Chemical Bonds Formed in Solid Wood by Reaction with Maleic Anhydride and Sodium Hypophosphite.

The reaction of wood with maleic anhydride (MA) and sodium hypophosphite (SHP) has been identified as a viable modification method, with macroscopical properties indicating formation of cross-linking to explain the results. However, the chemical reaction between wood and the modification reagents has not been studied yet. To resolve this, the reaction was studied with solid-state C cross-polarization magic-angle-spinning (CP-MAS) and P MAS nuclear magnetic resonance (NMR) and X-ray photoelectron spectroscopy (XPS) to reveal the formation of bonds between wood components, MA and SHP during the treatments to explain the formation of cross-linking and the possible fixation of phosphorus in wood.

Phosphorylated and carbamylated Kraft lignin for improving fire- and biological-resistance of Scots pine wood.

In this study, Kraft lignin was modified by ammonium dihydrogen phosphate (ADP) and urea for achieving phosphorylation and carbamylation, aiming to protect wood against biological and fire attack. Scots pine (Pinus sylvestris L.) sapwood was impregnated with a water solution containing Kraft lignin, ADP, and urea, followed by heat treatment at 150 °C, resulting in changes in the properties of the Kraft lignin as well as the wood matrix.

Dynamics and Structure of a Bitumen Emulsion as Studied by H NMR Diffusometry.

Self-diffusion in a bitumen emulsion was studied by H NMR. The emulsion forms two phases: continuous and dispersed. The continuous aqueous phase contains mainly water, with the energy of activation of the diffusion process equal to that of bulk water, while its diffusivity is smaller than that of bulk water by a factor of 2.

Molecular Architecture Effects on Bulk Nanostructure in Bis(Orthoborate) Ionic Liquids.

A series of 19 ionic liquids (ILs) based on phosphonium and imidazolium cations of varying alkyl-chain lengths with the orthoborate anions bis(oxalato)borate [BOB] , bis(mandelato)borate, [BMB] and bis(salicylato)borate, [BScB] , are synthesized and studied using small-angle neutron scattering (SANS). All measured systems display nanostructuring, with 1-methyl-3-n-alkyl imidazolium-orthoborates forming clearly bicontinuous L spongelike phases when the alkyl chains are longer than C (hexyl). L phases are fitted using the Teubner and Strey model, and diffusely-nanostructured systems are primarily fitted using the Ornstein-Zernicke correlation length model.

State of anion in ethylammonium nitrate enclosed between micrometer-spaced glass plates as studied by O and N NMR.

Some aprotic and protic ionic liquids (ILs) containing nitrate anion demonstrate unusual dynamic behavior of cations when these ILs are enclosed in micrometer-spaced layers between glass plates. We applied O and N NMR spectroscopy to discover the state and transformations of O and N isotopically enriched nitrate anion of ethylammonium nitrate (EAN) enclosed between glass plates. N NMR spectra demonstrated preferential orientation of the principal axes of the nitrate anions perpendicular to the normal of the glass surface.

High Leach-Resistant Fire-Retardant Modified Pine Wood () by In Situ Phosphorylation and Carbamylation.

The exterior application of fire-retardant (FR) timber necessitates it to have high durability because of the possibility to be exposed to rainfall. In this study, water-leaching resistance of FR wood has been imparted by grafting phosphate and carbamate groups of the water-soluble FR additives ammonium dihydrogen phosphate (ADP)/urea onto the hydroxyl groups of wood polymers via vacuum-pressure impregnation, followed by drying/heating in hot air. A darker and more reddish wood surface was observed after the modification.

Synthesis and structural characterisation of solid titanium(IV) phosphate materials by means of X-ray absorption and NMR spectroscopy.

Solid titanium phosphate, TiP, materials hold great promise for wastewater treatment for removal of metal ions and complexes. A series of TiP materials, synthesised at mild conditions and short reaction times, have been structurally characterised using solid-state X-ray absorption spectroscopy, phosphorus and titanium K edge XANES and EXAFS, and P and Ti NMR spectroscopy. The titanium K edge EXAFS data of α-Ti(HPO)·HO (α-TiP) revealed octahedral coordination of oxygens around titanium.

Structural characterisation of amyloid-like fibrils formed by an amyloidogenic peptide segment of β-lactoglobulin.

Protein nanofibrils (PNFs) represent a promising class of biobased nanomaterials for biomedical and materials science applications. In the design of such materials, a fundamental understanding of the structure-function relationship at both molecular and nanoscale levels is essential. Here we report investigations of the nanoscale morphology and molecular arrangement of amyloid-like PNFs of a synthetic peptide fragment consisting of residues 11-20 of the protein β-lactoglobulin (β-LG), an important model system for PNF materials.

Dynamics of ethylammonium nitrate near PTFE surface.

