Synthesis and structure of [(C5H5)Fe(C5H4PS2OCH2C6H4N3)]−, a new phosphonodithioate derivative, and its coordination chemistry with rhodium(I) and nickel(II)

The anion [(C5H5)Fe(C5H4PS2OCH2C6H4N3)]− (1) was synthesized in two steps from ferrocene, P4S10 and hydroxymethylbenzotriazole in the presence of triethylamine. The molecular structure of 1, determined by single-crystal X-ray structure analysis of the triethylammonium salt, shows the rare R(R′O)PS2 arrangement in the expected tetrahedral geometry; the substituents R=ferrocenyl and R′=methylenbenzotriazol impose a certain rigidity on the molecule. Anion 1 reacts with [RhCl(cod)]2 (cod=1,5-cyclooctadiene) to give Rh(cod)[(C5H5)Fe(C5H4PS2OCH2C6H4N3)] (2) and with [RhCl(CO)2]2 to give Rh(CO)2[(C5H5)Fe(C5H4PS2OCH2C6H4N3)] (3). With [NiCl2(C4Me4)]2 anion 1 gives the analogous nickel complex Ni(C4Me4)[(C5H5)Fe(C5H4PS2OCH2C6H4N3)] (4). However, with NiCl2·6H2O the anion 1 loses the methylenebenzotriazol unit to give the complex Ni[(C5H5)Fe(C5H4PS2O)]2 (5). The expected complex Ni[(C5H5)Fe(C5H4PS2OCH2C6H4N3)]2 (6) was obtained from the room-temperature reaction of 1 with anhydrous NiCl2 in aqueous acetonitrile. The single-crystal X-ray structure analyses reveal a tetrahedral rhodium coordination geometry for 2 and a square-planar nickel coordination geometry for 5.