Preparation and structural characterization of simple and donor-substituted triorganostannyl 1′-(diphenylphosphino)-1-ferrocenecarboxylates and their P-chalcogenide derivatives

Triorganotin chlorides Me₃SnCl and (L^NC)Me₂SnCl (L^NC = 2-[(dimethylamino)methyl]phenyl) reacted with potassium 1′-(diphenylphosphino)-1-ferrocenecarboxylate to give the respective carboxylates, Ph₂PfcCO₂SnMe₃ (1) and Ph₂PfcCO₂SnMe₂(L^NC) (2; fc = ferrocene-1,1′-diyl), while the analogous triphenylstannyl derivative 3 resulted by condensation of Ph₃SnOH with 1′-(diphenylphosphino)-1-ferrocenecarboxylic acid (Hdpf). Compounds 1 and 2 were smoothly oxidized with hydrogen peroxide or elemental sulfur to afford the corresponding P-chalcogen derivatives (P-oxides 1a and 2a; P-sulfides 1b and 2b). All compounds were characterized by multinuclear NMR, IR and mass spectroscopy, and the solid-state structures of 1, 1a, 2, 2a and 2b were determined by single-crystal X-ray diffraction. In the crystal structures of 1 and 1a, the tin atoms were found with distorted trigonal bipyramidal coordination environments completed by the CO or PO oxygens, respectively, from adjacent molecules, which in turn resulted in the formation of infinite linear assemblies. Tin atoms in 2, 2a, and 2b were found with trigonal bipyramidal surrounding as well, though with the donor substituent L^NC assuming one of the axial donor sites. Compounds 2 and 2a crystallized as stoichiometric hydrates (2·1/2H₂O, 2a·H₂O), in which the water molecules served as hydrogen bond donors for the polar groups (CO and PO) and thus aided the formation of closed H-bonded assemblies; the structure of 2b was essentially molecular.