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Thionyl chloride has been shown to react with the zwitterion from dimeric sulfene and triethylamine to give bis(methylsulfonyl dichloromethyl) disulfide, 3. The structure of 3 was determined from its spectral properties and was confirmed by an X-ray crystal structure analysis. Dechlorination of 3 gave bis(methylsulfonylmethyl) disulfide, 4. Raman spectra of 3 and 4, as well as of 5 and 6, two related sulfones derived from 2,4,6-trithiaheptane, are reported.

The crystal structure of trimeric phosphonitrilic isothiocyanate, I\T3Ps( NCS)6, has been determined by three-dimensional single-crystal %-ray studies. The compound crystallizes in the triclinic space group P i with a = 11.79 (3), b = 8.02 ( 2 ) , c = 10.31 (1) A, a = 96" 0' (30'), P = 99" 4' (30'), -/ = 97" 28' (33'1, and two molecules per unit cell. The calculated density is 1.70 (2) g c m P ; the experimental density is 1.62 ( 8 ) g ~m -~. The structure was solved from 1246 independent nonzero reflections collected on film by the Weissenberg technique and refined to a conventional R factor of 0.12. The nitrogen atoms of two isothiocyanate groups are bonded t o each phosphorus atom in the six-membered phosphorus-nitrogen ring.Five of the atoms of the phosphonitrilic ri;g are planar, with the sixth atom, a nitrogen, 0.15 A out of the plane. The average P-N bond length ia the ring is 1.58 A with a root-mean-square deviation of 0.05 A; the average P-N (exocyclic) bond length is 1.63 f 0.01 A. IntroductionTimeric phosphonitrilic isothiocyanate was first prepared by Audrieth and c o~o r k e r s .~~~ The isothiocyanate structure as opposed to the thiocyanate structure was assigned on the basis of the infrared s p e~t r u m .~ Stahlberg and Steger6 made a detailed study of the Raman spectrum of this compound in solution and also concluded that the structural unit in this compound is the isothiocyanate. They interpreted the spectrum in terms of D a h molecular symmetry.Crystal and molecular structures have been reported for several other trimeric compounds, including the f l~o r i d e ,~ chloride,8, and bromide, lo but no pseudohalide structure has been determined. This paper reports the results of a three-dimensional X-ray analysis on the structure of trimeric phosphonitrilic isothiocyanate.

The structure of 1,1-bis(diphenylphosphino)-2,2-dimethylhydrazine, [(C6H5)2P]2NN(CH3)2 has been determined crystallographically. The compound crystallizes from n-heptane in the space group P21/c with a = 8.910(1), b = 9.686(1), c = 27.489(4) Å, and β = 102.94(2)° with four molecules per unit cell. The structure was solved from 2669 independent reflections with I > 3σ(I) and refined by block diagonal least squares methods to R = 0.032 and Rω = 0.048. Each diphenylphosphino group is bonded to the same hydrazine nitrogen and the geometry about this nitrogen is nearly planar. The average dimensions of the structure are P—C = 1.828 ± 0.005, P—N = 1.715 ± 0.014, N—N = 1.451, and N—C = 1.457 ± 0.003 Å, [Formula: see text], [Formula: see text], [Formula: see text], [Formula: see text], and [Formula: see text].

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