Collection of Czechoslovak Chemical Communications - digital archive 

Abstract

Charge transfer (CT) complexes of 4-(dimethylamino)pyridine (DMAP) with iodine as a typical σ-type acceptor and with typical π-type acceptor, 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ), have been synthesized and characterized. Octafluorotoluene (OFT), octafluoronaphthalene (OFN), perfluorophenanthrene (PFP), and 2,3,5,6-tetrafluoropyridine-4-carbonitrile (TFP) were also used as acceptors for interaction with DMAP. Properties of such CT complexes were investigated by UV/VIS and IR spectra, and elemental analyses of the isolated complexes. The systems DMAP-iodine and DMAP-DDQ are characterized by formation of triiodide ions (I₃^-) and DDQ^•- anion radicals, respectively, which is proposed to occur via initial formation of outer-sphere CT complexes. The systems (DMAP-OFT, DMAP-OFN, DMAP-PFP and DMAP-TFP) are characterized by the appearance of new UV/VIS spectral bands assigned as CT bands; they also furnished the corresponding solid complexes with the stoichiometric ratio 1:1. ¹H and ¹⁹F NMR spectra were used on confirming the formation of the DMAP-PFP CT complexes. The formation constants (K_CT) and molar absorption coefficients (ε_CT) of the latter complex were obtained.

Keywords: Charge transfer complexes; CT complexes; 4-(Dimethylamino)pyridine (DMAP); Fluoroarenes acceptors; Formation constants; UV-VIS spectroscopy.

References: 52 live references.