Electron transfer reactions from alkali metal surfaces to (±) and (S)-(−)-1,3-dimethoxy-1,1-diphenylbutane. Studies on 1,3-elimination

1984 ◽  
Vol 62 (11) ◽  
pp. 2464-2470 ◽  
Author(s):  
Harry M. Walborsky ◽  
Martha Pass Murari
Keyword(s):  
Electron Transfer ◽  
Alkali Metal ◽  
Charge Radius ◽  
Alkali Metals ◽  
Transfer Reactions ◽  
Lithium Metal ◽  
Sodium Metal ◽  
Pure Product ◽  
Optically Pure ◽  
Sodium And Potassium

The 1,3-elimination of methoxide by carbanions generated from the reaction of (±)-1,3-dimethoxy-1,1-diphenylbutane with the alkali metals, lithium, sodium, and potassium, in various solvents was studied to determine the significance of cation–methoxyl coordination due to decreasing charge/radius ratio of the cations and also the cation complexing ability of the solvent. The stereochemistry of cyclization in the reaction of (S)-(−)-1,3-dimethoxy-1,1-diphenylbutane with lithium metal in tetrahydrofuran and with sodium metal in methylcyclohexane to yield 1-methyl-2,2-diphenylcyclopropane was determined. The reaction proceeded by an intramolecular SN2-type displacement to yield optically pure product of inverted configuration.

Elektronentransfer und Ionenpaar-Bildung, 47 [1] Titrationen von 1,2,4,5-Tetracyanbenzol und 7,7,8,8-Tetracyan-p-chinodimethan mit Natriummetall in aprotischen Lösungen / Electron Transfer and Ion Pair Formation, 47 [ 1 ] Titrations of 1,2,4,5-Tetracyanobenzene and 7,7,8,8-Tetracyano-p-quinodimethane with Sodium Metal in Aprotic Solutions

1996 ◽  
Vol 51 (9) ◽  
pp. 1215-1221 ◽  
Author(s):  
Hans Bock ◽  
Markus Kleine
Keyword(s):  
Electron Transfer ◽  
Ion Pair ◽  
Pair Formation ◽  
Transfer Reactions ◽  
The Novel ◽  
Band Shape ◽  
Novel Technique ◽  
Sodium Metal ◽  
Mndo Calculations ◽  
Donor Acceptor

In an especially designed and sealed glass apparatus, a combination of UV/VIS and ESR spectroscopy measurements are performed to follow electron transfer reactions in aprotic (cH⊕ < 0,1 ppm) solution. For the sodium metal reductions of the tetracyano-substituted title compounds, the novel technique provides the following detailed information: 1,2,4,5- tetracyanobenzene is uniformly reduced to its radical anion, for which additional geometryoptimized MNDO calculations predict an already significant cyanine disortion. For 7,7,8,8- tetracyano-p-quinodimethane, UV/VIS band shape analysis allows to detect in the saturated THF reduction solution the 16300 cm-1 absorption of the donor/acceptor complex formed in the equilibrium TCNQ·⊖ + TCNQ ⇆ {TCNQ·⊖···TCNQ}, which according to a literature search has been crystallized and structurally characterized in paramagnetic salts such as [Me2⊕ (TCNQ·⊖)2(TCNQ)].

scholarly journals THE REDUCTIVE DIMERIZATION OF N-BENZYLIDENE ANILINE

1966 ◽  
Vol 44 (21) ◽  
pp. 2497-2502 ◽  
Author(s):  
James G. Smith ◽  
C. Doreen Veach
Keyword(s):  
Alkali Metal ◽  
Lithium Metal ◽  
Reaction Products ◽  
Polar Solvents ◽  
Reductive Dimerization ◽  
Nonpolar Solvents ◽  
Diastereomeric Mixture ◽  
Metal Adducts ◽  
Sodium And Potassium

The formation of alkali metal adducts of N-benzylidene aniline in several inert solvents is studied by protonolysis of the adducts and analysis of the reaction products, the diastereomeric N,N′,1,2-tetraphenylethylenediamines. With sodium and potassium metal in polar solvents, the product is predominantly the dd,ll diamine. With lithium metal or with solvents of low polarity, the product contains approximately equal quantities of the two diastereomers.It is demonstrated that the initially formed diastereomeric mixture generally contains appreciable amounts of the meso isomer. In polar solvents with sodium, isomerization to the stable dd,ll diastereomer occurs. However, with lithium or with sodium in nonpolar solvents, the isomerization does not occur. The reasons for the preponderance of the dd,ll-disodio compound in the equilibrating systems are discussed.

On the atomic volume relations in certain isomorphous series. III.

