Optic nonlinearities of a copper complex of pyrazinoporphyrazine

For the copper complex of pyrazinoporphyrazine AzaPhcCu(C(CH 3 ) 3 ) 8 in CH 2 Cl 2 , we use nanosecond pulses to measure its third-order nonlinear optic effects at 532 nm. The results show that its effective third-order nonlinear refractive index n eff 2 (−7.85 × 10 −10 esu) is larger than that of the AzaPhcCu(C 12 H 25 ) 4 and the CuPc(OC 5 H 11 ) 8 . The reverse saturable absorption (RSA) of AzaPhcCu-(C(CH 3 ) 3 ) 8 is demonstrated by the ratio of effective excited state to ground state absorption cross sections. The observed intersystem crossing lifetime τ isc of AzaPhcCu(C(CH 3 ) 3 ) 8 (∼15 ns) and AzaPhcCu(C 12 H 25 ) 4 (∼45 ns) are longer than that of CuPc(OC 5 H 11 ) 8 (∼5.0 ns). The aza-substituents are suggested to form a S 1 (n, π * ) state as their lowest excited singlet-states, and their radiationless intersystem crossing rates (1/τ isc ) are discussed with the spin-orbit coupling 〈ψ S | H SO |ψ T 〉 and the vibronic coupling 〈χ S |χ T 〉 effects between S 1 and T 1 states.