Complexation behavior of two-coordinated carbon compounds containing fluorenyl ligands
Catharine Esterhuysen1, Gernot Frenking
1Department of Chemistry, University of Stellenbosch, Private Bag X1, Matieland, Stellenbosch, South Africa. ce@sun.ac.za
Dalton Transactions (Cambridge, England : 2003)
|June 5, 2013
Summary
Computational chemistry reveals that certain dicoordinated carbon molecules, when complexed with gold chloride (AuCl), exhibit unique bonding behaviors. These "hidden carbones" display characteristics of both carbenes and allenes, depending on their structure and AuCl interactions.
Area of Science:
- Computational Chemistry
- Organometallic Chemistry
- Quantum Chemistry
Background:
- Dicoordinated carbon molecules (carbenes and allenes) exhibit diverse electronic structures and reactivity.
- Understanding the interaction of these molecules with metal complexes is crucial for catalysis and materials science.
Purpose of the Study:
- To investigate the electronic structure and bonding of six dicoordinated carbon molecules.
- To explore the complexation behavior of these molecules with gold chloride (AuCl) moieties.
- To classify the bonding modes and chemical behavior of the free and complexed compounds.
Main Methods:
- Density Functional Theory (DFT) calculations using BP86 functional with SVP and TZVPP basis sets.
- Ab initio calculations utilizing the SCS-MP2 method.
- Electronic structure analysis of free and gold-complexed dicoordinated carbon molecules.
Main Results:
- Monoaurated adducts of phosphine-substituted carbenes show η(1) coordination to the central carbon.
- Monoaurated adducts of carbene-substituted allenes exhibit η(2) bonding across a C=C double bond.
- Daurated species display three distinct bonding modes: both η(1), both η(2), or a combination.
Conclusions:
- Compounds 1-4, initially classified as carbenes or bent allenes, behave as 'hidden carbones' upon AuCl complexation.
- Compounds 5 and 6, classified as typical allenes, maintain their allene character even after AuCl complexation.
- The study elucidates novel bonding interactions and chemical properties of dicoordinated carbon systems with gold.
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