Spectral Evidence for Heterodimerization of Water-Soluble Metalloporphyrins

1998 ◽  
Vol 02 (01) ◽  
pp. 61-68 ◽  
Author(s):  
SAFİYE SAĞ ERDEM
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Ir Spectra ◽  
Water Soluble ◽  
Paramagnetic Resonance ◽  
Metal Interactions ◽  
Spectral Evidence ◽  
Metal Metal ◽  
Electron Paramagnetic

The formation of water-soluble metalloporphyrin heterodimers from Fe ( III ), Cu ( II ) and Ni ( II ) complexes of 5,10,15,20-tetrakis(4-carboxyphenyl) porphyrin and 5,10,15,20-tetrakis(4-N-methylpyridyl)porphyrin has been investigated using UV-vis, IR and electron paramagnetic resonance spectra. Absorption and IR spectra confirmed the formation of dimers and electron paramagnetic resonance spectra showed evidence for the metal-metal interactions in the dimers.

scholarly journals A tentative approach to the molecular structure of humic acids: the spectral evidence for a derivation of humic acids from plant-borne esters. 1. The electron paramagnetic resonance (EPR) spectra.

1979 ◽  
Vol 27 (1) ◽  
pp. 79-91 ◽  
Author(s):  
G. Minderman
Keyword(s):  
Molecular Structure ◽  
Electron Paramagnetic Resonance ◽  
Humic Acids ◽  
Epr Spectra ◽  
Paramagnetic Resonance ◽  
Spectral Evidence ◽  
Heterogeneous Polymers ◽  
Electron Paramagnetic

It is suggested, from the evidence of EPR spectra, that humic acids are heterogeneous polymers of mixed esters derived from tannins. (Abstract retrieved from CAB Abstracts by CABI’s permission)

Tetranuclear supramolecular structures containing phthalocyanine cores

2007 ◽  
Vol 11 (07) ◽  
pp. 531-536 ◽  
Author(s):  
Ibrahim Özçesmeci ◽  
Sadik Güner ◽  
Ali Ihsan Okur ◽  
Ahmet Gül
Keyword(s):  
Electron Paramagnetic Resonance ◽  
Energy Levels ◽  
Water Soluble ◽  
Orbital Energy ◽  
Characteristic Line ◽  
Spin Hamiltonian ◽  
Paramagnetic Resonance ◽  
X Band ◽  
Hamiltonian Parameters ◽  
Electron Paramagnetic

A metal-free phthalocyanine with four pyridyl donor groups, bound through ethylthio ester bridges on the periphery, have been prepared. The pyridine donors were quaternized with iodomethane to a water-soluble tetracationic phthalocyanine. The tetranuclear supramolecular phthalocyanine was prepared by the coordination of peripheral pyridine donors with VO(acac)2. The paramagnetic tetranuclear structure was studied in powder and solution forms by the electron paramagnetic resonance (EPR) technique. Electron paramagnetic resonance studies, together with the other spectral data confirmed the presence of identical pyridine-coordinated VO(acac)2 paramagnetic centers attached to the peripheral positions of the phthalocyanine core. The X-band EPR signals recorded from powder and solution forms of supramolecules have a characteristic line shape that proves the presence of axial symmetry around the paramagnetic vanadium ions. The anisotropic Lande splitting factors were calculated as g ∥ < g ⊥ < g e = 2.0023. Orbital energy levels for magnetic electrons were determined from theoretically fitted Spin Hamiltonian parameters.

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