Infrared spectroscopic study of the adsoprtion of methacrylates on aerosil

The type and ratio of the attached groups was measured by FT-IR spectroscopy for the adsorption of three methacrylates. The adsorption enthalpies can be determined from a correlation with infrared frequency shifts.

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Ellipsometric and IR spectroscopic study of the surface interaction of binary Al-REM alloys with water

The effect of Al-REM binary alloys’ composition on the kinetics of their surface oxidation by water is studied by means of ellipsometry and IR spectroscopy. Intermetallides with ～21 at % rare-earth metal in aluminum are oxidized in distilled water at 100°C, along with alloys of eutectic composition (Al-～2 at % REM) in solid and disperse state. It is found that the kinetic dependences of the thickness of films formed on pollycrystalline alloy samples and the IR transmission spectra of dispersed samples show that increasing the quantity of dopant REM in aluminum lowers the reactive capability of aluminum under certain conditions. It is found that the experimental ellipsometric results are described by a two-layer model consisting of a substrate, an inner oxide layer and an outer layer of hydroxide.     

An infrared study of the interaction of γ-aminopropyl and gb-cyanoethyl derivatives of triethoxysilane with aerosil

Aerosil has been altered in surface properties by treatment with these compounds as vapors and in solution in benzene. The surface OH groups give rise to an organosiiyl layer that is stable up to high temperatures under vacuum. The condensation occurs mainly on surfaces not blocked by hydrogen bonds. Cyano groups linked to these layers provide a new type of adsorption center. The CN band at 2249 cm^–1 does not shift when various compounds are adsorbed.     

IR spectroscopic studies of CO interaction with surface zirconium hydrides

IR spectroscopic studies of CO interaction with surface zirconium hydrides have revealed that it proceeds through a step of CO adsorption on these hydrides at 163–273 K with the subsequent insertion of CO across the Zr-H bonds at T>293 K and the formation of surface formyl compounds.

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CO . , CO 163–273 CO Zr-H 293 .

     

Molecular spectroscopic study on the interaction of tetracyclines with serum albumins

A molecular spectroscopic investigation of the interaction between tetracyclines antibiotics and human serum albumin or bovine serum albumin was reported. The influences of some metal ions on the interaction were also studied. When tetracyclines drugs were added into the solution containing serum albumins, the fluorescence intensity of serum albumins decreased with the increasing of the drugs concentrations, which is due to the formation of new non-fluorescence complexes of drug-serum albumin. The tetracyclines acted as quenchers and quenched the fluorescence of the serum albumins. The binding constants and the number of the binding sites of the reaction of tetracyclines and serum albumins were obtained. The main sorts of acting force between the drugs and serum albumins were found and the action distances and the energy transfer efficiencies between donor-acceptor were calculated based on the Foster energy transference.     

Infrared spectroscopic study of O2 interaction with carbon nanotubes

Infrared reflection-absorption spectroscopic measurements have been performed on single-wall carbon nanotubes (SWNTs), cleaned by heating to approximately 500 degrees C in vacuo, during exposure to pure 16O2 or 18O2 at room temperature and at pressures of up to approximately 630 Torr. No vibrational signature of any form of adsorbed O is detected. However, structure is seen which is very similar to that observed for the adsorption of atomic H or D and which indicates changes in the SWNT vibrational spectrum. The close similarity between the spectra for atomic H and D, on one hand, and O2 on the other is an unexpected result. Changes are also noted in the broad background extending throughout the mid-IR which arises from the Drude contribution to the reflectance. All these effects increase with O2 exposure and are essentially irreversible upon evacuation of the gas. The results are consistent with other data indicating that O2 interacts only weakly with, and does not chemisorb on, pristine regions of the SWNT under these conditions. The small and irreversible effects seen upon O2 exposure are interpreted in terms of enhanced chemisorption, at or near defective regions of the SWNT wall, which saturates at a low O coverage.     

