Organometallic nanojunctions probed by different chemistries: Thermo-, photo-, and mechano-chemistry

Abstract

Based on ab-initio simulations, three different types of chemistry, namely thermo-, photo-, and mechano-chemistry are compared for organometallic nanojunctions. In the first part we provide the first direct comparison of mechanical versus thermal activation of bond breaking. Study of thiolate/copper interfaces thiolate/copper interfaces provides evidence for vastly different reaction pathways and product classes. This is understood in terms of directional mechanical manipulation of coordination numbers and system fluctuations in the process of mechanical activation. In the second part mechanically and opto-mechanically controlled azobenzene (AB) switch based on AB-gold break-junction have been studied. It was found that both cis → trans and trans → cis mechanically driven switchings in the lowest singlet state are possible. Bidirectional optical switching of mechanically strained AB through first excited singlet state was also predicted, provided that the length of the molecule is adjusted towards the target isomer equilibrium length. The simulations reveal the paramount importance played by mechanical activation for this class of systems. © 2009 Springer-Verlag Berlin Heidelberg.