Photodissociation of o-C6H4I(CH2Cl) in the near ultraviolet: a case of photoselective C-I bond dissociation

We report the photodissociation dynamics of ortho-iodobenzyl chloride (o-C6H4I(CH2Cl)) in the ultraviolet. The gas phase dissociation dynamics of o-iodobenzyl chloride at 222, 236, 266, 280, and ∼304 nm was monitored by probing the quantum yields of I* (2P1/2) as well as Cl* (2P1/2) production using suitable resonance enhanced multiphoton ionization detection schemes. We find that only iodine atoms in the ground (I (2P3/2)) as well as excited (I*) states are produced in the dissociation. No Cl (2P3/2) or Cl* atoms were detected. This accidental bond selective dissociation in o-iodobenzyl chloride is perhaps due to weak coupling among various chromophores present in the molecule and inefficient interchromophore energy transfer among them.