RESUMO
In a one-step reaction, we prepared a dibenzylamine perylene diimide derivative (PDI). Its double hook structure allows for self-association with a constant of Kd â¼108 â M-1 determined by fluorescence. We confirmed its ability to bind PAHs using UV/Vis, fluorescence, and 1 Hâ NMR titrations in CHCl3 . The complex formation signature in UV/vis is a new band at 567â nm. The calculated binding constants (Ka â¼104 â M-1 ) follow the trend pyrene>perylene>phenanthrene>naphthalene>anthracene. Theoretical modeling of these systems using DFT ωB97X-D/6-311G(d,p) proved helpful in rationalizing the complex formation and the observed association trend. The distinctive signal in UV/vis is due to a charge transfer in the complex from orbitals in the guest to the host. SAPT(DFT) confirmed that the driving forces in the complex formation are exchange and dispersion (π-π interactions). Still, the recognition ability depends on the electrostatic component of the interaction, a minor fraction.
Assuntos
Perileno , Hidrocarbonetos Policíclicos Aromáticos , Perileno/química , Imidas/química , Modelos TeóricosRESUMO
In this work the interaction of halide anions and simple aromatic compounds with a bichromophoric fluorescent dyad derived from 1,8-naphthalimide (NAPIM) and 5-(dimethylamino)naphthalene-1-sulfonyl (DANS) was studied using electronic spectroscopy, 1H, and 19F NMR spectroscopy and quantum chemistry modeling (b3lyp/def2-TZVP). The NAPIM-DANS dyad interacts with electron-rich guests with binding constants in the range of 6×103 to 8×103M-1 in CHCl3. The formed complexes are stabilized through aryl C-H anion and aryl C-H π interactions.