Langmuir–Blodgett films of bis-tetrathiafulvalene substituted macrocycle and TCNQ derivatives

Abstract

Tetracyanoquinodimethane (TCNQ) derivatives, 2-fluoroTCNQ (F 1TCNQ), 2,5-difluoroTCNQ (F 2TCNQ) and 2,5-dichloroTCNQ (Cl 2TCNQ) were applied to form molecular nanowire structures of charge transfer complex with dialkyl derivative of bis-tetrathiafulvalene substituted macrocycle ( 1). When we used Cl 2TCNQ, nanowire network structure was obtained as in the case of tetrafluoroTCNQ (F 4TCNQ) previously reported. Although the nanowires were shorter compared with those of F 4TCNQ complex and formed bundles, they oriented in specific directions recognizing the ionic array on mica surface. In the case of F 1TCNQ and F 2TCNQ, we obtained nanowire structures almost identical with those of pure 1. The Cl 2TCNQ formed an ionic complex with 1, in which donor units and Cl 2TCNQ were in fully charge-transferred state. Reflecting the electronic structure, the conductivity of nanowires was estimated to be 2×10 −4 S cm −1.