Novel Zn(ll)/Cd(ll) complexes based on ferrocenyl terpyridine: Crystal structures, electrochemical and third-order nonlinear optical properties using tunable femtosecond laser

Abstract

A series of zinc (II) and cadmium (II) complexes based on the ferrocenyl terpyridine were synthesized and fully characterized. Firstly, their structures were confirmed by single crystal X-ray diffraction analysis, which revealed that the central metal atom adopted a distorted tetragonal pyramidal geometry coordination model. Secondly, the photophysical properties of the complexes were investigated with aid of experimental and theoretical calculation methods. The results indicate that there are ICT, π⋯π*, LLCT and LMCT transition in the six complexes. Thirdly, their electrochemical behaviors showed that the ferrocenyl (Fc) terpyridine complexes exhibited a quasi-reversible Fc+-Fc redox couple. The E1/2 values of them were influenced by different halides. Lastly, the third-order nonlinear optical properties in the near-IR range were systematically determined by open/close aperture Z-scan methods using tunable femtosecond laser. The results revealed that LCdBr2 possesses largest 2 PA coefficient (β = 0.416 cm/GW) and cross sections (σ = 17835 GM) compared to others. However, the LZnBr2 possess largest values of the cubic hyperpolarizability χ(3) (5.64 × 10−13 esu), it shows that the ferrocenyl-based metal bromine complexes have better NLO properties.