Novel Nonlinear Transmission of Porphyrin Complexes Containing Rhenium Selenide Clusters

摘要

Nonlinear transmission is found to be significantly enhanced by introducing heavy metal atoms on the periphery of macrocycle porphyrin complexes via rhenium selenide clusters that are coordinated to four pyridyl groups. Experiments on 5, 10, 15, 20-tetra(4-pyridyl) porphyrin (H_2TPyP), CuTPyP, [Re_6μ_3-Se)_8(PEt_3)_5]4(H_2TPyP)(SbF_6)_8 (abbreviated as P5H_2TPyP), and [Re_6(μ_3Se)_8(PEt_3)_5]_4Cu(TPyP)(SbF_6)_8 (abbreviated as CuP5TPyP) using 10 ns laser pulses at 523 nm show that, in contrast to CuTPyP and P5H_2TPyP, which are saturable absorbers at a low fluence of 1-100 mJ/cm~2 and become nonlinear absorbers with a threshold larger than 1000 mJ/cm~2 at high fluence, CuP5TPyP exhibits an excellent nonlinear transmission performance with a threshold as low as 20 mJ/cm~2. A bulky rhenium selenide cluster was coordinated to pyridyl groups in tetrapyridyl porphyrin. The modified copper (II) porphyrin complex CuP5TPyP has strong nonlinear absorption at 523 nm and synergistic interaction between CuTPyP and P5H_2TPyP is one of possible mechanisms.