P. Mosae Selvakumar

Green synthesis of silver nanoparticles from the extract of the inflorescence of Cocos nucifera (Family: Arecaceae) for enhanced antibacterial activity.

Green synthesis of nanoparticles using plant source has been given much importance. In the present study, silver nanoparticles (AgNPs) were synthesized using the ethyl acetate and methanol (EA: M 40:60) extracts of the inflorescence of the tree Cocous nucifera. The synthesized nanoparticles were characterized by UV-visible spectroscope, FTIR and TEM analysis. The particle size of the synthesized AgNPs was 22nm as confirmed by TEM. The qualitative assessment of reducing potential of the extracts of inflorescence indicated the presence of reducing agents. Synthesized AgNPs exhibited significant antimicrobial activity against human bacterial pathogens viz., Klebsiella pneumoniae, Bacillus subtilis, Pseudomonas aeruginosa and Salmonella paratyphi.

Copper(II) bis-chelate paddle wheel complex and its bipyridine/phenanthroline adducts

Bola-shaped diester dicarboxylic acid 2-({2-[(2-carboxybenzoyl)-xy]ethoxy}carbonyl)benzoic acid (L1H2) was synthesized by desymmetrizing phthalic anhydride using 1,2-ethane diol. The corresponding dinuclear copper(II)-tetracarboxylate complex [Cu2(L1)2·(DMF)2] (1) has been synthesized. This paddle wheel complex was self-assembled with [15]-membered bis-chelate ring on either sides of the M–M axis. Upon treating with phenanthroline/bipyridine, the symmetrically formed bis-chelate rings in 1 were selectively desymmetrized into monochelate rings. The dinuclear association in 1 rearranged into mononuclear in [Cu(L1)·(bpy)] (2) and [Cu(L1)·(phen)]·(DMF) (3), where bpy = bipyridine and phen = phenanthroline. The paddle wheel arrangement in 1 is very similar to that in dimeric Cu(II) acetate; the symmetric arrangement in 1 rearranged in its corresponding monomeric species on reacting with phen and bpy. The symmetric bis-chelate ring in 1 and the desymmetrized monochelate ring in 2 and 3 are discussed following their crystal structures. The crystal structures for all the complexes and the electronic and fluorescence properties are discussed.

Synthesis, structure, EPR, and DFT calculation on dinuclear paddle wheel Cu(II) complexes with bis-chelate rings

A series of diester-dicarboxylic acids, L1H2, L2H2, L3H2, L4H2, and L5H2 and their dinuclear Cu2 complexes [Cu(L1)CH3CN]2 (1), [Cu(L2)H2O]2 (2), [Cu(L3)CH3CN]2 (3), [Cu(L4)EtOH]2 (4), and [Cu(L5)CH3CN]2 (5), were synthesized. The crystal structures obtained for 1, 2, and 4 and the density functional theory optimized structures for 2, 3, and 5 illustrated the formation of tetracarboxylate “paddle wheel” complexes. The phthalyl and diphenyl head groups and the spacer moieties were appropriately altered and the size of the chelate ring expanded from 15-membered in 1 to 21-membered in 5. The dinuclear units have strong Cu–Cu interaction with EPR spectra exploring spin coupled features.

Synthesis and spectroscopic characterization of fluorescent 4-aminoantipyrine analogues: Molecular docking and in vitro cytotoxicity studies.

Two substituted aromatic carbonyl compounds (compounds 1 and 2) of 4-aminoantipyrine were synthesized by condensation of fluorine substituted benzoyl chlorides and 4-aminoantipyrine. The structures of synthesized derivatives were established on the basis of UV-Vis, IR, and Mass, (1)H, (13)C NMR and Fluorescence spectroscopy. Both compounds showed significant fluorescence emission and two broad emission bands were observed in the region at 340 nm and 450 nm on excitation at 280 nm. Theoretically to prove that the molecule has anticancer activity against cervical cancer cells, the compounds were analyzed for molecular docking interactions with HPV16-E7 target protein by Glide protocol. Furthermore, 4-aminoantipyrine derivatives were evaluated for their in vitro cytotoxic activity against human cervical cancer cells (SiHa) by MTT assay. Compound 1 showed two fold higher activity (IC50=0.912 μM) over compound 2, and its activity was similar to that of Pazopanib, suggesting that although the two compounds were chemically very similar the difference in substituent on the phenyl moiety caused changes in properties.

Eco friendly natural dyes from Syzygium cumini (L) (Jambolan) fruit seed endosperm and to preparation of antimicrobial fabric and their washing properties

The present study has been focused on the extraction of natural dyes from Syzygium cumini (L.) Jambolan fruit dry seed endosperm and investigation of their phytochemicals and pharmacological characteristics. Dyes were prepared using aqueous, acidic, alcoholic and alkaline extraction techniques. UV spectral studies of the dyes showed a variation in absorption maxima and their color varied with respect to the pH and the solvent used during extraction. The dye was prepared from Jambolan fruit dry seed endosperm showed good antibacterial activity. The aqueous extraction of Jambolan fruit dry seed endosperm was able to inhibit the growth of many bacterial strains viz S. lutea, E.coli, P. aeruginosa, Pseudomonas fluorescens and S. aureus etc. The antimicrobial property of the dyes was used in developing antimicrobial fabric.

