Darstellung, Struktur und Thermolyse von Diimin

Wibeŕg, Nils; Fischer, Gerd; Bachhuber, Heinz

doi:10.1002/cber.19741070506

Cited by 46 publications

(14 citation statements)

References 37 publications

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“…It is generally much less stable towards decomposition, especially in the condensed phase, and shows significant differences in its chemistry [27][28][29][30][31][32]. It will be seen that some of these differences may be due to a stabilizing influence of an~nonia, either as a simple diluent or through complex formation at low temperatures, but it has also been suggested that different isomers of diimide are present in the two systems.…”

Section: Istence It Was Invoked As a Transient Intermediate In A Nummentioning

confidence: 99%

“…[ [27][28][29][30][31][32]69] have argued that different preparations of diimide produce different isomers, and claim to have identified and characterized each of the three isomers; it is worth examining their evidence in some detail. In their earliest studies of the decomposition of metal tosylhydrazides, it was concluded from the infrared spectrum of the solid condensed at 77K that the product was transdiimide [28].…”

Section: Structure and Molecular Propertiesmentioning

confidence: 99%

“…In their earliest studies of the decomposition of metal tosylhydrazides, it was concluded from the infrared spectrum of the solid condensed at 77K that the product was transdiimide [28]. In subsequent papers, however, evidence was presented for the formation first of aminonitrene [29], and finally, of cis-diimide [30].…”

Section: Structure and Molecular Propertiesmentioning

confidence: 99%

“…Spectra have been reported from various low-temperature condensates from flow discharge decomposition of N2H 4 [29,67,69,70,80], and HN 3 [70], from the thermolysis of metal tosylhydrazides [28][29][30]69,71], and from the matrix photolysis of HN 3 [68,81,82]. Bondybey and Nibler [70] argued convincingly that most of the discrepancies among the reported spectra arise from a failure to recognize that diimide is strongly hydrogen bonded in many of the systems studied, and from infrared and Raman spectra obtained in dilute matrices made assignments for most of the fundamental vibrations in N~2 and N2D 2.…”

Section: Spectroscopy Of Diimidementioning

confidence: 99%

“…Diimide vapour has also been produced at low pressure by the thermal decomposition of several metal tosylhydrazides [27][28][29][30][31][32]69], triazanium sulphate [69], and by the reaction of oxygen atoms with hydrazine [92].…”

Section: Wavelength(a)mentioning

confidence: 99%

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The preparation, properties and reactions of diimide

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1984

Res Chem Intermed

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Section: Istence It Was Invoked As a Transient Intermediate In A Nummentioning

confidence: 99%

Section: Structure and Molecular Propertiesmentioning

confidence: 99%

Section: Structure and Molecular Propertiesmentioning

confidence: 99%

Section: Spectroscopy Of Diimidementioning

confidence: 99%

Section: Wavelength(a)mentioning

confidence: 99%

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The preparation, properties and reactions of diimide

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1984

Res Chem Intermed

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Reduction with Diimide

1991

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The reduction of a double bond in the presence of hydrazine appears to have been first observed in 1905 during the reaction of glyceryl oleate, which produced stearic hydrazide. That hydrazine could act as a reagent for the reduction of a carboncarbon double bond was firmly established much later, at which point it was shown that oleic acid could be reduced to stearic acid by treatment with hydrazine, or with hydrazine and sulfur. In 1941 it was reported that vinyl groups in chlorins and porphyrins are selectively reduced to ethyl groups by hydrazine under mild conditions. The synthetic potential of this type of reduction was not recognized until the early 1960s when results from several independent laboratories implicated diimide (HNNH) as the actual reducing agent. Evidence for the existence of diimide (diimine and diazene) was first obtained in 1892 in the decarboxylation of dipotassium azodicarboxylate, which produced equimolar quantities of nitrogen and hydrazine by the proposed disproportionation of diimide. In 1910 it was proposed that diimide was formed in the reaction of benzenesulfonylhydrazide with hot alkali. Following the proposal that diimide is the reactive intermediate in these reduction reactions, numerous experimental and theoretical studies were launched to find other methods for the synthesis of diimide and to determine the structure(s) of the reactive intermediate(s) and the mechanism of the reduction reaction. An excellent review has appeared which covers the literature on the structure and molecular properties, spectral characterization, and gas‐phase reactions of diimide. In this chapter only highlights of such areas are covered. Two reviews covering reductions with diimide appeared in 1965, but none since that time. Most organic texts describe diimide reductions, but not in significant detail. There are three potential structures for diimide: cis ‐ and trans ‐diimide and 1,1‐diimide (aminonitrene). trans ‐Diimide can be generated and trapped at low temperature by a gas‐phase electric discharge in hydrazine and by the thermal decomposition of metal salts of p ‐toluenesulfonylhydrazide. Recently, 1,1‐diimide has been generated and trapped by the low temperature photochemical decomposition of carbamoyl azide. Although cis ‐diimide must be formed as a reactive intermediate in many systems, it has not yet been unambiguously characterized. The diimide system has been subjected to several theoretical studies at many different basis set levels. The results of stereochemical studies on the reduction of alkenes and alkynes have led to the suggestion that cis ‐diimide is the reactive hydrogen‐transfer reagent. These results support the suggestion that cis ‐diimide is the active hydrogen‐transfer reagent. The fact that cis ‐diimide has not been observed and that the calculated inversion and rotation barriers are too large to provide a rate of isomerization of trans ‐ to cis ‐diimide that would be sufficiently high to account for the observed rate of reduction provides for a mechanistic dilemma. In gas‐phase reactions isomerization of trans ‐ to cis ‐diimide has been proposed to be the rate‐limiting step. In solution, however, the isomerization in all probability occurs via a catalyzed process, probably involving a rapid protonation–deprotonation sequence. In this chapter the use of the term “diimide” implies cis ‐diimide as the reducing agent. The energy barriers for the disproportionation of cis ‐ with cis ‐, and cis ‐ with trans ‐diimide are calculated to be 19.3 and 23.8 kcal per mole, considerably smaller than the barriers for hydrogen transfer to a carboncarbon double bond. From a practical point of view, this competing disproportionation requires the use of considerable excesses of the diimide precursors in the reduction reactions.

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