Dual interaction of anisole with surface hydroxyls

1969 ◽  
Vol 47 (20) ◽  
pp. 3906-3909 ◽  
Author(s):  
M. J. D. Low ◽  
J. A. Cusumano
Keyword(s):  
Infrared Spectra ◽  
Porous Glass ◽  
Surface Structures ◽  
Surface Hydroxyls

Infrared spectra were recorded of anisole adsorbed on porous glass which had been dehydroxylated to various extents, on highly dehydroxylated silica, and on fully fluoridated porous glass. Spectra recorded at various surface coverages showed 2 broad bands near 3600 and 3400 cm−1 due to perturbed surface hydroxyls, indicating that the adsorbed anisole was weakly held to the surface in 2 ways. The surface structures and mechanism are discussed.

Infrared spectra of acetonitrile sorbed on porous glass

1970 ◽  
Vol 48 (1) ◽  
pp. 7-12 ◽  
Author(s):  
M. J. D. Low ◽  
P. L. Bartner
Keyword(s):  
Infrared Spectra ◽  
Porous Glass ◽  
Weakly Bound ◽  
Surface Complexes ◽  
Surface Hydroxyls ◽  
Hydrogen Bonded

Infrared spectra were recorded of acetonitrile sorbed on highly degassed porous glass as well as on silica and B-, Al-, and Zr-impregnated porous glass and silica. Most of the acetonitrile was weakly and reversibly adsorbed, becoming hydrogen-bonded to surface hydroxyls. A small amount of the adsorbate formed weakly bound surface complexes with Al- and Zr-, but not with B-impurities.

Infrared spectra of the interactions of aniline and porous glass surfaces

1969 ◽  
Vol 47 (8) ◽  
pp. 1281-1287 ◽  
Author(s):  
M. J. D. Low ◽  
V. V. Subba Rao
Keyword(s):  
Nitrogen Atom ◽  
Aromatic Ring ◽  
Secondary Amine ◽  
Infrared Spectra ◽  
Porous Glass ◽  
Weak Interactions ◽  
Amine Group ◽  
Oh Groups ◽  
Glass Surfaces ◽  
Adsorption And Dissociation

Infrared spectra were recorded of aniline sorbed on highly dehydroxylated, deuterated, and on fluoridated porous glass as well as on pure and boria-impregnated silica. The results suggest that two types of weak interactions involving the surface SiOH and B—OH groups occurred; the nitrogen atom of the amine was hydrogen bonded to surface OH and there was an interaction between OH groups and the π system of the aromatic ring. Some aniline chemisorbed on surface boron via the nitrogen atom of the amine group. Some aniline chemisorbed dissociatively to form secondary amine structures bonded through the nitrogen to surface boron atoms and new B—OH groups formed. Surface boron impurity acted as an adsorption and dissociation center.

Infrared study of the interactions of acetone and siliceous surfaces

1969 ◽  
Vol 47 (14) ◽  
pp. 2545-2554 ◽  
Author(s):  
J. C. McManus ◽  
Yoshio Harano ◽  
M. J. D. Low
Keyword(s):  
Hydrogen Bonds ◽  
Carbonyl Group ◽  
Boron Atom ◽  
Porous Glass ◽  
Carbonyl Groups ◽  
Infrared Study ◽  
Oh Groups ◽  
Silica Surfaces ◽  
Surface Hydroxyls ◽  
Glass Surfaces

Adsorbed acetone is held to silica surfaces by hydrogen bonds between surface silanols and the acetone carbonyl groups. Acetone is adsorbed by this mechanism on porous glass surfaces but there is also some decomposition, as shown by the increase in surface B—OH groups and by formation of new C—H absorptions at 2984 and 2940 cm−1. Experiments with boron-impregnated silica indicated that the presence of boron in the porous glass can account for this decomposition process. Bands at 1660–1670 and 1650 cm−1, observed when acetone and acetone-d6, respectively, were adsorbed on either porous glass or boron-impregnated silica, are attributed to ν(C=O) of the carbonyl group coordinated with a surface boron atom. The surface hydroxyls of both silica and porous glass could exchange with the deuterium of acetone-d6 via a mechanism involving an enol intermediate.

