Synthesis, spectroscopic, thermal and structural investigations of charge-transfer complexes of 4,4′-trimethylenedipiperidine with chloranil, TBCHD, DDQ, TCNQ and iodine

The charge-transfer interactions between the electron donor 4,4′-trimethylenedipiperidine (TMDP) and the acceptors 2,3,5,6-tetrachloro-1,4-benzoquinone (chloranil), 2,4,4,6-tetrabromo-2,5-cyclohexadienone (TBCHD), 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), 7,7′,8,8′-tetracyanoquinodimethane (TCNQ) and iodine have been studied spectrophotometrically in CHCI3 solutions. The formed solid charge-transfer complexes were also isolated and characterized through infrared spectra as well as thermal and elemental analysis. The stoichiometry of the complexes was found to be 1:1 in the case of TMDP–chloranil and TMDP–TBCHD systems and 1:2 in the case of TMDP–DDQ and TMDP–TCNQ systems and 1:3 in the case of TMDP–iodine system. Taking this into consideration along with infrared spectra and thermal and elemental analysis, the formed CT-complexes have the formulas [(TMDP)(chloranil)], [(TMDP)(TBCHD)], [(TMDP)(DDQ)2] [(TMDP)(TCNQ)2] and [(TMDP)I]+·I5−, respectively.