X-ray Structures and Charactrizations of Iron Complexes of Thiacalixarenetetrasulfonate

Research Institute of Natural Sciences, Okayama University of Science
â—‹Sachie Shimose Misato Ichikawa Haruo Akashi

Recently, we have reported the structure of Tetrasodium thiacalix[4]arenetetrasulfonate (H4TCAS)[1]. Odo and co-workers found that some metal complexes of H4TCAS attached on ionexchangers showed peroxidase-like catalytic activity[2]. This prompted us to make single crystals of metal complexes of TCAS for the structure analyses. We succeeded in the preparation of micro crystals of Fe(III) complex of TCAS. A blue thin plate-like crystal of K3[Fe(H2TCAS)(H2O)2].8H2O(1), selected for data collection, was mounted in the cold nitrogen stream (105 K) of RAXIS IV(Rigaku Corp.). The compound was found to crystallize in the orthorhombic space group Pcab with a = 18.552(1) Å, b = 18.7287(8) Å, c = 25.550(2) Å, V = 8863.1(9) Å3. The structure analysis of 1 revealed that the iron atom is located in a distorted octahedral site. The iron atom is bound to three oxygen atoms and one sulfur atom of the TCAS. This is the first example of the H4TCAS ligand attached directly to the Fe(III) moiety. Second-sphere coordination compounds, K[Fe(H2O)6](H4TCAS) and K2[Fe(H2O)6](H4TCAS), will also be reported.

[1] Akashi H., et al., Acta Cryst., 2003, E59, m336.
[2] Odo J., et al., Anal. Sci., 2004, 20, 707.