TY  - JOUR
A1  - Kozlevcar, Bojan
A1  - Golobic, Amalija
A1  - Strauch, Peter
T1  - Dynamic pseudo Jahn-Teller distortion in a compressed octahedral CuO6 complex
JF  - Polyhedron : the international journal of inorganic and organometallic chemistry
N2  - The crystal structure of cis-[Cu(C8H7O3)(2)(H2O)(2)] (115 K data) reveals bidentate vanillinate ions coordinated via methoxy and deprotonated hydroxy oxygen atoms and water molecules in a distorted octahedral CuO6 chromophore. A cis orientation of the ligands enables two non-identical O(methoxy)-Cu-O(water) coordination axes (2.354(l) + 2.163(1); 2.151(1) + 2.020(1) angstrom), and the third shortest O(hydroxy)-Cu-O(hydroxy) axis (1.919(1) + 1.914(1) angstrom). This 115 K coordination sphere differs importantly to the one obtained from the 293 K data of the same compound, where two long 0(methoxy)-Cu-O(water) axes are of the same length, and only minor changes at the short 0(hydroxy)-Cu-O(hydroxy) axis are noticed. An axial symmetry of the complex with an inverse g(1.2)(g(perpendicular to)) > g(3)(g(parallel to)) pattern is observed in the temperature range from 298 to 180 K. A further decrease of temperature reveals gradual changes from axial to rhombic symmetry (g(1) > g(2) > g(3)) that is reversible. A mean-square displacement amplitude (MDSA) analysis reveals a disorder in the Cu-O(methoxy) bonds, but not in the other metal-ligand Cu-O(hydroxy) and Cu-O(water) bonds at 293 and 115 K. The disorder is significantly weaker in the 115 K structure. The MSDA analysis and the structural-EPR agreement show vibrational disorder in two coordination axes, due to the cis conformation of the complex with two 0(methoxy)-Cu-O(water) axes.
KW  - copper
KW  - vanillin
KW  - Jahn-Teller distortion
KW  - MSDA
KW  - cis
KW  - EPR
Y1  - 2006
U6  - https://doi.org/10.1016/j.poly.2006.04.009
SN  - 0277-5387
VL  - 25
IS  - 15
SP  - 2824
EP  - 2828
PB  - Elsevier
CY  - Oxford
ER  -