Electron spin resonance investigation of copper(II) complexation by soil fulvic acid

Journal Article · Mon Dec 31 23:00:00 EST 1984 · Soil Sci. Soc. Am. J.; (United States)

DOI:https://doi.org/10.2136/sssaj1985.03615995004900010023x· OSTI ID:6184066

Senesi, N; Bocian, D F; Sposito, G

Electron Spin Resonance (ESR) spectra are reported and interpreted for Cu(II)-fulvic acid complexes. The data indicated the formation of anisotropic Cu(II) complexes, the metal cation being immobilized in inner-sphere coordination with ligands arranged in a distorted octahedral environment. For the lowest Cu/FA ratio (0.02), calculated ESR parameters suggested the existence of three different coordinating environments for copper ions. When the Cu/FA ratio was increased beyond 0.2, only a dipolar-broadened ESR absorption produced by a large excess of CuS aquo-ions was observable. A highly structured pattern in the g perpendicular to region exhibited by the ESR spectrum at the highest Cu/FA ratio was attributed to superhyperfine coupling of the CuS unpaired electron to N-ligand nuclei. The implied rearrangements of ligands in the complexes after the removal of water emphasize the importance of soil relative humidity to the Cu(II) complexation mechanisms of fulvic acid.

• Research Organization: Univ. di Bari, Italy
• OSTI ID: 6184066
• Journal Information: Soil Sci. Soc. Am. J.; (United States), Journal Name: Soil Sci. Soc. Am. J.; (United States) Vol. 49:1; ISSN SSSJD
• Country of Publication: United States
• Language: English

Related Subjects

510100* -- Environment
Terrestrial-- Basic Studies-- (-1989)
510200 -- Environment
Terrestrial-- Chemicals Monitoring & Transport-- (-1989)
54 ENVIRONMENTAL SCIENCES
CHEMISTRY
COMPLEXES
COPPER
ELECTRON SPIN RESONANCE
ELEMENTS
FULVIC ACIDS
HUMIDITY
LIGANDS
MAGNETIC RESONANCE
METALS
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC MATTER
RESONANCE
SOIL CHEMISTRY
SOILS
STRUCTURAL CHEMICAL ANALYSIS
SYNTHESIS
TRANSITION ELEMENTS