Charge-transfer complexes of 4-methylpiperidine with σ- and π-acceptors

• Three CT-complexes of donor 4MP with the acceptors DDQ, TBCHD and iodine are obtained.
• An adduct 7,7,8-tricyano-8-benzylpiperidinylquinodimethane [TCMPQDM] is produced with TCNQ.
• The CT-complexes are characterized through FTIR, UV–Vis, elemental and thermal analysis.
• The values of KCT, εCT, ECT, ΔG0 and Ip are calculated.

The solid charge-transfer (CT) molecular complexes formed in the reaction of the electron donor 4-methylpiperidine (4MP) with the σ-electron acceptor iodine and π-acceptors 7,7,8,8-tetracyanoquinodimethane (TCNQ), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) and 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD) have been investigated spectrophotometrically in chloroform at 25 °C. These were characterized through electronic and infrared spectra as well as elemental and thermal analysis. The obtained results showed that the formed solid CT-complexes have the formulas [(4MP) I]+I−3, [(4MP)(DDQ)2] and [(4MP)(TBCHD)] and with TCNQ the adduct [TCMPQDM] is obtained through N-substitution reaction in full agreement with the known reaction stoichiometries in solution as well as the elemental measurements.The formation constant KCT, molar extinction coefficient εCT, free energy change ΔG0, CT energy ECT and the ionization potential Ip have been calculated for the CT-complexes [(4MP) I]+I−3, [(4MP)(DDQ)2] and [(4MP)(TBCHD)].

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