Pyrrolopyrrole Cyanine as Fluorescent Probes
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mirror (AMKO, Germany). A water filter was used to avoid sample heat-
ing. In addition, either a 345- or 570-nm longpass filter was used. A 1.4-
mL quartz cuvette with 10-mm path length was used for the experiment.
The diameter of the beam at sample was 30 mm. Absorption spectra
were recorded on a Cary 50 UV/Vis spectrometer every 5 min for a total
of 60 min of illumination time.
3J=8.4 Hz, 2H; H-3) 6.94 (m, 4H; XX’), 6.92 (d, 3J=7.5 Hz, 2H; H-5),
3.98 (t, 3J=6.6 Hz, 4H; OCH2), 2.65 (s, 6H; CH3), 1.76 (qui, 3J=6.6 Hz,
4H; OCH2CH2), 1.5–1.1 (m, 20H; alkyl), 0.83 ppm (t, 3J=6.9 Hz, 6H,
CH3); UV/Vis/NIR (chloroform): lmax (e)=707 (145000), 644 nm
(42000 molꢀ1 dm3 cmꢀ1); MALDI-MS: m/z: calcd: 869.4 [M+H]+; found:
869.5; elemental analysis calcd (%) for C50H54B2F4N6O2: C 69.14, H 6.27,
N 9.68; found: C 68.49, H 6.30, N 9.55.
The syntheses of the reactants 1a, 7, and 9 are described in the Support-
ing Information. The synthesis and physical data of 8c–8 f and 11e have
already been reported.[9]
10d: Column chromatography (CH2Cl2) afforded 10d as a green crystal-
1
3
line powder in 38% yield. H NMR (400 MHz, C2Cl4D2): d=7.88 (d, J=
8.8 Hz, 2H; H-4), 7.73 (d, 4J=1.8 Hz, 2H; H-7), 7.70 (m, 4H; AA’) 7.53
(dd, 3J=8.8 Hz, 4J=1.8 Hz, 2H; H-5), 7.07 (m, 4H; XX’), 4.07 (t, 3J=
6.6 Hz, 4H; OCH2), 1.85 (qui, 3J=6.6 Hz, 4H; OCH2CH2), 1.55–1.2 (m,
20H; alkyl), 1.34 (s, 18H; tert-butyl), 0.90 ppm (t, 3J=6.8 Hz, 6H, CH3);
General procedure for the synthesis of the H–PPCy dyes 8: DPP 1a
(1 mmol) and heteroarylacetonitrile 7 (2.5 mmol) were heated to reflux
in absolute toluene under nitrogen. Phosphoryl chloride (8 mmol) was
then added. The reaction was monitored by UV/Vis/NIR spectroscopic
analysis and thin-layer chromatography. As soon as 1a was used up or
the concentration of the short-wavelength-absorbing by-products in-
creased, the reaction was quenched. The solvent and excess phosphoryl
chloride were removed under vacuum. The crude product was treated
with methanol in an ultrasonic bath and water was added until a solid
precipitated. The solid was collected by filtration and washed with meth-
anol until the filtrate was colorless. The remaining solid was purified by
column chromatography.
UV/Vis/NIR
(chloroform):
lmax
(e)=732
(190000),
663 nm
(52000 molꢀ1 dm3 cmꢀ1); MALDI-MS: m/z: calcd: 1065.5 [M+H]+;
found: 1065.8; elemental analysis calcd (%) for C60H66B2F4N6O2S2: C
67.67, H 6.25, N 7.89; found: C 67.76, H 6.26, N 7.88.
10 f: Column chromatography (CH2Cl2/MeOH 100:1) afforded 10 f as a
1
black crystalline powder in 36% yield. H NMR (400 MHz, C2Cl4D2): d=
9.10 (s, 2H; H-3), 8.29 (m, 2H; H-8), 7.99 (m, 2H; H-5), 7.67 (m, 8H;
3
AA’, H-6, H-7), 7.03 (m, 4H; XX’), 4.02 (t, J=6.6 Hz, 4H; OCH2), 1.79
(qui, 3J=6.6 Hz, 4H; OCH2CH2), 1.5–1.1 (m, 20H; alkyl), 0.83 ppm (t,
3J=6.8 Hz, 6H, CH3); UV/Vis/NIR (chloroform): lmax (e)=789 (210000),
715 nm (40000 molꢀ1 m3 cmꢀ1); MALDI-MS: m/z: calcd: 943.4 [M+H]+;
found: 943.5; elemental analysis calcd (%) for C54H52B2F4N8O2: C 68.80,
H 5.56, N 11.89; found: C 68.96, H 5.40, N 11.42.
