A new P , S ‐coordinating ferrocenyl ligand: synthesis of a precursor and its coordination compounds with Pd II and Pt II

In our ongoing development of ferrocene ligands, 1‐dimethylamino‐2‐(diphenylphosphinothioyl)ferrocene is being used as a convenient building block to obtain racemic or enantiomerically pure ligands. Using this building block in large excess allowed the formation of several by‐products, two of which have already been reported; the structure of a third by‐product, namely 1‐(diphenylphosphinothioyl)‐2‐{[(diphenylphosphinothioyl)sulfanyl]methyl}ferrocene, [Fe(C 5 H 5 )(C 30 H 25 P 2 S 3 )], is presented here. The crystal structure is built up from a ferrocene unit, with one of the cyclopentadienyl (Cp) rings substituted in the 1‐ and 2‐positions by a protected diphenylphosphinothioyl group and a [(diphenylphosphinothioyl)sulfanyl]methyl fragment, –CH 2 SP(=S)Ph 2 . There are C—H...S interactions which result in the formation of chains parallel to the c axis. After desulfurization, the crude material was then reacted with Pd and Pt ( M ) precursors [ M Cl 2 (CH 3 CN) 2 ] to yield two isostructural dinuclear complexes arranged around twofold axes, namely ( R , R / S , S )‐bis{μ‐[2‐(diphenylphosphanyl)ferrocen‐1‐yl]methanethiolato‐κ 3 P , S : S }bis[chloridopalladium(II)] pentane disolvate, [Pd 2 {Fe(C 5 H 5 )(C 18 H 15 PS)} 2 Cl 2 ]·2C 5 H 12 , and the platinum(II) analogue, ( R , R / S , S )‐bis{μ‐[2‐(diphenylphosphanyl)ferrocen‐1‐yl]methanethiolato‐κ 3 P , S : S }bis[chloridoplatinum(II)] toluene monosolvate, [Pt 2 {Fe(C 5 H 5 )(C 18 H 15 PS)} 2 Cl 2 ]·C 7 H 8 , in which the two metal atoms present a slightly distorted square‐planar geometry formed by two bridging S atoms and P and Cl atoms. The P , S ‐chelating ligand results from the rupture of one of the P—S bonds in the starting ligand. These dinuclear complexes display a butterfly geometry. Surprisingly, only the ( R , R / S , S ) diastereoisomer has been isolated.