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Trichloro[tris(3-tert-butyl-6-methoxyphenyl)methyl]germane (3), containing a tetradentate ligand with three methoxy groups as coordinating sites, was synthesized by the reaction of the corresponding (triarylmethyl)lithium species with tetrachlorogermane. In contrast to the case for the previously reported trichlorosilane analogue, 3 slowly decomposed during column chromatography on silica gel, although it was quite stable against moisture. The corresponding trifluoro-, tribromo-, and triiodogermanes 4−6 were prepared from the trichlorogermane 3. X-ray crystallographic analyses of 3−6 showed heptacoordinate structures with interatomic distances between the oxygen atom and the central germanium atom shorter than the sum of van der Waals radii. By systematic comparisons of these intramolecular interactions based on the interatomic distances, it was found that they strongly depend on the Lewis acidity of the trihalogenated germanium atom. An Atoms-in-Molecules (AIM) analysis of the model compound 4‘, in which three tert-butyl groups of trifluorogermane 4 were omitted, showed the existence of weak and ionic bonding between oxygen and germanium atoms. Reactions of these trihalogermanes with aqueous NaOH, LiAlH4, and BX3 were also investigated. Alkaline hydrolysis of trihalogermanes resulted in the cleavage of the carbon−germanium bond. LiAlH4 also caused the same kind of bond cleavage, together with nucleophilic attack on the germanium atom, giving the trihydrogermane 8. Reaction of the trihalogermanes with trihaloboranes was found to be an efficient procedure to give other trihalogermanes through a halogen exchange reaction.

Trichloro[tris(3-tert-butyl-6-methoxyphenyl)methyl]-stannane (1), containing a tetradentate ligand with three methoxy groups as coordinating sites, was synthesized by the reaction of the corresponding (triarylmethyl)lithium species with tin tetrachloride. In contrast to the cases of the previously reported silicon and germanium analogues, 1 decomposed during column chromatography on silica gel and was slightly unstable against moisture. X-ray crystallographic analysis of 1 showed a heptacoordinate structure with interatomic distances between the oxygen atom and the central tin atom shorter than the sum of van der Waals radii.

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