2 Homometallic Alkoxides

2.2.2 Magnesium
X-Ray Crystal Structures of Alkoxo Metal Compounds 237
Figure 4.10 Chain structure of [KOBu t ,Bu t OH]1.
Figure 4.11 Structure of [K8⊲OSiPh3⊳8⊲dme⊳3] (Ph
groups omitted).
It has long been known that the sparingly soluble magnesium methoxide slowly deposits
massive crystals from saturated methanolic solutions but attempts to characterize them
have been thwarted by their facile loss of coordinated methanol leading to disintegration
of the crystals. However Turova and co-workers have recently succeeded in
determining the crystal structure of the solvate Mg(OMe) 2 .3.5MeOH. 41 This remarkable
structure contains neutral molecules [Mg 4 ⊲ 3-OMe⊳4⊲OMe⊳4⊲MeOH⊳8] havinga
cubane Mg 4 O4 structure, dipositive cations [Mg 4 ⊲ 3-OMe⊳4⊲OMe⊳2⊲MeOH⊳10] 2C also
having a cubane Mg 4 O4 structure, and hydrogen-bridged [MeO..H..OMe] anions,
H