Iodine doping of ethynyl-copper compounds: A reinvestigation

Exposure of ethynyl-copper(I) compounds (copper acetylides), derived from cyclohexylacetylene, phenylacetylene and diethynylbenzene, to iodine vapour increases the relevant conductivities from 10-9 - 10-11 to 10-1 - 101 ohm-1 cm-1. Infrared, Raman, e.s.r., u.v.-vis and mass spectrometric analyses indicate that, unlike interpretations in the literature, iodine does not dope the above materials. Instead, they are converted into iodinated ethynyl compounds, symmetrical diynes and copper(I) iodide, the last accounting for the observed conductivity increase.