The vibrational bands of carbon monoxide bound to hemes or metal surfaces

• Infrared spectra of imidazole carbonyl complexes of 2,4-substituted hemes are presented. An increased CO stretch frequency is accompanied by a lowered FeC vibrational energy. Hartree-Fock-Slater electron structure calculations discern π and σ contributions to the observed shifts of vibrational energies. We conclude that an enhanced electron availability manifests itself as (i) a lowered ferric/ferrous reduction potential, (ii) increased filling of the 2π orbital of liganded CO which in turn reduces νCO and increases νFec, and (iii) increased basicity of the liganded CO. Analogies between CO liganded to heme and CO adsorbed onto metal surfaces are discussed.

Subject headings

NATURVETENSKAP  -- Fysik -- Annan fysik (hsv//swe)

NATURAL SCIENCES  -- Physical Sciences -- Other Physics Topics (hsv//eng)

Keyword

Fysik

Fysik

Publication and Content Type

ref (subject category)

art (subject category)