Raman spectroscopy traces the microstructural evolution of carbonaceous matter (CM) during artificial heating. Thermo-chemical reactivity and strength of blast furnace coke at 1100 degrees C is dependent on the graphitization state of the feed coke. A standard coke reactivity index (CRI) sample is composed of lumps, showing a high microstructural variability. The frequency distribution of the D-STA parameter estimated by the "Interactive Fitting of Raman Spectra" (IFORS) software suggests a positive correlation between degree of CM organization and CRI. Samples from the tuyere region of an operating blast furnace evidence graphitization of CM at temperatures higher than 1900 degrees C. IFORS parameters, calibrated by x-ray diffraction-based lattice dimensions and transmission electron microscopy data constrain a temperature gradient decreasing from the raceway to the deadman zone. The gradient controls a continuous variation of the petrographic coke texture. As an application, the IFORS method is able to map the graphitization zones in the hearth of a working blast furnace.

The organic ligand 4-Benzyl-1-(N,N-dimethylamino)-[1,2,4]triazolo[4,3a]quinoxaline 1 (L) and its polymeric silver(I) complex, [Ag2L(NO3)2]n (2), have been synthesized and characterized. The organic ligand 1 crystallizes in the triclinic space group P¯1. The unit cell contains two parallel-stacked molecules. The complex [Ag2L(NO3)2]n (2) crystallizes in the monoclinic space group P21/n. The structure contains two different silver(I) ions. Ag(2) is coordinated by three oxygens (involving two nitrate groups) and to a nitrogen of the triazole ring of 1. These ligands form a strongly distorted tetrahedral, nearly planar coordination sphere. Ag(1) has an approximately tetrahedral geometry. It is bonded to one oxygen of a nitrate anion and a nitrogen of two different L; this aspect giving rise to an infinite chain structure. A final bond to Ag(1) involves the carbon of a phenyl group. It is more weakly bonded to the phenyl carbons on either side of this, so that the Ag(1)-phenyl bonding has aspects of an Ag-allyl bond. Ag(1) and Ag(2) participate in bonding to a common nitrate anion and alternate, the two distinct modes of bridging between them lead to a zig-zag chain structure. In addition to spectroscopic studies, the biological activities of the ligand and of the complex were scanned over a wide range of Gram positive and Gram negative flesh- and bone-eating bacteria. The results are discussed in comparison with well-known antibiotics.

Presence of alkaline elements such as sodium and potassium are highly detrimental for blast furnace operations. Even a trace amount of alkali affects the performance of raw materials considerably. The performance of coke in the process suffers significantly in presence of alkalis by the catalysis of Boudouard reaction during its descent through the shaft and subsequent deterioration of its strength in the lower zone of the furnace, leading to various furnace operating problems. The aim of this work is to investigate the impact of these harmful elements on the coke structure in micro as well as nano level. The Coke Reactivity Index (CRI) and Coke Strength after Reaction (CSR) values of coke are determined for original industrial coke samples as well as the same samples artificially impregnated with alkaline elements in different amounts. The original and CRI-method treated samples (with and without added alkali) are characterized using X-Ray Diffractometry (XRD) and Transmission Electron Microscopy (TEM) to look into the lattice and crystalline structure of the constituent graphite of coke. The results demonstrate pronounced disturbance in the graphite lattice caused by alkali. An attempt has been made to explain the mechanism of the deterioration of coke properties under the influence of alkalis in terms of the difference in atomic radii of the constituent elements.

The molecular structure and relative stabilities of the six possible isomers of 6-hydroxy-3(2H)-pyridazinone (DHP) in the gas phase and in solutions of different polarities are predicted using the B3LYP/6-311++G(d,p) method. The oxo-hydroxo isomer is the most stable form in the gas phase and in solution. These results agree with our reported X-ray structure. The effect of solvents on the spectroscopic properties of the most stable isomer has been studied using the polarized continuum method (PCM) at the same level of theory. The vibrational spectra of the compound studied are calculated and compared with the experimentally measured FTIR spectra. The electronic spectra in gas phase and in solution were calculated using the TD-DFT method. The most intense absorption band is predicted at 312.4 nm and belongs mainly to a π→π(*) transition. In polar solvents, this spectral band undergoes a hypsochromic shift. Two stable dimer forms were calculated at same level of theory. Dimer A is more stable than dimer B, by 6.66 kcal mol(-1). The former is stabilized by stronger O-H⋯O H-bonds compared to the weaker N-H⋯O interactions in the latter. The effect of these H-bonding interactions on the molecular structure and vibrational spectra of these compounds are predicted. NBO analyses were carried out to investigate the stabilization energy of various inter- and intramolecular charge transfer interactions within the systems studied.

