Six-coordinate Co2+ with imidazole, NH3, and H 2O ligands: Approaching spin crossover

Ann Marie Schmiedekamp, Anthony Ginnetti, Brian Piccione, Kevin Charles Cannon, M. Dominic Ryan

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

Octahedral, six-coordinate Co2+ can exist in two spin states: S = 3/2 and S = 1/2. The difference in energy between high spin (S = 3/2) and low spin (S = 1/2) is dependent on both the ligand mix and coordination stereochemistry. B3LYP calculations on combinations of neutral imidazole, NH3, and H2O ligands show that low-spin isomers are stabilized by axial H2O ligands and in structures that also include trans pairs of equatorial NH3 and protonated imidazole ligands, spin crossover structures are predicted from spin state energy differences. Occupied Co d orbitals from the DFT calculations provide a means of estimating effective ligand strength for homoleptic and mixed ligand combinations. These calculations suggest that in a labile biological system, a spin crossover environment can be created.

Original languageEnglish (US)
Pages (from-to)1415-1429
Number of pages15
JournalInternational Journal of Quantum Chemistry
Volume107
Issue number6
DOIs
StatePublished - May 1 2007

Fingerprint

imidazoles
crossovers
Ligands
ligands
Stereochemistry
Biological systems
Discrete Fourier transforms
Isomers
stereochemistry
Electron energy levels
imidazole
estimating
isomers
orbitals
energy

All Science Journal Classification (ASJC) codes

  • Atomic and Molecular Physics, and Optics
  • Condensed Matter Physics
  • Physical and Theoretical Chemistry

Cite this

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abstract = "Octahedral, six-coordinate Co2+ can exist in two spin states: S = 3/2 and S = 1/2. The difference in energy between high spin (S = 3/2) and low spin (S = 1/2) is dependent on both the ligand mix and coordination stereochemistry. B3LYP calculations on combinations of neutral imidazole, NH3, and H2O ligands show that low-spin isomers are stabilized by axial H2O ligands and in structures that also include trans pairs of equatorial NH3 and protonated imidazole ligands, spin crossover structures are predicted from spin state energy differences. Occupied Co d orbitals from the DFT calculations provide a means of estimating effective ligand strength for homoleptic and mixed ligand combinations. These calculations suggest that in a labile biological system, a spin crossover environment can be created.",
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Six-coordinate Co2+ with imidazole, NH3, and H 2O ligands : Approaching spin crossover. / Schmiedekamp, Ann Marie; Ginnetti, Anthony; Piccione, Brian; Cannon, Kevin Charles; Ryan, M. Dominic.

In: International Journal of Quantum Chemistry, Vol. 107, No. 6, 01.05.2007, p. 1415-1429.

Research output: Contribution to journalArticle

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T1 - Six-coordinate Co2+ with imidazole, NH3, and H 2O ligands

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AU - Schmiedekamp, Ann Marie

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