Tetraphenylphosphonium salts

Reaction of Na2Se and Na2Sc2 with Se in the presence of ethanolic solutions of tetraalkyl-ammonium halides and catalytic amounts of I2 yields dark green or black crystalline polyselenides (jc = 3,5-9) depending on the conditions used and the particular cation selected. Tetraphenylphosphonium salts and crown ether complexes of alkali or alkaline earth cations in dimethylformamide solution can also be used. " )... 

Meanwhile, it was found by Asai and colleagues [48] that tetraphenylphosphonium salts having such anions as Cl, Br , and Bp4 work as photoinitiators for radical polymerization. Based on the initiation effects of changing counteranions, they proposed that a one-electron transfer mechanism is reasonable in these initiation reactions. However, in the case of tetraphenylphosphonium tetrafluoroborate, it cannot be ruled out that direct homolysis of the p-phenyl bond gives the phenyl radical as the initiating species since BF4 is not an easily pho-tooxidizable anion [49]. Therefore, it was assumed that a similar photoexcitable moiety exists in both tetraphenyl phosphonium salts and triphenylphosphonium ylide, which can be written as the following resonance hybrid [17] (Scheme 21) ... 

This species has been isolated as the tetraphenylphosphonium salt (Ph4P)8e which is produced in the following complex reaction at 20 °C [138] ... 

Aryl chlorides are not very reactive under normal Heck reaction conditions but reaction can be achieved by inclusion of tetraphenylphosphonium salts with Pd(OAc)2 or PdCl2 as the catalysts.138... 

TTF salts containing similar ferrocenium anions have been prepared through metathesis reactions between (TTF)3(BF4)2 and the tetraphenylphosphonium salts of the desired anions [71]. The crystal structure of (TTF)(CpFeCp-CONHCH2 S03)-1/3H20 contains isolated TTF dimers. Hydrogen bonds of the —NH—OS- and NH—0=C- type are present between anions. Two phases of the TTF salts with the... 

An oxoiron(V) species such as 6 derived from 1 and peroxides is accessible in nonaqueous media (51). The reaction of the tetraphenylphosphonium salt of la with 2 to 5 equivalents of m-chloroperbenzoic acid (mCPBA) at — 60°C in n-butyronitrile produces within about 10 s a bis-iron(IV)- i-oxo dimer followed by an as - yet uncharacterized EPR - silent iron(IV) intermediate. After 15 min, the deep green oxoiron(V) species 6 forms with distinct absorption maxima at 445 nm (e — 5400 Mr1 cm-1) and 630 nm (s — 4200 M-1 cm-1). At —60°C, 6 decays by 10% in 90 min, but it is stable for at least one month at 77 K. Selected spectral data for the oxoiron(V) species are shown in Fig. 13. DFT calculations favor the low-spin (S = 1/2) configuration of the ground state. The calculated Fe-0 bond length of 1.60 A is in excellent agreement with the EXAFS results. The Fe atom is displaced out of the 4-N plane by 0.5 A. 

The preparation of this extremely explosive material is reported, It once exploded spontaneously on isolation. It is recommended that no more than 100 mg be handled, using face-shields, leather aprons, Kevlar gloves and Teflon spatulas. Some pentaazidotellurate(IV) salts were also prepared a yellow oil probably the crude tetramethylammonium salt exploded on stirring [1], Tellurium tetraazide was reported by another group at much the same time, they also prepared a hexaazido-tellurate (2-) as the bis(tetraphenylphosphonium) salt [2],... 

Whereas the reaction of tetraphenylphosphonium salts with methyllithium had yielded solely degradation products 33,109 the analogous reaction of bis-2,2 -bi-phenylylenephosphonium ion 34 with methyl- and n-butyllithium produced the first stable phosphoranes 25a, b containing an alkyl groupS8>. 

Mercury bis[benzenetellurolate] and sodium benzenetellurolale in liquid ammonia formed a tris[benzenetcllurolato]mercurate(II) anion that was isolated as the tetraphenylphos-phonium salt. This salt and tetraphenylphosphonium benzenetellurolate combined in chloroform solution to give the tetraphenylphosphonium salt of undecakis[benzenetellur-olato ] trimercurate1. 

Treatment of the complex with donor molecules such as pyri-dines, phosphines, bipyridyl (2,2 -bipyridine), etc., results in the cleavage of the dimer and formation of diamagnetic five- and six-coordinate adducts.4 Nitric oxide reacts with the complex forming the unstable green mononitrosyl [Co(NO)S4C4(CN)4]-which has one unpaired electron.3 Treatment with Na2S2C2-(CN)2 results in the formation of [CoS6C6(CN6)]3 which can be isolated as the tetraphenylphosphonium salt.14... 

The rate of polymerization initiated by (l-naphthyl)triphenylphosphonium salts is four to five orders of magnitude slower than the one initiated by the corresponding tetraphenylphosphonium salts. Remarkably, control was maintained although no special attention was paid to the mixing of reactants. ... 

Fig. 27. Structures of (a) the SeBr4 and (b) the SegBre ions, both as analyzed in the tetraphenylphosphonium salts, with bond distances (A) (263).

The preparation and i.r. spectra of the tetraphenylphosphonium salts of the trinuclear anions (52) with pure metal isotopes 64Zn, 68Zn, 92Mo, and... 

The UV absorption curves of all the present complexes have peaks with e=ea.l03M-1cm- from 31,000 to 45,000 cm-1. Denning, Hartley and Venanzi assigned the absorption bands of Zeise s salt in this region to d-ir (ethylene) transition. (12) We have observed CD peaks with Ac s -1.3 and +3.3 at ea.35,000 and 39,500 cm-1 for the tetraphenylphosphonium salt of [PtCl3(5,5-tbn)] in acetonitrile. 13) The peak at 35,000 cm l must correspond to the same transition as that of the main CD band of Figure 10 (and Figure... 

Collins and Thomas114 have studied the electropolymerization of acrylonitrile, employing tetraalkylammonium and tetraphenylphosphonium salts. In both cases they found a direct activation of the monomer, and, with the phosphonium salt, they observed that electrochemical interaction takes place at the growing end of the polymer chain ... 

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