Event Title

Synthesis, structure and electrochemical properties of nickel(II) compounds bearing a chiral, amino-acid derived phosphine ligand

Presenter Information

Devon Sabo, Susquehanna University

Faculty Advisor

Dr. William Dougherty

Start Date

23-4-2019 12:00 PM

End Date

23-4-2019 1:00 PM

Description

Synthesis, structure and electrochemical properties of nickel(II) compounds bearing a chiral, N,N-bis(diphenylphosphino)valine ethyl ester (bdppval) ligand were investigated. Coordination of bdppval to NiII(X= Cl–, NO3–, BF4–) was achieved in warm acetonitrile forming 1:1, square planar (bddpval)NiX2 (X= Cl–, NO3–) complexes and 2:1 [(bddpval)2Ni][BF4]2 complex as determined by 1H-NMR, 31P-NMR and small-molecule X–ray diffraction. 1H-NMR spectra indicated a rigid bdppval ligand with diastereotopic protons from both the methylene in the ethyl ester and the methyl groups of the isopropyl substituent consistent with metal binding. 31P-NMR exhibits a single resonance at 51 ppm for all complexes suggesting that the identity of the X– ligand has minimal effect on the phosphorus magnetic environment. Cyclic voltammetry showed an irreversible, metal-based reduction for the (bddpval)NiCl2 complex at -1.57 V vs. Fc/Fc+ and lack of any oxidizing potentials indicated that metal binding suppresses phosphorus oxidation of the bisphosphine ligand.

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Apr 23rd, 12:00 PM Apr 23rd, 1:00 PM

Synthesis, structure and electrochemical properties of nickel(II) compounds bearing a chiral, amino-acid derived phosphine ligand

Synthesis, structure and electrochemical properties of nickel(II) compounds bearing a chiral, N,N-bis(diphenylphosphino)valine ethyl ester (bdppval) ligand were investigated. Coordination of bdppval to NiII(X= Cl–, NO3–, BF4–) was achieved in warm acetonitrile forming 1:1, square planar (bddpval)NiX2 (X= Cl–, NO3–) complexes and 2:1 [(bddpval)2Ni][BF4]2 complex as determined by 1H-NMR, 31P-NMR and small-molecule X–ray diffraction. 1H-NMR spectra indicated a rigid bdppval ligand with diastereotopic protons from both the methylene in the ethyl ester and the methyl groups of the isopropyl substituent consistent with metal binding. 31P-NMR exhibits a single resonance at 51 ppm for all complexes suggesting that the identity of the X– ligand has minimal effect on the phosphorus magnetic environment. Cyclic voltammetry showed an irreversible, metal-based reduction for the (bddpval)NiCl2 complex at -1.57 V vs. Fc/Fc+ and lack of any oxidizing potentials indicated that metal binding suppresses phosphorus oxidation of the bisphosphine ligand.