Synthesis and Properties of Thieno[2′,3′,4′:4,5]naphtho[1,8-cd]pyridines

Abstract

Thieno[2′,3′,4′:4,5]naphtho [1,8-cd]pyridines, S,N-doped pyrene analogs, were prepared by combination of Pd catalyzed cross-coupling reactions and acid-mediated cycloisomerization. The modular scope of the synthesis allowed for access to a variety of functionalized derivatives. The photophysical properties have been studied in detail by steady-state and femtosecond transient absorption accompanied by cyclic voltammetry and (TD)-DFT calculations. The introduction of a five-membered thiophene into the 2-azapyrene scaffold leads to redshifted emission and substantial effects on the excited state dynamics, e.g., quantum yield, lifetime, decay rates, and the ISC ability, which can be further tuned by the substitution pattern of the heterocyclic scaffold.

Synthesis and Properties of 5,7-Diazaullazines

“…IR (ATR, cm −1 ): ν̃= 2213 (m), 1319 (vs), 1164 (s), 1123 (s), 1107 (vs), 1065 (vs), 1012 (s), 962 (s), 843 (vs), 734 (vs), 723 (s). MS (EI, 70 eV): m/z (%) = 481 (100, M + ), 480 (50), 479 (8), 454 (11), 412 (8), 411 (9), 410 (5), 384 (6), 206 (5) (31), 381 (30), 216 (40), 215 (44), 208 (23), 207 (26), 185 (29), 147 (20), 134 (22), 109 (22), 107 (20). HRMS (ESI-TOF): calcd for C 28 (13), 354 (32), 353 (25), 352 (31), 290 (13) General Procedure B for the Synthesis of 4,6-Bis(phenylethynyl)-5-(1H-pyrrol-1-yl)pyrimidine (4a−e).…”

“…MS (EI, 70 eV): m/z (%) = 481 (100, M + ), 480 (50), 479 (8), 454 (11), 412 (8), 411 (9), 410 (5), 384 (6), 206 (5) (31), 381 (30), 216 (40), 215 (44), 208 (23), 207 (26), 185 (29), 147 (20), 134 (22), 109 (22), 107 (20). HRMS (ESI-TOF): calcd for C 28 (13), 354 (32), 353 (25), 352 (31), 290 (13) General Procedure B for the Synthesis of 4,6-Bis(phenylethynyl)-5-(1H-pyrrol-1-yl)pyrimidine (4a−e). In a pressure tube, 1 equiv (100 mg) of 4,6-bis(phenylethynyl)-5-(1H-pyrrol-1-yl)pyrimidine (3a−e) and 30 equiv of p-TsOH•H 2 O were dissolved in xylene (3 mL/100 mg).…”

“…IR (ATR, cm −1 ): ν̃= 2920 (m), 2852 (m), 2800 (m), 1603 (s), 1502 (s), 1354 (s), 1195 (s), 1053 (s), 880 (s), 820 (vs), 793 (vs), 713 (s), 517 (s). MS (EI, 70 eV): m/z (%) = 430 (M + , 100), 414 (31), 398 (15), 215 (19), 214 (28), 206 (13) (9). The title compound was synthesized according to a previously described method.…”

“…These values are similar to those of isoelectronic 2-azapyrene (τ 0 = ∼ 28 ns, k r = 3.6 × 10 7 s −1 in DCM), for which the weak S 1 ← S 0 absorption band increases in intensity due to the symmetry-lowering by nitrogen doping of pyrene. 31 On the other hand, the incorporation of nitrogen in positions 5 and 7 of the ullazine core (4a) results in the shortest lifetime (τ 0 = 11 ns) and the highest radiative decay rate (k r = 9.5 × 10 7 s −1 ) among the three aza-ullazine derivatives.…”