Synthesis and third-order nonlinear optical properties of linear p-acenequinones

The synthesis of 1,4-tetracenequinone (Q[3,0]) has been described, and the nonlinear optical properties of this quinone together with p-benzoquinone (Q[0,0]), 9,10-anthraquinone (Q[1,1]) and 6,13-pentacenequinone (Q[2,2]) have been investigated with 532 nm and 8 ns pulses. For the quinones of Q[0,0], Q[1,1] and Q[2,2], we applied the nonlinear transmittance and the z-scan techniques to determine their two-photon absorption (TPA) coefficient β and the third-order nonlinear refractive index n2eff. The results show that their β values increased with increasing aromatic rings of quinone, and the magnitudes of n2eff and χeff(3) are all approximately the order of 10−10 e.s.u. with negative sign. The feasible vertical transition states among their low-lying electronic energy levels have been predicted. For Q[3,0], its excited-state absorption cross section σexT and the excited-state refractive-index cross section σr have been measured with z-scan methods. The magnitudes of σrn2eff are comparable with those of well-known highly conjugated planar molecules of tetrabenzoporphyrin and metallophthalocyanines.