title: Synthesis, properties, and remarkable 2 D Self-Assembly at the Liquid/Solid interface of a series of triskele-shaped 5,11,17-triazatrinaphthylenes (TrisK).
abstract: A series of 5,11,17-triazatrinaphthylene (TrisK) derivatives, large disk-like π-conjugated molecules with C3h symmetry, has been synthesised by following an optimised synthetic pathway. The synthesis was performed by a four-step protocol based on the N-arylation of 1,3,5-tribromobenzene with appropriate anthranilate derivatives. This strategy permits the generation of either chlorinated (TrisK-Cl-OCn) or non-chlorinated (TrisK-H-OCn) alkoxy-substituted derivatives (OCn H2n+1 with n=3, 10, 12 and 16), thus providing additional versatility in the control of the structure-property relationships. The electronic properties of the various TrisK compounds have been characterised in solution by absorption and emission spectroscopies as well as cyclic voltammetry. The crystal structure of 2,8,14-propyloxy-5,11,17-triazatrinaphthylene TrisK-H-OC3 has been determined by X-ray diffraction analysis, which revealed the presence of stabilising weak intermolecular H bonds. Scanning tunnelling microscopy (STM) at the liquid/solid interface has revealed the remarkable 2D self-assembling properties of the TrisK compounds. In particular, it has shown that TrisK-H-OC12 forms three concomitant self-organised 2D phases with different row-packing arrangements. This 2D polymorphism arises from slow ordering due to the presence of three long dodecyloxy chains on the molecular backbone. Individual molecules can be imaged with spectacular intramolecular resolution, thus providing the possibility of correlating the STM features with the calculated charge density distribution.
authors.affiliation: Institut Parisien de Chimie Moléculaire (IPCM), Université Pierre et Marie Curie, Paris 6, UMR CNRS 7201-4, place Jussieu, 75005 Paris (France), Fax: (+33) 1-4427-7360; Institut Curie, Campus Universitaire d'Orsay, UMR CNRS 176, Bât. 110, 91405 Orsay (France).
authors.forename: Hélène
authors.initials: H
authors.lastname: Bertrand
authors.forename: Régis
authors.initials: R
authors.lastname: Guillot
authors.forename: Marie-Paule
authors.initials: MP
authors.lastname: Teulade-Fichou
authors.forename: Denis
authors.initials: D
authors.lastname: Fichou
mesh_terms: D001372:Aza Compounds / Q000737:chemistry*; D018360:Crystallography, X-Ray; D055664:Electrochemical Techniques; D016252:Microscopy, Scanning Tunneling; D008968:Molecular Conformation; D009281:Naphthalenes / Q000138:chemical synthesis / Q000737:chemistry*; D011789:Quantum Theory
chemical_list: D001372:Aza Compounds; D009281:Naphthalenes
keywords: Pi-conjugated molecules; polymorphism; scanning tunnelling microscopy; self-assembly; triazatrinaphthylenes