Site-selective supramolecular synthesis of halogen-bonded cocrystals incorporating the photoactive azo group
CrystEngComm 2008, 10, 1132?1136
D. Fox, P. Metrangolo, D. Pasini, T. Pilati, G. Resnati, G. Terraneo
Self-assembly of α,ω-diiodoperfluoroalkanes with trans-4,4-azobipyridine
Self-assembly of α,ω-diiodoperfluoroalkanes with trans-4,4-azobipyridine
ABSTRACT
The halogen-bonding-driven self-assembly of α,ω-diiodoperfluoroalkanes with trans-4,4-azobipyridine gives rise to infinite 1D networks in the crystalline state. The four nitrogen atoms of the azobispyridine module could allow for the formation of various isomeric products. Interestingly, a site-selective supramolecular synthesis occurs, since only the pyridyl nitrogen atoms are involved in the recognition process. This selectivity can be rationalized on the basis of a higher basicity and steric accessibility of the pyridine nitrogens, with respect to the azo nitrogens, and with the formation of an architecture where the hydrocarbon and perfluorocarbon modules segregate.