화학공학소재연구정보센터
Journal of the American Chemical Society, Vol.135, No.16, 6200-6210, 2013
Expanded Halogen-Bonded Anion Organic Networks with Star-Shaped Iodoethynyl-Substituted Molecules: From Corrugated 2D Hexagonal Lattices to Pyrite-Type 2-Fold Interpenetrated Cubic Lattices
Halogen bonding interactions between halide anions and neutral polyiodinated linkers are used for the elaboration of anion organic frameworks, by analogy with well-known MOF derivatives. The extended, 3-fold symmetry, 1,3,5-tris(iodoethynyl)-2,4,6-trifluorobenzene (1) cocrystallizes with a variety of halide salts, namely, Et3S+I-, Et3MeN+I-, Et4N+Br-, Et3BuN+Br-, Me-DABCO(+)I(-), Bu3S+I-, Bu4N+Br-, Ph3S+Br-, Ph4P+Br-, and PPN+Br-. Salts with 1:1 stoichiometry formulated as (1).(C+,X-) show recurrent formation of corrugated (6,3) networks, with the large cavities thus generated, filled either by the cations and solvent (CHCl3) molecules and/or by interpenetration (up to 4-fold interpenetration). The 2:1 salt formulated as (1)(2)center dot(Et3BuN+Br-) crystallizes in the cubic Ia (3) over bar space group (a = 22.573(5) angstrom, V = 11502(4) angstrom(3)), with the Br- ion located on (3) over bar site and molecule 1 on a 3-fold axis. The 6-fold, unprecedented octahedral coordination of the bromide anion generates an hexagonal three-dimensional network of Pa (3) over bar symmetry, as observed in the pyrite model structure, at variance with the usual, but lower-symmetry, rutile-type topology. In this complex system, the I centering gives rise to a 2-fold interpenetration of class Ia, while the cations and solvent molecules are found disordered within interconnected cavities. Another related cubic structure of comparable unit cell volume (space group Pa (3) over bar, a = 22.4310(15) angstrom, V = 11286.2(13) angstrom(3)) is found with (1)(2)center dot(Et3S+I-).