Close Columnar Packing of Triangulenium Ions in Langmuir Films
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Close Columnar Packing of Triangulenium Ions in Langmuir Films. / Simonsen, Jens Bæk; Kjær, Kristian; Howes, Paul; Nørgaard, Kasper; Bjørnholm, Thomas; Harrit, Niels Holger; Laursen, Bo Wegge.
I: Langmuir, Bind 25, Nr. 6, 2009, s. 3584-3592.Publikation: Bidrag til tidsskrift › Tidsskriftartikel › Forskning › fagfællebedømt
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TY - JOUR
T1 - Close Columnar Packing of Triangulenium Ions in Langmuir Films
AU - Simonsen, Jens Bæk
AU - Kjær, Kristian
AU - Howes, Paul
AU - Nørgaard, Kasper
AU - Bjørnholm, Thomas
AU - Harrit, Niels Holger
AU - Laursen, Bo Wegge
N1 - Paper id:: DOI: 10.1021/Ia803733s
PY - 2009
Y1 - 2009
N2 - Three new tris(dialkylamino)trioxatriangulenium (ATOTA(+)) salts rendered amphiphilic by attachment of two (5a center dot PF6 and 5b center dot PF6) or four (5c center dot PF6) n-decyl chains have been synthesized, and their Langmuir films have been studied by grazing incidence X-ray diffraction (GIXD). Compounds 5a center dot PF6 and 5b center dot PF6 both self-assemble into 2D-crystalline Langmuir monolayers, in which the planar triangular shaped carbenium ions form columnar aggregates segregated from the PF6- ions. The column width is found to be close to the width of the triangulenium moiety itself (similar to 17 angstrom), while the repeat distance along the columnar aggregates is only 3.45 angstrom, implicating a near cofacial columnar structure with only a small tilt of the planar carbenium ions relative to the columnar axis. A detailed Bragg rod analysis confirmed an 8-9 degrees tilt and inferred a large anisotropy in the smearing/thermal displacement along the pi-pi stacking and lamellar packing directions. Specular X-ray reflectivity (SXR) was used to confirm the model derived from the GIXD data and elucidate the average position of the disordered PF6- ions, showing that the majority of the anions are accommodated in the ATOTA(+) layer rather than in the water subphase.
AB - Three new tris(dialkylamino)trioxatriangulenium (ATOTA(+)) salts rendered amphiphilic by attachment of two (5a center dot PF6 and 5b center dot PF6) or four (5c center dot PF6) n-decyl chains have been synthesized, and their Langmuir films have been studied by grazing incidence X-ray diffraction (GIXD). Compounds 5a center dot PF6 and 5b center dot PF6 both self-assemble into 2D-crystalline Langmuir monolayers, in which the planar triangular shaped carbenium ions form columnar aggregates segregated from the PF6- ions. The column width is found to be close to the width of the triangulenium moiety itself (similar to 17 angstrom), while the repeat distance along the columnar aggregates is only 3.45 angstrom, implicating a near cofacial columnar structure with only a small tilt of the planar carbenium ions relative to the columnar axis. A detailed Bragg rod analysis confirmed an 8-9 degrees tilt and inferred a large anisotropy in the smearing/thermal displacement along the pi-pi stacking and lamellar packing directions. Specular X-ray reflectivity (SXR) was used to confirm the model derived from the GIXD data and elucidate the average position of the disordered PF6- ions, showing that the majority of the anions are accommodated in the ATOTA(+) layer rather than in the water subphase.
U2 - 10.1021/la803733s
DO - 10.1021/la803733s
M3 - Journal article
C2 - 19231877
VL - 25
SP - 3584
EP - 3592
JO - Langmuir
JF - Langmuir
SN - 0743-7463
IS - 6
ER -
ID: 12488556