Coordination chemistry and catalysis with mixed ligands associating iminophosphorane to thiolate or phenolate

Abstract : New classes of multidentate ligands, associating iminophosphoranes with thiolate or phenoxide, have been developed. These ligands could be easily synthesised from inexpensive, readily available starting materials and on a large scale. They show excellent ability to coordinate with various metal centres, including transition metals, aluminium (principal group), and yttrium (rare-earth metal). Their complexes have been characterised by multiple electromagnetic spectroscopies, such as NMR, EPR, UV-Vis and IR spectroscopies, X-ray diffraction. Some of them have been studied theoretically by DFT calculations in order to give better understanding of their electronic properties. Finally, the catalytic activities of complexes of the developed ligands have been explored for two processes: oligomerisation of ethylene and polymerisation of lactide to give biodegradable polymers. Of particular interest are tetradentate phosphasalen ligands, associating two iminophosphoranes and two phenoxides. They are the phosphorus analogues of a well-known and important class of ligands in coordination and catalysis: the salens. Phosphasalen ligands are more flexible and more electron donating than salens. Thanks to these properties, phosphasalens have the ability to stabilise high valent metals. The first example of this stabilisation was achieved by obtaining a [Ni(III)-phosphasalen] complex. Phosphasalen complexes have great potential use for catalysis. For example, while yttrium salen complexes only have limited performance in ring-opening polymerisation of lactide, yttrium complexes of phosphasalen ligands are among the best initiators in terms of both activity and stereo-selectivity. These results demonstrate the value of phosphasalen ligands in coordination chemistry and catalysis and one can extend the use of phosphalen ligands to other applications as well.
Document type :
Theses
Complete list of metadatas

Cited literature [43 references]  Display  Hide  Download

https://pastel.archives-ouvertes.fr/pastel-00765632
Contributor : Thi Phuong Anh Cao <>
Submitted on : Tuesday, December 18, 2012 - 4:58:21 PM
Last modification on : Wednesday, March 20, 2019 - 12:12:31 PM
Long-term archiving on : Tuesday, March 19, 2013 - 2:50:11 AM

Identifiers

  • HAL Id : pastel-00765632, version 1

Collections

Citation

Thi-Phuong-Anh Cao. Coordination chemistry and catalysis with mixed ligands associating iminophosphorane to thiolate or phenolate. Coordination chemistry. Ecole Polytechnique X, 2012. English. ⟨pastel-00765632⟩

Share

Metrics

Record views

438

Files downloads

2440