Rubidium methyl derivatives

Rubidium fluoride offers no advantage over cesium fluoride in fluorine replacement reactions. For example, in the reaction of / -(nitrophenyl)dimethylsulfonium methyl sulfonate (21) with cesium and rubidium fluoride, rubidium fluoride afforded the fluoro derivative 22 in 51 % yield as well as the side product 23. In contrast cesium fluoride gives 66% yield of 22 and only 20% of the side product 23.180... 

UV-Vis, H and NMR study of monometallic salts of 9,10-dihydroan-thracene and its 9,10-disubstituted derivatives in THE, showed lithium 9-phenyl-9,10-dihydroanthracene-9-ide, lithium 9,10-dimethyl-9,10-dihydroanthracenide and lithium 9,10-diphenyl-9,10-dihydroanthracenide exist as a solvent separated ion pair (SSIP). Sodium, potassium, rubidium and cesium 9,10-dihydroanthracenides, 9-methyl-9,10-dihydroanthracene-10-ides and 9-cyano-9,10-dihydroanthracenides exist as contact ion pairs (CIP) in solution. A model, taking into account the geometry and charge distribution, for the transition of CIP of alkali metal salts of 9,10-dihy-droanthracene and its derivatives into SSIP is proposed [283]. 

A large number of structurally characterized bis(trimethylsilyl)amido complexes now exist Table 5 gives a representative selection of monometallic homoleptic compounds, both base-free and with coordinated ethers. Other examples are known with coordinated fiuorobenzenes, isonitriles,methylated pyridines, various amines (TMEDA, PMDTA, TMPDA (Tetra-methylpropylenediamine), BzNMe2 (benzyldimethylamine)), Ph PO, (Bu"0)(Pr )C0, and l,3-(Pr )2-3,4,5,6-tetrahydropyrimid-2-ylidene. Their structures illustrate the complex interactions between metal size, ligand bulk, and molecular structure that exist with these metals. For example, among the alkali metal base-free species, the unsolvated Li derivative crystallizes as a cyclic trimer, whereas the Na salt is found both as a trimer " and as infinite chains of [Na-N(SiMe3)2—] units. The potassium, rubidium, and caesium derivatives exist as discrete dimers in the solid state, constructed around planar [M—N-]2 frameworks. 

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