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Hyperconjugative Interactions in Silylanilines (open access)

Hyperconjugative Interactions in Silylanilines

The purpose of the present work is to study the bonding interactions between the substituents and the ring π system for a series of ortho and para MeₙH₃₋ₙM (M = C or Si, n = 0-3) substituted N,N-dimethylaniline . Both ground and excited-state interactions were studied and their magnitudes determined. The experimental data were then used in conjunction with molecular orbital calculations to differentiate among inductive, hyperconjugative, and d-pπ interactions on the ground and excited states. Overall, the study indicates that d orbital involvement in the interactions of organosilicon substituents with unsaturated systems is much less significant than is generally held. The importance of pₛᵢ⁻π and pₛᵢ⁻π* hyperconjugative interactions between silicon σ* orbitals and π system in producing the effects of silicon substitution on unsaturated systems has become more apparent.
Date: May 1975
Creator: Jung, Il Nam
System: The UNT Digital Library
Synthesis and Study of Glutaryl-S-(ω-aminoalkyl)-L-cysteinylglycines as Inhibitors of Glyoxalase I (open access)

Synthesis and Study of Glutaryl-S-(ω-aminoalkyl)-L-cysteinylglycines as Inhibitors of Glyoxalase I

This thesis describes the synthesis and preliminary enzymatic study of glutaryl-S-(8-aminooctyl)-L-cysteinylglycine and glutaryl-S-(10-aminodecyl)-L-cysteinylglycine as inhibitors of glyoxalase I. These analogs of glutathione were prepared as potential ligands for affinity chromatography purification of glyoxalase I. The compounds were synthesized by a seven-step procedure in overall yields of 24% for the octyl analog and 33% for the decyl analog. Both compounds exhibited mixed type inhibition of the enzyme, with the decyl derivative being more inhibitory than the octyl derivative. The inhibition was nonlinear (parabolic) for both compounds. Although less inhibitory than the corresponding S-substituted glutathione derivatives, these analogs are promising candidates for affinity chromatography ligands. Such compounds may also be useful in studying the mechanism of glyoxalase I.
Date: May 1975
Creator: Phillips, Gerald Wayne
System: The UNT Digital Library
The Crystal and Molecular Structure of 2, 2' bipyridylglycinatochloro Copper (II) Dihydrate (open access)

The Crystal and Molecular Structure of 2, 2' bipyridylglycinatochloro Copper (II) Dihydrate

The three-dimensional x-ray structure of 2,2'-bipyridylglycinatochloro copper(II) dihydrate has been fully refined to a final R factor of 0.081. The bipyridyl and glycine ligands are arranged about the central copper atom in a square planar configuration while the chlorine atom is 2.635 angstroms above this plane directly over the copper atom. This unusually long distance is explained by the positioning of a glycine group on the opposite side of the square plane, resulting in a distorted octahedral arrangement. Also, the chlorine atom is linked to three oxygen atoms via hydrogen bonding, thus stabilizing the distorted octahedral complex.
Date: May 1975
Creator: Neitzel, Conrad J.
System: The UNT Digital Library
Isolation and Characterization of Proteus vulgaris Methylglyoxal Synthetase (open access)

Isolation and Characterization of Proteus vulgaris Methylglyoxal Synthetase

Methylglyoxal synthetase, which catalyzes the formation of methylglyoxal and inorganic phosphate from dihydroxyacetone phosphate, was found in extracts of Proteus vulgaris. An efficient purification procedure utilizing ion exchange column chromatography and isoelectric focusing has been developed. Homogeneity of the enzyme preparation was confirmed by polyacrylamide gel electrophoresis and rechromatography.Two components of methylglyoxal synthetase were obtained upon isoelectric focusing. A comparison of the chemical and physical properties of the two components was carried out. The enzyme is a dimer. In the presence of inorganic phosphate, the hyperbolic saturation kinetics with dihydroxyacetone phosphate are shifted to sigmoidal.
Date: May 1975
Creator: Tsai, Pei-Kuo
System: The UNT Digital Library