Benzenediazonium hexafluorophosphates

The hexafluorophosphates are among the most stable halogen complexes known. The highly symmetrical PF ion is stable to boiling aqueous alkaH and is decomposed only slowly in acidic solutions at ambient temperatures. It does hydrolyze rapidly at elevated temperatures in acid (85). The stabiHty of the PF 3 ion can be compared to the isoelectronic SF. The hexafluorophosphates can be decomposed yielding PF although in many cases only at temperatures where the PF reacts with the metal containers. Benzenediazonium hexafluorophosphate can be decomposed to PF, N2, and fluorobenzene at 120°C (86) and is a convenient source for laboratory amounts of PF as well as a frequently used catalyst. 

Ambroz and Kemp (1979 a, 1982 a, b) photolyzed benzenediazonium salts with donor substituents in the 4-position (2,5-di- -butoxy-4-morpholine-, 2,5-diethoxy-4-H-butylthio-, and 2,4,5-trimethoxy-benzenediazonium hexafluorophosphate in LiCl - H20 - acetone matrices at low temperatures, 77-130 K). Under these conditions the aryl cation formed is sufficiently stable to be identified spectroscopically. It is a triplet, a result that is consistent with earlier ab initio calculations by Dill et al. (1977), and with earlier observations by Lee et al. (1961), also at low temperature (77 K). 

The first diazonium-salt-crown-ether adduct was isolated and identified as a 1 1 complex by Haymore et al. (1975). Unfortunately Haymore never published the X-ray structural analysis of benzenediazonium hexafluorophosphate with 18-crown-6 which he performed in 1980. ORTEP drawings with measured bond angles and lengths from Haymore s investigation can be found in a review chapter by Bartsch (1983, p. 893). A few data from Haymore s work (e.g., R = 0.064) were also mentioned by Cram and Doxsee (1986, footnote 7). Groth (1981) published the results of his X-ray investigation of 4-methoxybenzenediazonium tetrafluoroborate and 21-crown-7 (R = 0.042) and Xu et al. (1986) those of 4-methoxybenzenediazonium tetrafluoroborate and dibenzo-24-crown-8 (R = 0.086). 

Diethylamino)benzenediazonium hexafluorophosphate also decomposes more rapidly and more efficiently than the corresponding diazonium tetrafluoroborate under UV irradiation (350 nm) at room temperature (yield 72% vs 53-55%).247... 

However, S. I. Schlesinger found that epoxides could be polymerized by a wide variety of diazonium salts, including p-chloro-benzenediazonium hexafluorophosphate, on exposure to ultraviolet radiation (16, 17). He delineated differences in behavior between various salts and identified those which are most effective in promoting rapid polymerization to high molecular weight. In particular, he showed that the hexafluorophosphates are much more effective as photoinitiators than the tetrafluoroborates (18). 

Rattray and Sutton s binuclear complex 10.42 contains Pd -atoms. Palladium(O) complexes resulted, however, in spontaneous elimination of N2 to give arylpalladi-um complexes (Kikukawa and Matsuda, 1977 Rattray and Sutton, 1978). Yet, Mat-suda s group (Yamashita et al., 1980) was able to obtain (aryldiazenido)palladium(O) complexes by adding two equivalents of an arenediazonium tetrafluoroborate or hexafluorophosphate to a suspension of [[P(C6H5)3)4Pd j in dichloromethane at — 78°C and allowing the mixture to warm to room temperature. Scheme (10-17) demonstrates that a mixture of the aryldiazenido and the aryl complex of Pd is formed. The aryldiazenido complex is subject to dediazoniation at room temperature. UV-irradiation facilitates this dediazoniation. Only in the case of 4-methoxy-benzenediazonium hexafluorophosphate was it possible to isolate the aryldiazenido complex and to identify it by elemental analysis, NMR, and IR spectroscopy. 

Benzene-1,3-diammonium sulfate. Seem-Phenylenediamine sulfate Benzenediazonium, 4-(phenylamino)-hexafluorophosphate (1-) polymer with formaldehyde CAS 68541-74-2 68201-72-9 Classiflcation Benzene diazonium salt Formula (C12H10N3 CH2OF6P)... 

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