Self-diffusion of ions in the protic ionic liquid ethylammonium nitrate (EAN) was studied by H NMR pulsed field gradient techniques between 294 and 393 K in the presence of a PTFE insert in a 5-mm NMR tube. At all temperatures, the bulk diffusion of ions (measured by H and N NMR) can be described by a unique diffusion coefficient. The presence of solid hydrophobic surfaces of PTFE induces regions of EAN in their vicinity, where diffusion of ions, both cations and anions, is reduced compared to the bulk values.

Transition anionic complex in trihexyl(tetradecyl)phosphonium-bis(oxalato)borate ionic liquid - revisited.

It was found that Li[BOB]·nH2O salts were not readily suitable for the synthesis of high-purity orthoborate-based tetraalkylphosphonium ionic liquids, as exemplified here for trihexyl(tetradecyl)phosphonium bis(oxalato)borate, [P6,6,6,14][BOB]; along with [BOB]-, a metastable transition anionic complex (TAC) of dihydroxy(oxalato)borate with oxalic acid, [B(C2O4)(OH)2·(HOOC-COOH)]-, was also formed and passed into the ionic liquid in the course of the metathesis reaction with trihexyl(tetradecyl)phosphonium chloride. On the contrary, Na[BOB] was found to be a more suitable reagent for the synthesis of this IL, because [BOB]- anions safely passed into the final IL without hydrolysis, when metathesis reactions were performed using aqueous-free media. Since ultra-pure Na[BOB] is not commercially available, in this work, a preparation protocol for ultra-pure (>99%) Na[BOB] was developed: (i) molar ratios of boric and oxalic acids were optimised to minimise boron-containing impurities, (ii) the Na[BOB] product was thoroughly purified by sequential washing of a fine powder product in hot acetonitrile and ethanol and (iii) characterised using powder X-ray diffraction and solid-state 11B MAS NMR spectroscopy.

Temperature dependence of H NMR chemical shifts and diffusivity of confined ethylammonium nitrate ionic liquid.

Some ionic liquids (ILs) change their dynamic properties when placed in a confinement between polar surfaces (Filippov et al., Phys. Chem.

Diffusion of Ions in Phosphonium Orthoborate Ionic Liquids Studied by H and B Pulsed Field Gradient NMR.

Non-halogenated boron-based ionic liquids (ILs) composed of phosphonium cations and chelated orthoborate anions have high hydrolytic stability, low melting point and exceptional properties for various applications. This study is focused on ILs with the same type of cation, trihexyltetradecylphosphonium ([P]), and two orthoborate anions, such as bis(salicylato)borate ([BScB]) and bis(oxalato)borate ([BOB]). We compare the results of this study with our previous studies on ILs with bis(mandelato)borate ([BMB]) and a variety of different cations (tetraalkylphosphonium, dialkylpyrrolidinium and dialkylimidazolium).

Rapid carbene formation increases ion diffusivity in an imidazolium acetate ionic liquid confined between polar glass plates.

1-Ethyl-3-methyl-imidazolium acetate ([EMIM][OAc]) is one of the most widely used ionic liquids for various applications. This study is focussed on the chemical stability of [EMIM][OAc] on the surfaces of polar glass plates. H and C NMR spectroscopy and NMR diffusometry of [EMIM][OAc] IL confined between glass plates with a specific surface area 10-10 m are thoroughly investigated.

Non-halogenated Ionic Liquid Dramatically Enhances Tribological Performance of Biodegradable Oils.

It is demonstrated that a phosphonium orthoborate ionic liquid may serve as a wear reducing additive in biodegradable oils at steel-steel surfaces in the boundary lubrication regime. Tribological tests were performed in a ball-on-three plate configuration. A set of surface characterization techniques-SEM/EDS, FIB and white light interferometry were used to characterize surfaces following the tribotests and to observe the formation of any tribofilms.

Electro-responsivity of ionic liquid boundary layers in a polar solvent revealed by neutron reflectance.

Using neutron reflectivity, the electro-responsive structuring of the non-halogenated ionic liquid (IL) trihexyl(tetradecyl)phosphonium-bis(mandelato)borate, [P][BMB], has been studied at a gold electrode surface in a polar solvent. For a 20% w/w IL mixture, contrast matched to the gold surface, distinct Kiessig fringes were observed for all potentials studied, indicative of a boundary layer of different composition to that of the bulk IL-solvent mixture. With applied potential, the amplitudes of the fringes from the gold-boundary layer interface varied systematically.

Magnetic field effects dynamics of ethylammonium nitrate ionic liquid confined between glass plates.

Self-diffusion and NMR relaxation of the ethylammonium (EA) cation were studied in the protic ionic liquid, ethylammonium nitrate (EAN), confined between polar glass plates separated by a few μm distance and exposed to an external magnetic field of 9.4 T. The diffusion coefficient of EA (D) and the transverse NMR relaxation rate (1/T) of -NH protons were increased immediately after placing the sample in the magnetic field by factors of ∼2 and ∼22, respectively, in comparison with those of bulk EAN.

Structure and dynamics elucidation of ionic liquids using multidimensional Laplace NMR.