Spectral Studies of UV and Solar Photocatalytic Degradation of AZO Dye and Textile Dye Effluents Using Green Synthesized Silver Nanoparticles

The photocatalytic degradation of the chemical dye AZO and dye effluents in different time duration has been investigated using biologically synthesized silver nanoparticles. Dye industry effluents and AZO dye undergo degradation to form harmless intermediate and colourless products following irradiation by UV and solar light in the presence of green synthesized silver nanoparticles. The degree of degradation was tested under the experimental conditions such as PH, temperature, and absorbance of the dye in UV and solar light was measured. The degradation was higher in the UV light source than in the solar light source. Green synthesized silver nanoparticles in the UV light source were found to expedite the dye degradation process.

Synthesis, structure and spectral investigation of hydrogen bonded helical chain in mixed ligand Cu(II) pyrimidone complex.

A simple mono-aqua-dichloro copper(II) pyrimidone complex has been synthesized and characterized using various spectral techniques such as Infrared and Raman in addition to the single crystal X-ray diffraction. The single crystal X-ray analysis carried out for the complex under study brings out the fact that there are two molecules in the unit cell with parameters a = 9.657(2); b = 3.857(2); c = 10.781(2); alpha = 90 degrees; beta = 107.781 degrees; gamma = 90 degrees; V = 382.891 and are crystallized in monoclinic crystal system with Pn space group. In solid state the molecules are interconnected through strong hydrogen bonding [O4...H21-O2W = 2.644 angstroms; O4...H21 = 1.853 angstroms; angleO4...H21-O2W = 172.87 degrees;] formed between the coordinated water molecule (O2W) and the exocyclic ketonic oxygen of the pyrimidone ring (O4). This H-bonding interaction causing a twist in the C1=O1...H21 segment [angleC1=O1...H21 = 122.29 degrees] in combination with weak pi-pi stacking interaction (3.857 angstroms) of the adjacent pyrimidone rings brings the single stranded helical chain which possesses both P and M sense of supramolecular helical assembly. The internal and external modes of vibrations of the crystal under study have been estimated and discussed by applying group theoretical methods.

Development of a fluorescent chemosensor towards sensing and separation of Mg2+ ions in chlorophyll and hard water

A dyad bearing a disulfide spacer and a naphtholyl terminal group with imine functionality has been synthesised (compound LH2) and assessed for its metal ion binding ability in an aqueous medium. This receptor molecule selectively binds Mg2+, with an enhancement in fluorescence intensity of the band at 550 nm. The results show a turn-on response for Mg2+ binding through a PET mechanism. The photophysical properties of the receptor in different solvents, at various pH values and with various metal ions are studied. The receptor molecule shows visible sensing for Mg2+ ions in a (Cynodon dactylon) plant leaf extract which contains chlorophyll. Also, a polysulphone memberane is prepared by incorporating the receptor in it and used for filtering water containing an excess of Mg2+ ions. Fluorescence signal output-based molecular logic gates (NOR, X-NOR) are proposed using H+ and Mg2+ ions as inputs into the molecule.

Green Synthesis and Antimicrobial Activity of Monodispersed Silver Nanoparticles Synthesized Using Lemon Extract

A simple, environmentally benign green synthesis of silver nanoparticles was achieved using lemon fruit extract (Citrus lemon). The synthesized silver nanoparticles were characterized using UV-Vis spectroscopy, infrared spectroscopy, powder X-ray diffraction, and transmission electron microscopy. The predominantly spherical monodispersed 2–10 nm sized silver nanoparticles were obtained for the first time using lemon extract. The antimicrobial activity of silver nanoparticles was also explored. Lemon extract–mediated synthesis is cost efficient, eco-friendly and an easy alternative to conventional methods of silver nanoparticles synthesis.

The first highly selective turn “ON” fluorescent sensor for vanadyl (VO2+) ions: DFT studies and molecular logic gate behavior

Vanadium compounds exhibit anti-tumor properties and insulin-like activity, but an excess is toxic. Development of a selective fluorescent chemosensor for the detection of vanadyl ions has not been reported so far. For the first time, we have reported an effective fluorescent chemosensor C1 for selective recognition and detection of vanadyl ions. C1 was evaluated as a turn “ON” fluorescent chemosensor for vanadyl ions (VO2+) based on a photoinduced electron transfer (PET) mechanism. The association constant for the complex C1–VO2+ was found to be 4.19 × 104 M−1. C1 also behaves as a NOT molecular logic gate where H+ and VO2+ were given as inputs. The proposed binding mode between C1 and vanadyl ions was explained using DFT calculations.