Synthetic Studies and Structural Aspects of Some Metallacyclic Compounds of Germanium(IV) Incorporating Nitrogen,Oxygen and Sulfur: 1. Reactions of Germanium(IV) isopropoxide with diols and crystal structure of a diolato bridged germanium(IV) compound [Ge 2 (O 2 C 2 H 4 ) 4 ] †

Germanium(IV) diolates of the type [(OPrⁱ)_4-2nGe(O-G-O) _n ] (n = 1, 2) have been prepared by the reaction of Ge(OPrⁱ)₄ with the corresponding diols in 1:1 and 1:2 molar ratios in anhydrous benzene. All these compounds are colourless viscous liquids except the bis(ethanediolato)germanium(IV), which is a white solid. They have been characterised by elemental analysis and IR and NMR (¹H and ¹³C) spectroscopy. Prismatic crystals of [Ge₂(O₂C₂H₄)₄] were separated out when [(OPrⁱ)₂Ge(O₂C₂H₄)] was kept for about 3 weeks at room temperature. Single crystal X-ray diffraction study indicates that it is a unique diolato bridged compound in which the geometry around the germanium atom is a distorted trigonal bipyramid of oxygen atoms which belong to one chelating diolato-O,O′ and to a second η¹–O, μ₂(η¹–O′) bound diolato group.