peaks. This is attributed to the positional difference among the ferrocenyl substituents on the tin atom. Additionally, while compounds 2 and 4 are electrochemically quite robust and do not decompose even after ten continuous CV cycles, compounds 1, and 3, 5–7 start to show decomposition after five cycles

Fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy and chemometric techniques for the determination of adulteration in petrodiesel/biodiesel blends

We propose an analytical method based on fourier transform infrared-attenuated total reflectance (FTIR-ATR) spectroscopy to detect the adulteration of petrodiesel and petrodiesel/palm biodiesel blends with African crude palm oil. The infrared spectral fingerprints from the sample analysis were used to perform principal components analysis (PCA) and to construct a prediction model using partial least squares (PLS) regression. The PCA results separated the samples into three groups, allowing identification of those subjected to adulteration with palm oil. The obtained model shows a good predictive capacity for determining the concentration of palm oil in petrodiesel/biodiesel blends. Advantages of the proposed method include cost-effectiveness and speed; it is also environmentally friendly