Alcoholic OH Groups Research Articles

Chemical transformations supported by the [Re6(μ3-Se)8]2+ cluster core

This Perspective article discusses three interesting chemical transformations promoted by the octahedral [Re(6)(μ(3)-Se)(8)](2+) cluster core. These include (1) nucleophilic addition of alcohols to cluster-bound nitrile(s) to produce imino ester complexes; (2) synthesis of cluster-imine complexes with geometric specificity by reacting cluster nitrile solvates with organic azides; and (3) preparation and reactivity studies of carbonyl complexes of the cluster. We found that cluster-bound nitrile ligands were activated toward nucleophilic attack by methanol or ethanol, affording predominantly the Z-configured cluster-imino ester complexes, for which a mechanism evoking bifurcated hydrogen bonding interactions involving both the alcohol OH group and two nearest Se atoms of the cluster core was proposed. When reacted with organic azides, cluster-bound nitrile ligands were displaced and cluster-imine complexes were obtained, presumably through the formation of the corresponding cluster-azide complexes, followed by their photodecomposition. Lastly, cluster complexes featuring all-terminal carbonyl ligands were synthesized. Back-bonding interactions were verified, both experimentally and by computational studies. Their thermal and photo-stabilities were also evaluated, so was their reactivity toward methyl lithium for the eventual making of cluster-carbene catalysts. These findings, together with those by others, portend an exciting, new direction in the chemistry of solid-state type transition metal clusters.

Decolourization, degradation and detoxification of textile dyes by Aspergillus species

Decolourization, degradation and detoxification of four textile dyes (Madonna Blue, Pagoda Red, Market Blue and Market Red) by four Aspergillus species was carried out. The decolourization/degradation ability of the isolates was analyzed on the fifth day using UV/Visible spectrophotometer and FTIR spectrophotometer, while detoxification of the dyes was determined using phytotoxicity test. At the initial concentration of 200 mg/L of the dyes, the percentage decolourization potential of the fungal isolates ranged between 80.89 and 86.26% for Madonna Blue, 71.38–84.76% for Market Red, 70.46–79.46% for Market Blue and 60.68–74.82% for Pagoda Red in decreasing order. Aspergillus fumigatus (8F) demonstrated consistently highest decolourization potential for all the dyes than other isolates. Decrease in percentage decolourization of the dyes was observed when the concentration of the dyes was increased gradually from 100 to 500 mg/L at 100 mg/L interval. Percentage decolourization of Pagoda Red reduced from 60.68 to 10.31%, 66.47 to 19.71%, and 74.82 to 26.19% with A. ustus (3D), A. fumigatus (3E) and A. fumigatus (8F) respectively. Degradation of the dyes moiety using FTIR spectrum showed loss of functional groups such as C=O, C=N, C=C and C–H stretch of benzene, with the formation of new functional groups such as N=O group, C≡C group and OH group of alcohol in the Madonna Blue and Pagoda Red samples treated with A. fumigatus (8F) when compared with untreated samples. Phytotoxicity study of the treated and untreated dye samples on maize germination showed the plumule and radicle length of positive control (water) to be 12.38 ± 1.20 and 5.62 ± 0.33 while untreated Madonna Blue was 6.68 ± 1.10 and 3.34 ± 0.92, A. fumigatus (3E) treated sample had 8.60 ± 0.59 and 4.32 ± 0.91 respectively. This study revealed the metabolic versatility of Aspergillus species to decolourize, degrade and detoxify textile dyes.

Highly Selective Chemical Vapor Sensing by Molecular Recognition: Specific Detection of C1–C4 Alcohols with a Fluorescent Phosphonate Cavitand

Fiat lux on alcohols: Molecular-level resolution was achieved for the detection of short-chain alcohols in the vapor phase using a fluorescent cavitand sensor. The transduction mechanism, activated exclusively by the complexation mode, is provided by the change of the electronic density on the fluorophore caused by the formation of an intracavity hydrogen bond between the cavitand PO and the alcohol OH group.

