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Crystalline Self‐Assembly into Monolayers of Folded Oligomers at the Air‐Water Interface
Author(s) -
Lederer Kay,
Godt Adelheid,
Howes Paul B.,
Kjaer Kristian,
AlsNielsen Jens,
Lahav Meir,
Wegner Gerhard,
Leiserowitz Leslie,
Weissbuch Isabelle
Publication year - 2000
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/1521-3765(20000616)6:12<2173::aid-chem2173>3.0.co;2-e
Subject(s) - crystallography , stacking , monolayer , molecule , alkyl , materials science , folding (dsp implementation) , ribbon , self assembly , diffraction , helix (gastropod) , perpendicular , chemistry , stereochemistry , nanotechnology , optics , geometry , organic chemistry , composite material , physics , mathematics , engineering , snail , ecology , electrical engineering , biology
Insertion of the 1,3‐bis(ethynylene)benzene unit as a rigid spacer into a linear alkyl chain, thus separating the two resulting stems by 9 Å, induces chain folding at the air‐water interface. These folded molecules self‐assemble into crystalline monolayers at this interface, with the plane of the folding unit almost perpendicular to the water surface, as determined by synchrotron grazing‐incidence X‐ray diffraction. Three distinct molecular shapes, of the types U, inverted U, and M, were obtained in the two‐dimensional crystalline state, depending upon the number of spacer units, and the number and position of the hydrophilic groups in the molecule. The molecules form ribbons with a higher crystal coherence in the direction of stacking between the molecular ribbons, and a lower coherence along the ribbon direction. A similar molecule, but with a spacer unit that imposes a 5 Å separation between alkyl chains, yields the conventional herringbone arrangement.