Metal-encapsulated fullerene compound and a method of synthesizing such compound

A method of synthesizing a metal-encapsulated fullcrene compound by adding functional groups to a metal-encapsulated fullerene, comprising reacting

• a disilirane derivative or digermiranc derivative having the following structure (2) ##STR10## with a metal encapsulated fullerene to produce said compound, wherein said compound has the following structure (1) ##STR11## wherein in structure (1):
• A is a silicon or germanium atom,
• R is an organic substituent selected from the group consisting of a stereochemically bulky alkyl group and a stereochemically bulky aryl group,
• M is an encapsulated metal atom.
• m is an integer from 1 to 3,
• M.sub.m @C.sub.n represents a metal-encapsulated fullerene contained as a part of said structure (1), and
• n is an even number from 28 to 200, and wherein in structure (2):
• A is a silicon or gennanium atom, and
• R is an organic substituent selected from the group consisting of a stereochemically bulky alkyl group and a stereochemically bulky aryl group which protects and stabilizes the ring comprising two of said A atoms and the methylene bridge of said structure (2).