Similar coordination different dimensionality: Synthesis, single crystal structures, and theoretical studies of hydrogen-bonded {[Ca(H2O)(2)L-4]I-2}(n/infinity) (1 : L = CH3COOC2H5, n=1; 2 : L = OC4H8, n=2)

摘要

CaI2(H2O)(2) reacts with O-donor ligands L to yield coordination compounds of the type ([Ca(H2O)(2)L-4]I-2)(n/infinity), (1: L = CH3COOC2H5, n = 1; 2: L = THF, n =2). Both compounds feature a coordination number of six around the calcium atom with two water molecules in axial positions and four ligands L in equatorial positions of a tetragonal bipyramid. Due to only a slight variation in the arrangement of the cationic units [Ca(H2O)(2)L-4](2+) hydrogen bonds can be built up between them and the iodide anions in different ways in order to lead to a one-dimensional polymer for 1 and a two-dimensional polymer for 2. Density functional theory calculations provide useful informations on the involved orbitals on the mu(2)-bridging iodide and on the structure of the systems, leading to a small H-I-H angle of 71.2 degrees in 1 compared to a large H-I-H angle of 121.8 degrees in 2. [References: 38]