The surface of aqueous solutions of 4-Nitro Benzo-15-Crown-5 (NB15C5) and Benzo-15-Crown-5 (B15C5) has been studied using the surface sensitive technique vibrational sum frequency spectroscopy (VSFS). The NO, CN, COC and CH vibrational modes of these compounds at the air-water interface as well as OH vibrational modes of the surface water hydrating this compound have been targeted in order to obtain molecular information about arrangement and conformation of the adsorbed crown ether molecules at the air-water interface. The CH(2) vibrational modes of crown ethers have been identified and found to be split due to interaction with ether oxygen. The spectra provide evidence for the existence of a protonated crown complex moiety at the surface leading to the appearance of strongly ordered water species. The interfacial water species are influenced by the resulting charged interface and by the strong Zundel polarizability due to tunneling of the proton species between equivalent sites within the crown ring.

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The acid was optically inactive and gave no methoxyl by Zeisel determination. It was soluble in alkali but precipitated on addition of carbon dioxide; neutral equivalent, 246-268. Titration of a purer sample with a Beckmann pH meter indicated a of 10 = 0.5 and a neutral equivalent of 230 = 5. It gave no color with ferric chloride, sublimed unchanged and was recovered unchanged after boiling for one hour with alcoholic alkali, after refluxing with pyridine-acetic anhydride and after treatment with semicarbazide acetate for two days. The ultraviolet absorption at 2220 Á. had log e = 2.38, decreasing steadily with increasing wave length. In alkaline solution the curve was shifted 350 Á. toward the visible, with a maximum between 2350-2450 Á.; log e = 2.74. Work designed to elaborate the structure of this compound is in progress.The crude cholesterol fractions contained a different neutral hapten, not yet isolated in pure form, but active in dilutions of 1:100,000. Perhaps these two substances are reponsible for two of the Rh subgroups.