Molecular self-assembly of rigid-rod alkynyl chromophores on inorganic oxide surfaces

The hydrolysis of surface-bound basic tin-amide moieties with acidic proton s of alkynyl chromophores leads to molecular self-assembly of a variety of rigid-rod alkynes on inorganic oxide surfaces such as glass, quartz, and si ngle crystal silicon. Characterization of these newly developed thin films was achieved by contact-angle goniometry, FTIR-ATR, ellipsometry, and X-ray photoelectron spectroscopy, which indicate that these thin films are dense ly packed. Comparative molecular mechanics modeling studies on unbound and chemisorbed -Sn-C drop C-H monomer, dimer, trimer, and a 12 x 12 (144 molec ule) model substrate, suggest that surface anchoring of Sn-alkynyl units is essential for highly ordered thin-film structures that can effect topochem ical polymerization Preliminary MO calculations on a 4 x 4 model show conju gated molecular orbitals through the system.