Coordination of zinc tetraphenylporphyrin with pyridine derivatives in chloroform solution and in the solid phase

Coordination of zinc tetraphenylporphyrin with 2-,3-, and 4-halopyridines, pyridin-2-amine, and pyrimidin-2-amine in chloroform has been studied by spectrophotometry. Protonation and complexation of halopyridines and haloanilines with zinc tetraphenylporphyrin are discussed. According to the X-ray diffraction data, enhanced stability of the 2: 2 zinc tetraphenylporphyrin complex with pyrimidin-2-amine in the solid phase and in chloroform solution is likely to be determined by hydrogen bonding between the two ligand molecules involving nitrogen atoms in the pyrimidine ring and amino group.