Synthesis of Highly Conjugated Two-Dimensional Molecular Scaffolds via Pd-Catalyzed Reactions on a Tetraphenylethylene Core

Abstract

A facile synthesis of ethylene centered highly conjugated two-dimensional molecular scaffolds is described via Pd-catalyzed coupling reactions (Sonogashira and Heck reactions) on a tetraphenylethylene core.

Key words

tetraphenylethylene - Sonogashira coupling - Heck ­reaction - two-dimensional conjugation

References

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13

A mixture of tetraphenylethylene (0.11 g, 0.33 mmol), I₂ (0.23 g, 0.80 mmol) and PhI(OAc)₂ (0.31 g, 0.80 mmol) in dry CHCl₃ (7 mL) was stirred at r.t. in the dark for 60 h. The reaction mixture was filtered and the residue washed with cold benzene. It was then recrystallized from CCl₄ to give the tetraiodide 5 (80%); mp >250 °C. UV/Vis (CHCl₃):
λ = 265 (ε = 38250 dm³mol^-1cm^-1), 330 (ε = 17375
dm³mol^-1cm^-1) nm. ¹H NMR (300 MHz, CDCl₃): δ = 6.78 (d, 8 H, J = 7.7 Hz), 7.40 (d, 8 H, J = 7.7 Hz).

15

Compound 8: IR (CHCl₃): 3000, 2910, 2090, 1480 cm^-1. ¹H NMR (300 MHz, DMSO-d ₆): δ = 3.24 (s, 4 H), 6.90 (d, 8 H, J = 8 Hz), 7.12 (d, 8 H, J = 8 Hz). C₃₄H₂₀ requires C, 95.32; H, 4.67%. Found: C, 95.16; H, 4.71; Compound 9: IR (CHCl₃): 3300, 3000, 1605, 1450 cm^-1. ¹H NMR (300 MHz, DMSO-d ₆): δ = 4.26 (d, 8 H, J = 5.4 Hz), 5.31 (t, 4 H, J = 5.4 Hz), 6.94 (d, 8 H, J = 7.8 Hz), 7.22 (d, 8 H, J = 7.8 Hz). Compound 10: IR (CHCl₃): 3000, 2930, 1700, 1650, 1600, 1465 cm^-1. ¹H NMR (300 MHz, DMSO-d ₆): δ = 4.31 (s, 8 H), 7.04 (d, 8 H, J = 8 Hz), 7.32 (d, 8 H, J = 8 Hz), 7.50-7.82 (m, 8 H), 7.86-8.30 (m, 16 H), 8.70 (br s, 4 H). C₈₂H₅₂O₈ requires C, 84.53; H, 4.46%. Found: C, 84.19; H, 4.66. Compound 11: IR (CHCl₃): 2920, 1708, 1630, 1360, 1305 cm^-1. ¹H NMR (300 MHz, DMSO-d ₆): δ = 1.33 (t, 12 H, J = 7 Hz), 4.20 (q, 8 H, J = 7 Hz), 6.56 (d, 4 H, J = 15 Hz), 7.07 (d, 8 H, J = 8 Hz), 7.40 (d, 8 H, J = 8Hz), 7.78 (d, 4 H, J = 15 Hz).