8a: Column chromatography (CH2Cl2/ethyl acetate 40:1) afforded 8a as
a
turquoise crystalline powder in 43% yield. 1H NMR (400 MHz,
C2Cl4D2): d=13.59 (s, 2; NH), 7.65 (m, 4H; AA’), 7.11 (m, 4H; XX’),
6.72 (s, 2H; H-5), 4.08 (t, 3J=6.6 Hz, 4H; OCH2), 2.49 (s, 12H; CH3),
1.83 (qui, 3J=6.6 Hz, 4H; OCH2CH2), 1.5–1.2 (m, 20H; alkyl), 0.89 ppm
(t, 3J=6.8 Hz, 6H, CH3); UV/Vis/NIR (chloroform): lmax (e)=684
(78000), 625 (30000), 410 nm (25000 molꢀ1 dm3 cmꢀ1); MALDI-MS: m/z:
calcd: 803.5 [M+H]+; found: 803.9; elemental analysis calcd (%) for
C50H58N8O2: C 74.78, H 7.28, N 13.95; found: C 74.43, H 7.19, N 13.21.
10e: Compound 1a (500 mg, 0.92 mmol) and 7e (452 mg, 2 mmol) in ab-
solute m-xylene were heated to reflux under nitrogen. Phosphoryl chlo-
ride (190 mL, 2 mmol) was added. The reaction was monitored by UV/
Vis/NIR spectroscopic analysis. When the DPP peak had disappeared,
the reaction mixture was cooled to 808C. N,N-Diisopropylethylamine
(3 mL, 18.4 mmol) and BF3·Et2O (4.6 mL, 36.8 mmol) were added. The
reaction mixture was heated to reflux for 10 min. The cooled mixture was
diluted with xylene, washed with water (3ꢄ), the organic layer was dried
over MgSO4, and the solvent was removed. Column chromatography
(CH2Cl2) afforded 10e as a green crystalline powder in a 67% yield
(650 mg, 0.62 mmol). The physical data were consistent with reported
values.[9]
8b: Column chromatography (CH2Cl2) afforded 8b as a green–blue crys-
1
talline powder in 40% yield. H NMR (400 MHz, CDCl3): d=12.38 (s, 2;
NH), 7.73 (m, 4H; AA’), 7.59 (s, 2H; H-4), 7.36 (d, 3J=8.5 Hz, 2H; H-
7), 7.30 (d, 3J=8.5 Hz, 2H; H-6), 7.14 (m, 4H; XX’), 4.08 (t, 3J=6.6 Hz,
4H; OCH2), 1.84 (qui, 3J=6.6 Hz, 4H; OCH2CH2), 1.55–1.2 (m, 20H;
alkyl), 1.39 (s, 18H; tert-butyl), 0.91 ppm (t, 3J=6.9 Hz, 6H, CH3); UV/
Vis/NIR (chloroform): lmax (e)=711 (98000), 647 (43000), 429 nm
(26000 molꢀ1 dm3 cmꢀ1); MALDI-MS: m/z: calcd: 937.5 [M+H]+; found:
937.4; elemental analysis calcd (%) for C60H68N6O4: C 76.89, H 7.31, N
8.97; found: C 76.90, H 7.18, N 8.77.
General procedure for the synthesis of the BPh2–PPCy dyes 11: H che-
late 8 (1 mmol) and Hꢂnig base (3 mmol) were heated to reflux in di-
chloromethane. Chlorodiphenylborane (9; 4.5 mmol) was added and the
reaction mixture was heated to reflux until the reaction was complete
(UV/Vis/NIR). The mixture was washed with water and dried over
MgSO4. After removing the solvent, the residue was dissolved in metha-
nol in an ultrasonic bath. The remaining solid was separated by filtration,
washed with methanol, and purified by column chromatography.
General procedure for the synthesis of the BF2–PPCy dyes 10: H–PPCy
dye 8 (1 mmol) and N,N-diisopropylethylamine (20 mmol) were heated
to reflux in dichloromethane. BF3·Et2O (40 mmol) was added and the
mixture was heated to reflux for 10 min. The reaction mixture was
washed with water and dried over MgSO4. After removing the solvent,
the crude product was purified by column chromatography.
