Hydrogen fluoride complexes

Perchloric acid (HCIO4 Ho —13.0), fluorosulfuric acid (HSO3F Ho — 15.1), and trifluoromethanesulfonic acid (CF3SO3H Ho —14.1) are considered to be superacids, as is truly anhydrous hydrogen fluoride. Complexing with Lewis acidic metal fluorides of higher valence, such as antimony, tantalum, or niobium pentafluoride, greatly enhances the acidity of all these acids. 

In contrast to pyridine-hydrogen fluoride, which is acidic and acts as a protonating agent, in alkylamine-hydrogen fluoride complexes, fluorine is a nucleophile. The difference of the nature of these two types of reagents has been... 

The trimethylsilyl protecting group can be removed by routine deprotection with triethylamine -hydrogen fluoride complex. 

A, A, A",/V-Tetramethylnaphthalene-l,8-diamine ( Proton Sponge ) Hydrogen Fluoride Complex (2) 3H... 

Phenylmercury(II) fluoride-hydrogen fluoride complex fluorinates phenyl(tribromo-methyl)mereury in 60-65% yield when the reaction is carried out in the presence of 48% hydrogen fluoride. Phenyl(trichloromethyl)mercury can be fluorinated to the trifluoromethyl derivative in this manner, but a reaction temperature of 90 C is required. Partial fluorination of (bromodichloromethyl)phcnylmcrcury to (dichlorofluoromethyl)phenylmercury in 60% yield can be achieved at room temperature, but attempted partial fluorination of phenyl(tri-bromomethyl)mercury, (dibromochloromethyl)phenylmercury, and (dibromofluoromethyl)-phenylmereury was unsuccessful phenyl(trifluoromethyl)mercury is the major product obtained.61... 

Stable dialkyl ether poly(hydrogen fluoride) complexes (R20-[HF]n, R = Me, Et, n-Pr) have recently been developed by Prakash, Olah, and colleagues.33 DFT calculations suggest a cyclic poly(hydrogen fluoride) bridged structure. Dimethyl ether-5 HF (DMEPHF) was shown to be a convenient and effective fluorinating agent (see Section 5.10.1). 

Pyridinium poly(hydrogen fluoride) (PPHF), which serves as an HF equivalent catalyst with decreased volatility,159 showed similar characteristics in liquid CO2.158 Other liquid amine poly (hydrogen fluoride) complexes with high (22 1) HF/amine ratios are also effective catalysts in the alkylation of isobutane with butenes and, at the same time, also act as ionic liquid solvents.160 Likewise the solid poly(ethyleneimine)/ HF and poly(4-vinylpyridinium)/HF (1 24) complexes have proved to be efficient catalysts affording excellent yields of high-octane alkylates with research octane numbers up to 94. 

Stable dialkyl ether poly(hydrogen fluoride) complexes have been shown to be convenient and effective fluorinating agents.553 Various open-chain and cyclic alkenes undergo hydrofluorination with dimethyl ether-5 HF (DMEPHF) atroom temperature to furnish the corresponding fluoro derivatives in high yields (73-94%) with excellent selectivities. The fluorination of secondary and tertiary alcohols exhibit similar features. Bromofluorination of alkenes can also carried out with DMEPHF in combination with /V-bromosuccinimide. The homologous diethyl ether and dipropyl ether complexes are also suitable for fluorinations. 

Fig. 12.2 The benzene-hydrogen fluoride complex connected through F-H—tt hydrogen bonding...

Fig. 6. The infrared spectrum of the dimethylether-hydrogen fluoride complex in the gas phase. From J. Arnold and D. J. Millen, J. Chem. Soc. 503 (1965). Reproduced by permission from the Chemical Society...

In an earlier paper Bevan, Legon, Millen and Rogers 84) presented the microwave spectrum of the water-hydrogen fluoride complex. For the O... F distance they obtain d 2.68 0.01 A and for the dipole moment component along the symmetry axis 3.82 0.02 D. For v they gave, as a preliminary value, 198 cm-1 and for the out-of-plane and in-plane bridge vibrations 94 and 180cm-1, respectively. A full paper has been announced. 

Potassium Hydrogen Fluoride or Sodium Hydrogen Fluoride Complexes... 

Gerber, S., and Huber, H., The sulfur dioxide-hydrogen fluoride complex. Additional information to the experiment from ab initio calculations. Coll. Czech. Chem. Commun. 53,1989—1994 (1988). 

Patten, K. O. J., and Andrews, L., Infrared spectra of diacetylene-hydrogen fluoride complexes in solid argon, J. Phys. Chem. 90, 3910-3916 (1986). 

Medhi, C., Majumdar, D., and Bhattacharyya, S. R, Theoretical studies on the topographical features and energetics of diacetylene-hydrogen fluoride complexes, J. Mol. Struct. (Theochem) 280, 191-197 (1993). 

Davis, S. R., and Andrews, L., Infrared spectra and ab initio SCF calculations for alkane-hydrogen fluoride complexes, J. Am. Chem. Soc. 109,4768-4775 (1987). 

Zeegers-FIuyskens, T., Isotopic ratio of hydrogen fluoride complexes in solid argon,... 

Simple aliphatic oxiranes can be converted to fluorohydrin with hydrogen fluoride only with great difficulty, but the reaction can be carried out in systems with rigid conformations (e.g., steroids, 9,10-epoxydecalin). Good yields can be attained from cyclopentene and cyclohexene oxides with 42% pyridine-polyhydrogen fluoride and in a series of terpene oxides with an amine-hydrogen fluoride complex. ... 

The bromofluorination of norbornadiene using A-bromosuccinimide in the presence of triethylamine-tris(hydrogen fluoride) complex (EtjN 3HF), a highly versatile and easy to handle source of fluoride ions, gave in near quantitative yield a mixture of exo-3-bromo-... 

Olah GA, Mathew T, Goeppert A et al (2005) Ionic liquid and solid HF equivalent amine-poly(hydrogen fluoride) complexes effecting efficient environmentally friendly isobutane-isobutylene alkylation. J Am Chem Soc 127 5964—5969... 

M. T. Carroll and R. F. W. Bader, An analysis of the hydrogen bond in base-hydrogen fluoride complexes using the theory of atoms in molecules. Mol Phys. 65, 695-722 (1988). 

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