Synthesis, Characterization, and Nonlinear Optical Study of Metalloporphyrins

Abstract meso‐Tetrakis{4‐[2‐(trimethylsilyl)ethynyl]phenyl}porphyrin [TPP(4‐CCTMS)_H2] and its complexes with Zn^II, Ni^II, Ga^III, In^III, and Sn^IV were synthesized and characterized. Their nonlinear optical transmission characteristics were determined using a 532 nm, 5 ns pulsed laser at a repetition rate of 20 Hz. Stronger nonlinear absorption was obtained with the zinc derivative, Zn^II‐meso‐tetrakis{4‐[2‐(trimethylsilyl)ethynyl]phenyl}porphyrin (TPP(4‐CCTMS)_Zn), than with the standard analogues, Zn^II‐meso‐tetraphenylporphyrin (TPP_Zn), and Zn^II‐meso‐tetratolyl‐porphyrin (TTP_Zn), indicating that the excited‐state absorption can be influenced via fine molecular modification on the para‐position of the meso‐phenyl rings, without changing the ground‐state absorption. The nonlinear optical response can be further enhanced via insertion of closed‐shell metal ions. In particular, In^IIICl‐meso‐tetrakis{4‐[2‐(trimethylsilyl)ethynyl]phenyl}porphyrin (TPP(4‐CCTMS)_InCl), exhibited a larger change in transmission with increasing energy than C₆₀ and a comparable change to the state‐of‐the‐art phthalocyanine dye, chloro(tetra(tert‐butyl)phthalocyanato)indium(III) (Pc(t‐Bu)_InCl).