IR absorption spectra from various K-phases of BEDT·TfF radical cation salts as well as from a-(BEDT·TIFhI, arc presented. From tbese spectra one special mode l'n representing the asymmetric ring C-C stretching vibration is assigned and the dependence of its frequency from the average charge on the donor molecule is given. The investigation of the metal-insulator phase transition of a-(BEDT·TrF)2I, at 135 K with respect to this vibrational model lin gives strong indication of a charge localization in at least one of the two crystallographic different stacks. Furthennore, we correlate the frequencies of the Cfh stretching modes of a variety of BEDT·TIF radical salts witb tbe superconducting phase transition temperatures. These frequencies are evidently not charge dependent, but significanUy reOect the strength of the interaction of the donor molecule with the respecti'Ye anion. It could be shown that phases with a higher Tc of their superconducting transition exhibit a smaller red shift of these frequencies, i.e., a less attractive donor-anion interaction.
Nylon 7, the polyamide from 7-aminoheptanoic acid, was discovered by coincidence by Manasse in 1902' who obtained the multiple of C,HlaNO-NH(CH2)LDwhen heating 7-aminoheptanoic acid to determine its melting point. Although, based on the fundamental work on polyamides by Carotheq2 polyamide fibers such as nylon 6 (polycaproamide) and nylon 66 (polyhexamethyleneadipamide) experienced a worldwide growth during the past twenty years, relatively little became known about nylon 7 (polyheptanamide). Laboratory samples of nylon 7 were prepared by academic routes, e.g., suberone + suberoneoxime + enantholactam ;3 pimelonitrile + 7-aminoheptanonitrile + 7-aminoheptanoic acid,4 and a few properties of the polyamide were determined. Wiloths conducted kinetic measurements on the polycondensation of 7-aminoheg tanoic acid, and Schaafa studied the polymerization of the enantholactam. During the past few years, however, a group of Russian researchers7 developed a process for 7-aminoheptanoic acid via telomerization of ethylene with carbon tetrachloride to the 1,1,1,7-tetrachloroheptane and its subsequent hydrolysis and amination. The development of a nylon 7 fiber based on this monomer synthesis has been reported to be under study.An industrially feasible synthesis for ethyl-7-aminoheptanoate, a monomer for nylon 7, and a simple polycondensation process to the high molecular weight polyamide were developed in this laboratory. Moreover, a detailed study of the fiber properties of this polymer was carried out.
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