Marziyeh Mohammadi - Department of Chemistry, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan,Iran
Reza Ranjbar-Karimi - Department of Chemistry, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
Marjan Ghafari - Department of Chemistry, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran
Ali Reza Poorfreidoni - Department of Chemistry, Faculty of Science, Vali-e-Asr University of Rafsanjan, Rafsanjan, Iran

۴-phenylsulfonyl-۲,۳,۵,۶-tetrachloropyridine was synthesized by the reaction of pentafluoropyridine with sodium benzenesulfonate under ultrasonic irradiation. This new methodology provides the excellent yield in a very short reaction time at ۰ oC. In the presence of ultrasound irradiation, the yield was ۹۰% after ۸ min, by using our previously established method the yield was ۸۵% after ۱۰ h. Also, in this research, the substituent effect in meta and para position of phenyl ring on intramolecular halogen bond strength has been investigated by theoretical studies. The calculations were performed with Gaussian۰۹ software in M۰۵-۲X/۶-۳۱۱++G(d,p) level. The results show that one of the oxygen atoms of the SO۲ group is co-planer with the pyridine ring and the other oxygen atom is out of this plane. Also, it is observed that the electron-withdrawing groups in meta and para positions reinforced the halogen bond that the oxygen atom of the SO۲ group is co-planer with pyridine ring. An opposite behavior is observed for electron-donating groups.

Pentachloropyridine, ۲, ۳, ۵, ۶-Tetrachloro-۴-phenylsulphonylpyridine, Synthesis, Ultrasound irradiation, Halogen bond