Bond dissociation energies for removal of the hydroxyl group in some alcohols from quantum chemical calculations

AbstractIn this theoretical work, 22 alcohols and their geometric structure properties have been investigated employing quantum chemical methods to calculate the COH equilibrium bond distances and bond dissociation energies (BDEs). Since DFT methods have been researched to have low basis sets sensitivity for small and medium molecules in our previous work (Zhao et al., J Mol Struct, 2006, 766, 87), 22 title compounds have been studied by employing the hybrid density functional theory (B3LYP, B3PW91, B3P86, PBE1PBE) in conjunction with the 6‐311G** basis set and the complete basis set (CBS–Q) method. Comparison with the available experimental data shows that CBS–Q and B3P86 methods calculated results agree very well with the experimental values, with the average absolute errors of 1.3 kcal/mol and 3.5 kcal/mol, respectively. So considering the expensive computational time, CBS–Q method can be chosen as a satisfactory method of predicting the accurate BDEs for removal of the OH group in small and medium size alcohols. And B3P86 method may give accurate BDEs for larger alcohols we haven't studied. © 2011 Wiley Periodicals, Inc. Int J Quantum Chem, 2011

MgCl2.6PhCH2OH – A new molecular adduct as support material for Ziegler–Natta catalyst: synthesis, characterization and catalytic activity

Benzyl alcohol has been used to prepare a single phase MgCl(2).6BzOH molecular adduct as a support for an ethylene polymerization catalyst (Ziegler catalyst). The structural, spectroscopic and morphological aspects of the MgCl(2).6BzOH molecular adduct and the Ziegler catalyst have been thoroughly studied by various physicochemical characterization techniques. The presence of MgO(6) octahedrons due to the interaction of Mg(2+) with six -OH groups of the benzyl alcohol is confirmed from a Raman feature at 703 cm(-1), and structural studies. The supported catalyst activity has been evaluated for the ethylene polymerization reaction. The lower polymerization activity of the titanated Ziegler-Natta catalyst compared with a standard catalyst is attributed to the strong interaction of titanium chloride with the support and associated electronic factors.

Estimation of the thermodynamic parameters of hydrogen bonding in alcohol solutions by the method of infrared spectroscopy

Hydrogen bonding (H-bonding) is a specific type of intermolecular interaction being formed for favorable mutual orientations of the interacting molecules. One of the authors had developed a model concept relating the H-bonding energy with the change of stretching vibrations Δν = νOH − νOH-NC of the alcohol OH-group in acetonitrile and acetone solutions: ΔH = 89.24Δν/ν0. The calculated H-bond energy was 10.45 kJ/mole for acetonitrile and ΔH = 12.12 kJ/mole for acetone. The results obtained are compared with the data calculated using the equilibrium constant of H-bonding reaction; they can also be used to calculate all other thermodynamic H-bond parameters by measuring the equilibrium constant K c in a certain temperature interval. The equilibrium constant is calculated from the Lambert–Bouguer–Beer law: $ {K_c} = \frac{{{C_{{\text{OH}} \cdots {\text{NC}}}}}}{{{C_{\text{OH}}} \cdot {C_{\text{NC}}}}} $ , ∆F = −RT ⋅ ln K c , ∆H = RT 2 ⋅ d(lnK c )/dT, and $ \Delta S = \frac{{\Delta H - \Delta F}}{T} $ . For the methanol solution in acetonitrile, Δν = 115 cm−1, ΔH = 10.87 kJ/mole, and K c = 42 L/mole. For the ethanol solution in acetonitrile, Δν = 118 cm−1, ΔH = 10.01 kJ/mole, and K c = 34 L/mole. For the propanol solution in acetonitrile, Δν = 110 cm−1, ΔH = 8.36 kJ/mole, and K c = 13 L/mole. All calculations are performed using the developed programs. The spectra are recorded on Perkin-Elmer-180 and Specord-84 IR-spectrometers. The values of the thermodynamic parameters calculated and estimated from K c – f(T) are in good agreement with each other and with the available literature data.

