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Synthesis, X‐ray Structures, NMR Studies and Density Functional Calculations of (η 2 ‐Fumarodinitrile)palladium(0) Complexes Containing Dihydro(phosphanylphenyl)oxazole Ligands
Author(s) -
Zehnder Margareta,
Neuburger Markus,
Schaffner Silvia,
Jufer Martin,
Plattner Dietmar A.
Publication year - 2002
Publication title -
european journal of inorganic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.667
H-Index - 136
eISSN - 1099-0682
pISSN - 1434-1948
DOI - 10.1002/1099-0682(200206)2002:6<1511::aid-ejic1511>3.0.co;2-c
Subject(s) - chemistry , diastereomer , palladium , crystallography , substituent , ligand (biochemistry) , density functional theory , moiety , stereochemistry , nuclear magnetic resonance spectroscopy , oxazoline , computational chemistry , organic chemistry , catalysis , biochemistry , receptor
The (fumarodinitrile)palladium(0) complexes 4a − 4d with various 4‐substituted 2‐[2′‐(diphenylphosphanyl)phenyl]‐4,5‐dihydrooxazole ligands 1a − 1d have been prepared and characterized. NMR spectroscopic investigations give evidence that the complexes exist in two forms in solution. The diastereomeric ratio is highly dependent on the 4‐substituent at the oxazoline moiety. Substituents reaching into the fumarodinitrile area ( 4a and 4d ) favor one diastereoisomer. Less intrusive substituents ( 4b and 4c ) lead to a diastereomeric ratio of about 1:1. X‐ray structures reveal that only one isomer is found in the crystalline solid state. For 4a and 4d it is the same as the major diastereoisomer in solution. The orientation of the fumarodinitrile ligand of 4b is opposite to that of 4a and 4d . In all complexes, the fumarodinitrile ligand is not planar. The C−CN and C−H bonds are bent away from the palladium atom. The NC−C=C−CN torsion angle is about 150°. DFT/B3LYP calculations confirm the structural features found in the solid‐state structures. For an accurate description of the coordination sphere, extended basis sets for the palladium and phosphorus atoms must be employed. The energetic difference computed for the two diastereoisomers of 4a reflect the ratios in solution as observed by NMR spectroscopy. (© Wiley‐VCH Verlag GmbH, 69451 Weinheim, Germany, 2002)