DESIGN AND SYNTHESIS OF NEAR-INFRARED ABSORBING PIGMENTS .1. USE OF PARISER-PARR-POPLE MOLECULAR-ORBITAL CALCULATIONS FOR THE IDENTIFICATION OF NEAR-INFRARED ABSORBING PIGMENT CANDIDATES

The usefulness of the Pariser-Parr-Pople molecular orbital method for the identification of near-infrared absorbing pigment candidates for p hotogenerator applications is outlined. Several pigments based on the well-known class of photogenerators N,N'-dialkyl-3,4,9,10-perylenetetr acarboxylic diimides were investigated and pigments of the dibenzopery lene, bisanthene, and zethrene classes were identified as the most pro mising candidates of the series. On the basis of the predictions, 7,8, 15,16-dibenzo[a, j]perylenetetracarboxylic diimide was prepared and th e validity of the calculations was verified.