The establishment of the oligomeric purity and molecular structure for n-methylated bis(8-hydroxyquinoline) zinc (n = 0, 2, 4, and 5)

Znq2 has been studied as electroluminescent material. However, no correlation of the structure of Znq2 to resulting device properties has been established. Most reports of Znq2 as an electroluminescent material have not considered the impact of higher order molecular structures on the device properties. By utilization of size exclusion chromatography it has been determined that the dominant species of nMeq2Zn (n = 0, 4, 5) is tetrameric in crystalline form dissolved in chloroform, in thermally vapor deposited films, and in crystalline form dissolved in chloroform and DMSO. The 2Meq2Zn was determined to be solely monomeric under the previously mentioned condition. The significance of this work is that it provides the oligomeric structure(s) of the methylated zinc chelates, and the data reveals that the process of thermal vapor deposition, which is used to create organic light emitting devices, do not break up the higher molecular order oligomer.