The Thioxophosphane H-P=S and Its Tautomer H-S-P, (Thiohydroxy) phosphinidene, are Stable in the Gas Phase -(confirmation by neutralization-reionization mass spectroscopy).-(WONG, T.; TER-LOUW, J. K.; KECK, H.; KUCHEN, W.; TOMMES, P.; J. Am. Chem. Soc. 114 (1992) 21, 8208-8210; Dep. Chem., McMaster Univ., Hamilton, Ont. L8S 4M1, Can.; EN)

Using the technique of neutralization-reionization mass spectrometry (NRMS) we have shown that the elusive thioxophosphane H-P=S and its tautomer H-S-P, (thiohydroxy)phosphinidene, are stable molecules in the gas phase.H-S-P"+ radical cations, generated by electron impact ionization of diethylphosphine sulfide, (C2H5)2HP=S, are cleanly reduced to H-S-P; whereas H-P=S"' anions, generated in a negative chemical ionization (NCI) experiment with the diethylphosphine sulfide, are readily oxidized to H-P=S. Double collision experiments on the 34S isotopomers of the two tautomeric species were used to confirm the connectivity of the atoms. H-S-P is the first example of a molecule of the composition "XPS" (e.g., X = F, Cl, or Br) in which P does not take the central position.

Cf. discussion on autocatalysis and asymmetric amplification for reactions of polar metal derivatives: H. Wynherg, Chimiu 1989, 43, 150-152; A. H. Alberts. H. Wynberg, J. Am. Chcm. Soc. 1989. / / I . 7265-7266, R. Noyori, M. Kitamura, Angew. Chem. 1991, 103. 34-55; Angew. Chem. h r . Ed. EngI. 1991. 30, 49-69. [5] For a description of a suitable low-temperature apparatus see D. Seebach,

No abstract

The preparation of lithiumphosphinoformates R,PCOOLi 1 (R = Ph, c-Hexyl, i-Pr, Et) and RHPCOOLi 2 (R = Ph, c-Hexyl) from R,PLi or RPHLi and CO, is described. In the latter reaction RP(COOLi), 3 and RPHz are formed in addition to 2. In protic media 1-3 are rapidly decomposed with decarboxylation and formation of R,PH and RPH,, respectively. Reactions of 1 with MeI, (MeO),SO,, Me,SiCI and CS, are similar to those of Ph,PCOONa and no significant influence of R was detected. With (MeO),SO, mixtures of 2 and 3 gave esters RHPCOOMe and RP(COOMe), while with Me,SiCI RHPCOOSiMe, was obtained as the sole product. Ah initio MO calculations (GAUSSIAN 90 system of programs; HF/3-21G*, HF/6-31G** and MP2/6-31G** basis sets) showed the phosphinoformic acid to be less stable than its decomposition products, from which it is separated by a high barrier of isomerization. Therefore the acid should be stable in the rarefied gas phase.Die Darstellung der Lithiumphosphinoforrniate R,PCOOLi 1 (R = Ph, c-Hex, i-Pr, Et) und RHPCOOLi 2 (R = Ph, c-Hex) aus R,PLi oder RPHLi und CO, wird beschrieben, wobei neben 2 auch RP(COOLi), 3 und RPH, gebildet werden. 1-3 zersetzen sich in protischen Medien unter Decarboxylierung und Bildung von R,PH bzw. RPH,. Die Verbindungen 1 reagieren ahnlich wie Ph,PCOONa mit MeI, (MeO),SO,, Me,SiCI und CS,, wobei ein nennenswerter Einflu5 von R auf den Reaktionsablauf nicht erkennbar war. Mit (MeO),SO, reagieren Gemische von 2 und 3 zu den Estern RHPCOOMe und RP(COOMe),, wahrend mit Me,SiCI RHPCOOSiMe, als einziges Produkt isoliert wird. A b initio MO Rechnungen (Gaussian 90 Programmsystem; HF/3-21G*, HF/6-31G** und MP2/6-31G** Basis) zeigen, daS die Phosphinoameisensaure weniger stabil ist als ihre Zersetzungsprodukte, von denen sie aber durch eine hohe Isomerisierungsbarriere getrennt ist. Daher sollte die Saure in der verdiinnten Gasphase stabil sein.