Reaction of 1Н,2Н,3Н,4Н-pyrido[4,3-d]pyrimidinium bromide derivatives with molecular iodine: Comparative structure and spectroscopic analysis

► New salts C27H22N3O2BrI2 (1) and C27H19N3O2Br4I2·2CHCl3·2H2O (2) were synthesized. ► The molecular and crystal structures 1 and 2 are studied by X-ray diffraction analysis. ► The negative value of ΔG as observed supports the assertion that complexation is spontaneous.