Title

Ruthenium incorporation into molecules and materials: New catalysts and strategies to prepare stable ruthenium-capped olefins

Date of Award

2005

Degree Type

Dissertation

Degree Name

Doctor of Philosophy (PhD)

Department

Chemistry

Advisor(s)

Michael B. Sponsler

Keywords

Triflates, Ruthenium, Olefins

Subject Categories

Chemistry | Physical Sciences and Mathematics

Abstract

Strategies such as olefin metathesis were investigated to make stable mixed-valence compounds and materials incorporating metal atoms in polyolefin chains, which are potential precursors in molecular electronics.

New olefin metathesis catalysts, having the general molecular formula (H 2 IMes)Ru(=CHR)(Cl) 2 (3-bromopyridine) 2 and (H 2 IMes)Ru(=CHR)(Cl) 2 (PCy 3 ), where R = Me, Et, and Pr, were prepared. Their kinetic reactivity towards olefins was studied. The PCy 3 catalysts initiated faster (6-14 times) than the Grubbs catalyst where R = Ph. The 3-bromopyridine catalysts were similar in reactivity to the Grubbs catalyst, where R = Ph.

Polyacetylene was prepared in powder and film forms from acetylene using ruthenium olefin metathesis. A new material, metathesis-doped polyacetylene (MDPA), with ruthenium incorporation in the polyacetylene, which was soluble in common organic solvents, was prepared. The 3-bromopyridine catalyst where R = Ph effected the polymerization of 1-hexyne and propargyl alcohol.

Two new ring-constrained polyenes, 1,5-dimethylene-1,2,3,4,5,6,7,8-octahydronapthalene and 1,5-dimethylene-decahydronapthalene, and two polyynes, 1,4-pentadiyne and 3,3,6,6-tetramethyl-1,4,7-octatriyne, were investigated as precursors for ring-constrained diruthenium complexes through sequential ene-yne, ring-closing, and stoichiometric olefin metathesis reactions. All compounds failed to give the desired complexes under a variety of conditions.

A new class of ruthenium alkylidene complexes of trimethylphosphine (H 2 IMes)Ru(=CHR)(Cl) 2 (PMe 3 ), where R = Ph and Et, were prepared. They were metathesis-unreactive at room temperature. Thus, a method of stopping the metathesis reactivity was found by the simple addition of PMe 3 . A new ruthenium alkylidene, namely (PCy 3 )Ru(=CHC 6 H 5 )(Cl) 2 (3-bromopyridine) 2 , was prepared. A new set of Fischer carbenes was prepared, including a tris(trimethylphosphine) complex with molecular formula (PMe 3 ) 3 Ru(=CHOCH 2 CH 3 )(Cl) 2 .

Two dienyl ditriflates, 2,3,4,6,7,8-hexahydronapthalene-1,5-ditriflate and 3,4,4a,7,8,8a-hexahydronapthalene-1,5-ditriflate, were prepared, the former in higher yield and greater reproducibility than done before. Their reactivity and potential application as ring-constrained precursors to prepare diruthenium complexes were investigated.

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