Adedibu C. Tella

Synthesis of copper–isonicotinate metal–organic frameworks simply by mixing solid reactants and investigation of their adsorptive properties for the removal of the fluorescein dye

The formation of [Cu(INA)2] (INA = isonicotinate) metal–organic frameworks (MOFs) by a highly efficient and environmentally benign method simply by mixing and heating solid reactants without milling has been investigated. The materials were characterized using elemental analysis, FT-IR spectroscopy and powder X-ray diffraction (PXRD) and scanning electron microscopy (SEM). Comparison of PXRD patterns of the materials with patterns simulated from single crystal X-ray diffraction data allowed identification of the products. The adsorption properties of [Cu(INA)2] were studied using the fluorescein dye (FS). The adsorption data followed both Langmuir and Freundlich equations but was best suited to the Langmuir model. The adsorption data were also correlated with the Temkin and Dubinin–Radushkevich adsorption model and the results showed that the adsorption process is physical. These results indicate that the adsorption of FS on [Cu(INA)2] is partly due to electrostatic interaction between fluorescein and the adsorbent. Compared with the traditional synthetic techniques, this method for the synthesis of MOFs was found to be highly efficient, environmentally benign and useful for the large-scale production.

Copper(II) Complexes of 4, 4- Diaminodiphenylsulphone: Synthesis, Characterization and Biological Studies

Five complexes of copper(II) 4,4-diaminodiphenylsulphone have been synthesized. Copper salts of counter ion (sulphate, nitrate, chloride) and different reaction media (solvents) were used for the synthesis. The complexes varied in colour and composition. The compounds were characterized by conductivity, IR, UV, NMR and mass spectroscopies. The ligand coordinated to metal ion in a monodentate and bidentate manner. All the five complexes have tetrahedral configuration. The biological activities data showed that the complexes are more active against Esherichia coli , Klebbsiella pneumoniae and Staphylococcus aureus than the free ligand (4,4- diaminodiphenyl sulphone). Antimalaria activities of the complexes and the ligand were investigated using mice infected with Plasmodium berghei . All the complexes exhibited lower activity than the ligand and chloroquine. The effect of administration of the complexes on alkaline phosphatase activities of kidney, liver and serum of Albino rats were investigated. The serum ALP activity showed no significant change (P> 0.05), suggesting non-damaging effect on the plasma membrane of liver and kidney cells.

Synthesis of zinc-carboxylate metal-organic frameworks for the removal of emerging drug contaminant (amodiaquine) from aqueous solution

We herein report the removal of amodiaquine, an emerging drug contaminant from aqueous solution using [Zn2(fum)2(bpy)] and [Zn4O(bdc)3] (fum=fumaric acid; bpy=4,4-bipyridine; bdc=benzene-1,4-dicarboxylate) metal-organic frameworks (MOFs) as adsorbents. The adsorbents were characterized by elemental analysis, Fourier transform infrared (FT-IR) spectroscopy, and powder X-ray diffraction (PXRD). Adsorption process for both adsorbents were found to follow the pseudo-first-order kinetics, and the adsorption equilibrium data fitted best into the Freundlich isotherm with the R2 values of 0.973 and 0.993 obtained for [Zn2(fum)2(bpy)] and [Zn4O(bdc)3] respectively. The maximum adsorption capacities foramodiaquine in this study were found to be 0.478 and 47.62mg/g on the [Zn2(fum)2(bpy)] and [Zn4O(bdc)3] MOFs respectively, and were obtained at pH of 4.3 for both adsorbents. FT-IR spectroscopy analysis of the MOFs after the adsorption process showed the presence of the drug. The results of the study showed that the prepared MOFs could be used for the removal of amodiaquine from wastewater.

Metal Complexes as Prospective Antibacterial Agents

Ninety elements occur naturally on earth. Out of these, nine are radioactive and among the remaining eighty one that could support life, sixty one are metals. Our bodies are 3% metal. Thus, it is surprising that some of the most serious challenges to human life, externally, the pollutants cadmium, mercury and lead are attracting more attention, whereas internally, there is a constant battle against sodium and calcium that are rejected by cells and accumulated elsewhere in the body during the ageing process. Furthermore, some diseases release metals into the blood stream. Their use in the fight against diseases was first described by Schubert in 1965. Man just like other vertebrates requires cations of the metals to facilitate a great many essential life processes. Moreover, many of the metals are essential for all other forms of life process. Around 5000 years ago the Egyptians used copper metal to sterilize water and gold was used in a variety of medicines in Arabian and China, but the practice emanated from the value of pure metal rather than from therapeutic effects.

Facile synthesis and vapochromic studies of Co(II) complexes bearing NO and OO donor ligands

Abstract Two Co(II) complexes containing malonic and isonicotinic acids have been prepared by manual grinding of stoichiometric amounts of the starting materials. Elemental analysis (CHN), IR, UV-vis spectroscopic techniques, TGA-DTG investigation and X-ray powder diffraction analysis were used to characterize the two compounds. Isonicotinic acid coordinated to the metal via the pyridine ring nitrogen and one oxygen atom of the carboxylic group while malonic acid coordinated via both oxygen atoms of the carboxylate groups indicating bidentate coordination mode in the two compounds. The compounds were exposed to some volatile organic compounds (VOCs) containing nitrogen or oxygen donor atoms in the solid state and their vapochromic behaviours studied using colour changes, FT-IR and solid state UV-vis spectroscopies. Heating the samples exposed to the VOCs for a few minutes at 100 °C regenerates the original material without degradation, even after several heating cycles.

