'Magic' Surface Clustering of Borazines Driven by Repulsive Intermolecular Forces

摘要

The different types of covalent bonds that carbon atoms can form yield a variety of fascinating structures with unique structural, chemical, and physical properties. For example, discrete and extended polycyclic aromatic hydrocarbons (PAHs), such as graphene or graphene nanorib-bons are emerging as novel, transformational molecular materials. Replacing carbon by isostruc-tural atoms is also emerging as a versatile function-alization strategy, for example, to tune optoelectronic and mechanical properties. In particular, the substitution of C=C bonds by B=N covalent couples leads to isoelectronic molecular mimics bearing strong local dipole moments. This polarity significantly affects the electronic properties triggering the formation of self-assembled architectures. In this respect, borazine (B,N,H3) and its derivatives have played a significant role as precursors for preparing bulk and thin-layer BN-based ceramics and ultrathin insulators,' and B-trimesityl-N-triphenylborazine derivative 1 was recently proposed as a viable active layer for optoelectronic devices. The study of borazine interactions on solid surfaces has to date been largely unexplored, although understanding and controlling the assembly of borazine molecular layers' could provide the conceptual basis to engineer functional supramolecular materials.