Irshad-ul-Haq Bhat

Synthesis of new piperazine derived Cu(II)/Zn(II) metal complexes, their DNA binding studies, electrochemistry and anti-microbial activity : Validation for specific recognition of Zn(II) complex to DNA helix by interaction with thymine base

New 3,4:9,10-dibenzo-2,11-dihydroxy-1,12-bispiperazine-5,8-dioxododecane complexes [C(24)H(36)N(4)O(6)Cu] (1), [C(24)H(32)N(4)O(4)Zn] (2) have been synthesized and characterized by elemental analysis, IR, NMR, Mass, EPR, UV-vis spectroscopy and molar conductance measurements. The complexes are non-ionic in nature and possess octahedral geometry around Cu(2+), Zn(2+) central metal ions. The binding studies of 1 and 2 with calf thymus DNA (CT-DNA) were investigated by UV-vis, fluorescence, cyclic voltammetery and viscosity measurements. The calculated binding constant K(b) for 1 and 2 obtained from UV-vis absorption studies was 7.6x10(3)M(-1), 80.8x10(4)M(-1), respectively. The intrinsic binding constants were also estimated to be 7.0x10(4)M(-1) and 7.53x10(5)M(-1) for 1 and 2, respectively by using emission titrations. These experimental results suggest that complexes are groove binders and interact to CT-DNA with different affinities. Both the complexes in presence and absence of CT-DNA show quasireversible wave corresponding to Cu(II)/Cu(I) and Zn(II)/Zn(I) redox couple. The changes in E(1/2), DeltaE, I(pa)/I(pc) ascertain the interaction of 1 and 2 with CT-DNA. Further, decrease in viscosity of CT-DNA with increasing concentration of complexes was observed. In vitro, antimicrobial activity against fungi A. brassicicola, A. niger and bacteria E. coli, P. aeruginosa of complexes were carried out, which indicate that complex 2 is more active against both fungal and bacterial strains as shown by % inhibition data.

Effect of Anhydride Modification on the Thermal Stability of Cultivated Acacia mangium

Abstract This paper tests the hypothesis that propionic and succinic anhydride modification will improve the thermal stability of cultivated Acacia mangium wood. The thermal stability of modified wood was characterized with thermogravimetric analysis. Evidence of modification was confirmed by Fourier transform infrared analysis. Our results show that chemical modification with anhydrides improves the thermal stability of the Acacia wood. The higher thermal stability of anhydride-modified Acacia wood compared with unmodified wood is attributed to the reduction in hydrophilic nature of the wood due to esterification. Succinylated wood has better thermal stability than propionylated wood based on the values of on-set degradation temperatures, the temperatures at which 30, 50, and 70% degradation occurred, and the activation energy. The improved thermal stability of modified wood compared with the unmodified wood will offer potential for better utilization of Acacia mangium.

Development and Material Properties of Chitosan and Phosphomolybdic Acid-based Composites

This work reports the development and characterization of chitosan/ phosphomolybdic acid-based composite membranes. The prepared composite membranes were characterized by Fourier transform infrared (FTIR) spectroscopy, X-ray diffraction (XRD), differential scanning calorimetry (DSC), tensile strength test, and thermogravimetric analysis (TGA). FTIR spectroscopy indicated the proper molecular interactions between chitosan and PMA. XRD spectroscopy indicated the semi crystalline nature of the composite membranes. DSC study showed the presence of single glass transition temperature (Tg) at 156°C in the 20% PMA-doped membrane, which indicates the miscible nature of chitosan and PMA blend. TGA study indicates increase in thermal stability of the composite membranes as compared to pure chitosan. Mechanical properties of the composite membranes were found to be enhanced significantly.

Thermal, spectroscopic, and flexural properties of anhydride modified cultivated Acacia spp.

The effects of chemical modification on the thermal stability of cultivated Acaciamangium and Acaciahybrid wood species were investigated. Evidence of modification was indicated by increase of weight and was confirmed by Fourier transform infrared analysis (FT-IR). The thermal stability measured by thermogravimetric analysis (TGA) increased after esterification with propionic and succinic anhydrides. Thermal stability of succinylated samples was found to be highest based on the values of on-set degradation temperatures, the temperatures at which 30, 50, and 70% degradation occurred. The observed higher thermal stability of the succinylated and propionylated Acacia wood samples when compared with unmodified wood was attributed to the reduction in hydrophilic nature of the wood due to esterification reaction.

Synthesis of new heterometallic macromolecules: their DNA binding, cleavage activity and in vitro model electrochemotherapy study.

The homodinuclear C(16)H(30)N(8)O(5)Sn(2)Cl(4) (1), heterotetranuclear C(16)H(38)N(8)O(9)Sn(2)Cu(2)Cl(8) (2) and C(16)H(38)N(8)O(9)Sn(2)Mn(2)Cl(8) (3) macrocyclic complexes were synthesized and characterized by elemental analysis, spectroscopic techniques and molar conductance measurements. The interaction studies of 1-3 with calf thymus DNA (CT-DNA) were carried out by UV-vis titration, fluorescence, cyclic voltammetry and viscosity measurements. These results were further authenticated by carrying out interaction studies of 1-3 with plasmid pBR322 DNA employing gel electrophoresis. To overcome the dose resistance, auto toxicity of the drugs, a model study based on electrochemotherapy (ECT) was carried out and the results were compared in the presence and in the absence of the applied electrical potential.