| Abstract
| - Self-assembled monolayers (SAM) of ω-(4‘-methylbiphenyl-4-yl)alkanethiols CH3(C6H4)2(CH2)nSH (BPn, n= 1−6) on Au(111) substrates, prepared at room and elevated temperatures, were studied using scanningtunneling microscopy (STM). Molecularly resolved images reveal that all BPn SAMs form well-ordered layersover areas easily exceeding 50 × 50 nm2. Only two basic structures are alternatingly adopted with n changingbetween odd and even. The unit cell of odd-numbered SAMs is described by an oblique (2√3 × √3)R30°structure and contains two molecules. In contrast, the even-numbered SAMs are described by a much larger,rectangular (5√3 × 3) structure with eight molecules per unit cell and occupying an area per molecule largerby about 25% compared to n = odd. With the exception of BP1 and BP6 the preparation at elevatedtemperatures resulted in a significant improvement in structural quality, yielding very large domains. ForBP6 prepared at 343 K a strong domain anisotropy is observed, which is explained by the influence of thealkane spacer chain. For BP1 prepared at 343 K formation of gold islands is concluded.
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