Raza Rasool

Antimicrobial agents: synthesis, spectral, thermal, and biological aspects of a polymeric Schiff base and its polymer metal(II) complexes

Some new coordination polymers of Mn(II), Co(II), Ni(II), Cu(II), and Zn(II) obtained by the interaction of metal acetates with polymeric Schiff base containing formaldehyde and piperazine have been investigated. Structural and spectroscopic properties have been studied by elemental, spectral (FT-IR, 1H-NMR, and UV-Vis), and thermogravimetric analysis. UV-Vis spectra and magnetic moments indicate that Mn(II), Co(II), and Ni(II) polymer metal complexes are octahedral, while Cu(II) and Zn(II) polymer metal complexes are square planar and tetrahedral, respectively. All compounds were screened for their antimicrobial activities against Escherichia coli, Bacillus subtillis, Staphylococcus aureus, Pseudomonas aeruginosa, Salmonella typhi, Candida albicans, Agelastes niger, and Microsporum canis using the Agar well diffusion method with 100 µg mL−1 of each compound.

Antimicrobial Polychelates: Synthesis and Characterization of Transition Metal Chelated Barbituric Acid–Formaldehyde Resin

A monomeric Schiff base was prepared by the condensation reaction of salicylaldehyde and semicarbazide, which further react with formaldehyde and barbituric acid-formed polymeric Schiff base. Its metal polychelates were then formed with Mn(II), Co(II), Ni(II), Cu(II), and Zn(II). All the synthesized compounds were characterized by elemental analysis, magnetic moment, FTIR, 1HNMR, and electronic spectroscopies. The elemental analysis data show the formation of 1:1 [M: L] metal polychelates. Thermogravimetric analysis was carried out to find the thermal behavior of all the synthesized polymeric compounds and thermal data revealed that all the metal polychelates are more thermally stable than their parent polymeric Schiff base. All the synthesized polymeric compounds were screened for antimicrobial activity against some clinically important microorganisms, such as Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Staphylococcus typhi, Candida albicans, Microsporum canis, and Aspergillus niger. In vitro antimicrobial activity was determined by the Agar Well Diffusion method and the result shows that all the metal polychelates exhibited better antimicrobial activity than their parent polymeric Schiff base.

Synthesis and characterization of metal-incorporated aniline formaldehyde resin modified by amino acid for antimicrobial applications

Advances in metal incorporated resins are now an active field of research. To develop resin having better antimicrobial and thermal activity, a series of metal-chelated resins have been synthesized by the condensation of (4-aminobenzene-1,3-diyl)dimethanol with 2,6-diaminohexanoic acid in alkaline medium and then this polymeric ligand further reacts with transition metal ions forming various coordination polymers. (4-Aminobenzene-1,3-diyl)dimethanol was initially prepared by the reaction of aniline and formaldehyde in 1 : 2 molar ratio in alkaline medium. The analytical data reveal that the polymer metal complexes of Mn(II), Co(II), and Ni(II) are coordinated with two water molecules, which are further supported by FTIR spectra and TGA data. Comparative analyses of the polymer metal complexes in thermal curves show better thermal stability than the polymeric ligand. Since these resins are relatively stable at high temperatures, they can be used for medical and biomaterial applications requiring thermal sterilization, solvent-resist coating materials because of their insoluble nature, and antifouling coating materials owing to antimicrobial activity in fields such as life-saving medical devices and the bottoms of ships.

Metal-based Schiff base polymers: preparation, spectral, thermal and their in vitro biological investigation

New polymer metal(II) complexes have been synthesized using Schiff base ligand, synthesized by the condensation reaction of 2-hydroxyacetophenone and o-phenylenediamine. The ligand and polymer metal(II) complexes have been characterized by micro-analytical, UV–vis, FT-IR, 1H-NMR spectral studies, as well as magnetic susceptibility and thermal studies. On the basis of spectral studies, a square-planar geometry has been proposed for the copper(II) polymer metal complex; manganese(II) polymer metal complex shows octahedral geometry while other polymer metal complexes have shown tetrahedral geometries. The in vitro antimicrobial activity of the compounds is tested against the bacteria Escherichia coli, Pseudomonas aeruginosa, Bacillius subtilis, Staphylococcus aureus, Salmonella typhi, and the fungi Candida albicans, Microsporum canis, and Aspergillus niger by well diffusion method. The polymer metal complexes show stronger antimicrobial activity than the free ligand and thermal studies were promising after coordination. The polymers represent a novel class of metal-based antimicrobial agents providing large number of opportunities for thermal and antimicrobial applications.

