Structures of three cis-dioxoazacycloalkanes: 3,3,4,4-tetramethyldiazetine 1,2-dioxide, 2,3-diazabicyclo[2.2.1]hept-2-ene 2,3-dioxide and 6,7-diazatetracyclo[3.2.1.13,8.02,4]non-6-ene 6,7-dioxide

Prout, Keith; Stothard, V. P.; Watkin, David J.

doi:10.1107/s0567740878008675

Cited by 8 publications

(4 citation statements)

References 7 publications

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“…In this compound, the N−N and N−O bond distances are both 1.31(2) Å 19a. Several crystal structures of constrained cis -(RNO) 2 compounds containing a “cyclic” (R 2 )-link have been determined. − In these latter compounds, the N−N and N−O bond lengths fall in the ranges of 1.29−1.32 and 1.25−1.27 Å, respectively. Importantly, the increased N−O bond lengths relative to those of monomeric RNO compounds are consistent with a contribution of the dipolar azodioxy structure.…”

Section: Spectroscopy and Structurementioning

confidence: 97%

Interactions of Organic Nitroso Compounds with Metals

et al. 2002

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Section: Spectroscopy and Structurementioning

confidence: 97%

Interactions of Organic Nitroso Compounds with Metals

et al. 2002

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“…The diazine ring has a nearly perfect twist conformation. In spite of these distortions, the bond lengths and angles in the dinitroso moiety do not differ much from those observed in unstrained dinitroso groupings (Prout, Stothard & Watkin, 1978). The N-N bond distance of 1.339(2)A is slightly longer than usual (1.29-1.32 A).…”

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confidence: 68%

4,5-Dimethyl-9,10-diazaphenanthrene N,N'-dioxide

Whittleton¹,

Dunitz²

1982

Acta Crystallogr Sect B

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“…[1] ) there is generally good agreement with the B3LYP/6-31G* data ( Figure 2) and with the known structure of DBH dioxide. [26] The elongation of the methylsubstituted, strained C-1(7)/C-10 bonds by 0.030 Å points to a slight buttressing effect. In the crystal, the symmetry is reduced from P2 1 /m to P2 1 /n; in the unit cell with four molecules, the packing is governed by short CH-O and CH-ONNO distances as had been observed for the DBH-/ DBO oxides.…”

Section: Full Papermentioning

confidence: 99%

“…In the crystal, the symmetry is reduced from P2 1 /m to P2 1 /n; in the unit cell with four molecules, the packing is governed by short CH-O and CH-ONNO distances as had been observed for the DBH-/ DBO oxides. [26] [27] Photochemistry [28] Of the bichromophoric combinations presented in Scheme 1 and Scheme 2, all have been made part of the photochemical study -except the unavailable NϭN/ONϭ NO systems (8,16,17). Given the minimal perturbation caused by the methyl substituent, the utilization of the mixtures 3/4 and 5/6 meant complications in the reaction control, but no detraction from the desired information.…”

Section: Full Papermentioning

confidence: 99%

Proximate,syn-Periplanar Diazene/Diazene(di)oxy, Diazeneoxy/Diazene(di)oxy, and Diazenedioxy/Diazenedioxy Skeletons: Syntheses, [2+2]Photocycloadditions, Metathesis

et al. 2000

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Of two very proximate syn‐periplanar bisdiazenes (1,2) mono‐, di‐, tri‐ and tetra‐N‐oxides were prepared, representing six combinations of the individual NN/NNO/ONNO chromophores. According to DFT calculations (B3LYP/6‐31G*), [2+2]photocycloaddition to the respective oxidized tetrazetidines is significantly to moderately endothermic. The metathesis isomerization of the oxidized tetrazetidines is generally highly exothermic and kinetically increasingly favorable with increasing oxidation state. In practice, four out of the six bichromophoric combinations undergo selectively, in competition with N2 elimination from a DBH unit (13) still partially, metathesis isomerization upon π → π* excitation (monochromatic 254 nm light). In the case of the syn‐NNO/NNO combinations (5/6, 14), the photoaddition is thermally reversed. For a ONNO/NN combination (30), internal electron transfer is responsible for a complex reaction pattern. The preparative value of the metathesis reactions, though, is limited: The metathesis‐derived bis[diazene mono(di)oxides] undergo relatively fast secondary photoreactions, while the tri(tetra)oxides undergo rapid thermal transformations. For the NN/NNO systems (12), of three potential pathways for its metathesis isomerization, the one that takes place via σ‐symmetric intermediates (63, 64) is excluded by virtue of the retention of optical purity in the photometathesis of a highly enriched enantiomer [(−)‐12]. Matrix irradiation experiments (12 K, IR control) with 12 result in the appearance of a kinetically highly labile transient. Supported by DFT calculations it is concluded that in the metathesis reactions, the respective tetrazetidine oxides (increasingly destabilized by interactions between oxygen lone pairs and NNσ* orbitals) function as vibrationally excited transients. That thermal reversion of these transients might be a general, nonproductive competition, is suggested by the experimental verification of a “reversed photometathesis” (51 → 15) and by the generally low rates in product formation upon irradiation. The question remains to be answered why in structurally analogous molecular skeletons, [2+2]photocycloaddition occurs in the CC/NN and variously oxidized NN/NN, and not, however, in the parent NN/NN combinations.

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Structures of three cis-dioxoazacycloalkanes: 3,3,4,4-tetramethyldiazetine 1,2-dioxide, 2,3-diazabicyclo[2.2.1]hept-2-ene 2,3-dioxide and 6,7-diazatetracyclo[3.2.1.1^3,8.0^2,4]non-6-ene 6,7-dioxide

Cited by 8 publications

References 7 publications

Interactions of Organic Nitroso Compounds with Metals

Interactions of Organic Nitroso Compounds with Metals

4,5-Dimethyl-9,10-diazaphenanthrene N,N'-dioxide

Proximate,syn-Periplanar Diazene/Diazene(di)oxy, Diazeneoxy/Diazene(di)oxy, and Diazenedioxy/Diazenedioxy Skeletons: Syntheses, [2+2]Photocycloadditions, Metathesis

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