Synthesis & cytotoxic activity of Bis (μ – chloro) bis (azobenzenyl analogue) di-palladium complexes

A novel light emitting palladacycles-chloride-bridged complexes namely bis (azobenzenyl)-Bis (μ-chloro)- di-palladium complex molecules are synthesized by the treatment of Rod shaped liquid crystals azobenzene analogues namely 4-((2-butoxy phenoxy) carbonyl) phenyl (E)-4-((4-butyl phenyl) di-azenyl) benzoate (R1) and 4-((2-butoxy phenoxy) carbonyl) phenyl (E)-4-((4-butyl phenyl) di-azenyl) benzoate (R2) with bis (benzonitrile) palladium chloride (HK-1) in chloroform at room temperature and obtained palladacycles namely Bis [(E)-4-((4-butoxy phenyl) di-azenyl) phenyl 4-nitrobenzoate)]-Bis-(μ–chloro)–di-palladium (HK-2) and Bis [(4-((2-butoxy phenoxy) carbonyl) phenyl (E)-4-((4-butylphenyl) di-azenyl) benzoate)]-Bis-(μ–chloro)–di-palladium (HK-3) respectively are characterized by TLC, LC/MS, FT–IR, NMR, and electronic spectroscopy- UV –vis spectroscopy, it reveals the spectra for Palladacycle: Bis [(E)-4-((4-butoxy phenyl) di-azenyl) phenyl 4-nitrobenzoate)]-Bis-(μ–chloro)–di-palladium (HK-2) and Bis [(4-((2-butoxy phenoxy) carbonyl) phenyl (E)-4-((4-butylphenyl) di-azenyl) benzoate)]-Bis- (μ–chloro)–di-palladium (HK-3) are shown three distinct bands at 252, 336.9 & 389 nm and 255, 358 and 485 nm respectively compare to two band for Rod shaped liquid crystals R1 and R2 and for these palladacycles (HK-2 and HK-3) and their Rod shaped Liquid crystals starting materials (R1 and R2) The emission spectra recorded in fluorimetry and further, it is observed that after making palladacycle it's hard to show liquid crystal property. It's because of substituents present on azobenzene core and its stability and the thermal stability studies obtained by Thermogravimetric analysis (TGA) results shows that palladacycle of (HK-3) is more stable than HK-2. Furthermore, the In -vitro cytotoxic activity against Hela Cell lines shown that HK-3 and R2 shown better cytotoxic activity compared to other molecules such as (R1, HK-1 and HK-2. Hence, these (HK-3) and R2 can be used to discover bioactive molecule that may serve as lead in the development of new pharmaceutical research activities.