We demonstrate the ability of multidimensional Laplace NMR (LNMR), comprising relaxation and diffusion experiments, to reveal essential information about microscopic phase structures and dynamics of ionic liquids that is not observable using conventional NMR spectroscopy or other techniques.

Acceleration of diffusion in ethylammonium nitrate ionic liquid confined between parallel glass plates.

Diffusion of EAN confined between polar glass plates separated by a few micrometers is higher by a factor of ca. 2 as compared to bulk values. Formation of a new phase, different to the bulk, was suggested.

Dynamic properties of imidazolium orthoborate ionic liquids mixed with polyethylene glycol studied by NMR diffusometry and impedance spectroscopy.

We used H pulsed field gradient nuclear magnetic resonance to study the self-diffusion of polyethylene glycol (PEG) with average molecular mass of 200 and ions in mixtures of PEG with imidazolium bis(mandelato)borate (BMB) and imidazolium bis(oxalato)borate ionic liquids (ILs). The IL was mixed with PEG in the concentration range of 0-100 wt%. Within the temperature range of 295 to 353 K, the diffusion coefficient of BMB is slower than that of the imidazolium cation.

DFT calculations in the assignment of solid-state NMR and crystal structure elucidation of a lanthanum(iii) complex with dithiocarbamate and phenanthroline.

The molecular, crystal, and electronic structures as well as spectroscopic properties of a mononuclear heteroleptic lanthanum(iii) complex with diethyldithiocarbamate and 1,10-phenanthroline ligands (3 : 1) were studied by solid-state C and N cross-polarisation (CP) magic-angle-spinning (MAS) NMR, X-ray diffraction (XRD), and first principles density functional theory (DFT) calculations. A substantially different powder XRD pattern and C and N CP-MAS NMR spectra indicated that the title compound is not isostructural to the previously reported analogous rare earth complexes with the space group P2/n. Both C and N CP-MAS NMR revealed the presence of six structurally different dithiocarbamate groups in the asymmetric unit cell, implying a non-centrosymmetric packing arrangement of molecules.

Adsorption of Butanol and Water Vapors in Silicalite-1 Films with a Low Defect Density.

Pure silica zeolites are potentially hydrophobic and have therefore been considered to be interesting candidates for separating alcohols, e.g., 1-butanol, from water.

Experimental and First-Principles NMR Analysis of Pt(II) Complexes With O,O'-Dialkyldithiophosphate Ligands.

Polycrystalline bis(dialkyldithiophosphato)Pt(II) complexes of the form [Pt{SP(OR)}] (R = ethyl, iso-propyl, iso-butyl, sec-butyl or cyclo-hexyl group) were studied using solid-state P and Pt NMR spectroscopy, to determine the influence of R to the structure of the central chromophore. The measured anisotropic chemical shift (CS) parameters for P and Pt afford more detailed chemical and structural information, as compared to isotropic CS and J couplings alone. Advanced theoretical modeling at the hybrid DFT level, including both crystal lattice and the important relativistic spin-orbit effects qualitatively reproduced the measured CS tensors, supported the experimental analysis, and provided extensive orientational information.

Atomistic Insight into Tetraalkylphosphonium Bis(oxalato)borate Ionic Liquid/Water Mixtures. 2. Volumetric and Dynamic Properties.

Atomistic molecular dynamics simulations have been performed to investigate volumetric quantities and dynamic properties of binary trihexyltetradecylphosphonium bis(oxalato)borate ([P6,6,6,14][BOB]) ionic liquid (IL)/water mixtures with different water concentrations. The predicted liquid densities for typical [P6,6,6,14][BOB] IL/water mixtures are consistent with available experimental data with a relative discrepancy of less than 3%. The liquid densities and excess molar volumes of all studied [P6,6,6,14][BOB] IL/water mixtures are characterized by concave and convex features, respectively, within full water concentration range.

Solid-state C, N and Si NMR characterization of block copolymers with CO capture properties.

Natural abundance solid-state multinuclear ( C, N and Si) cross-polarization magic-angle-spinning NMR was used to study structures of three block copolymers based on polyamide and dimethylsiloxane and two polyamides, one of which including ferrocene in its structure. Assignment of most of the resonance lines in C, N and Si cross-polarization magic-angle-spinning NMR spectra were suggested. A comparative analysis of C isotropic chemical shifts of polyamides with and without ferrocene has revealed a systematic shift towards higher δ -values (de-shielding) explained as the incorporation of paramagnetic ferrocene into the polyamide backbone.

The effect of inositol hexaphosphate on cadmium sorption to gibbsite.

Hypothesis: Oxides, hydrous oxides and hydroxides of aluminium and iron are important in determining the availability of trace and heavy metals in soil systems. The presence of complexing anions is also known to affect the binding of these metals in soils. Since organophosphates, such as inositol hexaphosphate (IP6), are present in most soil systems they are expected to affect the nature of the interaction between metal ions and metal (hyr)oxides.