Infrared spectroscopic study of the hydration of porous glass

1989 ◽  
Vol 54 (4) ◽  
pp. 878-891 ◽  
Author(s):  
Ondřej Ivanek ◽  
Pavel Schmidt ◽  
Bohdan Schneider
Keyword(s):  
Hydrogen Bonds ◽  
Spectroscopic Study ◽  
Infrared Spectra ◽  
Porous Glass ◽  
Glass Surface ◽  
Capillary Condensation ◽  
Water Molecules ◽  
Infrared Spectroscopic Study ◽  
Native State ◽  
Oh Groups

Infrared spectra of mesoporous and macroporous siliceous glasses were measured in the native state and after silylation, at various contents of H2O and D2O. By analysis of these spectra it was found that water is bound to the glass surface by strong hydrogen bonds between the water molecules and isolated Si-OH groups; capillary condensation was observed only in native mesoporous glasses.

Infrared spectra of pyridine sorbed on porous glass

1968 ◽  
Vol 46 (20) ◽  
pp. 3255-3261 ◽  
Author(s):  
M. J. D. Low ◽  
V. V. Subba Rao
Keyword(s):  
Hydrogen Bonding ◽  
Nitrogen Atom ◽  
Infrared Spectra ◽  
Porous Glass ◽  
Physical Adsorption ◽  
Hydrogen Atoms ◽  
Oh Groups ◽  
Pure Silica ◽  
Hydrogen Bonded

Infrared spectra were recorded of pyridine (PY) sorbed on highly dehydroxylated, deuterated, and fluoridated porous glass, as well as on pure silica and boria-impregnated silica. The hydrogen atoms of sorbed PY exchange with surface OD groups. Physical adsorption occurs by hydrogen bonding of PY to SiOH and B—OH groups via the PY nitrogen atom; there is some interaction of the ring π system with OH groups. Surface B:PY complexes form by coordination of PY to boron; the B:PY may be hydrogen bonded to B—OH groups. Some PY dissociates, and OH groups are generated.

Attribution of the OH stretching bands of kaolinite

Clay Minerals ◽  
1977 ◽  
Vol 12 (2) ◽  
pp. 171-179 ◽  
Author(s):  
P. G. Rouxhet ◽  
Ngo Samudacheata ◽  
H. Jacobs ◽  
O. Anton
Keyword(s):  
Infrared Spectra ◽  
Unit Cell ◽  
The Other ◽  
Oh Groups ◽  
Coupled Vibrations ◽  
Inner Surface ◽  
Surface Hydroxyls

AbstractExamination of the infrared spectra of synthetic kaolinites, with various degrees of substitution of hydroxyls by OD groups, allows a more detailed attribution of the stretching bands due to inner-surface hydroxyls of kaolinite. Among the three innersurface OH groups of the unit cell, two are nearly perpendicular to the sheet and give coupled vibrations which are responsible for the bands around 3695 and 3670 cm−1; the band near 3655 cm−1 is due to the other hydroxyl, which is lying close to the sheet.

Scanning and Transmission Microscopy of Nematocyst Batteries in Epitheliomuscular Cells of Hydra

1971 ◽  
Vol 29 ◽  
pp. 410-411 ◽  
Author(s):  
Jane A. Westfall ◽  
S. Yamataka ◽  
Paul D. Enos
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Osmium Tetroxide ◽  
External Surface ◽  
Three Dimensional ◽  
Surface Structures ◽  
Transmission Microscopy ◽  
Transmission Electron ◽  
Freeze Dried ◽  
Scanning Electron

Scanning electron microscopy (SEM) provides three dimensional details of external surface structures and supplements ultrastructural information provided by transmission electron microscopy (TEM). Animals composed of watery jellylike tissues such as hydras and other coelenterates have not been considered suitable for SEM studies because of the difficulty in preserving such organisms in a normal state. This study demonstrates 1) the successful use of SEM on such tissue, and 2) the unique arrangement of batteries of nematocysts within large epitheliomuscular cells on tentacles of Hydra littoralis.Whole specimens of Hydra were prepared for SEM (Figs. 1 and 2) by the fix, freeze-dry, coat technique of Small and Màrszalek. The specimens were fixed in osmium tetroxide and mercuric chloride, freeze-dried in vacuo on a prechilled 1 Kg brass block, and coated with gold-palladium. Tissues for TEM (Figs. 3 and 4) were fixed in glutaraldehyde followed by osmium tetroxide. Scanning micrographs were taken on a Cambridge Stereoscan Mark II A microscope at 10 KV and transmission micrographs were taken on an RCA EMU 3G microscope (Fig. 3) or on a Hitachi HU 11B microscope (Fig. 4).

