Surface photochemistry: translational motion of organic molecules adsorbed on silica gel and its consequences

1982 ◽  
Vol 104 (17) ◽  
pp. 4635-4644 ◽  
Author(s):  
Richard K. Bauer ◽  
Raphaela Borenstein ◽  
Paul De Mayo ◽  
Keiji Okada ◽  
Maria Rafalska ◽  
...  
Keyword(s):  
Silica Gel ◽  
Organic Molecules ◽  
Translational Motion

ChemInform Abstract: SURFACE PHOTOCHEMISTRY: TRANSLATIONAL MOTION OF ORGANIC MOLECULES ADSORBED ON SILICA GEL AND ITS CONSEQUENCES

1982 ◽  
Vol 13 (47) ◽  
Author(s):  
R. K. BAUER ◽  
R. BORENSTEIN ◽  
P. DE MAYO ◽  
K. OKADA ◽  
M. RAFALSKA ◽  
...  
Keyword(s):  
Silica Gel ◽  
Organic Molecules ◽  
Translational Motion

Surface photochemistry: generation of benzyl radical pairs on dry silica gel

1984 ◽  
Vol 62 (3) ◽  
pp. 403-410 ◽  
Author(s):  
Bradley Frederick ◽  
Linda J. Johnston ◽  
Paul De Mayo ◽  
S. King Wong
Keyword(s):  
Silica Gel ◽  
Radical Pair ◽  
Translational Motion ◽  
The State ◽  
Radical Pairs ◽  
Radical Recombination ◽  
Benzyl Radical ◽  
Radical Movement

Singlet and triplet benzyl radical pairs have been generated on silica gel by photolysis of a benzyl phenylacetate, a dibenzyl ketone, and a dibenzyl sulfone. The extent of geminate radical recombination has been measured and requires that translational motion of radicals occur on the silica gel surface. This motion was affected by the radical pair multiplicity and the photolysis temperature, but was relatively insensitive to the state of hydration of the silica gel and the presence of coadsorbates. The presence of certain rearranged starting materials, which are not formed in solution, amongst the products from photolysis of both dibenzyl ketone and dibenzyl sulfone on silica gel indicates the restrictions on radical movement on the surface on the shorter timescale of the benzyl–phenylacetyl and benzyl – benzyl sulfonyl radical pairs.

Sol-gel synthesis of silica gel disc as applied to supports of organic molecules with optical functions

1993 ◽  
Vol 28 (17) ◽  
pp. 4607-4614 ◽  
Author(s):  
S. Sakka ◽  
K. Aoki ◽  
H. Kozuka ◽  
J. Yamaguchi
Keyword(s):  
Silica Gel ◽  
Organic Molecules ◽  
Sol Gel ◽  
Optical Functions ◽  
Sol Gel Synthesis

Enhancement of association of organic molecules on silica gel by surface water: surface photoreaction of stilbene

2008 ◽  
Vol 6 (2) ◽  
pp. 107-111 ◽  
Author(s):  
Tadashi Hasegawa ◽  
Kakeru Usuba ◽  
Soichiro Kondo ◽  
Yutaka Maeda
Keyword(s):  
Surface Water ◽  
Silica Gel ◽  
Water Surface ◽  
Organic Molecules

Radioiodinations of organic molecules on silica gel surfaces

1985 ◽  
Vol 22 (11) ◽  
pp. 1109-1122 ◽  
Author(s):  
Thomas E. Boothe ◽  
Ronald D. Finn ◽  
Manhar M. Vora ◽  
Ali Emran ◽  
Paresh J. Kothari ◽  
...  
Keyword(s):  
Silica Gel ◽  
Organic Molecules

High Resolution Replication of Organoclay Surfaces

1982 ◽  
Vol 40 ◽  
pp. 576-577
Author(s):  
W. W. Barker ◽  
W. E. Rigsby ◽  
V. J. Hurst ◽  
W. J. Humphreys
Keyword(s):  
Clay Mineral ◽  
Organic Molecule ◽  
Organic Molecules ◽  
X Ray Diffraction ◽  
Xrd Pattern ◽  
X Ray ◽  
Naturally Occurring ◽  
Silicate Layers ◽  
Mineral Identification

Experimental clay mineral-organic molecule complexes long have been known and some of them have been extensively studied by X-ray diffraction methods. The organic molecules are adsorbed onto the surfaces of the clay minerals, or intercalated between the silicate layers. Natural organo-clays also are widely recognized but generally have not been well characterized. Widely used techniques for clay mineral identification involve treatment of the sample with H2 O2 or other oxidant to destroy any associated organics. This generally simplifies and intensifies the XRD pattern of the clay residue, but helps little with the characterization of the original organoclay. Adequate techniques for the direct observation of synthetic and naturally occurring organoclays are yet to be developed.

Direct phase determination in electron crystallography: small organic molecules

1992 ◽  
Vol 50 (2) ◽  
pp. 1166-1167
Author(s):  
Douglas L. Dorset
Keyword(s):  
Organic Molecules ◽  
Data Sets ◽  
Temperature Structure ◽  
3D Analysis ◽  
Intensity Data ◽  
Electron Crystallography ◽  
Phase Determination ◽  
Measured Intensity ◽  
3D Data

The quantitative use of electron diffraction intensity data for the determination of crystal structures represents the pioneering achievement in the electron crystallography of organic molecules, an effort largely begun by B. K. Vainshtein and his co-workers. However, despite numerous representative structure analyses yielding results consistent with X-ray determination, this entire effort was viewed with considerable mistrust by many crystallographers. This was no doubt due to the rather high crystallographic R-factors reported for some structures and, more importantly, the failure to convince many skeptics that the measured intensity data were adequate for ab initio structure determinations.We have recently demonstrated the utility of these data sets for structure analyses by direct phase determination based on the probabilistic estimate of three- and four-phase structure invariant sums. Examples include the structure of diketopiperazine using Vainshtein's 3D data, a similar 3D analysis of the room temperature structure of thiourea, and a zonal determination of the urea structure, the latter also based on data collected by the Moscow group.

Sign in / Sign up

Export Citation Format

Share Document