Ligand Field Strengths of Carbon Monoxide and Cyanide in Octahedral Coordination

Abstract

Ligand field splittings were extracted from absorption spectra of metal hexacarbonyl and hexacyano complexes over 35 years ago by Gray and coworkers (J. Am. Chem. Soc., 85, 2922 (1963); ibid. 90, 4260, 5713 (1968)). Recent time-dependent density functional theory calculations by Baerends and coworkers (J. Am. Chem. Soc., 121, 10356 (1999)) on M(CO)6 with M=Cr, Mo, W raised questions about the magnitudes of these ligand field splittings. In order to reexamine such effects systematically, we report here the splittings for a series of 3d6 metal hexacarbonyl, hexaisocyano and hexacyano complexes: V(CO)6(-) , Cr(CO)6, Mn(CO)6(+) and Fe(CO)6(2+); Co(CN)6(3) and Fe(CN)6(4); and V(CNH)(-6), Cr(CNH)6, Mn(CNH)6(+) and Fe(CNH)6(2+) . This work demonstrates that the 3d splittings induced by the ligands in question generally fall in the order CO>CNH>CN- . We agree with Baerends and colleagues that CO exerts a much stronger ligand field than was originally thought.

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Document Details

Document Type
Technical Report
Publication Date
Jan 10, 2005
Accession Number
ADA466847

Entities

People

  • Harry B. Gray
  • Jonas Oxgaard
  • Patrick Hummel
  • William Andrew Goddard III

Organizations

  • California Institute of Technology

Tags

Communities of Interest

  • Energy and Power Technologies

DTIC Thesaurus Topics

  • Absorption
  • Absorption Spectra
  • Carbon Monoxide
  • Charge Transfer
  • Chemical Compounds
  • Chemistry
  • Computational Science
  • Density Functional Theory
  • Dielectric Gases
  • Energy Levels
  • Ground State
  • Materials
  • Metals
  • Monoxides
  • Spectra
  • Splitting
  • Transitions

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  • Organic Chemistry
  • Quantum Chemistry