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The 500 to 1,800-cm-1 region of the Raman spectra of intact single muscle fibers from the giant barnacle are dominated by bands caused by the protein component of the fibers. The frequency and the intensity of the conformationally sensitive bands indicate that the contractile proteins adopt a predominantly alpha-helical structure and are not affected when the contractile state of the fibers is changed from relaxed to contracted by addition of ATP and Ca. However, the contraction induces a decrease of the scattering intensity of some of the Raman bands caused by the acidic and tryptophan side chains, showing that these amino acids are involved during the generation of tension.

. Can. J. Chem. 60,853 (1982). The macrocyclic ether 1,4,7,10,13,16-hexaoxaoctadecane (18-crown-6) has the remarkable property of being able to transfer the hydronium (H,O+) ion from an aqueous solution to an organic medium. This property has been used to synthetize a 1:l stoichiometric complex of this ether with hydronium tetrafluoroborate. This complex is very stable (mp 145°C) and dissolves readily, without decomposition, in solvents such as CHCI,. The presence of the H 3 0 + and BF4-ions in the complex has been confirmed by chemical analysis, and by IH nmr, Raman, and ir spectroscopy. The vibrational spectraindicate that a conformational change of the crown ether takes place in the complex over the temperature range -50°C to -100°C. The symmetry of the crown ether, which appears to be relatively high at room temperature, is considerably reduced below the transition temperature.ROBERT CH~NEVERT, AND& RODRIGUE, MARIE PIGEON-GOSSELIN et RODRIGUE SAVOIE. Can. J. Chem. 60,853 (1982). L'ether macrocyclique 1,4,7,10,13,16-hexaoxaoctad&cane (18-crown-6)

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