Synthesis, spectroscopic characterization and structural studies of bis{oxo-bis-[3-ferrocenoyl-propionatodialkyltin(IV)]} (R = Bu, Oct)

Two bis(oxo-bis(3-ferrocenoylpropionatodialkyltin(IV)))s, IIIA (R= butyl) a nd IIIB(R = octyl) were synthesized and characterized by IR and NMR (H-1, C -13, Sn-119). The results of an X-ray structural determination show that II IA is a dimer of oxo-bis[3-ferrocenoylpropionatodibutyltin(IV)]. Two Sn2O2 quadrilateral units are linked together in the dimer through the Sn-O bonds forming a nearly planar tortuous ladder-shaped skeleton. Both endo- and ex o-cyclic oxygen atoms are mu(3)-bridging. There are two types of tin atom, one is bridging (endo-cyclic) and has a coordination geometry of a bicapped trigonal bipyramid, the other is exo-cyclic and has a coordination geometr y of a monocapped trigonal bipyramid. Two kinds of anisobidentate bridging carboxylates coordinate pairwise to different tin atoms.