Phosphonitrilic derivatives. XX. Electronic properties of fluorophosphonitrilic substituents

Chivers, Tristram; Paddock, N. L.

doi:10.1021/ic50110a040

Cited by 20 publications

(13 citation statements)

References 3 publications

(4 reference statements)

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“…The values of the I9F nmr chemical shift (-22.2 ppm) and JPPF (1055 Hz) for 1 (R = F) are fairly typical for fluorocyclophosphazenes (21). The 1 9~ nmr spectrum of 2 (R = F) shows non-equivalent fluorine atoms as was found for the methyl substituents in 2 (R = Me) (1).…”

Section: Kinetic Measurementsmentioning

confidence: 66%

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R₂PN)(SN)₂ (R = Me, Ph, F)

Burford¹,

Chivers²,

Oakley³

et al. 1984

Can. J. Chem.

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The oxidative addition of Cl2 (using SO2Cl2) to the six-membered ring (R2PN)(SN)2 (R = Me, Ph) produces the mixed phosphazene–thiazyl heterocycles, (R2PN)(NSCl)2, which react with Me3SiNSNSiMe3 to give the bicyclic compounds R2PS3N5. The latter undergo thermal decomposition, at ca. 100 °C in toluene, via reductive elimination of an NSN unit to regenerate (R2PN)(SN)2 in high yield. Kinetic measurements of this process, using 31P nmr spectroscopy, yield an activation energy of 102.4 ± 6.0 kJ mol−1 for the release of the NSN fragment from Me2PS3N5. The thermolysis route has been used to prepare the thermally unstable (F2PN)(SN)2, characterized as a 1:1 adduct with norbornadiene.

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Section: Kinetic Measurementsmentioning

confidence: 66%

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R₂PN)(SN)₂ (R = Me, Ph, F)

Burford¹,

Chivers²,

Oakley³

et al. 1984

Can. J. Chem.

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“…The 19F spectra consist of doublets for the PFX and PF, groups, the former being at lower field, as in other mono-substituted fluorophosphazenes (1,24). As for the analogous fluorophenyl derivatives, two types of PF, groups are found for Ic ,d. The 3'P spectra of l a -d , similar to those of the dimethylamido derivatives, are more complex, and have not been analysed completely.…”

Section: Resultsmentioning

confidence: 99%

Conjugative interactions in 1-methylpyrrol-2-yl derivatives of the cyclic phosphazenes (NPF₂)_n (n = 3–6): the crystal and molecular structure of 1-methylpyrrol-2-ylheptafluorocyclotetraphosphazene

Sharma¹,

Rettig²,

Paddock³

et al. 1982

Can. J. Chem.

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. Can. J. Chem. 60,535 (1982). I-Methylpyrroles, in which the 2-position is occupied by a pentafluorocyclotriphosphazenyl (la), heptafluorocyclotetraphosphazenyl (lb), nonafluorocyclopentaphosphazenyl (Ic), or undecafluorocyclohexaphosphazenyl group (Id), have been prepared from 2-lithio-I-methylpyrrole and the corresponding fluorophosphazene. Crystals of Ib are monoclinic, a = 17.300(2), b = 5.0281(3), c = 16.902(2) A, P = 108.904(4)", Z = 4, space group P2,/n. The structure was solved by direct methods and was refined by full-matrix least-squares procedures to R = 0.038 and R, = 0.047 for 1167 observed reflections. The N4P4 ring is nearly planar.The P-N bond lengths (corrected for libration) range from 1.524(5) to 1.562(5) A with a mean value of 1.541(17) A, and the mean ring angles are 122.9(20)" at phosphorus and 146.4(23)" at nitrogen. The geometry of the 1-methylpyrryl group shows no unexpected features, but the P-C bond (1.756(5) A) is significantly shorter than in typical P-phenyl derivatives, and the P-F bond at the same atom is comparatively long (1.561(4) A). Conjugative electron release from the pyrryl group, invo1vingp.-d, bonding, is indicated both by these geometrical features and by the appearance of intramolecular charge transfer bands in the electronic spectra of l(a-d).RAJENDRA D. SHARMA, STEVEN J. RETTIG, NORMAN L. PADDOCK et JAMES TROTTER. Can. J. Chem. 60.535 (1982). L a reaction du lithio-2 methyl-l pyrrole avec un fluorophospazene approprie conduit a des methyl-1 pyrroles dans lesquels on trouve en position 2 soit un pentafluorocyclotriphosphazenyle (la), soit un heptafluorocyclotetraphosphazCnyle (lb), soit un nonafluorocyclopentaphosphaz~yle phazenyl groups are similar to those of cyano-or is strongest for electron-releasing substituents. nitro-groups (I), but the electronic spectrum of a The pyrryl group is a good electron donor, because phenyi group is little changed by attachment to a canonical forms of pyrrole like 2b make an imporphosphazene ring ( 3 , and the results of a photo-tant contribution to its electronic structure; experelectron spectroscopic investigation are in better imentally, the first ionization energies of pyrrole agreement with the transmission of the electronic (8.20 eV) (6) and especially I-methylpyrrole 2 (7.95 effects of a phenyl group through the o-bond eV) (7) are significantly less than that of benzene system (3). (9.25 eV) (8). As a consequence of the conjugative The bonding system in phosphazenes is closely charge transfer to phosphorus, the tri(pyrry1) phosanalogous to that in phosphoryl compounds, in phine oxides 3 show an intense low frequency band which, again, the spectroscopic evidence (4) indi-in their electronic spectra (9), similar to that found cates only weak p,-6, bonding between phenyl in formyl-and acetyl-pyrroles (lo), which is attriband phosphoryl groups. Electronic delocalization uted to p,-d, bonding (9). on to phosphorus is limited by the relatively high.In the expectation that phosphazenyl and phoselectronegativity of carbon, and in ge...

