Publications by authors named "Constantinos G Efthymiou"

Article Synopsis
  • Antibiotic resistance is a global issue, highlighting the need for new antibiotics or improved delivery systems, leading to the development of OnG6 MOFs as multi-drug carriers for treating bacterial infections.* -
  • OnG6 MOFs are created using the pro-drug 4,4'-azodisalicylic acid (AZDH), which produces aminosalicylic acid (ASA), and are characterized as mesoporous structures with unique metal configurations (Zn, Mg, Cu, Co) and 25 Å pores.* -
  • These MOFs can absorb specific antibiotics like isoniazid and ciprofloxacin, with results showing that OnG6-Mg has the best drug absorption, and those containing cip
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Metal-organic frameworks (MOFs) are promising multifunctional porous materials for biomedical and environmental applications. Here, we report synthesis and characterization of a new MOF based on the tetrahedral secondary building unit [ZnO(CBAB)] (NUIG4), where CBABH = 4-((4-carboxybenzylidene)amino)benzoic acid. NUIG4 belongs to the family of MOFs with primitive cubic pcu topology, being a rare example with 4-fold interpenetration.

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The goal of this work is to model the nature of the chemical species [CdCl(extractant)] that are formed during the solvent (or liquid-liquid) extraction of the toxic cadmium(II) from chloride-containing aqueous media using hydrophobic 2-pyridyl ketoximes as extractants. Our coordination chemistry approach involves the study of the reactions between cadmium(II) chloride dihydrate and phenyl 2-pyridyl ketoxime (phpaoH) in water-containing acetone. The reactions have provided access to complexes [CdCl(phpaoH)]∙HO (∙HO) and {[CdCl(phpaoH)]} (); the solid-state structures of which have been determined by single-crystal X-ray crystallography.

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The use of pyridine-2-amidoxime (pyaoxH) in Ni chemistry has provided access to a dodecanuclear complex and a hexadecanuclear Ni cluster, namely [Ni(pyaox)(pyaoxH)(MeOH)Cl]Cl·5MeOH (1·5MeOH) and [Ni(pyaox)(pyaoxH)(MeOH)](SO)·10HO·26MeOH (2·10HO·26MeOH). Complex 1·5MeOH was isolated by the reaction of NiCl·6HO, pyaoxH and NaOMe in a 1 : 1 : 2 molar ratio in MeOH in 60% yield. Treatment of NiSO·6HO with pyaoxH and NEt in a 1 : 1 : 2 molar ratio in MeOH afforded 2·10HO·26MeOH in good yield (65%).

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The reactions of various copper(ii) sources with 2-acetylpyridine, (py)(me)CO, and 2-benzoylpyridine, (py)(ph)CO, under strongly basic conditions have been studied and novel ligand transformations have been discovered. Reaction of Cu(ClO4)2·6H2O and (py)(me)CO in the presence of NBu4(n)OMe (1 : 1 : 1) in CHCl3 gave a mixture of [Cu2Cl2(HLA)2](ClO4)2 (1) and [Cu2Cl2(LB)2(ClO4)2] (2), where HLA is 3-hydroxy-1,3-di(pyridin-2-yl)-butane-1-one and LB is the zwitterionic-type ligand 3-hydroxy-1-methyl-3-(pyridin-2-yl)-3H-indolizin-4-ium. The ligand HLA is formed through an aldol reaction-type mechanism, while the formation of LB takes place via an intramolecular nucleophilic attack of the remote 2-pyridyl nitrogen atom on the positive carbonyl carbon of HLA, after the transformation of the latter through deprotonation and dehydration.

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The initial employment of 2-pyridinealdoxime in 3d/4f chemistry has led to a Ni(II)(8)Dy(III)(8) cluster with an unprecedented metal topology; the compound has an unusual structure, is the highest-nuclearity metal oxime cluster to date, and exhibits slow magnetization relaxation.

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Unusual {Ni(II)(3)Ln(III)(μ-OR)(6)}(3+) complexes with a "star" topology have been prepared with ligands derived from the metal-promoted reduction of di-2-pyridyl ketone under solvothermal conditions; the Dy(III) member shows weak single-molecule-magnet behavior.

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Using monoanionic forms of di-2-pyridyl ketone as the only primary ligand, triangular Ni(2)M (M = lanthanide, Y) complexes with interesting magnetic properties have been synthesized.

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The reactions of methyl(2-pyridyl)ketone oxime, (py)C(Me)NOH, with manganese(II) sulfate monohydrate have been investigated. The reaction between equimolar quantities of MnSO(4) . H(2)O and (py)C(Me)NOH in H(2)O lead to the dinuclear complex [Mn(2)(SO(4))(2){(py)C(Me)NOH}(4)] .

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The reactions of phenyl(2-pyridyl)ketone oxime (py)C(ph)NOH, with nickel(II) sulfate hexahydrate under reflux, in the absence of an external base, have been investigated. The reaction of NiSO4 x 6H2O with two equivalents of (py)C(ph)NOH in H2O/MeOH leads to the dinuclear complex [Ni2(SO4)2[(py)C(ph)NOH]4] (1), while an excess of the organic ligand affords the 1:3 cationic complex [Ni[(py)C(ph)NOH]3](SO4) (2). Compound 1 is transformed into 2 by a reaction with an excess of ligand in refluxing H(2)O/MeOH.

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