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 nuclea r magnetic resonance (NMR) to check that the products did not decompose dur ing the deposition process, They have also been characterized by visible an d near-ultraviolet absorption, X-ray diffraction (XRD), and X-ray photoelec tron spectroscopy (XPS) and their purities have been checked by melting poi nt measurements. The IR and NMR spectra of the films were identical to thos e of the reference powder spectra, which shows that the structure of the mo lecules is preserved. The presence of a hydrogen bond in I,4-DAAQ is clearl y 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 amor phous. The optical properties of 1,4-DAAQ thin films are modified by the pr esence of a silver thin film, Whereas those of 2,6-DAAQ are not. (C) 1998 A cademic Press.