Journal of Coordination Chemistry · 1995 · 10 citations · 9 references
Natural SciencesChemistryAnalytical ChemistryInorganic ChemistryOrganic ChemistryAcid-base ChemistryCoordination ChemistryHeterocyclic ChemistryInorganic SpectroscopyMetal-ligand BondingAlkali Metal ChemistryCrown Ether ComplexationCrown Ether-based MaterialsElectron DensityElectron Density DistributionsNickel ChemistrySpectroscopic Characterization Of Metal-ligand BondsTransition-metal-catalyzed Functionalization
Abstract Methods for the preparation of the 4-diphenylphosphino derivatives of N-phenylaza-15-crown-5 and -18-crown-6 are described. The properties of these systems and the 4′-diphenylphosphino derivative of benzo-15-crown-5 have been examined by way of picrate ion extraction abilities and IR spectra of their Ni(CO)3L (L = these phosphines) complexes. All three have abilities to extract Na+ and K+ that are comparable to benzo-15-crown-5. The IR studies (νCO, A1 band) indicate that the azacrown systems have better ability than the benzocrown system to increase the electron density on the nickel center. Further, the addition of alkali metal ions, Na+ and K+, to the Ni(CO)3L solutions results in maximum shifts of ca 1.5 cm−1 for the former systems and 0.7 cm−1 for the latter system. A rationale for this observation is presented in terms of Hammett substituent constants. Finally, an X-ray structure of the phosphine oxide of the phenylaza-15-crown-5 derivative is presented. A prominent feature of the structure is that the nitrogen atom is essentially planar with the result that the crown ether ring is large and not preorganized for coordination of spherical ions. Key Words: crown ethermacrocyclephosphine ligandsnickel tetracarbonyl
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