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

The chlorocadmate(II) compounds of formula (Hmepd) [CdCl3] (1) (Hmepd=1-methylpiperidine cation), (H(2)meen)(2)[Cd2Cl8]. H2O (2) (H(2)meen=N-methylethylenediamine dication) and (H(2)amepz) [Cd2Cl6(H2O)(2)] (3) (H(2)amepz=1-amino-4-methylpiperazine dication) are synthesised and their structural and thermal properties investigated. Compound 1 crystallises in space group P2(l)/a. The unit cell dimensions are a=15.046(2), b=10.408(2) and c=6.786(3) Angstrom, beta=92.39(2)degrees, Z=4. The final R value is 0.0353 (Rw=0.0328). Its structure consists of one-dimensional polymeric chains of face sharing CdCl6 octahedra running along the c axis and methylpiperidinium cations. Compound 2 crystallises in the C2/c space group. The unit cell dimensions are a=18.459(2), b=6.986(3) and c=18.167(2) Angstrom, beta=115.95(2)degrees, Z=4. The final R value is 0.0296 (Rw=0.0330). Its crystal structure consists of polymeric chains of [CdCl4](2-) anions running along the b axis, organic cations and non-coordinated water molecules. Compound 3 crystallises in the P2(1)/a space group, with a=7.542(2), b=14.658(4) and c=8.052(2) Angstrom, beta=106.91(3)degrees, Z=2. The final R value is 0.0330 (Rw=0.0340). The crystal structure consists of organic cations and polymeric chains of edge-sharing CdCl5 (H2O) 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 contacts less than 3.5 Angstrom. The thermal characterisation is also discussed. The structures are compared with other examples of chlorocadmate(II) compounds.