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A Definitive Study of Aliphatic and Aromatic ß-ketosulfoxides: Promising Aromatic Chelates
Erwin Boschmann,
Raymond Nevin Keller
Issue:
Volume 9, Issue 1, February 2021
Pages:
1-8
Received:
15 December 2020
Accepted:
31 December 2020
Published:
15 January 2021
Abstract: This paper begins with a detailed description of the conditions necessary for the formation of chelates in general, and ß-ketosulfoxides in particular. While symmetric chelates such as 2,4-pentanedione have been known and studied for a long time, asymmetric chelate structures, such as the aliphatic ω-(methylsulfinyl)-acetophenone, Ph-CO-CH2-SO-CH3, for example, have not been investigated. Our detailed studies of solubility, acidity, IR, UV, and NMR spectroscopies all indicate very low enolization and hence low chelation, if any. Nevertheless, using rather strong conditions – such as molten reagents – we experienced some evidence for reaction. We extended our studies to aromatic ketosulfoxides by fusing these into benzene, assuming that its resonating ring will not only withdraw electrons from the S=O group, but might also encourage conjugation. We focused on o-(methylsulfoxo)-acetophenone with its S=O group in one position on the benzene ring and the –OH group in an adjacent position. Three separate facts confirmed our belief that such a fused structure should undergo enolization and thus chelation. First, salicylaldehyde and 2-hydroxyacetophenone, both structurally analogous to the compound of interest o-(methylsulfoxo)-acetophenone, do show strong chelation; second, approximate linear combination of atomic orbitals-molecular orbital (LCAO-MO) calculations point to positive results; and third, a comparison of the acidity constants of six acids ranging from ω-(methylsulfinyl)-acetophenone (3 x 10-11) to salicylic acid (1.06 x 10-3) place the compound in question, o-(methylsulfoxo)-acetophenone, at the upper end of acidity. Indeed, metal derivatives of o-(methylsulfoxo)-acetophenone form rather easily as evidenced by O-H and S=O shifts in IR, UV, and NMR spectroscopies. Calcium forms a chelate, whereas iron and niobium form adducts.
Abstract: This paper begins with a detailed description of the conditions necessary for the formation of chelates in general, and ß-ketosulfoxides in particular. While symmetric chelates such as 2,4-pentanedione have been known and studied for a long time, asymmetric chelate structures, such as the aliphatic ω-(methylsulfinyl)-acetophenone, Ph-CO-CH2-SO-CH3,...
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Synthesis, Characterization and Antibacterial Activity of Mixed Ligands of Schiff Base and It’s Metal(II) Complexes Derived from Ampicilin, 3-Aminophenol and Benzaldehyde
Nasiru Pindiga Yahaya,
Muhammad Sani Mukhtar
Issue:
Volume 9, Issue 1, February 2021
Pages:
9-13
Received:
8 November 2020
Accepted:
18 November 2020
Published:
10 February 2021
Abstract: Schiff base ligands were synthesis via a condensation of the ligands in methanol in 1:1:1 molar ratio reactions. The transition metal(II) complexes were formed by the reaction of Co, Cu, Mn, Fe with the Schiff base and ampicillin and they were characterized via FTIR, electronic spectra, melting points, solubility and molar conductance. The invitro antibacterial activities of the complexes were tested using four bacterial strains; gramnegative; (Escherichiacoli, salmonellatyphi) and grampositive; (staphylococcus pyogenes and staphylococcus aureus). The complexes were formed in good yield and they have various shades of colors and sharp melting points. The IR spectrum of the HL (Table4) displays a new at (1651) cm-1 which is due to υ(HC=N) group of the azomethine stretching vibrations of the ligand, on complexation these band has been shifted to lower frequencies (1651), (1621), (1651), and (1627)cm-1 for complexes [Co(Ampi)(3AMPB)Cl], [Cu(Ampi)(3AMPB)], [Mn(Ampi)(3AMP)Cl] and [Fe(Ampi)(3AMPB)] respectively. The overlap band at (1688)cm-1 stretching vibration is due to υ(C=O) for β-Lactam group, these band has been shifted to lower frequency at (1370-1425)cm-1 for complexes showing that the coordination is through the Oxygen atom of β-Lactam group. The band sat (525), (526), (524) and (526)cm-1 were assigned to υ(M–O) for compounds of Co, Cu, Mn, Fe, indicating that to the carbocyclic oxygen, and oxygen of β-Lactam group of the ligand are involved in coordination with metalions. The bands at (659), (669), (660), and (698)cm-1 were assigned to υ(M–N) for compounds Co, Cu, Mn, Fe respectively, indicating that the nitrogen is involved in coordination with metal ions. The electronic spectral data of the complexes suggest an Octahedral and tetrahedral geometry for all the complexes. The molarconductivity indicates that the synthesized complexes are all non-electrolytes and soluble in protic solvent such as methanol and ethanol. The invitro antibacterial screening of Schiff base and its metal complexes showed that they are potential antibacterial agents against the tested microorganisms
Abstract: Schiff base ligands were synthesis via a condensation of the ligands in methanol in 1:1:1 molar ratio reactions. The transition metal(II) complexes were formed by the reaction of Co, Cu, Mn, Fe with the Schiff base and ampicillin and they were characterized via FTIR, electronic spectra, melting points, solubility and molar conductance. The invitro ...
