NMR-Detection of Cu(III) Intermediates in Substitution Reactions of Alkyl Halides with Gilman Cuprates

2007 ◽  
Vol 129 (37) ◽  
pp. 11362-11363 ◽  
Author(s):  
Tobias Gärtner ◽  
Wolfram Henze ◽  
Ruth M. Gschwind
Keyword(s):  
Alkyl Halides ◽  
Substitution Reactions

The effect of pressure on the rates of some substitution reactions of alkyl halides

1975 ◽  
Vol 28 (4) ◽  
pp. 693 ◽  
Author(s):  
SD Hamann
Keyword(s):  
Hydrostatic Pressure ◽  
Silver Nitrate ◽  
Aqueous Ethanol ◽  
Ion Pairs ◽  
Alkyl Halides ◽  
Halide Ions ◽  
Substitution Reactions ◽  
Effect Of Pressure ◽  
Mercuric Nitrate

Measurements have been made of the influence of hydrostatic pressure on the rates of three kinds of bimolecular substitution reactions of alkyl halides in solution. They are reactions with (a) halide ions in acetone solution (Finkelstein reactions), (b) silver nitrate in aqueous ethanol and (c) mercuric nitrate in aqueous dioxan. ��� The Finkelstein reactions were unsymmetrical with respect to the halogen atoms, for instance I- + PrCl → PrI+Cl-. They were all accelerated by an increase of pressure, in contrast to the sym- metrical exchange I*- + PrI → PrI* + I-, which is known to be retarded by an increase of pressure. This fact supports Gonikberg's view of the role of partial desolvation in the symmetrical reactions. Reactions involving LiCl as the source of halide ions were accelerated much more than those involving KI, simply because an increase of pressure enhances the dissociation of unreactive LiCl ion pairs. ��� Reactions of the types (6) and (c) were also accelerated by an increase of pressure, a fact which argues against a suggestion that the attacking species might be ion pairs.

Übergangsmetallkomplexe mit Schwefelliganden, XIII* Synthesen und Reaktionen der 1,2-Benzoldithiolatomolybdat-Komplexe [MO(C6H4S2)3]n- (n = 0, 1, 2) und des Hydrid-Komplexes [Mo(H)(C6H4S2)3]3- / Transition Metal Complexes with Sulfur Ligands, XIII* Syntheses and Reactions of the 1,2-Benzenedithiolato Molybdate Complexes [MO(C6H4S2)3]n- - (n = 0 , 1, 2 ) and the Hydride Complex [Mo(H)(C6H4S2)3]3-

1985 ◽  
Vol 40 (3) ◽  
pp. 380-388 ◽  
Author(s):  
Dieter Sellmann ◽  
Lothar Zapf
Keyword(s):  
Nmr Spectroscopy ◽  
Transition Metal Complexes ◽  
Metal Hydride ◽  
Complex Salt ◽  
Alkyl Halides ◽  
Molar Ratio ◽  
Substitution Reactions ◽  
Hydride Complex ◽  
H Nmr ◽  
First Time

Modes of formation as well as redox and substitution reactions of the 1,2-benzenedithiolate complexes [Mo(C6H4S2)3]n- (n = 0, 1, 2, (3)) are described. [MoCl4(THF)2] with neutral C6H4(SH)2 gives the Mo(VI) complex [Mo(C6H4S2)3]; with C6H4S22-, however, the Mo(IV) complex [Mo(C6H4S2)3]2- can be isolated as the PPh4+ or NR4+ salt; in the course of the synthesis of (NMe4)2[Mo(C6H4S2)3] in MeOH/THF, the complex salt trans-(NMe4)2[Mo(C6H4S2)2(OCH3)2] is also obtained. Directly and controlled by pH, [Mo(VI)(C6H4S2)3] can be reduced by NaOH/MeOH to afford [Mo(V)(C6H4S2)3]- or [Mo(IV)(C6H4S2)3]2-. [Mo(VI)(C6H4S2)3] and (NMe4)2[Mo(IV)(C6H4S2)3] symproportionate in MeOH to yield (NMe4)[Mo(V)(C6H4S2)3] , which was isolated for the first time. When butyllithium reacts with [Mo(VI)(C6H4S2)3] in the molar ratio of 1:1, 2 :1 or 3:1, one obtains the Mo(V), Mo(IV) dithiolates or an orange complex, respectively. The latter is extremely H2O - as well as O2-sensitive; it is identified by its reactions with H2O , ROH, O2 , alkyl halides and NO as well as by 1H NMR spectroscopy as a salt containing the [MO(H)(C6H4S2)3]3- anion. [Mo(H)(C6H4S2)3]3- is the first example of an exclusively sulfur coordinated metal hydride complex. With NO it reacts in several steps yielding first N2O and [Mo(IV)(C6H4S2)3]2-; subsequently the Mo(IV) complex is reductively nitrosylated by further NO yielding cis-[Mo(NO)2(C6H4S2)2]2-, which is isolated as NMe4+ salt.

Vitamin B12-based elimination of alkyl halides

2020 ◽  
Author(s):  
Julian West ◽  
Alexandros S Pollatos ◽  
Radha Bam
Keyword(s):  
Vitamin B12 ◽  
Alkyl Halides
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