Cyclophosphates as ligands for cobalt(III) in water.
Examination of cyclotriphosphate and cyclotetraphosphate as ligands for Co(III) in aqueous solutions revealed that cyclotetraphosphate affords stable complexes as a hemilabile ligand, while cyclotriphosphate exhibits facile hydrolysis.
Transformations of Alkynes at a Cyclotriphosphato Ruthenium Complex
Photolysis of the cyclotriphosphato complex (PPN)[Ru(P3O9)(η6-C6H6)] (2) with bpy (2,2′-bipyridyl) in alcohols generated a violet solution of (PPN)[Ru(P3O9)(bpy)(ROH)] (3) with a labile alcohol ligand. Complexes 3 were readily oxidized during recrystallization to give the Ru(III) alkoxo complexes (PPN)[Ru(OR)(P3O9)(bpy)] (4). Treatment of 3 with internal alkynes led to selective formation of η2-alkyne complexes (PPN)[Ru(P3O9)(bpy)(η2-RC≡CR′)] (7), which did not undergo vinylidene rearrangement under heating and photoirradiation conditions in contrast to its dppe analogues. On the other hand, diphenylacetylene complex 7c (R = R′ = Ph) gave the α-ketocarbene complex (PPN)[Ru(P3O9)(bpy)(═CPhCOPh)] (8) on reaction with m-CPBA. This observation provides a very rare example for the direct and controlled oxidation of a coordinated alkyne ligand. Reactions of 3 with the terminal alkynes in alcohols and in DMF afforded the alkoxycarbene complexes (PPN)[Ru(P3O9)(bpy){═C(OR)CH2CR′}] (9) and the carbonyl complex (PPN...
Acetylation analysis of saccharides. 2. Microanalysis of neutral glycosphingolipids by means of acetylation with radioactive acetic anhydride.
Abstract The quantitative analysis of mixtures of glycosphingolipids by acetylation with radioactive acetic anhydride and separation by thin-layer chromatography is described. The method was primarily developed for screening of glycosphingolipid composition of tissues, cultured cells, and virus preparations. The sensitivity and linearity of the method is demonstrated. Although theoretically a much higher sensitivity is achievable, in practive about 10 −9 g of glycosphingolipid can be detected and tentatively identified. As an example, the acetylation pattern of lipids from a preparation of herpes simplex virus is demonstrated.