The model of alkylphenol micelles bound to respective antibodies on the solid surface

The model of binding of micelles of nonylphenol molecules to respective antibodies immobilized on the solid surface is proposed. The actual dimensions of micelles obtained from AFM measurements were used in modelling and allowed to predict the shape of the micelle. An account of non-spherical shape of micelles and their simultaneous binding to several antibodies allows estimation of the micelle binding energy.     

Thermally changing lattice distance of lamella in the hydrated solid of octadecyltrimethylammonium chloride

A temperature scanning small-angle X-ray scattering measurement was carried out for the hydrated solids of octadecyltrimethylammonium chloride (OTAC). A gradual change of the lattice spacing of lamella-like structure from 40 nm at 5 degrees C to 20 nm at 18 degrees C was observed in the melting process of the hydrated solid that was incubated at 4 degrees C for a period of 24 h in the aqueous solution, while little change of the lattice spacing of about 20 nm was observed in the same process of the hydrated solid that was incubated at 4 degrees C for a period about 10 min. This indicates structural changes of the hydrated solid during the incubation at 4 degrees C and in the melting process. Corresponding to the nanostructure changes, broad endothermic peaks were observed at temperatures from 13 to 22 degrees C for the former hydrated solid and at temperatures from 15 to 21 degrees C for the latter hydrated solid in difference scanning calorimetry measurements. The structure change at temperatures below 13 degrees C is considered to be athermal from the fact that no endothermic peak is observed there. Large dielectric dispersions at frequencies at about 10 kHz were observed for the suspensions of hydrated solids but not for the solutions of dissolved solids. It was found that the electric conductance of the hydrated solid suspensions was much lower than that of the solutions of dissolved solids. The observed electric properties indicate that an amount of the free chloride ion is very small and that the chloride ions binding to the ammonium groups are movable in the hydrated solids by responding to an applied electric field. The electric conductance of suspension of the hydrated solid being incubated at 4 degrees C for 10 min was 4 times as large as that of a suspension of the hydrated solid being incubated at the same temperature for 24 h. This indicates that the structural change of the OTAC hydrated solid at 4 degrees C is related to the chloride ion binding to the hydrated solid. The experimental results described above suggest that the lamella in the hydrated solid of OTAC is undulated and that the wavelength of undulation increases with the incubation at a temperature much lower than the melting temperature.     

New solid extractants for preconcentrating noble metals

New solid extractants are synthesized with the use of imidazolium and phosphonium ionic liquids for preconcentrating noble metals. Ionic liquids are selected and conditions for their immobilization on various solid matrices are found. The adsorption properties of the synthesized solid extractants for platinum(IV) in hydrochloric acid solutions are studied. The solid extractants obtained by binding 1-hexadecyl-3-methylimidazolium bromide and trihexyltetradecylphosphonium chloride to polymeric matrices and multiwall carbon nanotubes possess good kinetic properties and selectivity in 1 M HCl, and can be used to preconcentrate Pt(IV), Pd(II), and Au(III) in combined methods of their determination.     

A case study of solid state inhibition lock opening of pyridine N-oxide in dicarboxylic acid recognition

An ethylene-linked mixed pyridine diamide receptor 1 is synthesised to study the binding with dicarboxylic acid in solid phase. In ¹H NMR, the amide proton adjacent to pyridine N-oxide shows almost negligible shift, which suggests the non-participation of the amide proton for acid binding in solution. However, in solid phase (X-ray, IR), we have found significant role of this amide proton in binding.     

Biosorption: a new rise for elemental solid phase extraction methods

Biosorption is a term that usually describes the removal of heavy metals from an aqueous solution through their passive binding to a biomass. Bacteria, yeast, algae and fungi are microorganisms that have been immobilized and employed as sorbents in biosorption processes. The binding characteristics of microorganisms are attributed to functional groups on the surface providing some features to the biosorption process like selectivity, specificity and easy release. These characteristics turn the biosorption into an ideal process to be introduced in solid phase extraction systems for analytical approaches. This review encompasses the research carried out since 2000, focused on the employment of biosorption processes as an analytical tool to improve instrumental analysis. Since aminoacids and peptides as synthetic analogues of natural metallothioneins, proteins present in the cell wall of microorganisms, have been also immobilized on solid supports (controlled pore glass, carbon nanotubes, silica gel polyurethane foam, etc.) and introduced into solid phase extraction systems; a survey attending this issue will be developed as well in this review.     

