A mixture of Intermediate L (778 mg, 2.0 mmol), 4-isobutoxyphenylboronic acid (970 mg, 5.0 mmol), tetrakis(triphenylphosphine)palladium(0) (500 mg, 0.43 mmol), solution of sodium carbonate (2.12 g, 20 mmol) in water (15 mL), butanol (50 mL), and toluene (30 mL) was vigorously stirred and heated under argon at 105° C. for 16 hours. The reaction mixture was poured into water (200 mL), stirred for 30 minutes and extracted with toluene/ethyl acetate/hexane (2:1:1, 400 mL). The extract was dried over magnesium sulfate, the volatiles were removed under reduced pressure, and the residue was chromatographed (silica gel, hexane/dichloromethane, 1:1). The separated product was crystallized from acetonitrile to give pure 4,7-bis(4-isobutoxyphenyl)-2-octyl-2H-benzo[d][1,2,3]triazole, Compound 45 (1.57 g, 62% yield). 1H NMR (400 MHz, CDCl3): δ 7.99 (d, J=8.8 Hz, 4H, 4-i-BuOC6H4), 7.54 (s, 2H, benzotriazole), 7.04 (d, J=8.8 Hz, 4H, 4-i-BuOC6H4), 4.76 (t, J=7.0 Hz, 2H, octyl), 3.79 (d, J=6.2 Hz, 4H, 4-i-BuOC6H4), 2.13 (m, 4H, octyl), 1.28 (m, 2H, octyl), 1.25 (m, 6H, octyl), 1.04 (d, J=6.6 Hz, 12H, 4-i-BuOC6H4), 0.86 (t, J=6.6 Hz, 3H, octyl). UV-vis spectrum (PVB): λmax=359 nm. Fluorimetry (PVB): λmax=431 nm.
