The phase behavior of three N-alkyl-substituted perylene diimide derivatives is examined by differential scanning calorimetry and polarized optical microscopy. The occurrence of multiple phase transitions indicates several crystalline and several liquid crystalline phases. X-ray diffraction measurements show that the liquid crystalline phases display high structural ordering in all three dimensions: smectic layers are formed, and within these smectic layers an additional ordering in columns is observed. Molecular modeling confirms this result and substantiates smectic ordering with interdigitating alkyl chains that determine the distance between the smectic layers. The ordering in columns is favored by π-π interactions between the cofacially oriented perylene molecules and by the elliptic shape of the molecule. Finally, intermolecular dipole-dipole interactions between the carbonyl groups of the imide moieties cause the perylene molecules to orient on average with a slight rotation between neighboring molecules within a columnar stack. Following the determination of the electronic transition dipole moment, this orientation, which still involves substantial π-π interactions, could be confirmed by UV/vis spectroscopy of perylene aggregates. To gauge the potential of these materials as organic semiconductors, the charge carrier mobility of one of the perylene derivatives has been measured by pulse-radiolysis time-resolved microwave conductivity. A value in excess of 0.1 cm 2 V -1 s -1 is found in the liquid crystalline phase, and a value in excess of 0.2 cm 2 V -1 s -1 is found for the crystalline phase. These values are comparable with the highest values previously found for other discotic materials.

A series of phthalimide-and 1,12-benzoperylene-1′,2′-dicarboxylic imido-linked alkynes were prepared and analyzed by UV, FT-IR, optical microscopy, and differential scanning calorimetry. The possibility to convert ω-alkynes (R-(CH 2)n-CtCH) to diacetylenic compounds (R-(CH2)nCtC-CtC-(CH2)n-R) was investigated for R ) phthalimide and 1,12-benzoperylene-1′,2′-dicarboxylic imide with n ) 1, 3, and 9. Formation of the diacetylenic compound is usually straightforward (as checked by comparison with independently synthesized diacetylenes), and in some cases heat-induced polymerization of the thusformed diacetylenes proceeds directly. For the perylene imide-linked materials with n ) 1 and n ) 3 1,2-polymerization occurs, while for n ) 9 1,4-polymerization occurs. The 1,4-polymerization is also observed for the phthalimide-linked materials. For R ) phthalimide and n ) 1 this 1,4-polymerization can only be induced by further heating, while for the analogous n ) 9 compound 1,4-polymerization is already induced by UV-vis irradiation at room temperature. This is related to the flexibility of the methylene spacer in the crystal.

The formation and transfer of ordered layers of poly(maleic anhydride-alt-alkyl vinyl ether)s and poly(maleic acid-alt-alkyl vinyl ether)s with and without (cyanobiphenylyl)oxy moieties on aqueous subphases is studied by use of the Langmuir−Blodgett technique. The length of the spacers, flexibility of the polyelectrolyte backbone, pH of the subphase, and the presence of counterions determine the orientation of the polymers at the air−water interface. As counterions Cu2+, Mg2+, tetrabutylammonium, n-dodecyltrimethylammonium, and n-dodecyl sulfate are used. The increase in lift-off area proves the interaction of both cationic and anionic surfactants with the maleic acid copolymers. This is due to electrostatic interactions between the charged groups and hydrophobic interactions between the side chains of the polymer and surfactant tail. The π−A isotherms and Brewster angle microscopy of the maleic acid copolymers on water and on a 1 mM n-dodecyltrimethylammonium solution show the formation of a triple layer upon compression of the monolayer. Monolayers of the maleic acid copolymers on both subphases could be transferred onto hydrophilic glass and quartz slides in a Z-type fashion. However, second harmonic generation (SHG) measurements showed that the noncentrosymmetry is not maintained in the deposited multilayers.

Morphological changes of monolayers of two polymerizable pyridine amphiphiles upon complexation with Cu(II) ions at the air-water interface Werkman, P.J.; Schouten, A.J.; Noordegraaf, M.A.; Kimkes, P.; Sudhölter, E.J.R. IMPORTANT NOTE: You are advised to consult the publisher's version (publisher's PDF) if you wish to cite from it. Please check the document version below. Document Version Publisher's PDF, also known as Version of recordPublication date : 1998 Link to publication in University of Groningen/UMCG research database Citation for published version (APA): Werkman, P. J., Schouten, A. J., Noordegraaf, M. A., Kimkes, P., & Sudhölter, E. J. R. (1998). Morphological changes of monolayers of two polymerizable pyridine amphiphiles upon complexation with Cu(II) ions at the air-water interface. Langmuir, 14(1), 157 -164. DOI: 10.1021/la970576a Copyright Other than for strictly personal use, it is not permitted to download or to forward/distribute the text or part of it without the consent of the author(s) and/or copyright holder(s), unless the work is under an open content license (like Creative Commons).Take-down policy If you believe that this document breaches copyright please contact us providing details, and we will remove access to the work immediately and investigate your claim.Downloaded from the University of Groningen/UMCG research database (Pure): http://www.rug.nl/research/portal. For technical reasons the number of authors shown on this cover page is limited to 10 maximum. The monolayer behavior of two amphiphilic, diacetylenic units containing pyridine ligands at the airwater interface is studied by measuring the surface pressure-area isotherms and by Brewster angle microscopy (BAM). Both amphiphiles form stable monolayers at the air-water interface. The amphiphile containing an ester group shows a well-defined liquid-expanded (LE) to liquid-condensed (LC) phase transition, while the amphiphile with the amide group forms only a condensed monolayer film at 9.4°C. For both amphiphiles, addition of CuCl 2 to the subphase causes an increase of the surface pressure (Πc) at which the phase transition appears, suggesting the formation of a coordination complex at the airwater interface. Addition of Cu(ClO4)2 to the subphase instead of CuCl2 causes an even larger increase in Πc, indicating that more copper ions bind to the monolayer which results in a more charged monolayer. On a pure water subphase, Brewster angle microscopy of the monolayer of the ester-containing ligand shows the formation of spiral dendritic crystalline domains at the plateau in the isotherm near the solid state region. The formation of spiral crystalline domains indicates that the LC phase is L1′. The amidecontaining ligand, however, forms two-dimensional crystalline domains directly after spreading at the air-water interface, which are pushed together upon compression. No chiral crystalline domains were observed for this amphiphile indicating that the ester and amide amphiphile have a different LC phase. Both amphiphiles spread...

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