Electron Microscopic Observation of Biological Specimens in Their Native State by Employing Cryogenic Techniques

1972 ◽  
Vol 30 ◽  
pp. 410-411 ◽  
Author(s):  
Tokio Nei ◽  
Haruo Yotsumoto ◽  
Yoichi Hasegawa ◽  
Yuji Nagasawa
Keyword(s):  
Electron Microscopic Observation ◽  
Surface Structures ◽  
Specimen Preparation ◽  
Native State ◽  
Electron Microscopic ◽  
Biological Specimen ◽  
Specimen Holder ◽  
Cold Stage ◽  
Preparation Techniques ◽  
Scanning Electron

In order to observe biological specimens in their native state, that is, still containing their water content, various methods of specimen preparation have been used, the principal two of which are the chamber method and the freeze method.Using its recently developed cold stage for installation in the pre-evacuation chamber of a scanning electron microscope, we have succeeded in directly observing a biological specimen in its frozen state without the need for such conventional specimen preparation techniques as drying and metallic vacuum evaporation. (Echlin, too, has reported on the observation of surface structures using the same freeze method.)In the experiment referred to herein, a small sliced specimen was place in the specimen holder. After it was rapidly frozen by freon cooled with liquid nitrogen, it was inserted into the cold stage of the specimen chamber.

Imaging molecules adsorbed onto electrodes under potential control by scanning probe microscopy

1991 ◽  
Vol 49 ◽  
pp. 376-377 ◽  
Author(s):  
N.J. Tao ◽  
J.A. DeRose ◽  
P.I. Oden ◽  
S.M. Lindsay
Keyword(s):  
Surface Charge ◽  
Environmental Effects ◽  
Scanning Probe Microscopy ◽  
Statistical Significance ◽  
Electrochemical Methods ◽  
Surface Structures ◽  
Scanning Probe ◽  
Potential Control ◽  
Afm Imaging ◽  
Special Circumstances

Clemmer and Beebe have pointed out that surface structures on graphite substrates can be misinterpreted as biopolymer images in STM experiments. We have been using electrochemical methods to react DNA fragments onto gold electrodes for STM and AFM imaging. The adsorbates produced in this way are only homogeneous in special circumstances. Searching an inhomogeneous substrate for ‘desired’ images limits the value of the data. Here, we report on a reversible method for imaging adsorbates. The molecules can be lifted onto and off the substrate during imaging. This leaves no doubt about the validity or statistical significance of the images. Furthermore, environmental effects (such as changes in electrolyte or surface charge) can be investigated easily.

Ultrathin Platinum Crystal Surface Structures

1985 ◽  
Vol 43 ◽  
pp. 394-395
Author(s):  
R. L. Hines
Keyword(s):  
Crystal Surface ◽  
Surface Structures ◽  
Platinum Surface ◽  
Platinum Surfaces ◽  
Resolution Level ◽  
Experimental Facilities ◽  
Carbon Backing ◽  
Mesh Grid ◽  
Atom Layer

The importance of atom layer terraces or steps on platinum surfaces used for catalysis as discussed by Somorjai justifies an extensive investigation of the structure of platinum surfaces through electron microscopy at the atomic resolution level. Experimental and theoretical difficulties complicate the quantitative determination of platinum surface structures but qualitative observation of surface structures on platinum crystals is now possible with good experimental facilities.Ultrathin platinum crystals with nominal 111 orientation are prepared using the procedure reported by Hines without the application of a carbon backing layer. Platinum films with thicknesses of about ten atom layers are strong enough so that they can be mounted on grids to provide ultrathin platinum crystals for examination of surface structure. Crystals as thin as possible are desired to minimize the theoretical difficulties in analyzing image contrast to determine structure. With the current preparation procedures the crystals frequently cover complete openings on a 400 mesh grid.

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