11a: Column chromatography (CH2Cl2/ethyl acetate, 100:1) afforded 11a
as
a
green crystalline powder in 49% yield. 1H NMR (400 MHz,
10a: Column chromatography (CH2Cl2/ethyl acetate, 50:1) yielded 10a
1
as a green crystalline powder in 31% yield. H NMR (400 MHz, CDCl3):
C2Cl4D2): d=7.11 (m, 20H; Ph), 6.43 (m, 4H; AA’), 6.25 (s, 2H; H-5),
3
6.02 (m, 4H; XX’), 3.92 (t, 3J=6.6 Hz, 4H; OCH2), 2.27 (s, 6H; CH3),
d=7.62 (m, 4H; AA’), 7.01 (m, 4H; XX’), 6.75 (s, 2H; H-5), 4.01 (t, J=
6.6 Hz, 4H; OCH2), 2.64 (s, 6H; CH3), 2.50 (s, 6H; CH3), 1.79 (qui, 3J=
3
1.78 (m, 10H; CH3, OCH2CH2), 1.5–1.2 (m, 20H; alkyl), 0.85 ppm (t, J=
3
6.6 Hz, 4H; OCH2CH2), 1.5–1.2 (m, 20H; alkyl), 0.89 ppm (t, J=6.9 Hz,
6.9 Hz, 6H, CH3); UV/Vis/NIR (chloroform): lmax (e)=737 (163000),
666 nm (27000 molꢀ1 dm3 cmꢀ1); MALDI-MS: m/z: calcd: 1131.6
[M+H]+; found: 1131.7; elemental analysis calcd (%) for C74H76B2N8O2:
C 78.58, H 6.77, N 9.91; found: C 78.34, H 6.78, N 9.77.
6H, CH3); UV/Vis/NIR (chloroform): lmax (e)=684 (125000), 625 nm
(35000 molꢀ1 dm3 cmꢀ1); MALDI-MS: m/z: calcd: 899.9 [M+H]+; found:
899.9; elemental analysis calcd (%) for C50H56B2F4N8O2: C 66.83, H 6.28,
N 12.47; found: C 66.75, H 6.28, N 12.44.
11b: Column chromatography (CH2Cl2) gave 11b as a green crystalline
powder in 52% yield. 1H NMR (400 MHz, C2Cl4D2): d=7.11 (m, 24H;
Ph, H-6, H-7), 6.62 (m, 4H; AA’), 6.32 (m, 6H; XX’, H-4), 4.06 (t, 3J=
6.6 Hz, 4H; OCH2), 1.68 (m, 4H; OCH2CH2), 1.5–1.2 (m, 20H; alkyl),
0.93 (s, 18H, tert-butyl), 0.83 ppm (t, 3J=6.8 Hz, 6H, CH3); UV/Vis/NIR
(chloroform): lmax (e)=747 (164000), 676 nm (39000 molꢀ1 dm3 cmꢀ1);
MALDI-MS: m/z: calcd: 1265.7 [M+H]+; found: 1265.3; elemental anal-
ysis calcd (%) for C84H86B2N6O4: C 79.74, H 6.85, N 6.64; found: C 79.66,
H 6.49, N 6.60.
10b: Column chromatography (CH2Cl2) afforded 10b as a green crystal-
line powder in 75% yield. 1H NMR (400 MHz, CDCl3): d=7.72 (m, 4H;
AA’), 7.63 (m, 2H; H-7), 7.45 (m, 4H; H-3, H-4), 7.09 (m, 4H; XX’),
4.07 (t, 3J=6.6 Hz, 4H; OCH2), 1.83 (qui, 3J=6.6 Hz, 4H; OCH2CH2),
1.55–1.2 (m, 20H; alkyl), 1.32 (s, 18H; tert-butyl), 0.90 ppm (t, 3J=
6.9 Hz, 6H, CH3); UV/Vis/NIR (chloroform): lmax (e)=690 (135000),
630 nm (42000 molꢀ1 dm3 cmꢀ1); MALDI-MS: m/z: calcd: 1033.5
[M+H]+; found: 1033.2; elemental analysis calcd (%) for
C60H66B2F4N6O4: C 69.77, H 6.44, N 8.14; found: C 69.77, H 6.76, N 8.16.
11c: Column chromatography (CH2Cl2/ethyl acetate, 100:1) afforded 11c
as
a
green crystalline powder in 29% yield. 1H NMR (400 MHz,
10c: Column chromatography (CH2Cl2/MeOH, 100:1) afforded 10c as a
green crystalline powder in 72% yield. 1H NMR (400 MHz, C2Cl4D2):
d=7.64 (dd, 3J=8.4, 3J=7.5 Hz, 2H; H-4), 7.56 (m, 4H; AA’), 7.47 (d,
C2Cl4D2): d=7.34 (m, 4H; H-3, H-4), 7.08 (m, 20H; Ph), 6.44 (m, 4H;
AA’), 6.40 (dd, 2H; H-5), 5.99 (m, 4H; XX’), 3.92 (t, 3J=6.7 Hz, 4H;
Chem. Eur. J. 2009, 15, 4857 – 4864
ꢁ 2009 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim
4863