Synthesis, spectral properties,in vitroα‐glucosidase inhibitory activity and quantum chemical calculations of novel mixed‐ligand M(II) complexes containing 1,10‐phenanthroline

Abstract

A series of mixed‐ligand M(II) complexes containing 1,10‐phenanthroline (phen) and 3‐methylpyridine‐2‐carboxylic acid (3‐mpaH) or 6‐methylpyridine‐2‐carboxylic acid (6‐mpaH), namely [Co(3‐mpa)2(phen)]·3H2O (1), [Hg(6‐mpa)2(phen)]·2H2O (2), [Mn(6‐mpa)2(phen)]·2H2O (3), [Co(6‐mpa)2(phen)]·H2O (4) and [Ni(6‐mpa)2(phen)]·H2O (5), were synthesized for the first time. Among them, 1 was obtained as single crystals. The structural characterization for 1 was conducted using X‐ray diffraction and that for 2–5 using mass spectrometry. The IC50 values for α‐glucosidase inhibition of 1–5 were obtained as 0.161 to >600 μM. The spectral properties were also investigated using Fourier transform infrared and UV–visible spectra. Furthermore, to investigate the geometrical parameters, spectral and electronic properties and second‐ and third‐order nonlinear optical parameters for 1–5, density functional calculations were applied.

A Water‐Rich Cobalt(II) Compound: Hydrothermal Synthesis, Spectroscopic, Thermal, Crystal Structure Characterization and Antimicrobial Properties

“…UV‐Vis spectrum of 1 in methanol showedthree characteristic bands at 205, 227 and 265 nm which were assigned to the ligand‐ centered (LC) π→π* or n→π* transitions originating from the metal‐bound phen and (ppda) 2− chromophores (Figure S2). [36,38–40] . A weak intensity band appearing as a shoulder at 315 nm could be assigned to the metal‐ligand or ligand‐ligand charge transfer.…”

“…. [36,[38][39][40] A weak intensity band appearing as a shoulder at 315 nm could be assigned to the metal-ligand or ligandligand charge transfer. The origin of visible spectra for cobalt(II) compounds may be due to spin-orbit coupling, vibrational or low symmetry components, and contribution of these parameters lead to difficulties in the total spectral analyses of cobalt(II) complexes.…”

“…The origin of visible spectra for cobalt(II) compounds may be due to spin-orbit coupling, vibrational or low symmetry components, and contribution of these parameters lead to difficulties in the total spectral analyses of cobalt(II) complexes. [36,39] A broad absorption band observed in the region 420-550 nm with low absorptivity is attributed to the 4 T 1g (F)! 4 T 1g (P) transition arising from the 3d 7 cobalt(II) center (vide infra).…”

A review on α-glucosidase inhibitory activity of first row transition metal complexes: a futuristic strategy for treatment of type 2 diabetes

“…Anti-α-glucosidase activity of various Co( ii ) complexes (53–58, Table 2 , entries 2c, 4d, 6c, 7a, 8a, and 8b) containing 6-methylpicolinic acid (L11) and 3-methylpicolinic acid (L17) ( Table 2 , entry 1) was reported by Avcı et al 62–64,67,68 All complexes 53–58 were inactive toward α-glucosidase (IC 50 > 600 μM). Introduction of different ligands such as water (complex 53, Table 2 , entry 2c), 2,2′-bipyridyl (L15, Table 2 , entry 1, complex 54, Table 2 , entry 4d), chlorine (complex 55, Table 2 , entry 6c), 2,2′-dipyridylamine (L13, Table 2 , entry 1, complex 55, Table 2 , entry 6c), and imidazole (L14, Table 2 , entry 1, complex 56, Table 2 , entry 7a) as well as changing the position of methyl group on the PicA moiety (57 and 58, Table 2 , entries 8a and 8b) 68 did not affect the inhibitory activity.…”

“…As studied by Avcı et al, Ni(II) complexes of L11 with distorted octahedral geometry (48-52, Table 2, entries 2c, 4b, 5, 7c and 8a) were not active toward aglucosidase (IC 50 > 600 mM, comparing with genistein (IC 50 ¼ 16.57 mM)). [62][63][64]67,68 It seems that Ni(II) complexes could not establish appropriate structural and electronic properties for the inhibition of enzyme as changing the number and nature of coordinated ligands did not afford anti-a-glucosidase activity.…”