2.1. Materials
All the reagents were purchased from commercial suppliers (Wako Chemical) and used without any further purification.
2.2. Measurements
The 1H NMR and 13C NMR spectra were measured by a Bruker DPX-300 MHz spectrometer using chloroform-d, DMSO-d6, and acetone- d6 as the solvents. The FT-IR spectra were obtained using a JEOL JIR-WINSPEC50 (32 scans, 4000–400 cm-1, 4 cm-1 resolution). The UV-vis spectra were recorded by a SHIMADZU (UV-2600) spectrophotometer. The fluorescence spectra were obtained by a JASCO FP-6500 spectrometer with the excitation and emission slit widths of both 3.0 nm. The optical rotations were measured by a POLAX-2L (Atago Co., Ltd.) at ambient temperature.
2.3. Synthesis of conjugated macrocycles (R,R)-1–(R,R)-3.
A typical procedure for the synthesis of the conjugated macrocyclic polyimine (R,R)-1 was as follows: The diformyl derivative 1 [37] (1.0038 g, 2.93 mmol) and o-phenylenediamine (2, 0.3174 g, 2.94 mmol) were stirred in 128 mL of DMF at 80 °C for 24 h. The usual aqueous workup with hexane/ethyl acetate gave the crude product as an orange solid. Treatment of the crude product with methanol gave the product as a yellow solid after filtration.
(R,R)-1: Yield 81%. m.p. > 300 °C. 1H-NMR (300 MHz, CDCl3, TMS, Figure 1S in the Supporting Information) δ (ppm) = 12.53 (s, 4H, OH), 8.76 (s, 4H, CH=N), 8.03 (s, 4H), 7.84–7.78 (m, 4H), 7.38–7.32 (m, 4H), 7.24–7.10 (m, 16H). FT-IR (KBr, cm-1): 3056 (νO-H), 1616 (νC=N). [α]D = –1692° (c = 0.065, CHCl3). UV-vis (CHCl3) λmax (ε) = 266 (1.0×105), 314 (7.2×104), 370 (3.5×104).
(R,R)-2: Yield 93%. m.p. > 300 °C. 1H-NMR (300 MHz, CDCl3, TMS, Figure 3S in the Supporting Information) δ (ppm) = 12.65 (s, 1H, OH), 12.61 (s, 1H, OH), 12.58 (s, 1H, OH), 12.54 (s, 1H, OH), 8.74 (s, 2H, CH=N), 8.73 (s, 2H, CH=N), 8.01 (s, 4H), 8.05–7.95 (m, 4H), 7.85–7.75 (m, 4H), 7.20–7.08 (m, 10H), 7.02–6.98 (m, 2H), 6.91–6.89 (m, 2H), 2.42 (s, 6H, CH3). FT-IR (KBr, cm-1): 3055 (νO-H), 1616 (νC=N). [α]D = –1604° (c = 0.235, CHCl3). UV-vis (CHCl3) λmax (ε) = 268 (1.1×105), 314 (7.0×104), 372 (3.8×104).
(R,R)-3: Yield 95%. m.p. > 300 °C. 1H-NMR (300 MHz, CDCl3, TMS, Figure 5S in the Supporting Information) δ (ppm) = 12.33 (s, 1H, OH), 12.31 (s, 1H, OH), 12.23 (s, 1H, OH), 12.21 (s, 1H, OH), 8.75–8.70 (m, 4H, CH=N), 8.06–8.01 (m, 4H), 7.83–7.78 (m, 4H), 7.46 (dd, J = 2.0 Hz, 8.3 Hz, 2H), 7.28–7.20 (m, 10H), 7.18–7.10 (m, 4H), 6.97 (dd, J = 1.8 Hz, 8.4 Hz, 2H). FT-IR (KBr, cm-1): 3055 (νO-H), 1616 (νC=N). [α]D = –1550° (c = 0.235, CHCl3). UV-vis (CHCl3) λmax (ε) = 268 (1.0×105), 316 (7.7×104), 370 (4.0×104).
2.4. Synthesis of non-conjugated macrocycles (R,R)-1H–(R,R)-3H.
A typical procedure for the synthesis of the non-conjugated macrocycle was as follows: A mixture of (R,R)-1 (0.4207 g, 508 mmol) and NaBH4 (powder (after ground) 0.114 g, 3.0 mmol, 6 equiv) in ethanol (80 mL) was refluxed for 4 h. The mixture was cooled to RT with stirring for another 2 h after the addition of ca. 1% HCl (62 mL) and CHCl3 (62 mL). The reaction mixture was neutralized with NaHCO3 aq., extracted with chloroform, washed with water, dried over Na2SO4, and evaporated to give the crude product as an orange solid. The crude product was purified by short column chromatography on silica with chloroform/methanol (= 100:1) eluent to give the product as a pale-yellow solid (0.2542 g, 60%).
(R,R)-1H: Yield 60%. 1H-NMR (300 MHz, CDCl3, TMS, Figure 2S in the Supporting Information) δ (ppm) = 7.80–7.74 (m, 8H), 7.28 (td, J = 1.6 Hz, 9.4 Hz, 4H), 7.18 (td, J = 1.7 Hz, 9.7 Hz, 4H), 7.02 (d, J = 8.4 Hz, 4H), 6.99–6.92 (m, 8H), 4.50–4.36 (m, 8H), 1.71 (br s, 4H, NH). FT-IR (KBr, cm-1): 3629, 3512 (νN-H), 3292 (νO-H). [α]D = +171° (c = 0.105, CHCl3). UV-vis (EtOH) λmax (ε) = 242 (1.5×105), 282 (4.1×104), 324 (2.6×104), 334 (2.8×104), 384 (3.8×104).
(R,R)-2H: Yield 93%. 1H-NMR (300 MHz, CDCl3, TMS, Figure 4S in the Supporting Information) δ (ppm) = 12.64–12.54 (m, 4H), 8.74–8.73 (m, 4H), 8.00 (s, 4H), 7.81–7.78 (m, 4H), 7.23–7.19 (m, 8H), 7.15–7.12 (m, 6H), 7.01–6.99 (m, 4H), 6.85 (s, 4H), 2.42 (s, 6H). [α]D = +170° (c = 0.182, CHCl3). UV-vis (CHCl3) λmax (ε) = 266 (1.1×105). UV-vis (EtOH) λmax (ε) = 230 (3.3×105), 334 (4.1×104).
(R,R)-3H: Yield 91%. 1H-NMR (300 MHz, CDCl3, TMS, Figure 6S in the Supporting Information) δ (ppm) = 7.85–7.70 (m, 8H), 7.40–7.15 (m, 8H), 7.10–6.90 (m, 8H), 6.77 (d, J = 8.3 Hz, 2H), 4.45–4.25 (m, 8H, CH2). FT-IR (KBr, cm-1): 3629, 3510 (νN-H), 3302 (νO-H). [α]D = +165° (c = 0.224, CHCl3). UV-vis (EtOH) λmax (ε) = 230 (3.8×105), 338 (3.1×104).