Tetramethylethylenediamine, solvation

Persulfate (41) reacts with transition metal ions (e.g. Ag, Fe21, Ti31) according to Scheme 3.42. Various other reduetants have been described. These include halide ions, thiols (e.g. 2-mercaptoethanol, thioglycolic acid, cysteine, thiourea), bisulfite, thiosulfate, amines (triethanolamine, tetramethylethylenediamine, hydrazine hydrate), ascorbic acid, and solvated electrons (e.g. in radiolysis). The mechanisms and the initiating species produced have not been fully elucidated for... 

An alternative bonding situation without it interaction has been found by Weiss and Koster (9) for the allyllithium-tetramethylethylenediamine (TMEDA) complex. A low-resolution X-ray structure shows an endless polymer with TMEDA-solvated lithium atoms attached to both terminal allyl carbons. 

The suggestion has been made that LiAlH4 is a covalently bonded species in solution and can undergo reactions of this sort by attack on the Li atom. NaAlH4, which is clearly ionic, does not react in the same way but will give amine solvates, e.g., with tetramethylethylenediamine (NaTMED)AlH4.45... 

Two complexes containing a dilithiated stilbene fragment have been prepared and isolated from the reactions of 1,2-diphenylethane with N-chelated butyl-lithium reagents. " The molecular and crystal structures of these compounds, stilbene bis(lithium tetramethylethylenediamine) (Figure 4a) and stilbene bis(lithium pentamethyldiethylenetriamine) (Figure 4b), have been determined by X-ray diffraction techniques. Each structure contains two amine-solvated Li atoms located above and below the olefinic bond of a stilbene molecule. The stilbene molecule is planar in both structures, and is in a trans configuration about the C(7)—C(7 ) bond, which is ca. 0.01 nm longer than that in trans-stilbene. " The optical and "C n.m.r. spectra of THF solutions of the related dilithium and disodium salts of tetraphenylethylene dianion, as well as the spectra of their mixtures, have been examined. " The data can be rationalized in terms of the... 

A cycloheptatrienide trianion would have ten ir-electrons and thus might be a stablised (4n+2) electron system. There is evidence for its formation in solution, when either hepta-1,3,6-triene or, more surprisingly, hepta-1,6-diene is treated with n-butyl lithium in tetramethylethylenediamine [390]. The lithium salt is apparently solvated by the amine. Its and n.m.r. spectra show singlets at 6 4.55 and 66.0, respectively. It reacts with deuterium oxide to give a mixture of trideuteriocycloheptadienes and with ethyl sulphate to give a mixture of triethylcycloheptadienes. 

N,N,N, N-tetramethylethylenediamine), 44B, 659 CngHyeLig, Cyclohexyllithium hexamer benzene solvate, 40B, 670 CAsHgoNyNa, Tris(p,p -diamino-2,3-diphenylbutane)sodium cyanide,... 

Solvation of Pb(CH3)4 in solution increases along the series of solvents cyclohexane < 1,2-dimethoxyethane dioxane = hexamethylphosphoric acid triamide < pyridine < tetrahydrothiophene < triethylamine < tetrahydrofuran < triethylphosphane < N,N,N, N -tetramethylethylenediamine = acetone < dimethylformamide < dimethyl sulfoxide as derived from the increase of the NMR coupling constants J( H, Pb). Coordination of only one solvent molecule and trigonal bipyramidal geometry of the complexes was supposed [8]. For studies of the dispersion interaction of Pb(CH3)4 and various solvents, see [9, 28]. For a correlation of the ionization potential and the solvation energy of Pb(CH3)4 and other tetraorganometal compounds in acetonitrile, see [36]. 

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