Role of the onium ion in the heterophase alkylation of ethyl 2-methylacetoacetate in the presence of solid alkali metal fluorides

Qnium salts are efficient catalysts for the alkylation of ethyl 2-methylacetoacetate (EMAA) in the presence of solid KF. The reaction rate depends on the nature of the anion and increases in going from onium chlorides to onium bromides and iodides. Inhibition of this reaction by a phase transfer catalyst QX was found. The alkylation rate depends on the amount of solid fluoride. The optimal KF/EMAA ratio is 8. A further increase in this ratio hinders the alkylation reaction. The major functions of the catalyst were found to be weakening of the K-F bond, binding of the leaving halide, activation of the alkyl halide, and generation of the solid phase surface.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 12, pp. 2697–2701, December, 1989.     

Competitive anion binding aptitude of benzimidazole and amide functionality of a non-symmetrical receptor in solid state and solution phase

A novel non-symmetric tripodal receptor (L) with benzimidazole and amide –NH functionalities has been synthesised and a comparative study for anion binding aptitude of those functionalities has been performed in solid state and solution phase. The protonated receptors in solid state tend to form a pseudo-cavity around the octahedral hexafluorosilicate anion whilst in second complex, binding of one sulphate and two bisulphates in unison by two protonated units arises. The benzimidazole –NHs are the strongest hydrogen bond donors in both the crystals controlling dominance over amide –NHs. The neutral receptor being selective towards fluoride anion induces a naked eye visible colorimetric change. The ¹H NMR studies with the neutral and protonated form of the receptor suggest the strong involvement of amide –NH in anion binding in solution phase.     

Molecularly imprinted solid phase extraction for rapid screening of metformin

A molecularly imprinted solid phase extraction (MISPE) method has been developed for the rapid screening of metformin. Newly synthesized molecularly imprinted polymer (MIP) particles were slurry-packed into a micro-column for selective solid phase extraction (SPE) of metformin. With CH₃CN flowing at 0.5 ml/min, a total binding capacity of 1600 ng metformin was determined for the 20 mg of MIP particles. A broad range of MISPE conditions was evaluated with respect to sample solvent, pH, and buffer compositions. A 95±2% binding could be achieved from one 20-μl injection of sample solution in acetonitrile plus phosphate buffer, up to 1200 ng of metformin. However, the micro-column interacted indiscriminately with phenformin, a structural analogue, to attain 49±2% binding. Separation of phenformin from metformin was ultimately achieved, using differential pulsed elution (DPE) with 1 M trifluoromethacrylic acid in acetonitrile. Final pulsed elution (FPE) using 3% trifluoroacetic acid in methanol was good for the quantitative elution of metformin. The MISPE–DPE–FPE method, with UV detection at 240 nm, afforded a detection limit of 0.8 μg/ml (or 16 ng) for metformin. Each MISPE–DPE–FPE analysis required less than 5 min to complete.     

X-ray photoelectron spectroscopic studies of solid electrolytes

A study of solid electrolytes by X-ray photoelectron spectroscopy reveals that silver (I) and copper (I) compounds generally show very small shifts in electron binding energies. The complex crystal structure of the β-aluminas, however, gives rise to different cation sites which can be distinguished by this technique. Calculations of self-potential show the importance of this term for determining shifts. The possibility of determining the partial ionic charge from the measured shift is also considered.     

