- Mixed-valence derivatives of phosphorus sulfides. Two new isomeric thiophosphoryl-μ-thio-phosphines containing fluorine and trifluoromethyl substituents and a discussion of their exchange properties
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Two new mixed-valence phosphorus compounds F2P(S)SP(CF3)2 and (CF3)2P(S)SPF2 are formed by the reaction of the acids F2PS2H or (CF3)2PS2H with the aminophosphines (CF3)2PN(CH3)2 or F2PN(CH3)2, respectively. Temperature-dependent nmr spectroscopy demonstrates the presence of an exchange process which destroys P-P coupling at room temperature in (CF3)2P(S)SPF2 but not in F2P(S)SP(CF3)2. The directly bound substituents are not interchanged by the exchange process and phosphorus valence is maintained. Concentration-dependent nmr studies indicate an intermolecular process and a plausible bimolecular process is described which accounts for the exchange process in X2P(S)SPX2 (X = F, CF3) molecules. When combined, the two new mixed-valence compounds equilibrate to form the two known symmetrically substituted isomers F2P(S)SPF2 and (CF3)2P(S)SP(CF3)2 and the equilibrium mixture can also be approached from these compounds. Thermal stability trends indicate a lower stability for compounds containing the PF2 moiety. Chemical reaction with protic species occurs with cleavage at the PIII-S link to yield phosphines and the parent acid and with halogens to yield halogeno phosphines and thiophosphinates. The reactions with mercury yield dithiophosphinato complexes and diphosphines or their decomposition products. Alkaline hydrolysis of CF3 species proceeds to yield 2 mol of CF3H per CF3 phosphino group and 1 mol per thiophosphinato group.
- Doty, Leon F.,Cavell, Ronald G.
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p. 2722 - 2729
(2007/10/14)
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- Trimethylsilyl esters of phosphorus acids. III. Esters of difluoro- and bis(trifluoromethyl)phosphinous and -thiophosphinous acids
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The esters R2PESi(CH3)3 (R = F, E = O; R = CF3, E = O, S) have been prepared using one or more of four synthetic routes (CF3)2PSSi(CH3)3 is the first known example of a PIII-S-Si bridged compound, but the analogous difluoro ester F2PSSi(CH3)3 appears to be thermally unstable at 25°. Attempted syntheses of the P(V) isomers R2P(E)Si(CH3)3 gave only the P(III) forms, indicating that these systems are susceptible to anti-Arbuzov rearrangements. The difference in the stability and polarity between the P-O-Si and P-S-Si bridge units was demonstrated by the reactions of the esters with HCl and (CH3)2NH. At least three different reactions of the esters with dimethylamine were observed: cleavage at the E-Si bond with or without concomitant subsequent reaction of (CH3)3SiN(CH3)2 with the ionic product R2PE- and, in the case of (CF3)2POSi(CH3)3, displacement of CF3H to yield CF3[N(CH3)2]POSi(CH3)3. The latter phosphine showed a temperature-dependent nmr spectrum consistent with conformational isomerism of the N(CH3)2 group.
- Cavell,Leary,Sanger,Tomlinson
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p. 1374 - 1380
(2008/10/08)
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