Synthesis, spectroscopic and magnetic properties of nonaalkoxodistannatocobalt(II) derivatives

772-777Nonaalkoxodistannate complexes of cobalt(II) of the types [Co{η⁴-Sn₂(OR)₉}(μ-Cl)]₂(R = Pri(1), Et (2)) and [Co{η³- Sn₂(OR)₉}₂] (R = Pri(3), Et(4)) have been prepared by the interactions of anhydrous CoCl₂ with NaSn₂ (OR)₉(R = Pri, Et) in 1:1 and 1:2 molar ratios, respectively (where η³ and η⁴ represent the tri- and tetradentate ligation of {Sn₂(OR)₉}⁻, respectively). The dimeric chloro(nonaalkoxodistannato)cobalt(II) complexes [Co{η⁴-Sn₂(OR)₉}(μ-Cl)]₂, (1) and (2) have been found to be useful precursors for the synthesis of a variety of interesting heterobimetallic derivatives such as [Co{η⁴-Sn₂(OPri)₉}(μ-OPri)]₂ (5), [Co{η⁴-Sn₂(OEt)₉}(μ-OEt)]₂ (6), [Co{η⁴-Sn₂(OPri)₉}(μ-OCH₂CH₂NH-CH₃)]₂ (7), [Co{η⁴-Sn₂(OEt)₉}(μ-OCH₂CH₂-NHCH₃)]₂ (8), [Co{η⁴-Sn₂(OPri)9}(μ-OCH₂CH₂-OCH₃)]₂ (9), [Co{η⁴-Sn₂(OEt)₉}(μ-OCH₂CH₂CH₃)]₂ (10), [Co{η⁴-Sn₂ (OPri)₉}(μ-OCH₂CH₂OC₂H₅)]₂ (11), and [Co{η⁴-Sn₂(OEt)₉}( μ-OCH₂CH₂OC₂H₅)]₂ (12). All these complexes (1)-(12) are highly moisture-sensitive, coloured solids, soluble in organic solvents. Molecular weights determined cryoscopically in benzene solutions show dimeric nature for (1),(2),(5)-(12) and monomeric behaviour for (3) and (4). These complexes have been characterized by elemental analyses, spectroscopic (UV-vis, IR) and magnetic measurements