Interaction of methanol with amorphous solid water

The interaction of methanol (MeOH) with amorphous solid water (ASW) composed of D2O molecules, prepared at 125 K on a polycrystalline Ag substrate, was studied with metastable-impact-electron spectroscopy, reflection-absorption infrared spectroscopy, and temperature-programmed desorption mass spectroscopy. In connection with the experiments, classical molecular dynamics (MD) simulations have been performed on a single CH3OH molecule adsorbed at the ice surface (T=190 K), providing further insights into the binding and adsorption properties of the molecule at the ice surface. Consistently with the experimental deductions and previous studies, MeOH is found to adsorb with the hydroxyl group pointing toward dangling bonds of the ice surface, the CH3 group being oriented upwards, slightly tilted with respect to the surface normal. It forms the toplayer up to the onset of the simultaneous desorption of D2O and MeOH. At low coverage the adsorption is dominated by the formation of two strong hydrogen bonds as evidenced by the MD results. During the buildup of the first methanol layer on top of an ASW film the MeOH-MeOH interaction via hydrogen-bond formation becomes of importance as well. The interaction of D2O with solid methanol films and the codeposition of MeOH and D2O were also investigated experimentally; these experiments showed that D2O molecules supplied to a solid methanol film become embedded into the film.     

Theoretical studies on the smallest fullerene: from monomer to oligomers and solid States

Hybrid B3LYP and density-functional-based tight-binding (DFTB) computations on the solid-state structures and electronic properties of the C(20) fullerene monomer and oligomers are reported. C(20) cages with C(2), C(2h), C(i), D(3d), and D(2h) symmetries have similar energies and geometries. Release of the very high C(20) strain is, in theory, responsible for the ready oligomerization and the formation of different solid phases. Open [2+2] bonding is preferred both in the oligomers and in the infinite one-dimensional solids; the latter may exhibit metallic character. Two types of three-dimensional solids, the open [2+2] simple cubic and the body-centered cubic (bcc) forms, are proposed. The energy of the latter is lower due to the better oligomer bonding. The open [2+2] simple cubic solid should be a conductor, whereas the bcc solids are insulators. The most stable three-dimensional solid-state structure, an anisotropically compressed form of the bcc solid, has a HOMO-LUMO gap of approximately 2 eV and a larger binding energy than that of the proposed C(36) solid.     

Study on the phosphorescence characterizations of palmatine chloride on the solid substrate and its interaction with ctDNA

The spectroscopic characterizations of solid substrate room temperature phosphorescence (SS-RTP) of palmatine (Pal) have been studied. Strong RTP signal at 615 nm can be induced on filter paper in the presence of TIAc. The interaction between calf thymus DNA (ctDNA) and Pal has been investigated at pH 6.90 using fluorescence, UV-vis, SS-RTP and cyclic voltammogram spectroscopy. Strong binding affinity of Pal with DNA is revealed from the absorption and fluorescence studies in the liquid state. With the addition of ctDNA, the fluorescence intensity of Pal is enhanced greatly and UV-vis spectra show no apparent hypochromicity and red shift, which indicates that Pal intercalates into ctDNA bases. However, this conclusion could not explain the phenomena from fluorescence polarization and denatured DNA measurements, which indicate that groove binding is at least the main binding mode. Binding constant and binding site size have been calculated to be 2.57 × 10⁴ L/mol and 0.16 based on Scatchard plot from fluorescence titration data. Groove binding has also been supported by phosphorescence lifetime and anion quenching experiments. Above studies demonstrate that there should exist intercalative binding and groove binding in the interaction of Pal and DNA. Furthermore, cyclic voltammogram study suggests that electrostatic binding exists at the same time exactly. Taken together, the binding model obtained in this study is mixed-mode.     

Design and synthesis of a dual linker for solid phase synthesis of oleanolic acid derivatives

A hydrophilic amino-terminated poly(ethylene glycol)-type dual linker for solid phase synthesis of oleanolic acid derivatives using trityl chloride resin was designed and synthesized for the first time. Model reactions in both liquid and solid phase were performed to show the feasibility of its selective cleavage at two different sites. The biological assay results indicated that the long and flexible alkyl ether functionality in the linker is less likely to be critical for the binding event. Following the successful solid-phase synthesis of model compounds, the potential of this dual linker in reaction monitoring and target identification is deemed worthy of further study.     

Thermophoretic motion of a solid spherical particle near a solid planar surface

The thermophoretic motion of a solid spherical aerosol particle directed normally to an infinite planar solid surface is analyzed. The solution is performed in a bispherical coordinate system with allowance for linear corrections in the Knudsen number. The finite thermal conductivity of a solid body is taken into account in the analysis.     

