Edelmann, Michael J.; Odermatt, Severin; Diederich, Francois, Chimia, 2001, vol. 55, # 3, p. 132 - 138
作者:Edelmann, Michael J.、Odermatt, Severin、Diederich, Francois
DOI:——
日期:——
Monodisperse Poly(triacetylene) Rods: Synthesis of a 11.9 nm Long Molecular Wire and Direct Determination of the Effective Conjugation Length by UV/Vis and Raman Spectroscopies
作者:Rainer E. Martin、Thomas Mäder、François Diederich
With 16 C-C double and 32 C-C triple bonds and a length of 11.9 nm, the hexadecameric poly(triacetylene) (PTA) of type 1 is currently the longest linear fully π-conjugated molecular wire that does not contain aromatic repeat units. A series of PTA oligomers 1 extending from monomer to hexadecamer was prepared by a rapid and efficient statistical deprotection-oligomerization sequence; the effective conjugation length at which saturation of molecular properties occurs was determined as n=10 (n=number of monomeric units) by both UV/Vis and Raman spectroscopies.
Poly(triacetylene) Oligomers: Conformational Analysis by X-Ray Crystallography and Synthesis of a 17.8-nm-Long Monodisperse 24-mer
作者:Michael J. Edelmann、Michael A. Estermann、Volker Gramlich、François Diederich
Starting from the octameric poly(triacetylene) (PTA) oligomer 1e as a large 'macromonomer', the monodisperse tetracosamer (24-mer) 1h was prepared by a previously introduced statistical deprotection-oligomerization sequence (Scheme). It is the longest known molecular rod featuring a fully conjugated, non-aromatic all-carbon backbone. Matrix assisted laser-desorption-ionization time-of-flight (MALDI-TOF) mass spectrometry was particularly useful in the characterization of oligomer 1h and clearly demonstrated its monodispersity (Fig. 1). In an effort to further clarify the conformational preferences of PTA oligomers, the X-ray crystal structure of the 3.2-nm-long tetramer 1c was solved (Figs. 2-4). In the solid start, the C=C bonds in 1c all adopt the s-trans conformation with respect to the buta-1,3-diynediyl moieties. The pi -conjugated system is perfectly planar, with the squared sum of the deviations of the backbone C-atoms from the best plane amounting to 0.077 Angstrom (2). Analysis of the crystal lattice revealed a layered structure, in which the pi -conjugated backbone of one oligomer is insulated by the trialkylsilyl groups of adjacent oligomers in neighboring layers.