A Comparative Study of a Triphenylene Tricarbonyl Chromium Complex and Its Uncoordinated Arene Ligand on the Ag(111) Surface: Influence of the Complexation on the Adsorption

An aromatic triphenylene molecule (2,3-diethyl-1,4-dimethoxytriphenylene; TPH) and its regioselectively Cr(CO)3-labeled complex (η6-(1,2,3,4,4a,12b)-tricarbonyl(2,3-diethyl-1,4-dimethoxytriphenylene)chromium(0); α-TPHC) were deposited on a Ag(111) surface by vapor deposition. The monolayers were investigated by X-ray photoelectron spectroscopy and scanning tunneling microscopy. Both substances adsorb with the extended π-system parallel to the surface and form long-range ordered monolayers. The Cr(CO)3 group of the α-TPHC complex is oriented toward the vacuum. Although the footprints of both substances are similar, the additional Cr(CO)3 group on the α-TPHC leads to a lateral order (unit cell) that is significantly different from that of TPH.