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 beta and the third-order nonlinear refractive index n(2)(eff). The results show that their beta values increased with increasing aromatic rings of quinone, and the magnitudes of n(2)(eff) and chi(eff)((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 sigma(ex)(T) and the excited-state refractive-index cross section a, have been measured with z-scan methods. The magnitudes of sigma(r) and n(2)(eff) are comparable with those of well-known highly conjugated planar molecules of tetrabenzoporphyrin and metallophthalocyanines. (C) 1998 Elsevier Science S.A.