83408-22-4Relevant academic research and scientific papers
Triplet-State Phosphoryl Diradicals
Wienk, Martijn M.,Janssen, Rene A. J.,Meijer, E. W.
, p. 9331 - 9336 (1995)
The first example of triplet-state phosphoryl diradicals is reported.Photoinduced dissociative electron capture of two diastereoisomeric m-phenylenebis(phosphinic chloride)s in a glassy toluene matrix at 130 K using an electron-rich olefin affords the corresponding phosphoryl monoradicals and triplet-state diradicals in a 5:2 ratio.The triplet-state ESR spectrum gives zero-field parameters of = 0.0120 cm-1 and = 0.0015 cm-1.Variable temperature ESR experiments reveal Curie behavior for the Δms = 2 ESR signals between 3.8 and 100 K, consistent with a low-energy triplet state that either corresponds to the ground state or is degenerate with a singlet state.For the corresponding p-phenylene diastereoisomers, no triplet-state diradicals can be detected under identical experimental conditions and the ESR spectra only reveal the primary phosphoryl monoradicals and their protonated forms, as secondary species.
Kinetic and Spectroscopic Characterization of the Diarylphosphonyl Radical, (2,4,5-But3C6H2)2=O
Winter, Nicholas Jeremy,Fossey, Jacques,Beccard, Bruno,Berchadsky, Yves,Vila, Francis,et al.
, p. 6749 - 6750 (1986)
The diarylphosphonyl radical, Ar2=O (Ar = 2,4,6-But3C6H2), was generated (1) by hydrogen abstraction from the corresponding phosphine oxide, Ar2P(O)H, and (2) from the precursor, Ar2P(O)Cl, by using methods pioneered by Lappert.Kinetic, spectroscopic, and theoretical methodologies were used to explore the structure and stability of this radical.It was discovered that the apparent lifetime of the Ar2=O species was dependent upon the method of generation.For radicals generated from Ar2P(O)H, the first-order decay constant can be represented by the Arrhenius expression, k ca./= 1.5*1014 exp(-93kJ/RT).The ESR spectrum of the 17O-enriched radical was uniquely informative.The experimental determination that the 17O isotopic hyperfine coupling is negative, AO = -9.4 G, provides strong evidence that the unpaired electron is delocalized.Ab initio MO calculations concur with this finding.
