Spectral, thermal and optical properties of metal(ІІ)–azo complexes for optical recording media

A novel ligand, (Z)-1,5-dimethyl-4-(2-(3-methyl-5-oxo-1-phenyl-1H-pyrazol-4(5H)-ylidene)hydrazinyl)-2-phenyl-1,2-dihydropyrazol-3-one] and its metal(II)–azo complexes were synthesized and characterized using elemental analyses, proton NMR, electrospray ionization mass spectrometry, FT-IR and UV–visible absorption. Smooth thin films of the metal(II)–azo complexes were prepared using spin-coating, and the absorption spectra of the films were measured. The thermal properties of the metal(ІІ)–azo complexes were investigated using TGA and DSC. The optical constants (complex refractive index N = n + ik) of the films on single-crystal silicon were determined using variable-angle scanning ellipsometry from which the complex dielectric function (ɛ) and absorption coefficient (α) were calculated. The photostabilities of the metal(II)–azo complex films were also investigated.