Decatungstodivanadogermanic heteropoly acid (H6GeW10V2O40.22H2O): A novel, green and reusable catalyst for efficient acetylation of alcohols and phenols under solvent-free conditions

Decatungstodivanadogermanic acid (H 6 GeW 10 V 2 O 40 .22H 2 O) was used as a novel and green heterogeneous catalyst for the acetylation of hydroxy compounds under solvent-free conditions at room temperature. Efficient and selective acetylation of various alcohols and phenols was conducted with acetic anhydride as an acetylating agent over H 6 GeW 10 V 2 O 40 .22H 2 O under solvent-free conditions. All acetylated products were selectively obtained in excellent yields with very short reaction times. The reaction times were longer for the acetylation of phenols than for alcohols, so that an alcoholic OH group could be selectively acetylated in the presence of a phenolic OH group by the appropriate choice of reaction time. The catalyst can be recycled several times without observable loss of activity and selectivity.

Enrichment of H217O from Tap Water, Characterization of the Enriched Water, and Properties of Several 17O-Labeled Compounds

A low-abundance form of water, H(2)(17)O, was enriched from 0.04% to ∼90% by slow evaporation and fractional distillation of tap water. The density and refractive index for H(2)(17)O are reported. Gas chromatography-mass spectrometry (GC-MS) of (16)O- and (17)O-1-hexanols and their trimethyl silyl ethers and of (16)O- and (17)O-hexamethyl disiloxanes was used to determine the percentage of (17)O enrichment in the H(2)(17)O. Furthermore, the chemical shifts of labeled and nonlabeled water dissolved in CDCl(3) differed sufficiently that we could verify the enrichment of H(2)(17)O. (17)O hexanol was synthesized by the reaction of iodohexane with Na(17)OH. (17)O-Labeled trimethylsilanol and (17)O-labeled hexamethyldisiloxane were prepared by the reaction of H(2)(17)O with bis(trimethylsilyl)trifluoroacetamide (BSTFA). To generate standards for (17)O NMR, H(2)(17)O(2), and (17)O camphor were prepared. H(2)(17)O was electrolyzed to form (17)O-labeled hydrogen peroxide which was quantified using two colorimetric assays. (17)O-Labeled camphor was prepared by exchanging the ketone oxygen of camphor using H(2)(17)O. The (17)O-labeled compounds were characterized using (17)O, (1)H, and (13)C NMR and GC-MS. While we were characterizing the labeled camphor, we also detected an unexpected oxygen exchange reaction of primary alcohols, catalyzed by electrophilic ketones such as camphor. The reaction is a displacement of the alcohol OH group by water. This is an example of the usefulness of (17)O NMR in the study of a reaction mechanism that has not been noticed previously.

Synthesis of epoxy resins from alcohol‐liquefied wood and the mechanical properties of the cured resins

AbstractNew wood‐based epoxy resins were synthesized from alcohol‐liquefied wood. Wood was first liquefied by the reaction with polyethylene glycol and glycerin. The alcohol‐liquefied wood with plenty of hydroxyl groups were precursors for synthesizing the wood‐based epoxy resins. Namely, the alcoholic OH groups of the liquefied wood reacted with epichlorohydrin under alkali condition with a phase transfer catalyst, so that the epoxy groups were put in the liquefied wood. The wood‐based epoxy resins and the alcohol‐based epoxy resins as reference materials were cured with polyamide amine. The glass transition temperature (Tg), the tensile strength, and the modulus of elasticity of the wood‐based epoxy resin were higher than those of the alcohol‐based epoxy resin. Also, the shear adhesive strength of the wood‐based epoxy resin to steel plates was higher than those of the alcohol‐based epoxy resins, which was equivalent to the level of petroleum‐based bisphenol‐A type epoxy resins. The higher Tg of the wood‐based epoxy resin than that of the alcohol‐based epoxy resin is one of the evidences that the wood‐derived molecules were chemically incorporated into the network structures. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2011

Nucleotide Recognition and Phosphate Linkage Hydrolysis at a Lipid Cubic Interface

