title: STM study on 2D molecular assemblies of luminescent quinacridone derivatives: structure fine-tuned by introducing bulky substitutes and co-adsorption with monofunctional/bifunctional acid.
abstract: We describe the 2D assemblies of a series of N,N'-dialkyl-substituted quinacridone derivatives on highly oriented pyrolytic graphite observed by scanning tunneling microscopy. Our experiments have demonstrated that pure quinacridone derivatives take contractive conformations, but quinacridone derivatives take extended conformations when co-adsorbed with dicarboxylic acid. Interestingly, by co-adsorption with monofunctional acid stearic acid, quinacridone derivative bearing two smaller substituted groups of trifluoromethyl takes an extended conformation, while quinacridone derivative bearing two larger substituted groups of tert-butyl still takes a contractive conformation. Therefore, the 2D structure of the quinacridone derivatives can be fine-tuned by co-adsorbing with monofunctional/bifunctional acid through hydrogen bonds.
authors.affiliation: Key Lab of Optoelectronics and Molecular Engineering, Department of Chemistry, Tsinghua University, Beijing 100084, People's Republic of China.
authors.forename: Xunyu
authors.initials: X
authors.lastname: Yang
authors.forename: Jia
authors.initials: J
authors.lastname: Wang
authors.forename: Xi
authors.initials: X
authors.lastname: Zhang
authors.forename: Zhiqiang
authors.initials: Z
authors.lastname: Wang
authors.forename: Yue
authors.initials: Y
authors.lastname: Wang