Structures and bonding situation of Pb2X2 (X = H, F, Cl, Br and I)

Taka Shimizu, Gernot Frenking

Research output: Contribution to journalArticlepeer-review

8 Scopus citations

Abstract

Quantum chemical calculations using DFT (BP86) and ab initio methods (MP2, MP4 and CCSD(T)) have been carried out for the title compounds. The nature of the Pb-Pb interactions has been investigated with an energy decomposition analysis. The energy minimum structures of the halogen substituted Pb2X2 molecules possess a doubly bridged butterfly geometry A like the parent system Pb2H2. The unusual geometry can be explained with the interactions between PbX fragments in the X2Π ground state which leads to one Pb-Pb electron-sharing σ bond and two donor-acceptor bonds between the Pb-X bonds as donor and vacant p(π) AOs of Pb. The energy difference between the equilibrium form A and the linear structure XPb≡PbX (E) which is a second-order saddle point is much higher when X is a halogen atom than for X = H. This is because the a4Σ- ← X2Π excitation energies of PbX (X = F-I) are higher than for PbH. The structural isomers B, D1, D2, E, F1, F2 and G of Pb2X2 are no minima on the potential energy surface.

Original languageEnglish
Pages (from-to)269-277
Number of pages9
JournalTheoretical Chemistry Accounts
Volume130
Issue number2-3
DOIs
StatePublished - Oct 2011
Externally publishedYes

Keywords

  • Ab initio calculations
  • Bonding analysis
  • DFT calculations
  • Diplumbaacetylene

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