The solid state molecular structure of 2,3-dihydroxyquinoxaline (DHQ) has been studied using X-ray single crystallography. The equilibrium geometry of six possible DHQ isomers have been calculated using the B3LYP/6-311++G(d,p) method in order to predict the most stable gas-phase isomer. The effect of solvent polarity on the relative stability of these isomers is assessed at the same level of theory using PCM. In agreement with the experimental results, it was found that keto form, DHQ1, is the most stable isomer both in the gaseous state and solution. The scaled harmonic vibrational frequencies are in good agreement with the experimental data. The effect of solvent on the vibrational frequencies of the DHQ1 tautomer showed a bathochromic shift for the υ(CO) and υ(NH) bands. These shifts increase with the polarity of the solvent. The electronic transitions of the most stable isomer DHQ1 were calculated using TDDFT and the NMR chemical shifts were calculated using the GIAO method. The NLO properties are predicted to be greater than urea by a factor of five. Two stable dimer forms of DHQ were calculated at same level of theory. Dimer A is more stable by 13.38kcalmol−1 than dimer B. The former is stabilized by stronger NH⋯O H-bonds compared to the weaker CH⋯O interactions in the latter. The effect of these H-bonding interactions on the molecular structure and vibrational spectra of these compounds are predicted.

The inventory of the single-crystal X-ray structures of aliphatic and aromatic 2-oxazolines, namely 2-nonyl-2-oxazoline, 2,2'-tetramethylenebis(2-oxazoline) and 2-phenyl-2-oxazoline, reveals significant delocalization of pi-electrons along the N-C-O segment. The delocalization of p-electrons is stabilized by inductive and resonance contributions of the side-chains; in 2-phenyl-2-oxazoline, also pi-arene interactions between the benzene ring and the C-N and the C-O bond stabilize the crystalline phase. This delocalization gives a partial negative charge to the nitrogen atom and a partial positive charge to the oxygen atom. The partial negative charge of the nitrogen atom makes this atom the exclusive reaction partner also for highly reactive non-selective cations, which explains the regioselectivity of electrophilic attacks in cationic ring-opening polymerizations. (C) 2011 Society of Chemical Industry

The Fischer indole reaction between phenylhydrazines and tosyl-4-piperidone furnishes tetrahydropyrido[4,3-b]indoles. In a Witkop–Winterfeldt-oxidation using ozone such indole derivatives are converted into medium-sized dicarbonyl ring systems, which cyclize to pyrroloquinolones. A detailed study of the reaction intermediates and the characterization of a cinnoline betaine side product formed by an unprecedented ring closure mechanism are reported.

Anhydrous thallium hydrogen L-glutamate [Tl(L-GluH)] crystallizes from water (space group P2(1)) with a layer structure in which the thallium ions are penta- and hexacoordinated exclusively by the oxygen atoms of the γ-carboxylate group of the hydrogen L-glutamate anions to form a two-dimensional coordination polymer. The thallium-oxygen layer is composed of Tl(2)O(2) and TlCO(2) quadrangles and is only 3 Å high. Only one hemisphere of the thallium ions participates in coordination, indicative of the presence of the 6s(2) lone pair of electrons. The thallium-oxygen assemblies are shielded by the hydrogen l-glutamate anions. Only the carbon atom of the α-carboxylate group deviates from the plane spanned by the thallium ions, the γ-carboxylate groups and the proton bearing carbon atoms, which are in trans conformation. Given the abundance of L-glutamic and L-aspartic acid in biological systems on the one hand and the high toxicity of thallium on the other hand, it is worth mentioning that the dominant structural motifs in the crystal structure of [Tl(L-GluH)] strongly resemble their corresponding analogues in the crystalline phase of [K(L-AspH)(H(2)O)(2)].

cis,cis-Trihydroxynonamethylcyclohexasilane (2) is easily accessible by the controlled hydrolysis of Cl3Si6Me9 in the presence of Et3N as an auxiliary base. The crystal structure of 2, as determined by single-crystal X-ray crystallography, exhibits "barrel-type" face-to-face dimeric aggregates held together by six intermolecular hydrogen bonds. NMR and IR spectra suggest that these OH-bonded aggregates are also present in nonpolar solutions. Full geometry optimization (B3LYP/TZVP) of the gas-phase structure of 2 further reveals unusually high energy differences between different conformers and a considerable stabilization of the molecule upon dimerization due to O-H hydrogen bonding. Time-dependent DFT B3LYP/TZVP calculations allow for a detailed interpretation of the UV absorption spectra of 2. The electronic transitions occur between occupied molecular orbitals with predominant sigma(Si-Si) character and a small contribution of the oxygen lone pairs, and virtual MOs with contributions from sigma*(Si-C), sigma*(Si-O), and sigma*(Si-Si) type orbitals. If 2 is reacted with MeSiCl3/Et3N, the adamantane-like cage MeSi(O3Si5Me9) (4) is obtained without the formation of considerable amounts of polymeric material, which is most likely a consequence of the preferred conformation of 2 with three adjacent OH groups in axial positions.

