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Synlett 2005(8): 1259-1262  
DOI: 10.1055/s-2005-868474
LETTER
© Georg Thieme Verlag Stuttgart · New York

Bi-Directional Synthesis of a Series of 2,5-Dodecanoxy-phenyleneethynylene Oligomers

Norma González-Rojanoa, Eduardo Arias-Marín*a, Dámaso Navarro-Rodrígueza, Steffen Weidnerb
a Centro de Investigación en Química Aplicada (CIQA), Boulevard Enrique Reyna 140, 25100 Saltillo, Coahuila, México
Fax: +52(844)4389839; e-Mail: earias@ciqa.mx;
b Bundesanstalt für Materialforschung und -prüfung (BAM), Unter den Eichen 87, 12205 Berlin, Germany
Further Information

Publication History

Received 9 February 2005
Publication Date:
21 April 2005 (online)

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Abstract

A family of rigid rod like 2,5-dodecanoxy-phenyleneethynylene oligomers having 3, 5, 7, and 9 repeating units was selectively synthesized by a bi-directional iterative divergent-convergent approach. Starting from a central 1,4-bis(dodecanoxy)-2,5-diiodobenzene monomer, only two repetitive reactions were involved with each cycle of oligomerization: a Pd/Cu cross-coupling with the bifunctional monomer 1-(3,3-diethyltriazene)-2,5-bis(dodecanoxy)-4-(ethynyl)benzene, generating oligomers with terminal triazene groups, followed by a further nucleophilic substitution with iodine.

Key words

conjugated oligomers - phenyleneethynylenes - tri­azenes - aryl iodides - Sonogashira-Heck reaction

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Trimer 12: Mp 84 °C. 1H NMR (300 MHz, CDCl3): δ = 0.87 (br s, 18 H, CH3), 1.25 (br s, 96 H, CH2), 1.47 (br s, 12 H, CH2-γ-O), 1.82 (m, 12 H, CH2-β-O), 3.99 (m, 12 H, CH2-α-O), 6.90 (s, 2 H, Ar-H), 6.99 (s, 2 H, Ar-H), 7.30 (s, 2 H, Ar-H). 13C NMR (75 MHz, CDCl3): δ = 14.20 (CH3), 22.78 (CH2), 25.90 and 26.10 (C-γ-O), 29.37 (CH2), 29.45 (C-β-O), 29.58 (CH2), 29.70 (CH2), 29.76 (CH2), 32.01 (CH2), 69.75 and 70.13 (C-α-O), 87.62 (ArCI), 90.88 (C≡C), 91.15 (C≡C), 114.06 (ArC≡), 114.32 (ArC≡), 116.19 (Ar-H), 117.32 (Ar-H), 124.20 (Ar-H), 151.94 (ArCO), 153.56 (ArCO), 154.27 (ArCO). MALDI-TOF: m/z calcd for C94H156I2O6, 1635.54; found, 1636.05.
Pentamer 14: Mp 105 °C. 1H NMR (300 MHz, CDCl3): δ = 0.88 (br s, 30 H, CH3), 1.24 (br s, 160 H, CH2), 1.50 (br s, 20 H, CH2-γ-O), 1.83 (br s, 20 H, CH2-β-O), 4.02 (m, 20 H, CH2-α-O), 6.91 (s, 2 H, ArH), 7.0 (s, 6 H, ArH), 7.30 (s, 2 H, ArH). 13C NMR (75 MHz, CDCl3): δ = 14.20 (CH3), 22.78 (CH2), 26.03 and 26.11 (C-γ-O), 29.37 (CH2), 29.46 (C-β-O), 29.59 (CH2), 29.70 (CH2), 29.77 (CH2), 29.79 (CH2), 32.01 (CH2), 69.76 and 70.12 (C-α-O), 87.61 (ArCI), 90.93 (C≡C), 91.16 (C≡C), 91.68 (C≡C), 114.08 (ArC≡), 114.28 (ArC≡), 114.44 (ArC≡), 116.19 (Ar-H), 117.35 (Ar-H), 124.20 (Ar-H), 151.94 (ArCO), 153.57 (ArCO), 154.27 (ArCO). MALDI-TOF: m/z calcd for C158H260I2O10, 2572.34; found, 2573.56.
Heptamer 16: Mp 116 °C. 1H NMR (300 MHz, CDCl3): δ = 0.87 (br s, 42 H, CH3), 1.24 (br s, 224 H, CH2), 1.50 (br s, 28 H, CH2-γ-O), 1.84 (br s, 28 H, CH2-β-O), 4.03 (m, 28 H, CH2-α-O), 6.90 (s, 2 H, Ar-H), 7.0 (s, 10 H, Ar-H), 7.31 (s, 2 H, Ar-H). 13C NMR (75 MHz, CDCl3): δ = 14.19 (CH3), 22.78 (CH2), 26.03 and 26.12 (C-γ-O), 29.46 (C-β-O), 29.58 (CH2), 29.80 (CH2), 32.01 (CH2), 69.76 and 70.13 (C-α-O), 87.60 (ArCI), 91.0 (C≡C), 91.14 (C≡C), 91.69 (C≡C), 114.09 (ArC≡), 114.45 (ArC≡), 116.20 (Ar-H), 117.35 (Ar-H), 124.21 (Ar-H), 151.94 (ArCO), 153.58 (ArCO), 154.28 (ArCO). MALDI-TOF: m/z calcd for C222H364I2O14, 3508.75; found: 3511.07.
Nonamer 18: Mp 125 °C. 1H NMR (300 MHz, CDCl3): δ = 0.87 (br s, 54 H, CH3), 1.24 (br s, 288 H, CH2), 1.50 (br s, 36 H, CH2-γ-O), 1.83 (br s, 36 H, CH2-β-O), 4.03 (br s, 36 H, CH2-α-O), 6.91 (s, 2 H, Ar-H), 7.0 (s, 14 H, Ar-H), 7.30 (s, 2 H, Ar-H). 13C NMR (75 MHz, CDCl3): δ = 14.19 (CH3), 22.78 (CH2), 26.12 (C-γ-O), 29.46 (C-β-O), 29.58 (CH2), 29.80 (CH2), 32.02 (CH2), 69.76 and 70.13 (C-α-O), 91.69 (C≡C), 114.0 (ArC-≡), 114.45 (ArC-≡), 117.36 (Ar-H), 153.57 (ArCO). MALDI-TOF: m/z calcd for C286H468I2O18 4448.57; found, 4445.56.