Mononucleotides, when entrapped within a mono-olein-based cubic Ia3d liquid crystalline phase, have been found to undergo hydrolysis at the sugar-phosphate ester bond in spite of their natural inertness toward hydrolysis. Here, kinetics of the hydrolysis reaction and interactions between the lipid matrix and the mononucleotide adenosine 5'-monophosphate disodium salt (AMP) and its 2'-deoxy derivative (dAMP) are thoroughly investigated in order to shed some light on the mechanism of the nucleotide recognition and phosphate ester hydrolysis. Experiments evidenced that molecular recognition occurs essentially through the sn-2 and the sn-3 alcoholic OH groups of mono-olein. As deduced from the apparent activation energies, the mechanism underlying the hydrolysis reaction is the same for AMP and dAMP. Nevertheless, the reaction proceeds slower for the latter, highlighting a substantial difference in the chemical behavior of the two nucleotides. A model that explains the hydrolysis reaction is presented. Remarkably, the hydrolysis mechanism appears to be highly specific for the Ia3d phase.

Tri- and Tetranuclear Nickel(II) Inverse Metallacrown Complexes Involving Oximato Oxygen Linkers: Role of the Guest Anion (Oxo versus Alkoxo) in Controlling the Size of the Ring Topology

A trinuclear oximato complex, [(NiHL(1))(3)(μ(3)-O)]ClO(4) (1), with inverse metallacrown 9-MC-3 topology has been synthesized using a Schiff-base ligand (H(2)L(1)) formed by condensation of ethanolamine (Hea) and diacetylmonoxime (Hdamo). The diamagnetic compound has been characterized by electrospray ionization mass spectrometry as well as by single-crystal X-ray diffraction analysis. In the solid state, the alcoholic OH group in this molecule stays away from coordination. Surprisingly in a similar chemical reaction, when intact Hea and Hdamo have been used as ligands instead of their Schiff-base forms, the product obtained is a 12-MC-4-type metallacrown, (Et(3)NH)[Ni(4)(damo)(4)(Hea)(2)(ea)(2)](ClO(4))(3) (2), with a larger cavity size needed to accommodate a pair of hydrogen-bonded (O-H···O)(-) anions. Unlike in 1, the alcoholic OH groups in 2 take part in metal coordination. Compound 2 on being refluxed with lithium hydroxide in methanol is converted to 1 in almost quantitative yield. This appears to be a novel reaction type, leading to contraction of a metallacrown ring size. A family of 12-MC-4 Ni(4) metallacrowns in inverse topology, viz., [Ni(4)(damo)(4)(H(2)dea)(2)(Hdea)(2)](ClO(4))(2)·2H(2)O (3), [Ni(4)(dpko)(4)(Hea)(2)(ea)(2)](ClO(4))(2)·4H(2)O (4), and [Ni(4)(mpko)(4)(Hmea)(2)(mea)(2)](ClO(4))(2) (5), have been synthesized following a methodology similar to that adopted for 2, using different combinations of free oximes [viz., dipyridylketonoxime (Hdpko) and methylpyridylketonoxime (Hmpko)] and amino alcohols [viz., diethanolamine (H(2)dea), and N-methylethanolamine (Hmea)]. Crystal and molecular structures of 3-5 have been reported, each involving either a quasi (in 3) or a perfect (in 4 and 5) square plane (S(4) symmetry) with four octahedral Ni centers occupying the corners, and serve as a backbone of puckered metallacrown rings that accommodate a pair of hydrogen-bonded (O-H···O)(-) anions. Antiferromagnetic interactions within the [Ni(4)] core [J/k(B) ≈ -20 to -27 K based on the following spin Hamiltonian: H = -2J(S(1)·S(2) + S(2)·S(3) + S(3)·S(4) + S(4)·S(1))] lead to an S(T) = 0 ground state for these complexes.

