Chain-Length Effects on the Self-Assembly of Short 1-Bromoalkane and n-Alkane Monolayers on Graphite

Autor: Tova L. Werblowsky, Thomas Müller, Gina M. Florio, Boaz Ilan, Bruce J. Berne, George W. Flynn
Rok vydání: 2008
Předmět:
Zdroj: The Journal of Physical Chemistry C. 112:18067-18075
ISSN: 1932-7455
1932-7447
DOI: 10.1021/jp8064689
Popis: The structural properties of self-assembled monolayers of short 1-bromoalkanes and n-alkanes on graphite were investigated by a combination of ultrahigh vacuum scanning tunneling microscopy (UHV-STM) at 80 K and theoretical methods. STM images of 1-bromohexane reveal a lamellar packing structure in which the molecules form a 57° ± 3° lamella-molecular backbone angle and a head-to-head assembly of the bromine atoms (Muller, et al. Proc. Natl. Acad. Sci. U.S.A. 2005, 102, 5315). STM images of 1-bromoheptane also show a head-to-head 60° ± 3° lamella-molecular backbone pattern; however, the molecules pack in a herringbone structure. The odd/even chain-length alternation in the monolayer morphologies of 1-bromoalkanes is similar to that observed for the self-assembly of short n-alkanes on graphite, suggesting that the bromine atom acts effectively as an extension of the carbon backbone. The analogy, however, is incomplete. Odd and even short n-alkanes (hexane, heptane, octane) display 60° herringbone and recta...
Databáze: OpenAIRE