Zinc(II) Complex of Meso-Tetraphenylporphyrin With 4-Methoxyaniline: Crystal Structure and Antimicrobial Activities of 4-Methoxyaniline-5, 10, 15, 20-Tetraphenyl-Porphyrinatozinc (II)

4-Methoxyaniline-5,10,15,20-tetraphenylporphyrinatozinc(II), [(ZnTPP(MOAN)] 1 was synthesized (MOAN = 4-methoxyaniline) and characterized by elemental analysis and spectroscopic techniques. The molecular structure of 1 was determined by single-crystal X-ray crystallography. The structure revealed a triclinic crystal system and the space group P1 with the central metal adopting slightly distorted square pyramidal geometry with 4-methoxyaniline in the axial position. The antimicrobial activities were carried out using a well diffusion method and the zone of inhibition of four bacteria and two fungi was measured.

Synthesis, crystal structure and desulfurization properties of zig-zag 1D coordination polymer of copper(II) containing 4-methoxybenzoic acid ligand

ABSTRACT Combustion of fuels containing organosulfur compounds has resulted in the emission of sulfur oxides (SOx) into the atmosphere, therefore, causing serious environmental and health hazards. Herein, slightly distorted octahedral zig-zag 1D coordination polymer of copper(II) [Cu(4-mba)2(H2O)3] was synthesized by reacting copper sulfate pentahydrate with a carboxylate-containing ligand (H-4mba = 4-methoxybenzoic acid) and employed for sulfur compound uptake. The ligand coordinates to the copper(II) atom via two pairs of deprotonated ligating atoms (carboxylate oxygens) and two water molecules. Structural characterization also reveals that interplay of O–H···O, N–H···O, C-H···O and C–H···π interactions between lattice and coordinated water and ligands significantly contribute to the crystal packing leading to the formation and strengthening of three-dimensional supramolecular assembly. The complex, [Cu(4-mba)2(H2O)3], show potential for desulfurization of fuel with an observed adsorption capacity of 9.6 mg/g at 32°C for 6 h. DFT calculations further revealed a transfer of electron sulfur-containing compounds and the complex, [Cu(4-mba)2(H2O)3], thus leading to a stronger pi–pi interaction. GRAPHICAL ABSTRACT

Rising profile on the use of metal–organic frameworks (MOFs) for the removal of heavy metals from the environment: an overview

This review study is dealing with the recent advances and developments in the metal–organic framework (MOF) materials especially in the aspect of environmental remediation of heavy metals. Its application in some area of technological and mechanical advancement was also considered. The process of its synthesis and characterization was also put into consideration. Metal-organic frameworks can be said to be an exciting new class of nanoporous crystalline materials containing a metal as its central ion surrounded by organic ligands. An overwhelming characteristic of MOFs lies in its surface area which is amazingly large, exceeding those of known best activated carbons and zeolites. There is an increasingly high demand in the application of MOFs for a multitude of environmental uses or application to be used for capturing and separating various unwanted or even environmentally harmful chemicals, elements or materials. The advantage of MOFs over other known adsorbent materials, such as zeolites and carbon black, is that it possesses a far greater surface area along with amazingly great pore properties. In this review the synthesis and characterization of MOFs, the fate of heavy metals, the application of MOFs in heavy metals remediation and other means of heavy metals remediation are well discussed.

Synthesis of new ruthenium(II) complexes derived from labile nitrile ligands: an alternative route to the preparation of trans-dichlorotetrakis(diphenylphosphine)ruthenium(II)

Abstract New ruthenium(II) complexes containing labile nitrile ligands have been prepared by treatment of either the polymer [{RuCl2(COD)}x] (COD = cycloocta-1,5-diene) (1) or its derivative [RuCl2(COD)(NCCH3)2]·NCCH3 (2) with the appropriate nitrile ligands in refluxing acetonitrile under argon. A new route to synthesis of trans-dichlorotetrakis(diphenylphosphine)ruthenium(II) (7) was also reported. A redetermination of the structure of 7 was undertaken and X-ray crystallographic data revealed that the complex crystallizes in the triclinic space group P-1 with unit cell dimensions a = 12.7016(9) Å, b = 13.0847(10) Å, c = 14.1498(10) Å, α = 101.46(3)°, V = 2080.6(3) Å3, Z = 2 and R = 0.0309. Its polymorph 7′ was also obtained. The crystal structure of 4 was also determined. This complex crystallizes in the monoclinic space group C2/c with unit cell dimensions a = 27.0510(3) Å, b = 11.0984(13) Å, c = 13.0450(16) Å, α = 90°, V = 3886.5(8) Å3, Z = 8 and R = 0.0282.

Synthesis, thermal properties, and biological study of metal(II) nicotinamide complexes containing fumarate dianion and fumaric acid: Crystal structure of [Ni(H2O)4(nia)2](fum)·(H2fum)

ABSTRACT New divalent transition metal nicotinamide (nia) complexes containing fumarate (fum) dianion and fumaric acid (H2fum), [M(H2O)4(nia)2](fum)·(H2fum) [M = Co (1), Cu (2), and Ni (3)] have been synthesized.The compounds were characterized by elemental analyses, infrared, UV-vis, XRPD, and TGA. Structural analysis of 3 using single-crystal X-ray diffraction technique revealed that the Ni(II) ion is coordinated by four aqua and two nia ligands in an octahedral geometry. The structure of 3 is completed with fumarate (fum2−) dianion acting as a counterion while fumaric acid (H2fum) is present as a molecule of solvation. The three complexes were investigated for biological activities.