Maltol → Gallium Maltol

Beteiligte Stoffe

Reaktionsbedingungen

Reaktionsschritte

Maltol is dissolved in chloroform to form a 0.75M solution, and gallium nitrate nonohydrate is dissolved in ethanol to form a 0.5M solution. To 20 mL of the 0.75M maltol solution is slowly added, with continuous stirring, 10 mL of the 0.5M gallium nitrate nonohydrate solution. The resulting solution is stirred for 5 minutes at 23° C. Approximately 5.5 g (a large excess) of powdered Na2CO3 is added with stirring to raise the pH to close to 7. When the sodium carbonate is added, a trace of water may sometimes need to be added to facilitate the reaction, which is evidenced by some effervescence. Stirring is then continued for an additional ten minutes. The mixture is filtered to remove all solids, and the filtrate is evaporated in a rotary evaporator. The remaining crystalline solid is the 3:1 maltol:gallium composition. This composition is analyzed using powder x-ray diffraction and found to consist of orthothrombic crystals with unit cell dimensions of about a=18.53(1)Å, b=16.96(1)Å, c=12.05(1)Å. Crystallization from other solvents or under other conditions may produce other crystal structures. It is contemplated that amorphous structures can also be used in the methods and compositions of this invention.

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