Comparison of Oligo(ethylene glycol)allkanethiols versus n-Alkanethiols: Self-Assembly, Insertion, and Functionalization

摘要

We describe the self-assembly and chemical functionalization of oligo(ethylene glycol)alkanethiol (OEG) molecules. Insertion of OEGs into n-alkanethiolate monolayer matrices depends considerably on terminal functionality, unlike insertion of n-alkanethiols. Thus, inserted fractions of OEGs cannot be inferred from related systems, yet tuning, to some extent, is possible by controlling insertion parameters. Furthermore, while the in situ reactivities of dilute inserted carboxy-or amine-terminated OEGs versus n-alkanethiols protrudingfrom the surrounding matrix are similar in amide bond formation reactions, complete monolayers of OEGs react to a greater extent compared to n-alkanethiols with similar terminal functionalities. We interpret these differences in terms of the reduced crystalline packing of terminal ethylene glycol groups of OEGs,