Optically active transition metal complexes. Part 115. Synthesis, crystal structure and properties of chiral (η5-C5H5)Ru complexes with pyrrolecarbaldiminato and salicylaldiminato ligands
| Autor: | Bernhard Nuber, Thomas Neuhierl, Henri Brunner |
|---|---|
| Rok vydání: | 1998 |
| Předmět: |
Chemistry
Ligand Stereochemistry Organic Chemistry Substituent Diastereomer chemistry.chemical_element Crystal structure Ring (chemistry) Biochemistry Ruthenium Inorganic Chemistry chemistry.chemical_compound Crystallography Transition metal Materials Chemistry Chelation Physical and Theoretical Chemistry |
| Zdroj: | Journal of Organometallic Chemistry. 563:173-178 |
| ISSN: | 0022-328X |
| DOI: | 10.1016/s0022-328x(98)00539-7 |
| Popis: | The chiral complexes CpRu(LL*)PPh3, Cp=η5-C5H5, LL*-1=anion of 2-N-[(S)-l-phenylethyl]pyrrolecarbaldimine (1a/1b), LL*-2=anion of 2-N-[(R)-hydroxybut-2-yl)]pyrrolecarbaldimine (2a/2b) and LL*-3=anion of N-[(S)-1-phenylethyl]salicylaldimine (3a/3b), can be prepared by reaction of CpRu(PPh3)2Cl and the corresponding ligand HLL* in boiling toluene. An X-ray structure analysis of diastereomerically pure 1a shows SRu configuration. The phenyl substituent of the ligand adopts a T-shape arrangement with respect to the Cp ring. The PPh3 ligand is in a right handed propeller conformation. The activation parameters of the epimerization 1a⇌1b were determined to be ΔH≠=(133±33) kJ mol−1 and ΔS≠=(77±26) J K−1 mol−1. The equilibrium ratios are 1a:1b=86:14, 2a:2b=1:1 and 3a:3b=88:12, the attractive interaction between the Cp ring and the phenyl substituent of the chiral center in the chelating ligand LL* favoring one diastereomer of the complexes 1a/1b and 3a/3b. |
| Databáze: | OpenAIRE |
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