Palladium(II)-Catalyzed Dehydrogenative Strategy for Direct and Regioselective Oligomerization of BODIPY Dyes

Abstract

A family of directly β,γ-linked BODIPY oligomers up to pentamers were regioselectively prepared via Pd­(II)-catalyzed oxidative C–H cross-coupling. The structural integrity of β,γ-linked dimers was unambiguously confirmed by X-ray crystallography. These structurally unprecedented oligomers showed red-shifted absorptions and near-infrared emissions along with efficient intersystem crossing, giving ΦΔ in the range of 12–43%, for potential use as heavy-atom-free photosensitizers.

Unsymmetrical Benzothieno-Fused BODIPYs as Efficient NIR Heavy-Atom-Free Photosensitizers

“…Proton signals appearing at δ 3.87 (s, 3H) and 2.35 (s, 3H) can be assigned to OCH 3 on benzene and CH 3 on the pyrrole ring, respectively. The proton signals of double bond with E-geometry, appearing at δ 7.71 (d,J = 16.3 Hz,1H) and 7.38 (d,J = 16.2 Hz,1H), and 4-methoxyphenyl group, appearing at δ 7.63 (d, J = 8.4 Hz, 2H) and 6.94 (d,J = 8.7 Hz,2H), can also be found in the 1 H NMR spectrum of 11e. Further evidence of 11e comes from its high-resolution mass spectrometry in which a protonated molecular ion ([M + H] + ) at m/z 515.2142 was observed.…”

“…Mp: 158−159 °C. 1 H NMR (600 MHz, CDCl 3 ) δ 8.33 (s, 1H), 7.68 (d,J = 8.6 Hz,1H),7.53 (d,J = 8.6 Hz,1H),7.02 (d,J = 2.3 Hz,1H),4.40 (q,J = 7.1 Hz,2H),1H), 2.83 (s, 3H), 1.42 (t, J = 7.1 Hz, 3H), 1.38 (d, J = 6.9 Hz, 6H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ) δ 164.…”

“…Mp: 206−207 °C. 1 H NMR (600 MHz, CDCl 3 ) δ 8.58 (s, 1H), 7.94 (d,J = 8.3 Hz,1H),7.69 (d,J = 7.0 Hz,2H),7.62 (d,J = 8.5 Hz,1H),7.48 (t,J = 7.3 Hz,2H),7.44 (s,1H), 7.34 (t, J = 7.5 Hz, 1H), 4.42 (q, J = 7.1 Hz, 2H), 2.86 (s, 3H), 1.44 (t, J = 7.3 Hz, 3H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ) δ 163.8,143.0,137.1,135.2,130.5,129.0,127.9,126.6,125.1,124.5,123.7,121.7,120.4,117.9,116.5,61.2,14.6,14.0.…”

“…Mp: 252−253 °C. 1 H NMR (600 MHz, CDCl 3 ) δ 10.30 (s, 1H), 8.40 (s, 1H), 7.71 (d, J = 8.6 Hz, 1H), 7.58 (d,J = 8.6 Hz,1H),7.11 (s,1H), 3.27 (h, J = 6.6 Hz, 1H), 2.84 (s, 3H), 1.40 (d, J = 6.9 Hz, 6H). 13 C{ 1 H} NMR (151 MHz, CDCl 3 ) δ 183.3, 145.2, 136.3, 134.3, 130.2, 127.2, 126.3, 126.2, 120.3, 117.9, 115.1, 25.5, 23.4, 12.7.…”

Development of Geometry-Controlled All-Orthogonal BODIPY Trimers for Photodynamic Therapy and Phototheragnosis

“…Just a weak long-wavelength shoulder is recorded from trimer 12 , featuring both 2–8′ and 3–8′ junctions, which can be attributed to a small degree of excitonic coupling in such a geometry ( Figure 2 ). 15 Theoretically optimized geometries (CAM-B3LYP) reveal that the steric hindrance around both BODIPY–BODIPY linkage positions imposes an orthogonal disposition of the involved BODIPY subunits [torsion angles approaching 90° ( Figure S7 )], which hampers any resonant interaction between them. However, the molar absorption markedly depends on the linked chromophoric positions (see Table S1 ).…”