Halogen-bonded co-crystal containing 1,3-di­iodo­perchloro­benzene and the photoproduct rtct-tetra­kis­(pyridin-4-yl)cyclo­butane resulting in a zigzag topology

The formation and crystal structure of a zigzag network held together by I⋯N halogen bonds is reported. In particular, the halogen-bond donor is 1,3-di­iodo­perchloro­benzene (C(6)I(2)Cl(4) ) while the acceptor is the photoproduct rtct-tetra­kis­(pyridin-4-yl)cyclo­butane (TPCB). Curiously, within the resulting co-crystal (C(6)I(2)Cl(4) )·(TPCB), the photoproduct accepts only two halogen bonds between neighbouring 4-pyridyl rings and as a result behaves as a bent two-connected node rather than the expected four-connected centre. In addition, the photoproduct, TPCB, is also found to engage in C—H⋯N hydrogen bonds, forming an extended zigzag chain.