A new dinuclear Ag(I)–N-heterocyclic carbene complex derived from para-xylyl linked bis-imidazolium salt: synthesis, crystal structure, and in vitro anticancer studies

Abstract

This manuscript describes synthesis, spectral (FT-IR and NMR), and structural studies of a new para-xylyl linked bis-imidazolium salt (1) and the dinuclear Ag(I)–N-heterocyclic carbene complex (2). Both 1 and 2 were tested for their potential against human colon cancer (HCT 116) and breast cancer (MCF-7) cell lines. According to cell viability measurements using MTT assay, the test compounds showed dose-dependent cytotoxic activities against both cell lines. The complex displayed significant activity (IC₅₀ = 20.9 μM for HCT 116 and 2.4 μM for MCF-7) compared to their respective imidazolium salt (IC₅₀ > 200 μM for HCT 116 and  = 137 μM for MCF-7). The photomicrographs of the cells treated with 2 revealed that the cytotoxic efficacy of 2 is mainly by deposition of silver in the cytoplasm of the affected cells since clear signs of black silver deposits in the cytoplasm of the affected cells were observed.

Keywords:

• Bis-imidazolium salt
• Ag(I)–N-heterocyclic carbene
• Anticancer
• HCT 116
• MCF-7
• Crystal structure

Supplementary data

CCDC 917,387 contains the supplementary crystallographic data for 2. This data can be obtained free of charge from http://www.ccdc.cam.ac.uk/conts/retrieving.html, or from the Cambridge Crystallographic Data Center, 12 Union Road, Cambridge CB2 1EZ, UK; Fax: [phone]; or E-mail: [email protected].

Acknowledgments

RAH thanks Universiti Sains Malaysia (USM) for the Research University (RU) grant (1001/PKIMIA/811217) and short term grant (1001/PKIMIA/823082). SFN is grateful to (IPS) USM for the PRGS grants (1001/PKIMIA/834083). MAI is grateful to (IPS) USM for financial support [fellowship: USM.IPS/JWT/1/19 (JLD 6): P-KD0030/11(R)].