ADSORPTION OF ALKANENITRILES AND ALKANEDINITRILES ON GOLD AND COPPER

Valeronitrile, heptadecanenitrile, nonadecanenitrile, heneicosanenitrile, malonodinitrile, succinodinitrile, glutarodinitrile, and tetradecanedinitrile adsorb on gold and copper from hexane or acetone solution or from the neat liquid. The adsorbed layers were analyzed by reflection infrared spectroscopy at grazing incidence, ellipsometry, contact angle measurements, surface profilometry, and X-ray photoelectron spectroscopy. The compounds with more than 10 methylene units form layers of a thickness of 6-8 angstrom on copper and gold. The advancing contact angle of water on these layers is 90-94-degrees; i.e. the wetting properties of these layers are very close to poly(ethylene) but different from poly(acrylonitrile) or monolayers of nitrile terminated alkanethiols. Valeronitrile behaves similar to long chain nitriles on gold, but on copper "multilayers" are formed (layer thickness up to ca. 1000 angstrom). This is also observed for malonodinitrile and glutarodinitrile on copper. There is spectroscopic evidence for eta2-bonded nitrile groups of some alkanenitriles and alkanedinitriles on copper.