Synthesis, characterization, computational study, and biological relevance of a family of isostructural, mononuclear Ln (Ln = Gd, Tb, Dy, Ho, Er) complexes containing pyridoxine, an essential ingredient of vitamin B6 enzyme

A Gadolinium(III) Complex Based on Pyridoxine Molecule with Single-Ion Magnet and Magnetic Resonance Imaging Properties

Pyridoxine (pyr) is a versatile molecule that forms part of the family of B vitamins. It is used to treat and prevent vitamin B6 deficiency and certain types of metabolic disorders. Moreover, the pyridoxine molecule has been investigated as a suitable ligand toward metal ions. Nevertheless, the study of the magnetic properties of metal complexes containing lanthanide(III) ions and this biomolecule is unexplored. We have synthesized and characterized a novel pyridoxine-based GdIII complex of formula [GdIII(pyr)2(H2O)4]Cl3 · 2 H2O (1) [pyr = pyridoxine]. 1 crystallizes in the triclinic system and space group Pī. In its crystal packing, cationic [Gd(pyr)2(H2O)4]3+ entities are connected through H-bonding interactions involving non-coordinating water molecules and chloride anions. In addition, Hirshfeld surfaces of 1 were calculated to further investigate their intermolecular interactions in the crystal lattice. Our investigation of the magnetic properties of 1, through ac magnetic susceptibility measurements, reveals the occurrence of a slow relaxation in magnetization in this mononuclear GdIII complex, indicating an unusual single-ion magnet (SIM) behavior for this pseudo-isotropic metal ion at very low temperatures. We also studied the relaxometric properties of 1, as a potential contrast agent for high-field magnetic resonance imaging (MRI), from solutions of 1 prepared in physiological serum (0.0-3.2 mM range) and measured at 3 T on a clinical MRI scanner. The values of relaxivity obtained for 1 are larger than those of some commercial MRI contrast agents based on mononuclear GdIII systems.

Erbium(III) coordination compounds with substituted salicylaldehydes: Characterization and biological profile

Five erbium(III) complexes with salicylaldehyde (saloH for 1), and mono- (5-X-saloH; X = NO₂ and Me for 2 and 3, respectively) or di-substituted salicylaldehydes (3,5-diX-saloH; X = Cl and Br for 4 and 5, respectively) were synthesized and characterized by physicochemical and spectroscopic techniques and single-crystal X-ray crystallography. All five complexes have the general formula [Er(deprotonated salicylaldehyde)₃(MeOH)(H₂O)]. The structure of complexes [Er(3,5-diCl-salo)₃(MeOH)(H₂O)]·1.5MeOH (complex 4) and [Er(3,5-diBr-salo)₃(MeOH)(H₂O)]·1.75MeOH (complex 5) were verified by single-crystal X-ray crystallography. The evaluation of antioxidant activity of the complexes was focused on their ability to scavenge 1,1-diphenyl-picrylhydrazyl and 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonic acid) free radicals and to reduce H₂O₂. The interaction of the complexes with calf-thymus DNA was investigated by UV-vis spectroscopy, viscosity measurements and via competitive studies with ethidium bromide in order to evaluate the possible DNA-binding mode and to determine the corresponding DNA-binding constants. The affinity of the complexes for bovine and human serum albumins was explored by fluorescence emission spectroscopy and the corresponding binding constants were determined.

Di-μ-benzoato-di-μ-ethanolato-tetrakis[μ3-5-(hydroxymethyl)-2-methyl-4-(oxidomethyl)pyridin-1-ium-3-olato]tetrakis[μ3-5-(hydroxymethyl)-2-methyl-4-(oxidomethyl)pyridin-3-olato]di-μ3-oxido-heptamanganese(II,III) ethanol octasolvate

The synthesis and structure of a hepta­nuclear cage-like complex, which includes six Mn^III ions and one Mn^II ion, are presented.

Our work in the area of synthesis of polynuclear manganese complexes and their magnetic properties led to the synthesis and crystallization of the title compound, [Mn₇(C₈H₉NO₃)₄(C₈H₁₀NO₃)₄(C₂H₅O)₂(C₇H₅O₂)₂O₂]·8C₂H₅OH. Herein, we report the molecular and crystal structure of the title compound, which was synthesized by the reaction of Mn(C₆H₅COO)₂ with pyridoxine (PNH₂, C₈H₁₁NO₃) followed by the addition of tetra­methyl­ammonium hydroxide (TMAOH). The core of this centrosymmetric complex is a cage-like structure consisting of six Mn^III ions and one Mn^II ion bound together through Mn—O bonds. The compound crystallizes in hydrogen-bonded layers formed by O—H⋯N hydrogen bonds involving the aromatic amine group of the ligand PN²⁻ with the neighboring O atoms from the PNH⁻ ligand. The crystal structure has large voids present in which highly disordered solvent mol­ecules (ethanol) sit. A solvent mask was calculated and 181 electrons were found in a volume of 843 ų in one void per triclinic unit cell. This is consistent with the presence of seven ethanol mol­ecules per formula unit, which accounts for 182 electrons per unit cell. Additionally, one ethanol mol­ecule was found to be ordered in the crystal.

Glycerol fructose combined with vitamin B6 is beneficial to postoperative recovery of patients with cerebral aneurysm

The aim of the present study is to investigate whether glycerol fructose combined with vitamin B6 is beneficial to the postoperative recovery of patients with cerebral aneurysm (CA). A total of 134 patients receiving embolization of CA in the Central Hospital of Wuhan between February, 2013 and June, 2015 and were divided into observation and control groups according to the random number table method, with 67 cases in each group. The control was given vitamin B6 routine treatment, while the observation group received glycerol fructose on the basis of treatment in the control group. The incidence rate of postoperative complications after treatment, Glasgow coma scale (GCS) score, Barthel index score, and neurological fatigue index (NFI) score were compared between the two groups. After treatment, the GCS, Barthel index and NFI scores of patients in the observation were better than those in the control group (p<0.05), and the Barthel index score in the observation group was significantly higher than that in the control group (p<0.01). The mean flow velocity of middle cerebral artery (MCA) in the observation group after treatment was significantly different from that in the control group (p<0.05). As for complications, the incidence rates of postoperative cerebral vasospasm (1.49%), cerebral ischemia (1.49%), hematoma at puncture site (2.98%) and aneurysm rupture and hemorrhage (4.47%) in the observation group were lower than those of cerebral vasospasm (8.95%), cerebral ischemia (7.46%), hematoma at puncture site (8.95%) and aneurysm rupture and hemorrhage (10.44%) in the control group, and the differences were statistically significant (p<0.05). In conclusion, glycerol fructose combined with vitamin B6 can reduce the incidence rate of postoperative complications and improve patients self-care ability and quality of life. Therefore, it is beneficial to postoperative recovery and it is worthy of clinical application.