Chemistry of diruthenium alkynyls: Materials for molecular electronics and supermolecules

Jiewen Ying, Purdue University

Abstract

Over the last three decades, intense interest has been focused on the development of π-conjugated oligo/polymers due to their unique optical and electronic properties. These oligo/polymers can be utilized as (semi)conductors, organic field effect transistors, electrochemical and fluorescent sensors, and molecular wires and devices. The introduction of a metal center into the conjugated oligomeric backbone may result in enormous opportunities to fine-tune the physical properties of the oligo/polymers. The primary focus of my dissertation is on the development of conjugated hybrid oligomers containing both Ru 2(DMBA)4 units and organic components, such as oligo(yne)s or oligo(phenyleneethynylene)s (OPEs), specifically, for applications as electronic materials. A number of diruthenium alkynyl compounds were designed, synthesized, and studied. The weak base protocol turned out to be the best method for the syntheses of Ru2(DMBA)4 (DMBA is N,N’-dimethylbenzamidinate) based bis-alkynyl compounds. A new class of trans-Ru 2(DMBA)4[(OPEn-SCH2CH2SiMe 3]2 (n=1-3) compounds was prepared and characterized. The deprotected dithiol compounds generated from the removal of TMSE groups in situ were utilized as connectors of variable length for the preparation of Au nanoparticle dimers and chains. A series of symmetric and unsymmetric Ru2(DMBA)4 and Ru2(mMeODMBA) 4 compounds containing terminal donor/acceptor substitution were synthesized and characterized. Electrochemical studies reveal that the characteristics for Ru2-based oxidation and reduction depend on the strength of the donor-acceptor substitutes on the aryl ring of the axial ligands. The single crystal X-ray diffraction shows that the push-pull effect has a strong influence on the Ru-Ru bond length and orientation of two aryl rings. New heterotrimeric diruthenium complexes bridged by 1,4-butadiyn-diyl or 1,4-diethynylbenezene linkers were synthesized and fully characterized. The electronic coupling between two Ru2(ap)4 (ap is 2-aminopyridinate) endgroups was investigated through electrochemical and optical studies. In addition, linear Ru2(DMBA)4 building blocks bearing 120° m-phenylene diethynylene linkers for the construction of shape-persistent linear and cyclic supramolecules were investigated.

Degree

Ph.D.

Advisors

Ren, Purdue University.

Subject Area

Chemistry

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