Asymmetry and steric hindrance in tripodal ligands: Reaching the limit for octahedral geometry with the newly synthesized [(6-bromo 2-pyridylmethyl) (6-fluoro 2-pyridylmethyl) (2-pyridylmethyl)] amine tripod in FeCl2 complexes
| Autor: | Laila Benhamou, Mohammed Lachkar, Hassen Jaafar, Dominique Mandon, Aurore Thibon |
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| Rok vydání: | 2011 |
| Předmět: |
Steric effects
Ligand Stereochemistry Substituent Tripod (photography) Medicinal chemistry Inorganic Chemistry chemistry.chemical_compound Trigonal bipyramidal molecular geometry chemistry Octahedral molecular geometry Pyridine Materials Chemistry Amine gas treating Physical and Theoretical Chemistry |
| Zdroj: | Inorganica Chimica Acta. 373:195-200 |
| ISSN: | 0020-1693 |
| Popis: | We have synthesized the fully unsymmetrical [(6-bromo 2-pyridylmethyl) (6-fluoro 2-pyridylmethyl) (2-pyridylmethyl)] amine tripod FBrTPA. The synthesis involves preparation of the already known [(6-bromo 2-pyridylmethyl) (2-pyridylmethyl)] amine BrDPA, which is obtained either by classical condensation of α-substituted pyridine carboxaldehyde with aminomethyl pyridine, or by a pathway involving the protection/deprotection sequence of this primary amine. This second way is useful for syntheses of monosubstituted DPAs in the cases where α-substituted pyridine carboxaldehydes are unavailable. The crystal structure of the FeCl2 complex shows that the ligand binds in a κ4-N fashion, with however relatively long ligand-to-metal distances. The spectroscopic and electrochemical studies support decoordination of the bromopyridyl substituent in solution, with κ3-N coordination mode of the tripod within a complex displaying a trigonal bipyramidal geometry at the metal centre. This complex reacts easily with dry oxygen to yield an unsymmetrical μ-oxo diferric complex, the structure of which is also reported. |
| Databáze: | OpenAIRE |
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