Aluminium-, Gallium- and Indium-Chalcogen Rings

An extensive series of chalcogenolates of group 13 metals of the type (R2MER ) is known for all combinations of M and E. Most commonly these compounds are dimeric ( = 2) with a central, planar, four-membered M2E2 ring. For example, all three aluminium derivatives [ Bu2Al(p-E Bu)]2 are 

Housecroft and A. G. Sharpe, Inorganic Chemistry, 2nd edn., Pearson Education, Harlow, 2005. 

Schnockel, W. Uhl and N. Wiberg, in Molecular Clusters of the Main Group Elements, ed. M. Driess and H. Noth, Wiley-VCH, Weinheim, 2004, pp. 126-168. 

Maringgele, in The Chemistry of Inorganic Homo- and Heterocycles, ed. I. Haiduc and D. B. Sowerby, Academic Press, London, Vol. 1, 1987, Chapter 2, pp. 17-101 (b) B. Anand, H. Noth, H. Schwenk-Kircher and A. Troll, Eur. J. Inorg. Chem., 2008, 3186. 

Housecroft, Cluster Molecules of the p-Block Elements, Oxford University Press, Oxford, 1994, pp. 24-25 (b) A. Y. Timoshkin, Coord. Chem. Rev., 2005, 249, 2094. 

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