Novel Series of Ribbon Structures in Dialkylammonium Chlorocadmates Obtained By Dimensional Reduction of the Hexagonal CdCl2 Lattice

Small dialkylammonium cations (DMA + = dimethylammonium, DEA + = diethylammonium, and DPA + = dipropylammonium) were used as molecular “scissors” to obtain ribbon structures based on edge-sharing octahedra derived from the parent hexagonal CdCl 2 lattice. Retro-crystal engineering concepts were used to analyze and interpret the observed structures. The chloride salts all contain coordinated solvent molecules that stabilize the ribbon structures through O−H···Cl hydrogen bonds. The simplest of these, the α and β polymorphs of [DEA][Cd 2 Cl 5 (H 2 O)], are made up of double chains of edge-shared octahedra with stoichiometry [Cd 2 Cl 5 (H 2 O) - ] ∞ . The more complex ribbon structures found in [DMA][Cd 2 Cl 5 (H 2 O)]·H 2 O, [DPA] 2 [Cd 5 Cl 12 (H 2 O) 2 ]·H 2 O, and [DPA] 2 [Cd 3 Cl 8 (CH 3 OH)]·H 2 O are made up of [Cd 4 Cl 10 (H 2 O) 2 2- ] ∞, [Cd 5 Cl 12 (H 2 O) 2 2- ] ∞, and [Cd 6 Cl 16 (CH 3 OH) 2 2- ] ∞ moieties, each with its own distinctive packing characteristics. A wide selection of hydrogen bonding plays a crucial role in the three-dimensional stability of this unique family of structures.