摘要:
Synthesis, redox properties, and crystal structures of tris(alkylamino)phenalenyliums (TAP) having alkyl groups (n-Pr, i-Pr, t-Bu) and their charge-transfer salts with tetracyanoquinodimethane radical anion (TCNQ(center dot-)) were investigated. The electrochemical measurements revealed that TAP exhibits two irreversible reduction processes to neutral radical and anion species. The introduction of an alkylamino group caused a large negative shift of the first reduction potential and a significant decrease of the on-site Coulomb repulsion because of the electron-donating nature of amino groups and the extension of the pi-electronic system. In the crystal structures of the BF(4)(-)salts, the TAP skeleton possesses a nearly 3-fold symmetric molecular plane indicating the delocalization of positive charge. The face-to-face stack of TAP former pi-dimer or columnar structures, which were connected through intermolecular N-(HF)-F-... hydrogen bonds with BF4- to construct multidimensional network structures. The TCNQ(center dot-) salts prepared by the metathesis method were characterized as fully ionic salts with a 1:1 component ratio. In the crystal structures, both TAP and TCNQ(center dot-) molecules formed pi-dimers, and the intermolecular hydrogen bonds between TAP and TCNQ(center dot-) constructed a two-dimensional sheet.