Design, synthesis, structural and thermal characterisation of polymeric chlorocadmate(II) compounds with one-dimensional inorganic chain structures

Abstract

The chlorocadmate(II) compounds of formula (Hmepd) [CdCl 3] ( 1) (Hmepd = 1-methylpiperidine cation). (H 2meen) 2[Cd 2Cl 8] ∗d H 2O ( 2) (H 2meen = N-methylethylenediamine dication) and (H 2amepz) [Cd 2Cl 6(H 2O) 2] ( 3) (H 2amepz = 1-amino-4-methylpiperazine dication) are synthesised and their structural and thermal properties investigated. Compound 1 crystallises in space group P2/ a. The unit cell dimensions are a = 15.046(2), b = 10.408(2) and c = 6.786(3) A ̊ , β = 92.39(2)°, Z = 4 . The final R value is 0.0353 ( Rw = 0.0328). Its structure consists of one-dimensional polymeric chains of face-sharing CdCl 6 octahedra running along the c axis and methylpiperidinium cations. Compound 2 crystallises in the C2/ a space group. The unit cell dimensions are a = 18.459(2), b = 6.986(3) and c = 18.167(2) A ̊ , β = 115.95(2)°, Z = 4 . The final R value is 0.0296 ( Rw = 0.0330). Its crystal structure consists of polymeric chains of [CdCl 4] 2− anions running along the b axis, organic cations and non-coordinated water molecules. Compound 3 crystallises in the P2/ a space group, with a = 7.542(2), b = 14.568(4) and c = 8.052(2) A ̊ , β = 106.91(3)°, Z = 2. . The final R value is 0.330 ( Rw = 0.340). The crystal structure consists of organic cations and polymeric chains of edge-sharing CdCl 5(H 2O) octahedra. In compounds 1 and 2 hydrogen bond interactions between the inorganic chains, the organic cations and the water molecules, if present, contribute to the crystal packing, while in compound 3 this contribution comes from the contact less than 3.5 Å. The thermal characterisation is also discussed. The structures are composed with other examples of chlorocadmate(II) compounds.