Molecular interaction of N-formylmorpholine with alkanols,a spectroscopic study

The interactions of N-formylmorpholine (NFM) with different alkanols were monitored using proton nuclear magnetic resonance and IR spectroscopy. It was found that the NFM interaction with alkanols decreases with increasing length and branching of the alkanols. A good correlation was obtained between the proton chemical shift and the volume of mixing of alkanols with NFM.     

IR spectroscopic study of the reaction of polyalkylhydrosiloxanes with a silica surface

Using IR spectroscopy, we have studied the reaction of polyalkylhydrosiloxanes with a silica surface and the change in the chemical nature and structure of the modified layer upon its thermal oxidation. Upon modification of aerosil A-175 by polymethyl- and polyethylhydrosiloxane, the modifying agent molecules reacts with the surface OH groups. Some of the surface hydroxyl groups are not involved in chemical reaction with the modifying agent, but judging from the position of the corresponding OH-stretch band (3400 cm^–1) they experience the perturbing effect of the polyorganosiloxane film. Thermal oxidation leads to an increase in the number of the lateral bonds in the polyorganosiloxane-modified film; the maximum degree of crosslinking is observed in the case of the aerosil treated with polymethylhydrosiloxane.Translated from Teoreticheskaya i Éksperimental'naya Khimiya, Vol. 25, No. 6, pp. 753–755, November–December, 1989.     

Interparticle diffusion of aromatic hydrocarbons on aerosil surface

It has been demonstrated by the photobleaching method that the photostability of pyrene molecules on the surface of pyrogenic nonporous SiO₂ (aerosil) is independent of the surface concentration of the fluophor. Through a kinetic analysis of the recovery of fluorescence of the luminophore and solution of the two-dimensional diffusion equation, coefficients of interparticle diffusion were estimated for the molecules of pyrene and N,N-dimethylaniline. Institute of Surface Chemistry, National Academy of Sciences of Ukraine, 31 Nauki Prospect, Kiev, Ukraine 252039. Translated from Teoreticheskaya i éksperimental’naya Khimiya, Vol. 34, No. 1, pp. 23–26, January–February, 1998.     

Thermal activation of complexation reaction on aerosil surface

The influence of temperature in the 20–100°C range on processes of bimolecular interaction in the aerosil-phenanthrene-trinitrobenzene system has been studied. Temperature-stimulated CTC accumulation on the surface is found. Activation energies of complex formation are estimated. Quenching of phenanthrene fluorescence by acceptor has a mixed static and dynamic character.     

Reaction of tetrahydropyran with chlorosilanes

Summary In the reaction of tetrahydropyran with chlorosilanes in presence of anhydrous zinc chloride the ring is opened with formation of 1,5-dichloropentane and chlorine-substituted orthosilicic esters. The relative amounts of these products depend on the number of chlorine atoms in the molecule of the chlorosilane with which the tetrahydropyran reacts.     

A study of the interaction of diethylzinc with the Aerosil surface

The interaction of diethylzinc with Aerosil has been examined by IR spectroscopy and mass spectrometry. The reaction involves both free hydroxyl groups and siloxane groups of the surface resulting in the formation of Si-O-Zn-Et and Si-Et fragments. At temperatures above 300 °C, these structures undergo decomposition with the recovery of Si-OH groups on the Aerosil surface and liberation of metallic zinc.Translated fromIzvestiya Akademii Nauk. Seriya Khimicheskaya, No. 9, pp. 1666–1668, September, 1994.The authors are grateful to M. B. Molotovshchikova for continuous help in performing the experiment.     

A spectroscopic study of the interaction of octacarboxylic metal phthalocyanine with bovine serum albumin

The interaction of octacarboxylic metal phthalocyanines (MPc(COOH)₈, M =?Al(III) and Co(II) with bovine serum albumin (BSA) has been studied. From the binding isotherm based on spectrophotometric titration, the association constant and a number of ligands per binding site were calculated at 25°C. By using the well studied Hemin chloride (HE), Ibuprofen(IB) and L-tryptophan (TRP) as competitive ligands, the binding sites of AlPc(COOH)₈ were found to be on domain I and II of BSA, while on domain I for Co(COOH)₈.