Biologically active and thermally stable polymeric Schiff base and its metal polychelates: Their synthesis and spectral aspects

New metal polychelates of Mn(II), Co(II), Ni(II), Cu(II) and Zn(II) obtained by the interaction of metal acetates with polymeric Schiff base containing formaldehyde and piperazine, have been investigated. Structural and spectroscopic properties have been evaluated by elemental analysis, FT-IR and (1)H-NMR. Geometry of the chelated polymers was confirmed by magnetic susceptibility measurements, UV-Visible spectroscopy and Electron Spin Resonance. The molecular weight of the polymer was determined by gel permeation chromatography (GPC). Thermogravimetric analysis indicated that metal polychelates were more thermally stable than their corresponding ligand. All compounds were screened for their antimicrobial activities against Escherichia coli, Staphylococcus aureus, Bacillus subtilis, (bacteria) and Candida albicans, Microsporum canis, Cryptococcus neoformans (fungi) by agar well diffusion method. Interestingly, the polymeric Schiff base was found to be antimicrobial in nature but less effective as compared to the metal polychelates. On the basis of thermal and antimicrobial behavior, these polymers hold potential applications as thermally resistant antimicrobial and antifouling coating materials as well as antimicrobial packaging materials.

Preparation, spectral and biological investigation of formaldehyde-based ligand containing piperazine moiety and its various polymer metal complexes.

A novel tetradentate salicylic acid-formaldehyde ligand containing piperazine moiety (SFP) was synthesized by condensation of salicylic acid, formaldehyde and piperazine in presence of base catalyst, which was subjected for the preparation of coordination polymers with metal ions like manganese(II), cobalt(II), copper(II), nickel(II) and zinc(II). All the synthesized polymeric compounds were characterized by elemental analysis, IR, (1)H NMR and electronic spectral studies. The thermal stability was determined by thermogravimetric analysis and thermal data revealed that all the polymer metal complexes show good thermal stability than their parent ligand. Electronic spectral data and magnetic moment values revealed that polymer metal complexes of Mn(II), Co(II) and Ni(II) show an octahedral geometry while Cu(II) and Zn(II) show distorted octahedral and tetrahedral geometry respectively. The antimicrobial screening of the ligand and coordination polymers was done by using Agar well diffusion method against various bacteria and fungi. It was evident from the data that antibacterial and antifungal activity increased on chelation and all the polymer metal complexes show excellent antimicrobial activity than their parent ligand.

Coordination Polymers: Preparation, Physicochemical Characterization, Thermal and Biological Evaluation of Thiosemicarbazide Polychelates

Coordination polymers were prepared by the condensation reaction of salicylaldehyde and thiosemicarbazide with formaldehyde, transition metal acetates Mn(II), Co(II), Ni(II), Cu(II) and Zn(II). Structural and spectral properties have been studied by elemental, spectral (FT-IR, 1H NMR, and UV–Vis), and thermogravimetric analysis. The geometry of the chelated coordination polymers was confirmed by magnetic susceptibility measurements and UV–Visible spectroscopy. Antimicrobial screening was done against microbes such as Escherichia coli, Pseudomonas aeruginosa, Bacillus subtilis, Staphylococcus aureus, Staphylococcus typhi, Candida albicans, Microsporum canis, Aspergillus niger. In vitro antimicrobial activity was determined by the Agar Well Diffusion method and result show that all the coordination polymers exhibited better antimicrobial activity than their parent polymeric Schiff base. Coordination polymers were found to be more stable than their corresponding ligand as deduced by on thermogravimetric analysis. Because of antimicrobial and thermal behavior, these coordination polymers have broad range of applications as thermally resistant as well as antimicrobial-biocidal and antifouling coating materials.

Synthesis and Characterization of Thermally Stable and Biologically Active Metal-Based Schiff Base Polymer

Schiff base was prepared via condensation of ethanedihydrazide with 2-hydroxy benzaldehyde and further this monomeric Schiff base polymerize with formaldehyde and barbituric acid and form polymeric Schiff base (PLSB) ligand. The ligand and its polymer metal complexes were characterized by using elemental analysis, IR, UV–VIS, 1HNMR, magnetic susceptibility and thermogravimetric studies. On basis of elemental analysis and spectral studies, six coordinated geometry was assigned for Mn(II), Co(II) and Ni(II) complexes and four coordinated for Cu(II) and Zn(II) complexes. PLSB act as a tetradentate and coordinate through the azomethine nitrogen and phenolic oxygen. The thermal behavior of these polymer metal complexes showed that the hydrated complexes losses water molecules of hydration in the first step followed immediately by decomposition of the anions and ligand molecules in the subsequent steps. The (PLSB) ligands and its polymer metal complexes were screened against bacterial species Escherichia coli, Staphylococcus aureus, Bacillus subtilis and fungal species Aspergillus flavus, Candida albicans, A. niger. The activity data show that the metal complexes were more potent than the parent Schiff bases.