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Ecotoxicological Risk Assessment of Surface Water Receiving Abattoir Effluent
Doris Fovwe Ogeleka,
Mildred Chukwuedum Emegha,
Felix Ebhodaghe Okieimen
Issue:
Volume 9, Issue 1, February 2021
Pages:
14-22
Received:
9 February 2021
Accepted:
20 February 2021
Published:
3 March 2021
Abstract: Background: This research examined the surface water ecotoxicological risk of untreated abattoir effluent discharged directly into nearby rivers that could result in likely damage to aquatic species. Objective: The study was aimed at evaluating the deleterious ecological effects resulting from discharge of abattoir effluent into surface waters of some selected rivers in Effurun metropolis, Delta State, Nigeria. Method: The American Public Health Association (APHA) standard protocol was used for testing the water quality in addition to the Surface Water Ecotoxicological Risk Assessment Matrix (SW-ERAM), which was used to evaluate the ecological effects. Results: The pH values ranged from 5.48±0.14 (Agbaroh river) to 6.76±0.18 (Agbaroh abattoir effluent) indicating a slightly acidic environment. The waters were moderately to highly turbid with values between 10±1 NTU and 196.11±9.0 NTU. Total suspended solids (TSS) were relatively high and varied from 14±1.0 (Ugbomro river - control) to 242±12 (Ekpan abattoir effluent). Besides the control, the water samples from all the locations showed high levels of total coliform bacteria. The risk level was rated high [5E or 25 (A, P, E)], which was designated as harmful and capable of affecting aquatic animals (A), plants (P) and the environment (E). Conclusion: The indication from this study is that continuous discharge of untreated abattoir effluent into surface waters may pose threat to aquatic species and human health.
Abstract: Background: This research examined the surface water ecotoxicological risk of untreated abattoir effluent discharged directly into nearby rivers that could result in likely damage to aquatic species. Objective: The study was aimed at evaluating the deleterious ecological effects resulting from discharge of abattoir effluent into surface waters of s...
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Crystal Structure of a Bis[1-(benzothiazole-2yl-2κN)(2-Pyridylmethyliden-1κN)(hydrazino-2κN)] Cobalt(II) Complex
Ibrahima Elhadji Thiam,
Papa Aly Gaye,
Mouhamadou Moustapha Sow,
Ousmane Diouf,
Pascal Retailleau,
Mohamed Lamine Gaye
Issue:
Volume 9, Issue 1, February 2021
Pages:
23-28
Received:
12 March 2021
Accepted:
22 March 2021
Published:
30 March 2021
Abstract: The Schiff base 1-(benzothiazol-2-yl)(2-pyridylmethylidene)hydrazine (HL) was synthesis via a condensation of 1-(benzo[d]thiazol-2-yl)hydrazine and 2-pyridine carboxaldehyde in methanol in 1:1 molar ratio reaction. The crystal structure of a mononuclear complex Bis[1-(benzothiazole-2yl-2κN)(2-pyridylmethyliden-1κN)(hydrazino-2κN)] cobalt(II) complex (1) (CoC26H20N8S2) was obtained by the reaction of HL with Co(CH3COO)2.4H2O, in 2:1 ratio, in methanol at room temperature. The ligand and the complex are characterized by IR, and physical measurement. The spectroscopic study shows that the Schiff base possesses five potential donor sites. Upon coordination the results show that the ligand acts in tridentate mode. Suitable crystals of the compound 1 were grown by slow evaporation of methanol solution for one week. The structure of 1 was elucidated by X-ray diffraction analysis. The compound crystallizes in the monoclinic crystal system with a space group of P21/c. The asymmetric unit of compound 1 contains a mononuclear complex in which the cobalt ion is coordinated to two monodeprotonated molecules of the Schiff base. Each of the ligand molecule acts through three nitrogen atoms. The Co(II) center is hexacoordinated and the environment is best described as a distorted octahedral geometry. The two ligand molecules occupy mean planes which are quasi-perpendicular with a dihedral angle of 89.77(2)°. Each molecule of complex is connected to its neighbor via hydrogen bond of type C–H•••S resulting in chains along b axis.
Abstract: The Schiff base 1-(benzothiazol-2-yl)(2-pyridylmethylidene)hydrazine (HL) was synthesis via a condensation of 1-(benzo[d]thiazol-2-yl)hydrazine and 2-pyridine carboxaldehyde in methanol in 1:1 molar ratio reaction. The crystal structure of a mononuclear complex Bis[1-(benzothiazole-2yl-2κN)(2-pyridylmethyliden-1κN)(hydrazino-2κN)] cobalt(II) comple...
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