Supported transition metal complexes

Characterization of modified silica powders by fourier transform infrared spectroscopy and cross-polarization magic angle spinning NMR

“…Although covalent attachments of trifunctional silanes to silica can be formally described as mono-, bi-, or tridentate linkages, there is, apart from recently published NMR work (2), no analytical evidence reported in the literature to suggest which of these representations are appropriate. Nevertheless, all three notations are in use (3)(4)(5). Previous work concerning the binding of silanes to substrates has been performed mainly by vibrational spectroscopy (6)(7)(8).…”

An Efficient Synthetic Method for 3,3',4,4'-Biphenyltetracarboxylic Anhydride

“…Compared to the synthetic methods reported in previous literatures, [6][7][8][9][10][11][12][13][14][15][16][17][18][19][20] not only was the yield of product greatly improved, but also the operating units were easy workup. One of the noticeable points in our paper was that the catalysts are easy to handle and could be recycled and reused without any significant loss of catalytic activity, and another glittery point was that the facile manipunations in the isolation of the products.…”

“…The oxidative coupling reaction of dimethyl phthalate (DMP) under oxyen pressure in the presence of palladium acetate is another well-known method. 12,13 Other notable methods to accomplish this include the coupling reaction of terephthaloyl chloride, 14,15 the electrolytic oxidative coupling reaction, 16,17 the coupling reaction of 4-(chlorocarbonyl) phthalic acid, 18 etc. 19,20 Although these methods are suitable for certain synthetic conditions sometimes, however, some of these procedures are invariably associated with one or more disadvantages such as high cost, long reaction time, low yield, use of stoichiometric and even excess amounts of reagents or catalysts, special apparatus, etc.…”

Coated silicas and small-angle X-ray intensity behaviour

“…* We now report the results of the analysis of the X-ray intensities that we have directly measured. They have been scattered by four reversed-phase silicas obtainedt by derivatizing the same silica support (AKZO Chemic F-22), having a mean pore size of ---90A, with different amounts of tertiary phosphine groups according to the reaction (Allum et al, 1975) -…”