First trigonal-antiprismatic tris-dichloroglyoximate iron(ii) clathrochelate and its reactivity in nucleophilic substitution reactions

Abstract

Tris-dichloroglyoximate clathrochelate [Fe(Cl₂Gm)₃(SnCl₃)₂]²⁻ dianion has been synthesized by a procedure differing from those described earlier for boron-capped analogs. The co-ordinately saturated SnCl₆²⁻ dianion is now used as the capping agent instead of boron-containing Lewis acids. The tris-dichloroglyoximate tin-capped product obtained is far less reactive than its boron-capped analogs, and only in the case of a thiophenolate anion was the “regular” hexafunctionalized clathrochelate obtained. The complexes synthesized have been characterized by elemental analysis, PD and MALDI-TOF mass, IR, UV-vis and ¹H, ¹³C and ¹¹⁹Sn NMR spectra, cyclic voltammetry, and X-ray crystallography for the clathrochelate [Fe(Cl₂Gm)₃(SnCl₃)₂]²⁻ dianion. The geometry of the functionalized complex (the distortion angle φ and main bond lengths in the clathrochelate framework) has been deduced from the quadrupole splitting value in the ⁵⁷Fe Mössbauer spectrum and EXAFS data, respectively.