Magnetic susceptibility of some organic semiconductor

Abstract

The magnetic susceptibilities of certain organic semiconductors, namely the semicarbazones of acetophenone as well as their nuclear substituents were studied. The substituents were divided into two main categories: those which are electron attracting groups (e.g. chloro-, nitro-,) acetophenone semicarbazone, and those which are electron repelling groups (e.g. hydroxy-, methoxy-) acetophenone semicarbazone. Our magnetic susceptibility values obtained experimentally confirm the existence of both the normal and the cyclic structures. It seems that the quinonoid structure exists in small percentage. The experimental molecular diamagnetism of these compounds were as follows: For electron attracting groups: χ M† = 116·59 for P-chloro-acetophenone semicarbazone; 135·24 for 3:4 dichloroacetophenone semicarbazone; 108·01 for m-nitro acetophenone semicarbazone, 116·06 for 3:5 dinitro acetophenone semicarbazone and 112·97 for M-amino acetophenone semicarbazone, while χ M for electron repelling groups were as follows: χ M = 102·79 for O-hydroxy acetophenone semicarbazone, 104·46 for P-hydroxy acetophenone semicarbazone; 109·37 for 2:5 dihydroxy acetophenone semicarbazone; 114·21 for 2:3:4 trihydroxy acetophenone semicarbazone; 116·72 for P-methoxy acetophenone semicarbazone; 132·44 for 2:5 dimethoxy acetophenone semicarbazone and 155·40 for 2:3:4 trimethoxy acetophenone semicarbazone.