The development of an unexpected Cu(I)‐pyrazolo pyrimidine‐based complex: Synthesis, spectroscopic characterizations, and biological activity

A novel unexpected pyrazolo[1,5‐a]pyrimidine‐based Cu(I) complex, [Cu (DQPC)2]ClO4, has been synthesized by reaction of 2,7‐diamino‐5‐phenyl‐3‐(phenyldiazenyl)pyrazolo[1,5‐a]pyrimidine‐6‐carbonitrile (DQPC) and Cu (ClO4)2.6H2O in ethanol. Full characterizations of [Cu (DQPC)2]ClO4 are achieved via CHNCu‐analyses, Ʌm calculation, spectroscopic techniques, and confirmed unambiguously by single crystal X‐ray diffraction. The crystallographic data revealed a distorted tetrahedral environment around the Cu(I) center in the inner sphere, where the (DQPC) acted as a neutral bidentate ligand, while one perchlorate ion, in the outer sphere. [Cu (DQPC)2]ClO4 and DQPC have been screened against six pathogenic microorganisms and breast carcinoma human cancer cell lines (MCF‐7). The data revealed high anti‐bacterial, anti‐fungal, and interesting cytotoxic activities. Furthermore, [Cu (DQPC)2]ClO4 showed significant cell growth inhibition activity (IC50 = 0.89 ± 0.06 μg/ml), even higher than the standard anticancer drugs; cisplatin (IC50 = 5.71 ± 0.55 μg/ml); and vinblastine sulfate (IC50 = 5.44 ± 0.64 μg/ml), while DQPC itself has the lowest cytotoxicity (IC50 = 9.9 ± 1.4 μg/ml). DNA binding study showed that DQPC and [Cu (DQPC)2]ClO4 strongly bind to DNA, presumably via intercalation and electrostatic mechanisms. A novel pyrazolo[1,5‐a]pyrimidine‐based copper(I) complex has been developed stepwise, starting with their primary components. The formula [Cu (DQPC)2]ClO4 was confirmed by single‐crystal X‐ray diffraction spectral analysis. The investigated compounds showed significant activity against six pathogenic microorganisms and breast carcinoma human cancer cell lines (MCF‐7). DNA binding study to wheat DNA showed that the synthesized compounds strongly bind to DNA, presumably via intercalation and electrostatic mechanisms.