ChemInform Abstract: STRUKTUR AROMATISCHER UND HETEROCYCLISCHER FORMAZANE 3. MITT. BERECHNUNG DER PI‐ELEKTRONENSYST. VON FORMAZANEN NACH DEM PARISER‐PARR‐POPPLE‐VERFAHREN

Frontiers of Formazans Chemistry: A Review

“…The relation between the structure and color of formazans have also been studied [144,145] and several attempts have been made to explain the intense color of formazans based upon quantum mechanical calculations on π-electron system. [146][147][148][149][150][151] Hausser et al [123][124][125] showed that some formazans could be changed from red to yellow forms upon exposure to visible light. Formazan can, in principle, adopt any one of sixteen possible geometric isomers due to isomerization about double bonds.…”