[CuCl<sub>3</sub>(H<sub>2</sub>O)]<sup>−</sup>complexes aggregated to form hydrate columns in methyl-substituted pyridinium or piperidinium salts
作者:Sowjanya Nalla、Marcus R. Bond
DOI:10.1107/s0108270111017306
日期:2011.6.15
1,2,3-Trimethylpyridinium aquatrichloridocuprate(II), (C8H12N)[CuCl3(H2O)], (I), 3,4-dimethylpyridinium aquatrichloridocuprate(II), (C7H10N)[CuCl3(H2O)], (II), and 2,3-dimethylpyridinium aquatrichloridocuprate(II), (C7H10N)[CuCl3(H2O)], (III), exhibit the same fundamental structure, with (I) and (II) isomorphous and with the unit-cell constants of (III) similar to the reduced unit-cell constants of (I) and (II). The distorted square-planar [CuCl3(H2O)](-) complex [mirror symmetric in (I) and (II)] forms two semicoordinate Cu center dot center dot center dot Cl bonds to a neighboring complex to produce a dimer with 2/m symmetry [only inversion symmetry in (III)]. The semicoordinate Cu center dot center dot center dot Cl bond length of the dimer shows significant elongation at 295 K compared with that at 100 K, while the coordinate Cu-Cl bond lengths are slightly contracted at 295 K compared with those at 100 K. The inorganic dimers are linked by eight hydrogen bonds to four neighboring dimers to establish a checkerboard network layer in the ab plane, with voids between the dimers that accommodate, on both sides, inversion-related organic cation pairs. The organic cations are required by mirror-plane symmetry to be disordered in (I) and (II). The organic cations and [CuCl3(H2O)](-) complexes are nearly coplanar and tilted out of the layer plane to establish a hybrid organic-inorganic layer structure parallel to (202) [(11 (2) over bar) in (III)], with hydrate columns (defined by water molecules) and hydrophobic columns (defined by methyl groups) parallel to each other [and along the 2(1) axes in (I) and (II)]. In 1,1-dimethylpiperidinium aquatrichloridocuprate(II), (C7H16N)[CuCl3(H2O)], (IV), the bulkier organic cation prevents semicoordinate bonding between complexes, which are hydrogen bonded side-to-side in zigzag chains that place water molecules in columns along half of the 2(1) axes.