Copper(II) coordination chemistry of 2-methyl-2-(2-pyridyl)-1,3-propan-diol: Syntheses and structures of mono-, di-, and tricopper complexes

Six copper(II) complexes with N,O-donor ligand 2-methyl-2-(2-pyridyl)-1,3-propan-diol (H 2ppdo) were synthesized and characterized. Treatment of CuCl 2 or Cu(OTf) 2 with H 2ppdo led to the formation of bis(H 2ppdo) monomers [Cu(H 2ppdo) 2][CuCl 4] ( 1) and [Cu(H 2ppdo) 2](OTf) 2 ( 2), respectively. Both 1 and 2 are comprised of the copper atom coordinated by two ligands in an axially-compressed tetragonal geometry with the pyridyl N atoms in the axial positions and the alcohol O atoms in the equatorial plane. The treatment of 1 or 2 with Et 3N produced copper(II) complexes of varying nuclearity. Treatment of 1 with excess Et 3N generated two binuclear Cu(II) clusters [Cu 2(Hppdo) 2Cl 2] ( 3) and [Cu 2(Hppdo) 2Cl 2(CH 3OH) 2] ( 4), where only one alcohol OH group per ligand has been deprotonated, while similar treatment of 2 with excess Et 3N afforded the trimeric copper(II) species [Cu 3(Hppdo) 4](OTf) 2 ( 5). The structures of 3 and 4 are similar, with alkoxo-O ligand atoms bridging between two square pyramidal copper atoms, and the alcohol-O ligand atoms either coordinating in the axial position in 3, or uncoordinated in 4. Treatment of CuCl 2 with H 2ppdo and Et 3N afforded the trinuclear Cu(II) complex, [Cu 3(Hppdo) 4]Cl 2 ( 6). Complexes 5 and 6 are made up of one square-planar copper sandwiched between two tetragonally distorted six-coordinate Cu(Hppdo) 2 moieties, where the bridging alkoxo-O atoms link the copper atoms.

Infrared spectroscopy of methanol-hexane liquid mixtures. II. The strength of hydrogen bonding

The study by Fourier transform infrared attenuated total reflectance spectroscopy at 27 degrees C of methanol (MeOH) and hexane mixtures is presented. In the 0-0.25 and 0.75-1.00 molar fractions, the mixtures form homogeneous solutions, whereas from 0.25 to 0.75, the mixtures are inhomogeneous forming two phases. These mixtures have the near 3300 cm(-1) OH stretch band only slightly displaced throughout the whole concentration range indicating very little variation in the H-bonding condition. This result is very different from that of MeOH in CCl(4) where the OH stretch bands are scattered in a wide frequency range. Factor analysis applied to the MeOH/hexane spectra gave seven principal factors (one hexane and six methanol factors) and retrieved their principal spectra and abundances. In the inhomogeneous region, the two phase volumes changed inversely with concentration, but their factor compositions are invariable at 1:3 and 3:1 molar ratios. Five of the six principal methanol factors have the O-H and the C-O stretch bands situated near, respectively, 3310 and 1025 cm(-1) with little displacement in the whole concentration range. The sixth factor observed at 3654 cm(-1) (full width at half height<40 cm(-1)) was assigned to free methanol OH by Max and Chapados [J. Chem. Phys. 128, 224512 (2008)]. This species concentration is very low but constant at around 0.01 M in the methanol range of 0.5-2.5 M. The main OH stretch bands (approximately 3300 cm(-1)) were simulated with six Gaussian components that were assigned to different hydrogen-bonding situations. These form reverse micelles at low methanol concentrations and micelles at high concentrations that persist in pure methanol. A very different state of affairs exists in MeOH in CCl(4) where free OH groups are formed in almost all mixtures except in pure MeOH. Since hexane is a better model of a lipidic milieu than CCl(4), the results for MeOH/hexane give a better representation of the fate of alcoholic OH groups in such a milieu.

Ethanol adsorption on MgO surface with and without defects from a theoretical point of view

In this work, the ethanol adsorption on a perfect MgO(1 0 0) surface, and also on topologic surface defects of MgO, is studied. Terrace, edge and corner sites were analyzed, whose O and Mg ions are five, four and three fold coordinated, respectively. All the calculations were performed using a cluster approach and the DFT based method. The ethanol molecule chemisorbs non-dissociatively on terrace sites of MgO by means of a two fold interaction while strong dissociative chemisorptions are produced on edge and corner sites. The weakened alcohol OH group is always oriented so that its oxygen (O a) atom is linked to a Mg cation and the H atom to a surface O anion. The Mg O a distance for edge and corner sites is smaller than that for the terrace site. This indicates that lowering the coordination number of ions in the adsorption site yields an increase of molecule-surface bond strength in agreement with a greater basicity of low coordinate sites. The behavior of the adsorption energy and the charge transfers are in accord with the idea of a strong basic character for the MgO substrate, which is more pronounced as the coordination number of ions decrease.

