SynopsisA model for the hydration behavior of human stratum corneum has been developed from measurements on in vitro samples isolated in a manner which minimized tissue treatment and trauma. Water sorpt~ion/desorption rate meslsurements as a function of water activity, temperature, and tissue integrity are reported. These data, together with thermodynamic data (infrared and nmr results reported earlier) are consistent with a model in which rapidly sorbed/desorbed water (ca. 0.5 mg water/mg stratum corneum) is associated with ("bound" by) the tissue, while slowly sorbed/desorbed "free" water (up to 12 mg water/mg stratum corneum) is kinetically restricted and probably intracellular in location. Both equilibrium water binding and desorption kinetic data suggest structural changes of this cellular water barrier upon hydration. Evidence for hysteresis in water sorption isotherms (reported by others) could not be reproduced.

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An improved synthesis of the recently described dialkyl sulfone diimines1•2 in acetonitrile is described. Reaction of chloramine-ammonia with dialkyl sulfides in 2-propanol has been shown to yield sulfoxide and sulfone imine by-products, as well as sulfone diimines. Their formation is best accounted for by assuming that displacement of sulfur on chloramine occurs to some extent on chlorine, as well as on nitrogen. The crystalline and aqueous solution Raman spectra of dimethyl, diethyl, and methyl dodecyl sulfone diimine have been measured and are shown to be consistent with tetrahedral bonding for sulfur (C2v local symmetry). Tentative band assignments are presented based on comparison with analogous compounds and the Raman spectra of dimethyl sulfide, diethyl sulfide, and dimethyl sulfone imine. Characteristic vibrational bands for R2S(NH)2 are tabulated and the spectral evidence for hydrogen bonding of this new semipolar group is discussed. The sulfone diimines were shown to be considerably more stable thermally than sulfimines but less stable than sulfoxides. Hydrolysis by acid or base catalysis could not be effected, although decomposition via other routes occurred in acid.2 The basicity and metal complexing abilities 436 m 506 r(SN2), rock 460 w 486 t(SN«), twist 679 vs, P 691 vs, P 700 vs, P rs(CS), sym stretch 720 r(NH2), NH2 rock 741 m 742 s 770 s yaa(CS), asym stretch 947 s, P 902 vs(SN), sym stretch (975 vw)' 929 ras(SN), asym stretch 1162 w 1131 r(NHi), NH2 rock 1026 w,P