Hexamethylphosphoramide spectrum

Hexamethylphosphoramide, S -2 reaction and. 371 Hexane, 1R spectrum of. 424 mass spectrum of, 413 1,3,5-Hexatriene, molecular orbitals of, 1180... 

The absorption spectrum and first formation constant of [Cr(bipy)]2+ have been determined spectrophotometrically in hexamethylphosphoramide (HMPA) (see also Table 39). Since log Ki (4.61) is slightly larger in HMPA than in water, it is said that [Cr(bipy)(HMPA)2]2+ is tetrahedral, although from the general chemistry of chromium(Q) the ion would be expetrted to be in planar or distorted octahedral coordination.52... 

Metal hydride reduction of methyl dehydroabietate (64b) afforded alcohol (65) whose tosyl derivative on heating with sodium iodide and zinc in dimethylformamide yielded (66). The use of hexamethylphosphoramide gave an inferior yield of (66). Regio and stereoselective acetoxylation with Pb(OAc)4 in acetic acid at 100°C gave only 30% yield of (67) but the same experiment realized with Pb(OAc)4 using a Hg medium-pressure lamp at room temperature yielded (67) in 74%. The H NMR spectrum of (67) showed that the OAc group was introduced in 7a-position. This on subjection to acid-catalyzed 13-elimination (EtOH/10% HC1) produced (68) in quantitative yield. 

Germanium.— The microwave spectrum of (trifluoromethyl)germane, prepared in < 5 % yield by adding bromotrifluoromethane to a cold solution of the potassium derivative KGeHg in hexamethylphosphoramide, has been examined. The spectrum of a sample which was left in a copper waveguide for over 2 weeks remained very intense, so little or no decomposition (CFs GeHs FGeHa + CFa) appears to have occurred. 

The reaction of trispentailuorophenylmethane with sodium or lithium hydride under an argon atmosphere in hexamethylphosphoramide at 20— 25 °C gives a solution of the trispentafluorophenyl carbanion [(C F, C ] (c/ p. 392), the n.m.r. spectrum of which has been described. It seems probable that bispentafluorophenyl carbanions are involved in the formation of 1,1,2,2-tetrakispentafluorophenylethane from bispentafluorophenylmethyl bromide and cyanide ion, triphenylphosphine, or butyl-lithium, and their failure to carbonate during the last reaction at - 70 °C has been attributed to their relatively high stability. ... 

Figure 18-1 Visible spectra of quinacridone — absorption spectrum of quinacridone in hexamethylphosphoramide solution ...

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