Effect of the substitution pattern of diaminoanthraquinone on some physical properties

Two diaminoanthraquinones have been deposited under vacuum: 1,4-DAAQ and 2,6-DAAQ, They have been characterized by infrared (IR) absorption and nuclear magnetic resonance (NMR) to check that the products did not decompose during the deposition process, They have also been characterized by visible and near-ultraviolet absorption, X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) and their purities have been checked by melting point measurements. The IR and NMR spectra of the films were identical to those of the reference powder spectra, which shows that the structure of the molecules is preserved. The presence of a hydrogen bond in I,4-DAAQ is clearly put in evidence by the IR, NMR, XPS, and optical absorption measurements. Whereas 2,6-DAAQ thin films are crystallized, 1,4-DAAQ thin films are amorphous. The optical properties of 1,4-DAAQ thin films are modified by the presence of a silver thin film, Whereas those of 2,6-DAAQ are not. (C) 1998 Academic Press.