Synthetic Conducting Materials: Charge Transfer Complex of 2,2′-butanediyl-bisisoquinolinium with TCNQ

ABSTRACT

2,2′-Butanediyl-bisisoquinolinium diiodide (DIQC₄I₂) was synthesized by reaction of isoquinoline with 1,4-diiodobutane. This salt was further reacted with TCNQ and TCNQ⁻ to obtain the charge transfer complex DIQC₄⋅TCNQ₃. This charge transfer complex was characterized by elemental analysis, infrared, electronic, and mass spectrometry. The crystal structure of DIQC₄⋅TCNQ₃ is triclinic with a = 8.1478(11), b = 10.2302(13), c = 15.041(2)Å, α = 80.987(10), β = 81.335(10), γ = 70.402(10), Z = 1, and space group P¯1. The donors and acceptors are packed in segregated columns. The IR spectrum shows a very strong absorption envelope in the range of 4000 to 1000 cm⁻¹ resulting from the electronic conduction band. The electrical conductivity of DIQC₄⋅TCNQ₃ is 2.4 × 10⁻² S/cm at room temperature with activation energy 0.20 eV, typical of semiconductor behavior.

Keywords:

• charge transfer salt
• organic conductor
• TCNQ

Acknowledgments

National Science Council, Taiwan (ROC) and Tamkang University supported this work.