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Synlett 2004(3): 439-444  
DOI: 10.1055/s-2004-817741
LETTER
© Georg Thieme Verlag Stuttgart · New York

Highly Luminescent Probes from Terpyridine, Phenanthroline, and Pyrromethene·BF2 Auxiliaries

Gilles Ulrich, Raymond Ziessel*
Laboratoire de Chimie Moléculaire, associé au CNRS, ECPM, 25 rue Becquerel, 67087 Strasbourg Cedex 02, France
Fax: +33(3)90242689; e-Mail: ziessel@chimie.u-strasbg.fr;
Further Information

Publication History

Received 14 November 2003
Publication Date:
06 February 2004 (online)

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Abstract

The synthesis of novel bodipy based fluorophores appended to pyridine (py), terpyridine (terpy), and phenanthroline (phen) cores has been performed using three different methods. The most effective and reliable method consists in cross coupling an iodo functionalized bodipy with ethynyl grafted oligopyridines. The cross coupling the other way around from an ethynyl functionalized bodipy is less effective due to a homocoupling reaction leading to the butadiyne bridged species. For the less stable alkynes, a one-pot protocol, under phase transfer conditions, using the trimethylsilyl-protected alkynes has been finalized. Compounds exhibit very strong absorption and emission properties in the visible.

Key words

indacene - bipyridine - fluorescent dyes - terpyridine - alkyne - palladium coupling

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A representative experimental procedure is given for the preparation and purification of compound 10 using the phase transfer conditions sketched in Scheme [4] . A benzene (15 mL)/H2O (10 mL) biphasic mixture containing 5,5′-bis-trimethylsilylethynyl-2:2′;6′:2′′-terpyridine (14; 0.042 g, 0.099 mmol), 1 (0.100 g, 0.198 mmol), NaOH (0.04 g, 0.99 mmol), Et3BzNCl (0.001 g, 0.006 mmol) was strongly degassed with argon. To this solution Pd(PPh3)4 (0.014 g, 0.012 mmol) and CuI (0.0025 g, 0.01 mmol) was then added and the reaction was heated under argon, at 60 °C during 1 d. The benzene was then removed, H2O added, and the compound extracted with CH2Cl2. The organic fractions were dried over MgSO4, and a chromatography on alumina (Al2O3, CH2Cl2/hexane, 1:1, v:v) afforded the pure compound as a red powder (0.089 g, 87%).1H NMR (300.1 MHz, CDCl3): δ = 0.99 (t, 12 H, 3 J = 7.5 Hz, CH3), 1.35 (s, 12 H), 2.31 (q, 8 H, 3 J = 7.5 Hz, CH2), 2.54 (s, 12 H), 7.56 (ABsys, 8 H, J AB = 8.2 Hz, ν0δ = 114.5 Hz), 7.96-8.02 (m, 3 H), 8.51 (d, 2 H, 3 J = 7.9 Hz), 8.66 (d, 2 H, 3 J = 8.3 Hz), 8.87 (d, 2 H, 4 J = 2.1 Hz).11B NMR (128.4 MHz, CDCl3): δ = 3.86 (t,
J B-F = 33.30 Hz).UV/Vis (CH2Cl2, 23 °C): λmax (ε, M-1
cm-1) = 347 (140,000), 497 (sh, 86,000), 526 (225,000). IR (KBr): 3437, 2920, 1620 (br, νC=N), 1594, 1384, 1115 cm-1. MS (FAB+, mNBA): m/z (%) = 1037 (100) [M]+, 1018 (20) [M - F]+. Anal. Calcd for C65H61B2F4N7: C, 75.22; H, 5.92; N, 9.45; Found C, 75.05; H, 5.77; N, 9.22.