Hexaphenylethane The Classical Period

The first attempt to make hexaphenylethane seems to have been by Gombeig [1,2], His stated reason for this seems now quite prosaic it was ancillary to another problem, namely to compare its behavior with that of tetrapheitylmethane toward a color test, thus checking the reliability of this test as evidence for the tetrapheiyl-methane stmcture. Interestingly, the tetraphenylmethane work, the motive force for the attempted hexapheiylethane synthesis, evidently fonnd its justification in the desire to probe the limits to the crowding of groups around a carbon atom, a matter clearly closely connected to the stracture and properties of hexaphertylethane. 

Ltwars, Modeling Marvels, jyO 10.l007/978-l-4020-6973-4 8, Springer Science+Business Media B.V. 2008 

The histoiy of the hexapheitylethane problem is a counterpoint of experiments and their interpretations experiments in which a principal performer was Moses Gombeig, and interpretations of these by him and others. The tale has been ably chronicled and will be only briefly recounted here, where the emphasis is rather on the significance of hexapheitylethane for stmctural theory. 

In the same year as Gombeig s review, a monograph by Schmidlin interpreted the situation more succinetly the main process was said to be probably an equi-hbrium between tripheityhnethane radicals and hexaphenylethane [8]. This became the standard interpretation until 1968, but was apparently never fidly accepted by Gomberg, and in particular, the quinoid Jacobsen stmcture 3 was by no means excluded as late as 1919, when the equilibrium below (with Ph generahzed to R) is said to have been fairly well established (the structure with the danghng bond we would now consider to be a resonance form of the radical) [9]  

In a 1923 paper the possibility was considered of a dibromo molecule related to 3 reacting with silver [10]  

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