Abstract

The understanding of fundamental processes concerning the deposition and functionalisation of films and surfaces of elemental silicon can benefit from preparative molecular chemistry. For instance, the Si=Si bond of stable disilenes is a suitable molecular model for the most prominent characteristic of the reconstructed Si(001) 2×1 surface, the so-called ‘buckled dimer’.1 This dimer and also single unsubstituted silicon atoms on the surface are pivotal to the expansion of silicon structures. In addition, nucleation in chemical vapour deposition techniques is known to proceed via unsaturated species such as disilenes, small rings, and (partially) substituted silicon clusters.2 The lecture is going to discuss the experimental exploration of the Si6R6 manifold starting from small homo- and heterocyclic silanes.3 The Si6R6 potential energy surface is of particular theoretical interest due to its relationship to the widely studied case of benzene (C6H6) in carbon chemistry. However, as will be shown on selected examples the stability of the respective isomers is quite different on the silicon side. Along the way surprises concerning the reactivity of Si6R6 isomers will be unveiled and a new type of aromaticity defined.4 _ 1 Review: J. Yoshinobu, Prog. Surf. Sci. 2004, 77, 37. 2 (a) E. W. Draeger, J. C. Grossmann, A. J. Williamson, G. Galli, J. Chem. Phys. 120, 10807 (2004); (b) D. K. Yu, R. Q. Zhang, S. T. Lee, J. Appl. Phys. 92, 7453 (2002). 3 Review: K. Abersfelder, D. Scheschkewitz, Pure Appl. Chem. 2010, DOI : 10.1351/PAC-CON-09-08-09. 4 K. Abersfelder, Andrew J. P. White, Henry S. Rzepa, D. Scheschkewitz, Science 2010, 327, 564.