NMR study of hindered rotation in 1-aryl-3,3-dimethyltriazenes

Akhtar, Mohd; McDaniel, Robert S.; Feser, Manfred; Oehlschlager, A. C.

doi:10.1016/s0040-4020(01)92598-0

Cited by 58 publications

(21 citation statements)

References 11 publications

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“…We have shown that bis-triazenes undergo facile hydrolysis in phosphate buffer (with 1.7% DMSO) at pH 7.5 to give the corresponding arylamine, via the intermediate 1-aryl-3-methyltriazene, ArN=N.NHMe; for example, the p-bromophenyl-bistriazene (3a) decays with a half-life of 12.0 min at a pH 7.5 (13). This ease of decomposition has been attributed to the aminal character of the bis-triazene (14).…”

Section: Resultsmentioning

confidence: 99%

Open chain nitrogen compounds. Part XI. 3,7-Bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes: the reaction of diazonium ions with ammonia–formaldehyde mixtures

Singer¹,

Vaughan²,

Hooper³

1986

Can. J. Chem.

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Reaction of a series of diazonium salts with either hexamine or an aqueous mixture of ammonia–formaldehyde affords 3,7-bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes; several new examples of this novel class of bicycloheterocycle have been prepared and characterized. Analysis of the low-temperature nmr spectra of one compound in this series shows that the bicyclic system prefers the chair–chair conformation. The bis(arylazo)tetraazabicyclononanes, which are surprisingly stable in aqueous buffer compared to analogous triazenes of open-chain structure, do undergo slow decomposition at slightly acidic pH in an acetone–buffer mixture. The apparent product of this decomposition is the arylamine, which is observed as the Mannich condensation product, ArNH•CH2CH2COCH3.

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Section: Resultsmentioning

confidence: 99%

Open chain nitrogen compounds. Part XI. 3,7-Bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes: the reaction of diazonium ions with ammonia–formaldehyde mixtures

Singer¹,

Vaughan²,

Hooper³

1986

Can. J. Chem.

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“…Similar effects were observed for 1-aryl-3,3-dialkyltriazenes at low temperatures and Scheme 3. were subject to studies in the past. [33,34] The authors could show that the triazene group exists as the sterically less hindered trans isomer. However, hindered internal rotation on the N 2 , N 3 bond was observed due to formation of a 1,3-dipolar structure (Scheme 4).…”

Section: Nmr Studies and The Degree Of Branchingmentioning

confidence: 99%

Hyperbranched Poly(triazene ester)s as Novel Globular Photolabile and Thermolabile Polymers

Eigner

Komber

Voit

2001

Macromol. Chem. Phys.

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“…Again these high AH* values seem to argue against a dissociative process in our case. Moreover, large negative AS* values are possible for sterically and electronically restricted transition states (40,41). Unfortunately, there is not enough information in the spectra to come to a definite conclusion about the pathway of the process.…”

Section: (L-l)l2 Mo(co)br2 Complexesmentioning

confidence: 99%

Seven-coordinate metal carbonyl derivatives of cis-(CH₃)₂AsC(CF₃)=C(CF₃)As(CH₃)₂

Cullen¹,

Mihichuk²

1976

Can. J. Chem.

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In the course of studies on seven-coordinate prepared from the six-coordinate derivatives complexes of metal carbonyls (1, 2) we became (L-L)M(C0)4 (25) where (L-L) is the fluorointerested in related tertiary arsine derivatives of carbon-bridged ligand (CH3)2AsC(CF3)=C(CF3)-molybdenum and tungsten. There are two main A s ( C H~)~. methods of preparation of this type of complex as summarized in eqs. 1 and 2. The first method Experimental was ' yholm and cO-workers (3-6)Air-sensitive starting-materials were handled in a and second by alld associates (7-14). nitrogen atmosphere. A standard vacuum system was (M = Mo, W; X = C1, Br, I; 2L can be a used for the manipulation of volatile reactants. Infrared bidentate ligand.) T V -spectra were recorded on a Perkin-Elmer 457 spectrophotometer and calibrated using polystyrene and cyclo-hexane. Nuclear magnetic resonance (nmr) spectra were run on VarianT-60, XL-100, HA-100, and CFT-20 2L[2]M(CO)6 2 M(CO),X2 + LZM(CO)~XZ spectrometers with chemical shifts given in ppm downfield from internal TMS for 'H spectra and uufield from These products are nonelectrolytes and their internal CFC13 for 19F spectra.'~he HA-100'instrument, solid state structures are generally based on a equipped with a Varian V-4343 variable temperature unit calibrated against ethylene glycol standard, was used for distorted octahedron with a carbonyl group variation studies. capping one face (15-18) (e.g. Fig. 1). An alterna-The synthesis of the ligand cis-2,3-bis(dimethy1arsino)-tive seven-coordinated structure based on a 1,1,1,4,4,4,-hexafluorobut-2-ene, (L-L), has been precapped trigonal prism is found in related cations viously described (253 26). For personal use only.

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NMR study of hindered rotation in 1-aryl-3,3-dimethyltriazenes

Cited by 58 publications

References 11 publications

Open chain nitrogen compounds. Part XI. 3,7-Bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes: the reaction of diazonium ions with ammonia–formaldehyde mixtures

Open chain nitrogen compounds. Part XI. 3,7-Bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes: the reaction of diazonium ions with ammonia–formaldehyde mixtures

Hyperbranched Poly(triazene ester)s as Novel Globular Photolabile and Thermolabile Polymers

Seven-coordinate metal carbonyl derivatives of cis-(CH₃)₂AsC(CF₃)=C(CF₃)As(CH₃)₂

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NMR study of hindered rotation in 1-aryl-3,3-dimethyltriazenes

Cited by 58 publications

References 11 publications

Open chain nitrogen compounds. Part XI. 3,7-Bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes: the reaction of diazonium ions with ammonia–formaldehyde mixtures

Open chain nitrogen compounds. Part XI. 3,7-Bis(arylazo)-1,3,5,7-tetraazabicyclo[3,3,1]nonanes: the reaction of diazonium ions with ammonia–formaldehyde mixtures

Hyperbranched Poly(triazene ester)s as Novel Globular Photolabile and Thermolabile Polymers

Seven-coordinate metal carbonyl derivatives of cis-(CH3)2AsC(CF3)=C(CF3)As(CH3)2

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Seven-coordinate metal carbonyl derivatives of cis-(CH₃)₂AsC(CF₃)=C(CF₃)As(CH₃)₂