Synthesis, spectroscopic and thermal studies on solid charge-transfer molecular complexes formed in the reaction of 1-(2-aminoethyl)piperidine with π- and σ-acceptors

The solid charge-transfer molecular complexes formed in the reaction of the electron donor 1-(2-aminoethyl) piperidine (AEP) with the σ-acceptor iodine and π-acceptors 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 7,7,8,8-tetracyanoquinodimethane (TCNQ) and 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD)were studied in chloroform at 25 0C. These were investigated through electronic spectra, infrared spectra, thermal and elemental analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(AEP)I]+I3-, [(AEP)(DDQ)2], [(AEP)(TCNQ)2] and [(AEP)(TBCHD)] in full agreement with the known reaction stoichiometries in solution as well as the elemental measurements. The formation constant KCT (L mol−1), the molar extinction coefficient εCT (L mol−1 cm−1), the free energy change ΔG° (cal mol−1), the charge transfer energy ECT, and the ionization potential Ip   were calculated for the CT-complexes [(AEP)I]+I3-, [(AEP)(DDQ)2], [(AEP)(TCNQ)2] and [(AEP)(TBCHD)].

► We studied the C-T reactions of the donor 1-(2-aminoethyl)piperidine with π- and σ-electron acceptors. ► We analyzed the obtained CT-complexes via FT-IR, UV-Vis, elemental and thermal analysis. ► We calculated KCT, εCT, ΔG, ECT and Ip calculated.