Date of Award

Spring 2020

Document Type

Open Access Dissertation

Department

Chemistry and Biochemistry

First Advisor

Dmitry V. Peryshkov

Abstract

Carboranes are of topical interest due to their unique structures and applications in the fields of catalysis, polymers, material sciences and supramolecular chemistry. Icosahedral closo-dicarbadodecaboranes are remarkably robust three-dimensional boron-carbon clusters with two slightly acidic C-H bonds. Moreover, coordinatively unsaturated transition-metal complexes containing C-functionalized ortho-carborane are considered as potential catalysts for activation of small molecules.

Recently, we reported the synthesis of a pyridine-backbone pincer complex {(C5H3N)(C2B10H10)2}Ni(CH3CN) (1) in which two C-functionalized ortho-carborane clusters act as the arms of the pincer ligand. The complex 1 was determined to be a competent catalyst for nucleophilic addition of piperidine to acetonitrile. Upon addition of KOtBu, activation of a C-H bond of a labile acetonitrile ligand at the nickel center afforded a C-bound cyanomethyl ligand bearing complex K{(C5H3N)(C2B10H10)2}Ni(CH2CN) (2). Oxidation of 2 by introducing oxygen yielded a cyano complex K{(C5H3N)(C2B10H10)2}Ni(CH(CN) (3), along with HCHO, CO2 and HO-CH2CN via a free radical mechanism. The complexes, 1 and 2, also mediated the formation of acrylamide through C-C coupling of acetonitrile with aldehyde. The double deboronation of the pincer ligand by a methanolic potassium hydroxide solution, followed by homometalation by Ru resulted in the formation of a mixture of racemic and meso ruthenacarborane clusters.

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