Coordination-Driven Self-Assembly of Complexes Constructed from Two Helical Ligands: Synthesis, Structures, and Selective Gas Adsorption Properties.

Two helical ligands ( and ) were designed and synthesized by a Schiff base condensation reaction. Eight complexes, {[Zn()I]·HO} (), [Cd()I(CHOH)] (), [Hg()I] (), [Ag()NO] (), [Ag()(NO)DMSO]·HO (), {[Zn()Cl]·2CHCl} (), {[Ag()]·NO} (), and {[Ag()NO]·CHOH} (), were synthesized and characterized based on these two ligands. The crystal structures show that both Schiff base compounds exist as racemic ligands with equal amounts of - and -helicity, and the assembly of these racemic ligands with metal ions can lead to homochiral or heterochiral complexes via a chiral self-recognition or self-discrimination process. Complexes , , and exist as heterochiral metallomacrocycles with a figure-eight conformation. Complexes , , and exist as one-dimensional (1D) homochiral helical chain coordination polymers, while complexes and exist as 1D heterochiral helical chain coordination polymers. Furthermore, gas and vapor adsorption measurements show that all of the synthesized complexes exhibit good selective adsorption capacities toward methanol and ethanol vapor over N, H, and O.