Identifier

etd-04102013-170059

Degree

Doctor of Philosophy (PhD)

Department

Chemistry

Document Type

Dissertation

Abstract

Bimetallic Ni complexes Ni21M and Ni21R and monometallic transition metal complexes were investigated as possible alkene hydration catalysts under a multitude of different reaction conditions. All attempts at performing this catalytic reaction failed to give any alcohol products. Catalytic screening experiments were conducted using a mixture of racemic-et,ph-P4 and meso-et,ph-P4, 1M and 1R, and various transition metals. These experiments gave several different products including 1-phenylethanol from styrene. During the course of the hydration experiments, an aldehyde product was identified from experiments conducted with the bimetallic complexes in air. Experiments have shown that the aldehyde is produced from the oxidative cleavage of the double bond of an alkene. The oxidative cleavage is a non-catalytic reaction and all attempts to produce a catalytic reaction have failed. The evidence collected suggests the oxidative cleavage is coupled with phosphine oxidation and a catalytic reaction will not be possible. A detailed solution-state investigation of Ni21M and Ni22R was conducted via 1H and 31P{1H} NMR spectroscopy in the presence of water. These experiments have shown that a complex reaction occurs between the bimetallic complexes and water which ultimately leads to the formation of bimetallic Ni complexes with two tetraphosphine ligands bound. The reaction that occurs is dependent on several variables. One of these bimetallic complexes, [Ni2(µ-Cl)(1M)2][BF4]3, has been independently synthesized and characterized via X-ray crystallography. The NMR experiments have allowed us to propose a reaction scheme in which phosphine dissociation from one of the complexes formed in solution ultimately leads to the formation of the double ligand species. The synthesis, separation and characterization of racemic- and meso-(Et2P-1,2-C6H4)PCH2P(1,2-C6H4-PEt2), 2R and 2M has been successfully achieved. A successful synthesis of the bimetallic Ni complexes has been developed which allows for clean separation of both diastereomers. Cyanolysis of the two bimetallic complexes has allowed us to isolate each diastereomer of the ligand in greater than 95% purity. Unfortunately the cyanolysis suffers from low yields of the free ligand and is not a practical means for isolating the pure diastereomers. Two monometallic Ni cyanide complexes isolated from the cyanolysis experiments have been characterized via X-ray crystallography.

Date

2013

Document Availability at the Time of Submission

Release the entire work immediately for access worldwide.

Committee Chair

Stanley, George

Included in

Chemistry Commons

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