Chemistry and Chemical Biology ETDs

Publication Date

4-18-1977

Abstract

The binuclear tartrate-bridged complexes [Cr2 (tartH)2 (L)2] and Na[Cr2 (tart) (tartH) (L)2]("tart" = C4H2O64-, "tartH" = C4H3O63- and "L"= 1,10-phenanthroline or 2,2'-bipyridyl) have been synthesized where each complex contains either two optically active or two meso bridging ligands. A discussion of the number of isomers and symmetries of these complexes is presented, as well as a complete description of the syntheses of the complexes and their sodium salts. Steric constraints force the octahedral coordination geometry for the dimer containing two d-tartrate ligands to possess a Δ configuration about both chromiums. The chromium ions in the binuclear complexes containing ℓ­tartrate must have a Λ configuration. The ms-tartrate complexes must have either a Δ configuration or a Λ configuration about both chromium atoms. The ms-tartrato­bipyridyl complex was resolved using (-)-quinine and the ΛΛ absolute configuration assigned to the (+CD)589 enantiorner. The complexes have been characterized by pH titrations, molecular mass determinations by vapor pressure osmometry, IR, optical, and ultraviolet spectra. Differences in various spectra have been explained using the geometrical coordination differences between the dd and ms-ms complexes. Visible spectra are discussed using a D4h symmetry about the chromium center. The ΔΔ-dd as well as the ΛΛ-ℓℓ complexes are optically active as shown by CD spectra. The resolved ΛΛ-ms-ms complex gave a CD spectrum that was the mirror image of the ΔΔ-dd Permanganate oxidation of the d-or ℓ-tartrate bipyridyl complexes result in the formation of optically active [Cr(Ox)2(bipy)]- in neutral pH solutions. Oxidation of d-or ℓ-tartrate phenanthroline complexes result in the formation of the optically active [Cr(Ox)(OH2)2(phen)]+ in neutral pH solutions. Oxidation of the ms-tartrate bipyridyl complex produces the optically inactive [Cr(Ox)2(bipy)]- while the ms-tartrate phenanthroline formed the optically inactive [Cr(Ox)(OH2)2(phen)]+. Oxidation of the resolved ΛΛ-ms-ms-tartrate bipyridyl results in the formation of the optically active complex, [Cr(Ox)2(bipy)]-.

Language

English

Document Type

Dissertation

Degree Name

Chemistry

Level of Degree

Doctoral

Department Name

Department of Chemistry and Chemical Biology

First Committee Member (Chair)

Robert Edwin Tapscott

Second Committee Member

Fritz Schreyer Allen

Third Committee Member

William Fletcher Coleman

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