Some Novel Manganese(III) Mixed Ligand Complexes and its Decolourization Studies

Some novel mixed ligand complexes of Mn(III) with glycine ligand namely [Mn(gly)2 Cl(en)], [Mn(gly)2 Br(en)], [Mn(gly)2 N3 (en)] and [Mn(gly)2 NCS(en)] have been synthesized starting from Mn(gly)2 Cl, Mn(gly)2 Br, Mn(gly)2N3 and Mn(gly)2 NCS respectively. These newly synthesized complexes have been characterized by UV/Vis, FT-IR and Mass spectrometry. The spectroscopic data suggest distorted octahedral geometry for all these mixed ligand complexes. The λmax values of these complexes for 5T2g → 5Eg transitions are 482 nm for [Mn(gly)2N3(en)], 488 for [Mn(gly)2NCS(en)], 486 for [Mn(gly)2 Br(en)] and 484 for [Mn(gly)2Cl(en)], all these transitions are red shifted in comparison to their parent complexes. The ligand field parameters such as 10 Dq, B and β have also been calculated and suggest covalent metal ligand bonding. One peculiar finding is that the FT-IR spectra shows frequencies for both free and coordinated NH2 group in all complexes indicating that the ethylenediamine ligand present here is non bridging in nature. The mass spectrometry results show molecular ion peaks at m/z 300, 345, 307 and 323 for [Mn(gly)2Cl(en)], [Mn(gly)2Br(en)], [Mn(gly)2N3(en)] and [Mn(gly)2NCS(en)] respectively. The coordination of ethylenediamine to Mn(III) enhances its efficiency towards decolourization methyl red dye.

Structures and Ligand Field Parameters of Sm3+ Doped Tellurite Glass: Gold Nanoparticles Mediation

Controllable modifications of overall properties of rare-earth doped glasses via gold nanoparticles (Au NPs) mediation prompted gamut research interests. Such glass systems are interesting due to their technological prospects and well as fundamental understanding of surface plasmon resonance effects at metal glass interface responsible for diverse emerging attributes. This motivate us to determine the effects of varying concentration of Au NPs on the structure and ligand field parameters of samarium (Sm3+) doped zinc tellurite glass. Glass samples with composition (79-x)TeO2-20ZnO-1Sm2O3-xAuCl3, where 0 ≤ x ≤ 0.10 mol% are prepared using melt quenching method. X-ray diffraction pattern of all glasses confirmed their amorphous nature. Transmission electron microscopic images verified the existence of Au NPs in a glass matrix matrix with an average size of 10.52 nm. Two surface plasmons resonance band of gold are probed at 652 and 715 nm. Using the UV-Vis absorption spectral data, quantities such as nephelauxetic ratio, bonding parameter and Racah parameters are evaluated. Both bonding parameter and nephelauxetic ratio revealed a reduction with increasing concentration of Au NPs, where decrease in the ionic bonding between Sm3+ and surrounding ligand have clearly indicated an enhancement in the covalency. The values of Racah parameters are decreased as the concentration of Au NPs are increased. The observed reduction in the nephelauxetic function is attributed to the weakening of the localized d-electrons aroused from overlapping d-orbital and ligand orbital. Furthermore, the Raman spectra displayed the structural modification in terms of TeO4 trigonal bipyramidal (tbp) unit, where many TeO4 tbp units are converted into their TeO3 trigonal pyramid (tp) counterparts. Raman bands are found to be located around 102-105 cm-1, 420-424 cm-1, 657-661 cm-1 and 729-736 cm-1. Results are analyzed and compared. Present glass composition is asserted to be useful for the development of photonic devices.

OPTICAL PROPERTIES AND STRUCTURE OF COBALT CHLORIDE DOPED PVA AND ITS BLEND WITH PVP

Solution cast technique has been used to prepare films of PVA and its blend with PVP. Moreover, cobalt chloride ( CoCl 2) has been doped in PVA and also PVA/PVP 90/10 as a host matrix for it. Also, UV/VIS optical analysis has been used to drop more light on the structural modification that occurs due to doping CoCl 2 with different levels in different polymeric matrixes. Indeed, UV–Vis spectra is a useful tool for studying the absorption spectra and estimating the values of absorption edge, Eg, and band tail, Eu, for all samples. The optical absorption measurements have been carried out in the wavelength region from 200 nm to 900 nm. In addition, the ligand field parameters and optical energy gaps have been calculated and discussed. X-ray diffraction (XRD) and fourier transform infrared (FTIR) spectroscopy have been used to characterize the studied samples which illustrates that PVA is strongly affected by mixed fillers.

Synthesis and Structural Studies of Transition Metal Complexes with Bidentate Schiff Base Derived from 3-Acetyl-6-methyl-(2H)-pyran-2,4(3H)-dione

The solid complexes of Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) with Schiff base ligands derived from heterocyclic compounds 3-acetyl-6-methyl-(2H)-pyran-2,4(3H)-dione (Dehydroacetic acid) ando-chloroaniline were synthesized and characterized by elemental analysis, conductance, magnetic, thermal, UV-Vis and1H-NMR spectroscopy. The ligand field parameters have been evaluated for Cu(II), Ni(II), Co(II), Mn(II) and Fe(III) complexes which suggest an octahedral geometry for each of them. The magnetic moment and spectral data suggest the dimeric nature of Mn(II) complexes with octahedral geometry. The fungicidal activities of the ligands and their metal complexes have been screened in vitro againstAspergillus nigerand the percentage inhibition of the metal complexes is found to be increased considerably then that of their corresponding ligands and the order is Cu>Ni>Fe>Mn>Co.