Xenon difluoride fluorination. IV. Photochemically initiated xenon difluoride fluorination of norbornene

Norbornene was selectively fluorinated with xenon difluoride by photochemical means. Unrearranged 2,3-difluoronorbornane isomers and acetonitrile solvent adducts were the exclusive products. This represents a novel example of controlled XeF₂ radical fluorination by light initiation.     

Pentafluorophenylbromine(III) difluoride

Pentafluorophenylbromine(III) difluoride has been prepared by oxidation of pentafluorophenyl bromide at 128°C with elemental fluorine.     

Pentafluorophenylchlorine(III) difluoride

Pentafluorophenylchlorine(III) difluoride has been prepared by the oxidation of pentafluorophenyl chloride at 117°C with elemental fluorine.     

Pentafluorophenylchlorine(III) difluoride

The title compound has been synthesized by oxidation of pentafluorophenyl chloride with elemental fluorine.

Pentafluorophenylchlorine(III) difluoride was a colorless liquid (Boiling Point 96–98°C) which fumed when exposed to air. It oxidized 2.0 equivalents of iodide ion and did not decolorize a 0.1 M potassium permanganate solution. Anal. calcd. for C₆F₅ClF₂: C, 29.96; F, 55.29; Cl, 14.74. Found: C, 29.79; F, 55.07; Cl, 14.90. The ¹⁹F nuclear magnetic resonance spectrum at 25°C consists of a doublet at 141.63, a triplet at 157.05, and a triplet at 162.25 ppm (CFCl₃). The liquid phase infrared spectrum contains absorption bands as 703 (s), 640 (vs), 621 (vs), 553 (vs), 530 (s), 502 (w), 459 (s), 425 (s), 395 (m), 370 (m), 334 (m), 315 (vs), 301 (m), 278 (m), 242 (vw), and 220 (vw) cm^?1.Molecular ions at m/e 240 and 242 accompanied by supporting fragmentation patterns, were present in the mass spectrum along with the isotopic ratio of approximately 3:1 as expected for the ³⁵Cl and ³⁷Cl. The mass spectrum of C₆F₅ClF₂ consists of peaks assigned to C₆F₅ClF₂⁺ (13), C₆F₅ClF⁺ (0.71), C₆F₅Cl⁺ (26), C₆F₄Cl⁺ (0.92), C₆F₆⁺ (6.7), C₆F₅⁺ (29), C₆F₄⁺ (0.72), C₅F₃⁺ (100), ClF₂⁺ (1.1), ClF⁺ (0.7), and Cl⁺ (0.2). Metastable ions were observed in the following region: 184.5, 170.0, 165.6 and 56.0. The peak at m/e 240 showed a very weak metastable peak at m☆ = 144.0 from the process: 240→186 + ClF°.     

Crystal structure of boron difluoride acetylnaphtholates

The crystal structure of luminescent isomeric boron difluoride acetylnaphtholates: 2-acetyl-1-naphthoboron difluoride (1) and 1-acetyl-2-naphthoboron difluoride (2) has been studied. Molecules of 1 make infinite stacks of coplanar molecules in crystals, and molecules of 2 are arranged in the crystalline cell in the form of isolated π-dimers. Unlike a planar molecule of 1, the methyl group in α-position of the diketonate ring drops out of the molecule plane in a molecule of 2, thus forcing the chelate ring to bend considerably along the line C(11)-B. The structure features of 1 cause a bathochromic shift of the luminescence band in comparison with 2.     

Oxidation of nitroxyl radicals by xenon difluoride

Conclusions Oxoammonium fluorides have been prepared for the first time by oxidizing nitroxyl radicals with xenon fluoride. Nitroso compounds are formed in the oxidation of piperidinoxyl radicals.Translated from Izvestiya Akademii Nauk SSSR, Seriya Khimicheskaya, No. 3, pp. 572–576, March, 1978.     

Photodegradation of boron difluoride dibenzoylmethanate in solutions

The UV photostability of boron difluoride dibenzoylmethanate (DBMBF₂) in the aprotic solvents acetonitrile, dimethylsulfoxide, acetone, methyl cyclohexane, dioxane, and tetrahydrofuran has been studied. The DBMBF₂ half-life largely depends on the solvent and varies from 3 min in tetrahydrofuran to 9 h 40 min in acetonitrile. It has been found that the photodegradation of DBMBF₂ involves the detachment of the BF₂ molecule to yield dibenzoylmethane occurring in the ketone (absorption at 220–240 nm) and enol (absorption at 340–345 nm) forms. It has been shown that DBMBF₂ can be stabilized by sterically hindered piperidines, thereby suggesting the participation of singlet oxygen in the photodegradation of DBMBF₂.