EVIDENCE FOR THE HIGH-ENERGY (COLLINEAR) VAN DER WAALS ISOMER OF THE ACETONITRILE DIMER

摘要: While the stable configuration of acetonitrile dimer has antiparallel dipole moments, recent calculations [Popelier, et al. Faraday Discuss. 1994, 97, 243] reveal a high-energy isomer in which dipoles are collinearly aligned. We report direct evidence for existence this using strategy we enforce less-favorable orientation neutrals by electrostatically binding them to iodide ion I-·(CH3CN)2 cluster. The collinear is then released photoexcitation dipole-bound excited state I-·(CH3CN)2, producing (CH3CN)2- anion as dominant ionic photofragment. fragment mass selected and stripped excess electron modest external electric field (∼10 kV/cm), indicating that consists diffuse expected “dipole-bound” species. This behavior suggests force neutral “core” complex supports minimum highly dipolar, configuration.