Blends of conjugated polymers and inorganic semiconductors are an interesting class of materials with various applications in the field of plastic electronics. This work presents a direct approach to obtain composites consisting of a conjugated polymer, poly(3-(ethyl-4-butanoate)thiophene) (P3EBT), and a sulfur-based semiconductor (i.e. CdS, PbS or ZnS) using an in-situ formation route. The metal sulfide semiconductor is formed by reaction of the corresponding metal salt (cadmium acetate, zinc acetate or lead thiocyanate) dispersed within the conjugated polymer matrix with thiourea at temperatures below 200 °C. Nanoscaled networks are formed in the case of the CdS- and ZnS-P3EBT composites as shown by X-ray diffraction and transmission electron microscopy investigations, whereas the PbS-P3EBT blend exhibits inorganic structures on the μm-scale. The materials were used as active layer in bulk-heterojunction type hybrid solar cells. First photovoltaic devices containing an active layer of CdS- or ZnS-P3EBT show photovoltaic action, though efficiencies are low (≤ 0.06%).

The reaction of 1,1,2,2,3,3,4-hepta-(t)butyl-1-(chloromagnesio)tetrastannacyclobutane with 1,2-halogenopropane leading to halogeno substituted four membered tin ring systems is presented. In addition, the crystal structures of the chloro and the bromo substituted tetrastannacyclobutanes will be discussed.Supplemental materials are available for this article. Go to the publisher's online edition of Phosphorus, Sulfur, and Silicon and the Related Elements to view the free supplemental file.

Copper zinc tin sulfide (Cu2ZnSnS4, CZTS) is a very promising alternative to semiconductors based on Ga or In as solar absorber material. CZTS consists of abundant and cheap elements and in addition it displays very beneficial properties like a high optical absorption coefficient and an ideal band gap for photovoltaic applications. In this contribution, we present the preparation of thin films of copper zinc tin sulfide from metal salts (copper(I) iodide, zinc(II) acetate, and tin(II) chloride) and thioacetamide as sulfur source by a solution-based precursor method. The influence of synthesizing temperatures and concentration of thioacetamide in the precursor solution on the obtained CZTS materials was investigated. X-ray diffraction studies show that kesterite CZTS is formed. Depending on the temperature, nanocrystalline films with primary crystallite sizes from 8 nm (180 degrees C) up to approximately 150 nm (450 degrees C) were obtained. The early stages of the CZTS formation were monitored by time-resolved simultaneous grazing incident small- and wide-angle X-ray scattering (GISAXS, GIWAXS) analysis directly in thin layers revealing that the thermally induced reaction already starts at approximately 105 degrees C. The thin films exhibit high optical absorption (> 1 x 10(4) cm(-1)) and an optical band gap between 1.41 and 1.81 eV depending on the heat treatment. The obtained CZTS materials are of copper-poor and zinc-rich nature, which is ideal for the use in photovoltaic applications.

Multilayer technology relies heavily on the chemical compatibility of metal and ceramic. This work focuses on the ceramic–electrode interaction between 92Bi0.5Na0.5TiO3–6 BaTiO3–2K0.5Na0.5NbO3 [(Bi0.46Na0.47Ba0.06K0.01)(Nb0.02Ti0.98)O3], a promising actuator material and forerunner to an emerging class of lead‐free actuator materials, and a silver–palladium alloy for inner electrodes, the only currently viable material for the firing temperatures necessary (1100°C). Of special concern was the high content of bismuth in the ceramic since prior investigations suggest that Bi2O3 (as well as various bismuth titanates) used as a fluxor in electroceramics are prone to forming the intermediate‐phase bismuth palladate (Bi2PdO4), which can lead to poor contacting and delamination of multilayer stacks. Remarkably, no evidence of bismuth palladate formation could be found. However, the phase relations of the bulk ceramic have proven to be quite complex. Potassium was being drained out of the bulk ceramic either constituting the secondary phase K4Na2(TiO3)3 in unmodified experiments or evaporating and being replaced by silver in samples in contact with Ag. Mechanisms for the formation of these phases or the lack thereof are proposed. These findings were obtained by XRD, TG‐DSC, and SEM with EDX, and LA‐ICPMS.

The reaction of di(t)butyldichlorostannane with 5 equivalents of magnesium leads to 1,1,2,2,3,3,4-hepta-(t)butyl-4-(chloromagnesio)-tetrastannacyclobutane 1. A mechanism of this reaction is proposed. 1 is structurally characterized by 1D and 2D (119)Sn NMR experiments. New monofunctionalised four membered cyclostannanes could be obtained by derivatisation of 1. X-Ray analysis of 1,1,2,2,3,3,4-hepta-(t)butyl-4-methyl-tetrastannacyclobutane 2 and 1,1,2,2,3,3,4-hepta-(t)butyl-4-chlorpropyl-tetrastannacyclobutane 5 show bent ring systems with folding angles about 157 degrees. (C) 2009 Elsevier B.V. All rights reserved.