Surfactant Control of Gas Transport and Reactions at the Surface of Sulfuric Acid

Aerosol particles in the atmosphere are tiny chemical reactors that catalyze numerous reactions, including the conversion of benign gases into ozone-destroying ones. In the lower stratosphere, these particles are often supercooled mixtures of water and sulfuric acid. The different species present at the surface of these droplets (H(2)O, H(3)O(+), HSO(4)(-), H(2)SO(4), and SO(4)(2-)) stand at the "gas-liquid frontier"; as the first to be struck by impinging molecules, these species provide the initial environment for solvation and reaction. Furthermore, aerosol particles may contain a wide range of organic molecules, some of which migrate to the surface and coat the droplet. How do ambient gases dissolve in the droplet if it is coated with an organic layer? At one extreme, monolayer films of insoluble, long-chain alcohols can dramatically reduce gas transport, packing so tightly at the surface of water that they impede water evaporation by factors of 10,000 or more. Shorter chain surfactants are expected to pack less tightly, but we wondered whether these incomplete monolayers also block gas transport and whether this system could serve as a model for understanding the surfaces of atmospheric aerosol particles. To address these questions, our research focuses on small, soluble surfactants such as butanol and hexanol dissolved in supercooled sulfuric acid. These amphiphilic molecules spontaneously segregate to the surface and coat the acid but only to a degree. Gas-liquid scattering experiments reveal that these porous films behave in surprisingly diverse ways: they can impose a barrier (to N(2)O(5) hydrolysis), be "invisible" (to water evaporation), or even enhance gas uptake (of HCl). The transition from obstacle to catalyst can be traced to specific interactions between the surfactant and each gas. For example, the hydrolysis of N(2)O(5) may be impeded because of its large size and because alcohol molecules that straddle the interface limit contact between N(2)O(5) and its H(3)O(+) and H(2)O reaction partners. However, these same alcohol molecules assist HCl dissociation because the alcohol OH groups provide extra interfacial protonation sites. Interestingly, butanol does not impede water evaporation, in part because the butyl chains pack much more loosely than insoluble, long-chain surfactants. Through these investigations, we hope to gain insight into the mechanisms by which surfactants on sulfuric acid and other aqueous solutions affect transport and reactivity at the gas-liquid interface.

Toward an Allosteric Metallated Container

AbstractPolytopic ligands L1 and L2 in which three 2,2′‐bipyridine units are linked to a central tris(pyrid‐2‐yl)amine (L1) or tris(pyrid‐2‐yl)methanol (L2) moiety by alkyl spacers were prepared by multistep organic syntheses. The parent tris(pyrid‐2‐yl)‐type ligands were shown to be modest‐to‐good chelators for Zn2+ and Cu2+ ions in solution, and bi‐ and tridentate N‐coordination was confirmed by crystal structures of CuII and RuII complexes, respectively. FeII and RuII smoothly form stable, cage‐like 1:1 complexes with L1 and L2, in which the metal ion is coordinated to the tris(bpy) site of the ligands. The vacant tris(pyrid‐2‐yl) site of these complexes is, however, a poor donor site for Zn2+ and Cu2+ ions. In addition, FeII modulates the coordination behaviour of the tris(pyrid‐2‐yl) site toward Zn2+: Whereas tris(5‐methylpyrid‐2‐yl)amine forms a 2:1 complex with Zn2+ in CH2Cl2, [Fe(L1)]2+ forms a 1:1 Zn complex. Spectrophotometric titrations suggest that [Fe(L2)]2+ forms a polynuclear Zn2+ complex in CH2Cl2, possibly involving bridging coordination of the alcohol OH group, which contrasts the smooth formation of a 2:1 complex of the parent tris(pyrid‐2‐yl)‐type ligand with Zn. FeII might therefore be considered as an allosteric effector, which modulates the metal binding properties of the second tris(pyrid‐2‐yl) site of L1 and L2. Contrary to expectation, Zn2+ and Cu2+ appear to associate weakly with donor atoms directed toward the exterior of the cage‐like complexes [Fe(Ln)]2+ and [Ru(L1)]2+, rather than locating in the interior of the container by tripodal coordination to the tris(pyrid‐2‐yl) site.(© Wiley‐VCH Verlag GmbH &amp; Co. KGaA, 69451 Weinheim, Germany, 2009)

