Molecular Tailoring: Substituent Design for Hexagermabenzene

The preparation of new,, heavy element compounds with an unusual bonding situation is still a real challenge since, with the lack of solid chemical knowledge, every synthesis is unpredictable and eventual. In this paper, we analyze the general reaction scheme of reductive dehalogenation of halogermanes, which has led to the formation of several interesting structures, for example, digermyne, tetragermahedrane, hexagermaprismane, and octagermacubane, and point out that all of these syntheses can be explained by the principle of energy minimum and the special steric effect of bulky substituents. We have found that the proper choice of the bulky substituent can result in only one stable minimum on the potential energy surface, which could be realized in the synthetic works. We also demonstrate that this recognition can be exploited to design appropriate substituents for the synthesis of new organometallic structures. On the basis of our approach, we suggest Rind-type and terphenyl-type substituents for the synthesis of tetragermacyclobutadiene and hexagermabenzene, respectively.