1929 ◽  
Vol 22 (124) ◽  
pp. 70-76
Author(s):  
A. F. Hallimond
Keyword(s):  
Alkali Metal ◽  
Internal Pressure ◽  
Alkali Metals ◽  
Alkali Halides ◽  
Atomic Volume ◽  
Free Alkali ◽  
Large Measure ◽  
Accurate Knowledge ◽  
Sodium And Potassium ◽  
Large Contraction

Accurate knowledge of the compressibility of solids was first due in a large measure to the investigations of T. W. Richards, who showed that the pressure-volume curves for sodium and potassium approximate in form to rectangular hyperbolae, that the compressibilities of the free alkali metals are nearly proportional to the atomic volumes, and that the atoms can be treated as filling the available space. Richards then endeavoured to calculate the relative volumes of the combined elements in the alkali halides, assuming that the large contraction which takes place on forming the compound was due to an internal pressure which affected equally the alkali metal and the halogen.

THE ELECTRONIC SPECTRA OF SOME ANIONIC POLYMERIZATION SYSTEMS

1964 ◽  
Vol 42 (6) ◽  
pp. 1255-1260 ◽  
Author(s):  
S. Bywater ◽  
A. F. Johnson ◽  
D. J. Worsfold
Keyword(s):  
Alkali Metal ◽  
Absorption Spectra ◽  
Anionic Polymerization ◽  
Electronic Spectra ◽  
Alkali Metals ◽  
Ultraviolet Absorption ◽  
Tetrahydrofuran Solution ◽  
Sodium And Potassium

The ultraviolet absorption spectra of living anionic polymerizing systems have been measured with sytrene, butadiene, and isoprene as the monomers; with lithium, sodium, and potassium as the alkali metals; and with tetrahydrofuran, cyclohexane, and benzene as the solvents. For any monomer the similarity of the spectra obtained with the various metals and solvents leads to the conclusion that the alkali metal – carbon band has the same structure under the various conditions. From other evidence the bond is considered to be ionic in all cases. The diene monomer anions in tetrahydrofuran solution were found to undergo a series of isomerizations, some of them comparable in speed to the consumption of monomer.

Ambient Temperature Alkali Metal Transfer in Hydrocarbons - A New Route to Intercalation Compounds and Alloys

1982 ◽  
Vol 20 ◽  
Author(s):  
J.O. Besenhard ◽  
I. Kain ◽  
H.-F. Klein ◽  
H. MöHwald ◽  
H. Witty
Keyword(s):  
Alkali Metal ◽  
Ambient Temperature ◽  
Alkali Metals ◽  
Reducing Power ◽  
Metal Transfer ◽  
Intercalation Compounds ◽  
Transfer Reactions ◽  
Polar Solvents

ABSTRACTDissolved cobalt(0) complexes of the type [L3L'Co] (L = phosphanes, e.g. PMe3, L' = olefins, e.g. C2H4) are reversibly reduced by alkali metals A (A = Li, K, Rb, Cs)n[L3L'Co] + A ⇋ A[L3L'Co]and hence can be used as A-carriers. These carrier complexes A[L3L'Co]n are even soluble in apolar solvents like pentane.Action of [L3L'Co] plus A in pentane solution on graphite yields binary intercalation compounds ACn. By contrast, conventional ambient temperature A-transfer reagents (e.g. solutions of A in naphthalene-ether or in NH3) require strongly polar solvents and yield ternary intercalation compounds A(solv)yCn.The “reducing power” of the alkali cobaltates is close to that of free A: alkali-rich phases like 1st stage KC8 or LiC6 or highly doped polyacetylenes (e.g. K(CH)5) are readily prepared. If intercalation of solvated species is unlikely, the A-transfer reactions may also be performed in polar solvents like ethers.

Diffusion of Alkali Metals in SiC

2014 ◽  
Vol 778-780 ◽  
pp. 297-300 ◽  
Author(s):  
Margareta K. Linnarsson ◽  
Anders Hallén
Keyword(s):  
Mass Spectrometry ◽  
Alkali Metal ◽  
Ion Implantation ◽  
Alkali Metals ◽  
Secondary Ion Mass Spectrometry ◽  
Temperature Range ◽  
Metal Diffusion ◽  
Induced Defects ◽  
Secondary Ion ◽  
Sodium And Potassium

Diffusion of lithium, sodium and potassium in SiC has been studied by secondary ion mass spectrometry. The alkali metal diffusion sources have been introduced by ion implantation. Subsequent anneals have been carried out in vacuum or in Ar atmosphere in the temperature range 700 °C - 1500 °C for 5 min to 16 h. The bombardment-induced defects in the vicinity of the ion implanted profile are readily decorated by the implanted . In the bulk, the diffusing alkali metals are most likely trapped and detrapped at boron and/or other defects during diffusion. The diffusivity of the studied alkali metals decreases as the mass increases, Li+<Na+<K+, but the sodium mobility in SiC is substantial already at 1100 °C.

Sign in / Sign up

Export Citation Format

Share Document