Preparative manipulation of gold nanoparticles by reversible binding to a polymeric solid support

A preparative scheme is presented for controlled modification of gold nanoparticles (NPs) by using reversible binding to a polymeric solid support through boronic acid chemistry. Octanethiol-capped Au NPs were bound to a boronic acid functionalized resin by custom-synthesized bifunctional linker molecules. The NPs were chemically released from the resin to the solution, with one (or a few) linker molecules embedded in their capping layer. This was confirmed by rebinding the linker-derivatized NPs to a boronic resin, exploiting the reversibility of the boronic acid/diol chemistry. The same scheme was employed to demonstrate a new method for affinity separation of NPs by means of a solid-phase reaction. The use of boronic acid provides versatility and chemical reversibility, while the polymeric solid support affords the separation and preparative aspects. The method presented here may be useful in various facets of NP handling, manipulation, and separation.     

Reflectometry in kinetic studies of immunological and enzymatic reactions on solid surfaces

An optical method is described, by means of which immunological and enzymatic reactions can be followed at a primary level on a solid surface, without labelling procedures. When plane-polarized light is reflected at a solid surface, there is a minimum in reflectance at a certain angle of incidence, the pseudo-Brewster angle. For example, a layer of protein adsorbed on a silicon surface increases the reflectance with increasing amount of adsorbed material. High sensitivity is obtained because of the large difference in refractive index between silicon and organic material; about 0.1 μg cm^?2 adsorbed protein can be detected. In a model system of human IgG and anti-human IgG, the primary adsorption of IgG on a hydrophobic surface is first measured, and on this IgG-coated surface the binding kinetics of anti-IgG could be measured. The kinetics of proteolytic degradation of IgG-coated surfaces by trypsin was also investigated.     

Enthalpimetric measurements in solid—solid reactions. VII. A study of the uranyl acetate—phenylurea system

The solid—solid interaction reactions between uranylacetate and phenylurea have been investigated by DSC. The associated ΔH values, apparent activation energy and apparent reaction order have been evaluated. The kinetic parameters suggest that the solid—solid interaction can be considered to be a chemically-controlled process.     

Spectroscopic and structural characterization of the CyNHC adduct of B2pin2 in solution and in the solid state

The Lewis base adduct of B(2)pin(2) and the NHC (1,3-bis(cyclohexyl)imidazol-2-ylidene), which was proposed to act as a source of nucleophilic boryl groups in the β-borylation of α,β-unsaturated ketones, has been isolated, and its solid state structure and solution behavior was studied. In solution, the binding is weak, and NMR spectroscopy reveals a rapid exchange of the NHC between the two boron centers. DFT calculations reveal that the exchange involves dissociation and reassociation of NHC rather than an intramolecular process.     

Covalent functionalization of solid cellulose by divergent synthesis of chemically active dendrons

Covalent surface modification of solid cellulose with well‐defined and chemically reactive dendrons is introduced as a platform for cellulose grafting with functional materials. Surface functionalization with a first generation dendron is achieved by esterification employing bifunctional molecules based on 2,2‐bis(hydroxymethyl) propionic acid (bis‐MPA) under mild conditions and short reaction times. The activated cellulose surface displays hydrophobic properties and contains two reactive alkene end‐groups per graft, which are used for covalent binding to active agents, as demonstrated by selective functionalization of the modified cellulose with fluorescent dye via photopatterning. The number of active end‐groups on the surface of cellulose is multiplied by divergent solid‐state synthesis of second and third generation dendrons having four and eight reactive sites per dendron, respectively. The dendrons are assembled in only few hours by a sequence of thiol‐ene/esterification reactions. The ability to accurately control the number of binding sites on the surface of cellulose allows fine tuning of the surface properties, as shown by the attachment of hydrophobic small molecules to the dendronized cellulose. The first, second and third generation dendrons allow preparing surfaces with increasing hydrophobicities; second and third generation dendrons functionalized with small perfluoroalkyl molecule display superhydrophobic properties. © 2018 Wiley Periodicals, Inc. J. Polym. Sci., Part A: Polym. Chem. 2018 , 56, 2103–2114