Structural comparison of [PdX2(P-P)] complexes (X- = Cl, Br and I; P-P = α,ω-bis(diphenylphosphino)alkanes) and their trends of redox potentials

Moses Abdullai Abukari, Takayoshi Suzuki, Masakazu Kita

Research output: Contribution to journalArticlepeer-review

5 Citations (Scopus)

Abstract

X-ray crystallographic analyses revealed that the Pd-P and Pd-X bond lengths of [PdX2(P-P)] complexes (X- = Cl, Br and I and P-P = Ph2P(CH2)nPPh2; n = 1: dppm, 2: dppe, 3: dppp, 4: dppb) are: Pd-P (dppm, dppe) < Pd-P (dppp, dppb) and Pd-X (dppm, dppe) > Pd-X (dppp, dppb). The oxidation potentials values, E1/2(ox), of the shorter Pd-P and longer Pd-X bond lengths in the dppm and dppe complexes are high and reflect strong dxy (dπ (Pd)) interaction with dx2-y2 (dσ * (Pd)) and that this interaction is less dependent on X -. The longer Pd-P and shorter Pd-X bonds for the dppp and dppb complexes reflect that the dx2-y2 (dσ* (Pd)) interaction is largely dependent on X -. The reduction potential, E1/2(red), which reflects the dx2-y2 (dσ* (Pd) LUMO energy, and the oxidation potential, E1/2(ox), which reflects the (dxy (dπ (Pd) HOMO energy were, determined. The E 1/2(red) and E1/2(ox) values indicate the σ-bonding properties and π-interaction in the system, respectively. Good linear relationships were observed between the potentials difference [E 1/2(ox) - E1/2(red)] and the ligand-field transition energy (dπ (dxy) → dσ* (d x2-y2)) in the series of dihalogenopalladium(II) complexes. The linear relationship shows that the energies of the d-d transitions and ΔE(Redox) of the dppm and dppe complexes are less dependent on X- whilst those of the dppp and dppb are largely X- dependent.

Original languageEnglish
Pages (from-to)364-369
Number of pages6
JournalPolyhedron
Volume52
DOIs
Publication statusPublished - Mar 22 2013

Keywords

  • Redox potential
  • The d-d transition energy
  • d Square planar system
  • π-Interaction
  • σ-Orbital energy

ASJC Scopus subject areas

  • Physical and Theoretical Chemistry
  • Inorganic Chemistry
  • Materials Chemistry

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