Xα Calculations and Spectroscopic Studies of Triruthenium and Triosmium Dodecacarbonyls

Bernard Delley, Mark C. Manning, D. E. Ellis*, Joseph Berkowitz, William C. Trogler

*Corresponding author for this work

Research output: Contribution to journalArticlepeer-review

76 Scopus citations

Abstract

Nonempirical calculations of the Xα type are reported for Ru3(CO)12 and Os3(CO)12. Two procedures were used to model the molecular charge density for calculating the self-consistent potential: an approximate self-consistent charge scheme and the more rigorous superposition of multipolar densities. This latter type of procedure accurately calculates the splitting of occupied d orbitals in Ru3(CO)12 and Os3(CO)12. Centrally directed metal-metal σ- and π-bonding orbitals are occupied as well as their antibonding counterparts. Stability of the latter levels results from metal—carbon monoxide π bonding. A filled degenerate cyclopropane-like edge-bonding orbital furnishes four bonding electrons to the cluster framework. Difference electron density maps aid the analysis of the two lowest energy electronic transitions. The dipole-allowed transition (15e′ 6a2′) should be strongly metal—metal antibonding, and the dipole-forbidden HOMO →LUMO excitation [formula omitted] is predominantly transition-metal—CO antibonding. Raman spectra for Ru3(CO)12 exhibit resonance enhancement of both the 185 (a1′) and 130-cm−1 (e′) Ru–Ru stretching vibrations. This behavior confirms the predicted antibonding nature of the lowest allowed transition and suggests a Jahn–Teller distortion in the excited state or B-term scattering. Spectrophotometric titrations show the metal center in Os3(CO)12 to be approximately 5 times more basic toward the proton than that in Ru3(CO)12.

Original languageEnglish (US)
Pages (from-to)2247-2253
Number of pages7
JournalInorganic chemistry
Volume21
Issue number6
DOIs
StatePublished - Jan 1 1982

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry

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