Physical Properties of Cyanine–7,7,8,8,8-Tetracyanoquinodimethane Charge Transfer Complexes

A novel intramolecular charge transfer complex–cyanine–7,7,8,8,8-tetracyanoquinodimethane (TCNQ) dye was formed by grafting. The cyanine–TCNQ complex was characterized by UV–vis spectroscopy, fluorescence emission spectroscopy, and magnetic techniques. The optical properties of the cyanine–TCNQ dye, which forms an intramolecular charge transfer complex, are significantly different from cyanine–I with the same basic structure. A g factor of 2.0029 was determined. The magnetic susceptibility of intramolecular complexes with linkers containing three or five carbon atoms, E03–TCNQ and E05–TCNQ, increase rapidly as temperature decreases below 70 K. E03–TCNQ and E05–TCNQ are paramagnetic and plots of 1/(χ M -χ TIP ) versus T show that the Curie–Weiss temperatures θ are 8×10 -5 K and 0.398 K for E03–TCNQ and E05–TCNQ, respectively.