Frank P. Cassaretto

Studies in the tetraarylborates : The preparation and reagent properties of sodium tetrakis(p-chlorophenyl)borate

Abstract Sodium tetrakis(p-chlorophenyl)borate was synthesized. It formed precipitates with K+, Rb+, Cs+, quarternary ammonium and protonated basic nitrogen compounds. The potassium salt was more soluble than potassium tetraphenylborate but flocculated more readily and filtered more easily. The salts formed with nitrogen compounds offer possibilities as derivatives suitable for qualitative analysis.

Studies in the tetraarylborates

Abstract The stability of sodium tetraarylborates toward acid attack can be enhanced by placing electron-withdrawing substituents at the m - or p -positions of the phenyl rings, thus rendering them less susceptible to electrophilic attack. A series of tetraarylborates has been studied, and the following order of decreasing resistance toward acid attack has been established: m -fluorophenyl > p -trifluoromethylphenyl > m -trifluoromethylphenyl > p -fluorophenyl ≧ p -chlorophenyl ⋍ phenyl > p -methylphenyl > p -methoxyphenyl. Sodium tetrakis ( m -fluorophenyl) borate does not undergo acid decomposition at pH 2.0 and 50.0°, but it is partially decomposed under these conditions via other pathways.

Studies in the tetraarylborates: Part II. The preparation and reagent properties of sodium tetrakis(p-fluorophenyl)borate, a selective reagent for cesium

Abstract Sodium tetrakis(p-fluorophenyl)borate has been synthesized and found to be a very selective gravimetric reagent for the determination of cesium. It formed precipitates with cesium, silver, thallium(I) and rubidium but not with potassium and ammonium ions. The cesium tetrakis(p-fluorophenyl)borate separated as a white crystalline compound, which was easily filterable. It achieved constant weight rapidly at 110° and showed no signs of decomposition after 18 h of drying.

Studies in the tetraarylborates: The preparation and reagent properties of sodium tetrakis(p-trifluoromethylphenyl) borate and sodium tetrakis (m-fluorophenyl) borate

Abstract Sodium tetrakis(p-trifluoromethylphenyl) borate and sodium tetrakis(m-fluorophenyl) borate were synthesized by a new in situ method. Both salts formed precipitates with potassium, rubidium and cesium ions, quaternary ammonium and protonated basic nitrogen compounds. Potassium tetrakis(p-trifluoromethylphenyl) borate was more insoluble than potassium tetraphenylborate while cesium tetrakis (m-fluorophenyl) borate was less soluble than cesium tetrakis(p-fluorophenyl) borate. The salts formed with nitrogen-containing compounds offer possibilities for qualitative and quantitative analyses.

Studies in the tetraarylborates: Part IV. The, preparation and reagent properties of sodium tetrakis(m - trifluoromethylphenyl) borate

Sodium tetrakis(m-trifluoromethylphenyl)borate has been synthesized and shown to be a highly selective reagent for cesium ion even in the presence of other alkali metal ions. Equivalent amounts of rubidium or potassium do not interfere.

Vibrational spectra of several potassium para-substituted tetraarylborates

Abstract Vibrational spectra for several potassium para-substituted tetraarylborate compounds: KB(C 6 H 4 p -X) 4 , where X is H, OCH 3 , CH 3 , Br, Cl, F, CF 3 , have been obtained in the solid state from 4000 to 200 cm −1 . Emphasis is placed on the X-sensitive modes located between 650 and 200 cm −1 because they are found to react to electronic substituent effects. The parent molecule, potassium tetraphenylborate, is discussed in detail within this region. Tentative assignments are made for absorptions arising from the low frequency phenyl ring modes, vibrations of the tetrahedral skeleton, ionic lattice vibrations, and vibrations that are either internal vibrations of the para -substituent group or vibrations involving the ring-substituent bond. However, these spectra do not yield any information on the electron densities in the vicinity of the central boron atom within these tetraarylborate anions.