Contents lists available at ScienceDirect Journal of Inorganic Biochemistry journal homepage: www.elsevier.com/locate/jinorgbio Complexes containing benzimidazolyl-phenol ligands and Ln(III) ions: Synthesis, spectroscopic studies and preliminary cytotoxicity evaluation Andrea Hernández-Morales a , José María Rivera a , Aracely López-Monteon a , Soledad Lagunes-Castro a , Silvia Castillo-Blum b , Karla Cureño-Hernández b , Angelina Flores-Parra c , Osvaldo Villaseñor-Granados c , Raúl Colorado-Peralta a, ⁎ a Maestría en Ciencias en Procesos Biológicos, FCQ-UV, C.P. 94340 Orizaba, Ver., Mexico b Departamento de Química Inorgánica, FQ-UNAM, C.P. 04510 CDMX, Mexico c Departamento de Química, CINVESTAV-IPN, C.P. 07360 CDMX, Mexico ARTICLE INFO Keywords: Cytotoxicity Lanthanides Benzimidazoles Bidentate ligands DFT calculations HeLa cells ABSTRACT Fourteen new complexes were obtained from Ln(III)(NO 3 ) 3 ∙n-H 2 O and the chromophores 2-(1H-benzo[d]imi- dazol-2-yl)-phenol (Bzp1) or 2-(5-methyl-1H-benzo[d]imidazol-2-yl)-phenol (Bzp2). The complete characterization allowed us to assign unequivocally the structures of all the complexes. The techniques used for this purpose were Ultraviolet-Visible (UV–Vis) and Fourier-Transform Infrared (FT–IR) spectroscopies, High-Resolution Mass Spectrometry (HRMS), Magnetic Susceptibility (MS), Elemental Analysis (EA) and Molar Conductivity (MC). HRMS allowed us to fnd the molecular ion and its isotopic pattern. The FT–IR spectral data suggested that benzimidazolyl-phenol ligands coordinate with Ln(III) ions through iminic nitrogen and phenolic oxygen. Thermogravimetric Analysis (TGA) studies of NdBzp1 and GdBzp2 complexes indicate the presence of lattice water along with three nitrates and two benzimidazolyl-phenol ligands; the thermal decomposition was con- sistent with the minimal formula suggested by EA. The coordination type of the benzimidazolyl-phenol ligands, the geometry and the structural organization of these coordination complexes have been interpreted by Density Functional Theory (DFT) calculations, and they coincided with the physicochemical data suggesting a co- ordination number eight for the Ln(III) ions. The cytotoxicity of the chromophores and their coordination complexes was tested against a cancer cell line (HeLa), as compared with structure/support cells (NIH-3T3) and defense cells (J774A.1), revealing that three coordination complexes showed moderate cytotoxicity against the cell lines studied. 1. Introduction Benzimidazole derivatives have an extensive diversity of pharma- cological and biological applications due to their structural relationship with purines and pyrimidines [1,2]. In addition, vitamin B 12 contains a 5,6-dimethyl-benzimidazole fragment coordinated to the Co(III) ion [3,4]. Literature data describe a large amount of properties for benzi- midazole derivatives, such as antiparasitic, antioxidant, anti-in- fammatory, analgesic, antihypertensive, anthelmintic, antiprotozoal, anticancer, antimicrobial, among others [5]. In addition, they are active constituents of biocides, such as fungicides and insecticides, and they have formed important compounds in photochemical, photophysical and bioinorganic chemistry [6]. Benzimidazole derivatives are ligands extensively used in coordination chemistry, due to their structural stability and low reactivity [7]; therefore, there is a great interest in synthesizing and characterizing metal complexes of the p, d and f block with benzimidazolic ligands [8,9]. Additionally, the benzimidazolyl-phenol derivatives act as a bi- dentate (N,O) ligand [10–12]. The complexes with these ligands are important, due to their thermal stability, optical properties, catalytic efciency and their biological applications [13–26]. The benzimida- zolyl-phenol complexes are a novel category of photochemical com- pounds that can be handled as electroluminescent materials, whose properties can be delimited using diverse metal ions [27–29]. In this sense, metal complexes are of unlimited importance for OLED tech- nology, as specifed by numerous patents [30]. The benzimidazolyl- phenol complexes are also useful as high-energy radiation detectors, laser dyes, molecular energy storage systems, fuorescent probes and selective complexes for determining Hg(II) [31–36]. The deprotonated species of these organic ligands are appropriate for the creation of https://doi.org/10.1016/j.jinorgbio.2019.110842 Received 30 April 2019; Received in revised form 6 September 2019; Accepted 7 September 2019 ⁎ Corresponding author. E-mail address: racolorado@uv.mx (R. Colorado-Peralta). Journal of Inorganic Biochemistry 201 (2019) 110842 Available online 11 September 2019 0162-0134/ © 2019 Elsevier Inc. All rights reserved. T