Studies On Some New Transition Metai. Complexes Of The Schiff Bases Derived From Ouinoxaline - 2 - Carboxaldehyde

This thesis deals with the synthesis, characterisation and catalytic activity studies of some new transition metal complexes of the Schiff bases, derived from quinoxaline—2—carboxaldehyde. The model complexes derived from specially designed and synthesised Schiff bases help us to understand the chemistry of biological systems. Schiff bases derived from heterocyclic aldehydes like quinoxaline-2-carboxaldehyde provide great structural diversity during complexation. The Schiff bases synthesised in the present study ' are quinoxaline—2—carboxa.lidene-2-aminophenol (QAP). quinoxaline—2carboxaldehyde semicarbazone (QSC), quinoxaline-2—carboxalidene—o— phenylenediamine (QOD) and quinoxaline-2-carboxalidene-2-furfurylamine (QFA). The elucidation of the structure of these complexes is done using conductance, magnetic susceptibility measurements. infrared, UV—Vis and EPR spectral studies.

IRIS BIOMETRIC RECOGNITION SYSTEM EMPLOYING CANNY OPERATOR

Biometrics has become important in security applications. In comparison with many other biometric features, iris recognition has very high recognition accuracy because it depends on iris which is located in a place that still stable throughout human life and the probability to find two identical iris's is close to zero. The identification system consists of several stages including segmentation stage which is the most serious and critical one. The current segmentation methods still have limitation in localizing the iris due to circular shape consideration of the pupil. In this research, Daugman method is done to investigate the segmentation techniques. Eyelid detection is another step that has been included in this study as a part of segmentation stage to localize the iris accurately and remove unwanted area that might be included. The obtained iris region is encoded using haar wavelets to construct the iris code, which contains the most discriminating feature in the iris pattern. Hamming distance is used for comparison of iris templates in the recognition stage. The dataset which is used for the study is UBIRIS database. A comparative study of different edge detector operator is performed. It is observed that canny operator is best suited to extract most of the edges to generate the iris code for comparison. Recognition rate of 89% and rejection rate of 95% is achieved

Syntheses, EPR spectral studies and crystal structures of manganese(II) complexes of neutral N,N donor bidentate Schiff bases and azide/thiocyanate as coligand

Four manganese(II) complexes Mn2(paa)2(N3)4 (1), [Mn(paa)2(NCS)2] 3/2H2O (2), Mn(papea)2(NCS)2 (3), [Mn(dpka)2(NCS)2] 1/2H2O(4) of three neutral N,N donor bidentate Schiff bases were synthesized and physico- chemically characterized by means of partial elemental analyses, electronic, infrared and EPR spectral studies. Compounds 3 and 4 were obtained as single crystals suitable for X-ray diffraction. Compound 4 recrystallized as Mn(dpka)2(NCS)2. Both the compounds crystallized in the monoclinic space groups P21 for 3 and C2/c for 4. Manganese(II) is found to be in a distorted octahedral geometry in both the monomeric complexes with thiocyanate anion as a terminal ligand coordinating through the nitrogen atom. EPR spectra in DMF solutions at 77 K show hyperfine sextets with low intensity forbidden lines lying between each of the two main hyperfine lines and the zero field splitting parameters (D and E) were calculated.