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“…Again, this system failed to extrude carbon dioxide under a variety of conditions. In order to determine whether oxazolinone 6 is an intermediate in the photochemical conversion of 5 to 8, a sample of 6 was subjected to photolysis. The only product isolated from the irradiation was 3-allylphenanthro[9, 10d]oxazol-2-one (9).…”

Section: Resultsmentioning

confidence: 99%

Studies dealing with the aza Claisen rearrangement of 2-allyloxy-substituted oxazoles

Padwa¹,

Cohen²

1984

J. Org. Chem.

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The scope of the thermal [3,3]-sigmatropic rearrangement of a number of 2-allyloxy-substituted 4,5-diphenyloxazoles has been examined. These systems undergo a facile aza-Claisen rearrangement to give 3-allyl-substituted 4,5-diphenyl-4-oxazolin-2-ones. In contrast to the thermal results, irradiation of the 2-allyloxyor benzyloxy-substituted oxazole gave rise to a mixture of 3-and 5-substituted oxazolinones. The photolysis proceeds via C-0 bond scission to generate a radical pair which subsequently recombines to produce the mixture of oxazolinones. A series of related oxazoles was prepared in which the heterocyclic ring and the ir bond are connected by an alkoxy side chain. All attempts to induce an intramolecular Diels-Alder reaction failed. The only product that could be obtained corresponds to that derived from an intramolecular ene reaction. The excited-state behavior of several 2-and 5-allyloxy-substituted oxazoles was also studied. The rationale for the difference in thermal and photochemical behavior is discussed.

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Phosphonitrilic derivatives. XX. Electronic properties of fluorophosphonitrilic substituents

Cited by 20 publications

References 3 publications

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R₂PN)(SN)₂ (R = Me, Ph, F)

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R₂PN)(SN)₂ (R = Me, Ph, F)

Conjugative interactions in 1-methylpyrrol-2-yl derivatives of the cyclic phosphazenes (NPF₂)_n (n = 3–6): the crystal and molecular structure of 1-methylpyrrol-2-ylheptafluorocyclotetraphosphazene

Studies dealing with the aza Claisen rearrangement of 2-allyloxy-substituted oxazoles

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Phosphonitrilic derivatives. XX. Electronic properties of fluorophosphonitrilic substituents

Cited by 20 publications

References 3 publications

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R2PN)(SN)2 (R = Me, Ph, F)

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R2PN)(SN)2 (R = Me, Ph, F)

Conjugative interactions in 1-methylpyrrol-2-yl derivatives of the cyclic phosphazenes (NPF2)n (n = 3–6): the crystal and molecular structure of 1-methylpyrrol-2-ylheptafluorocyclotetraphosphazene

Studies dealing with the aza Claisen rearrangement of 2-allyloxy-substituted oxazoles

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Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R₂PN)(SN)₂ (R = Me, Ph, F)

Synthetic and kinetic studies of the reversible addition of a bridging NSN fragment to the electron-rich heterocycles (R₂PN)(SN)₂ (R = Me, Ph, F)

Conjugative interactions in 1-methylpyrrol-2-yl derivatives of the cyclic phosphazenes (NPF₂)_n (n = 3–6): the crystal and molecular structure of 1-methylpyrrol-2-ylheptafluorocyclotetraphosphazene