Influence of Co(II) and Cd(II) Metal Ions on Structural, Electronic and Nonlinear Optical Properties of 4-Methoxypyridine Acid Complexes: An Experimental and Computational Study

Abstract

Molecular engineering of metal -organic frameworks has attracted increasing attention due to their potential technological applications in the fields of optics and photonics. Therefore, a number of organometallic complexes are investigated for nonlinear optical applications. The current research aimed to synthesize and investigate spectroscopic and nonlinear optical properties of two metal -organic coordination compounds, namely Co (MeOPic) 2 center dot(H 2 O) 2 and Cd(MeOPic) 2 center dot(H 2 O) 2 . The FT-IR and UV-Vis spectra for the distorted octahedral Co(II) and Cd(II) complexes were recorded. In order to provide a deep understanding about the relation between structure and nonlinear optical properties, density functional theory studies were also applied to both of the complexes by using B3LYP/6 - 311++G(d,p)/LanL2DZ level. TG-DTA analysis demonstrated that Cd(II) complex is approximately stable up to 134 degrees C, and the same complex only loss the aqua ligands between 134 and 189 degrees C. Therefore, the main skeleton part continues to remain stable up to 208 degrees C. Static NLO studies also demonstrated that both complexes have weak responses due to centrosymmetric structures, while Co(II) complex is appropriate to third -order NLO applications ( gamma (0;0,0,0) = 148.70x10 - 36 esu and gamma (-2w;w,w,0)=-1521.4x10 - 36 esu).