Crystallization of strontium carbonate in alcohol or water solution containing mixed nonionic/anionic surfactants

The crystallization of strontium carbonate is performed in aqueous solution or alcohol/water solution in the presence of mixed nonionic/anionic surfactants Pluronic F127/sodium dodecyl sulfate. With an increase of the volume ratio of ethanol/water, SrCO 3 pancakes transform into flowers, and then to irregular flakes. X-ray diffraction (XRD) pattern reveals that both of pancake-like and flower-like SrCO 3 particles are orthorhombic phases. Larger pancakes with porous structure are produced when the content of ethylene glycol reaches a relatively high value. Results indicate that –OH groups of alcohol play an important role in morphological controlling of SrCO 3.

Effect of varying water content on the structure of butyl alcohol/water mixtures: FT-NIR two-dimensional correlation and chemometric studies

Effect of varying water content on the structure of butyl alcohol/water mixtures has been examined by Fourier-transform near-infrared (FT-NIR) spectroscopy. The experimental spectra were analyzed by two-dimensional (2D) correlation and chemometric methods. Our results do not provide evidences for the presence of significant amounts of water free from any specific interactions. The molecules of water predominantly form two hydrogen bonds between different associates of alcohol. This way, the structure of liquid alcohols becomes more stable. Our previous and current studies did not reveal a meaningful reduction in the population of the free OH groups of alcohols on addition of water. The free OH groups of water are present in the mixtures at all studied water contents and they originate mostly from the molecules acting as a single proton donor. The population of molecules of water that act as a proton acceptor is limited. The hydrogen bonds between water and alcohol are broken more easily in s-BuOH and t-BuOH and hence, the number of the free OH groups of water in these alcohols is higher than that in the primary alcohols. This results from smaller degree of self-association in s-BuOH and t-BuOH relative to that in the primary butanols. At higher water content the water–water interactions become more important. The clusters of water are created around the molecules of water attached to the terminal molecules of alcohol leading to decrease in the population of the free OH groups of water.

The chemistry of the processes involved in the production of lanthanide titanates by the polymerized-complex method

The composition, some spectral characteristics, and thermal decomposition of solid lanthanide–titanium (lanthanide (Ln) = Y, La, Ce) and lanthanide–titanium citrates (CA) and tartrates (TA) have been studied. The complexes have been prepared in ethylene glycol medium at conditions modeling those of the polymerized-complex method applied for Ln2Ti2O7 preparation. Special attention has been paid to the chemical nature of the bimetallic products as well as to the factors influencing the deprotonation of the alcoholic OH groups of the acidic ligands. The results contribute to further elucidation of the complexation and thermal decomposition processes involved in the polymerized-complex method.Key words: inorganic compounds, sol–gel chemistry, infrared spectroscopy, nuclear magnetic resonance, thermogravimetric analysis (TGA).

Enzymatic Synthesis of α-Anomer-SelectiveD-Glucosides Using Maltose Phosphorylase

A maltose phosphorylase (EC 2.4.1.8; MPase) showed novel acceptor specificity and transferred the glucosyl moiety of maltose not only to sugars but also to various acceptors having alcoholic OH groups. Salicyl alcohol acted as acceptor for MPase from Enterococcus hirae, and the product, salicyl-O-alpha-D-glucopyranoside (alpha-SalGlc) was identified. The yield based on supplied salicyl alcohol was 86% (mol/mol).