Which Intermediate Product Causes the Blue Colouring in a Grignard Reaction Involving Zirconium Chelates?

Christof Troeltzsch, Bliesenrader Weg 5, Born/Darss, Germany

Journal of Unsolved Questions, 2, 1, Open Questions, 3, 2011 (Received November 3rd 2011, accepted November 25th 2011, published December 3rd 2012)

While working on the doctoral thesis about chelates of zirconium and hafnium – cf. [1] for preparation of the ligands and [2] for preparation of the chelates – we made an observation which could not be explained and therefore was only described in the doctoral thesis of Christof Troeltzsch, Leipzig, 1960, in the following way: ….