Stereochemistry of eight-coordinate zirconium(IV) and uranium(IV). beta. -diketonates in solution and stereochemistry and geometric isomerization of cis- and trans-bis-(5-amino-2,2-dimethylhex-4-ene-3-onato)-palladium(II)

Thesis/Dissertation · Sat Jan 01 04:00:00 EST 1977

OSTI ID:6742501

Howie, J K

For the first time, splitting at low temperatures (-85 to -145/sup 0/) of the time-averaged alkyl resonances into equal intensity doublets was observed for Zr(RCOCHCOCH/sub 3/)/sub 4/ (R = CH/sub 3/ or t-C/sub 4/H/sub 9/), Hf(CH/sub 3/COCHCOCH/sub 3/)/sub 4/, Zr(CH/sub 3/COCHCOCH/sub 3/)/sub 2/(NO/sub 3/)/sub 2/, and for U(RCOCHCOR)/sub 4/ (R = CH/sub 3/, t-C/sub 4/H/sub 9/, or i-C/sub 3/H/sub 7/). The CF/sub 3/ resonance in the /sup 19/F spectrum of Zr(CF/sub 3/COCHCOCH/sub 3/)/sub 4/ splits into a quartet (relative intensities 1; 3.1; 2.9; 1.8). Splitting at low temperatures of the time-averaged alkyl resonances and ring proton resonances into equal-intensity doublets was observed for U(RCOCHCO-t-C/sub 4/H/sub 9/)/sub 4/ (R = CH/sub 3/ or CF/sub 3/). Activation parameters were obtained by nmr line-shape analysis for the exchange of alkyl groups between the two nonequivalent sites. First-order rate constants (sec/sup -1/), extrapolated to -110/sup 0/, activation energies (kcal/mole), and activation entropies (eu), respectively, for Zr(RCOCHCOCH/sub 3/)/sub 4/ Zr(CH/sub 3/CHCOCH/sub 3/)/sub 2/, and U(RCOCHCOR')/sub 4/, are listed. Mechanisms that rationalize the extreme lability of the complexes are discussed. For the first time, the geometric isomers of Pd(t-C/sub 4/H/sub 9/-COCHC(NH)(CH/sub 3/)/sub 2/ were separated by column chromatography on Florisil. The geometric isomers are reversibly interconverted at slightly elevated temperatures. The enthalpy (kcal/mole), entropy (eu), and the free energy (kcal/mole) for the reaction cis reversible trans in chlorobenzene are, respectively, -0.40 +- 0.07, 1.43 +- 0.20, and -0.83 +- 0.01. For the reaction trans reversible cis in pyridine, the thermodynamic parameters are, respectively, -1.57 +- 0.18, - 3.78 +- 0.52, and -0.45 +- 0.02.

• Research Organization: Cornell Univ., Ithaca, NY (USA)
• OSTI ID: 6742501
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC, ORGANIC, PHYSICAL, AND ANALYTICAL CHEMISTRY
38 RADIATION CHEMISTRY, RADIOCHEMISTRY, AND NUCLEAR CHEMISTRY
400201 -- Chemical & Physicochemical Properties
400702* -- Radiochemistry & Nuclear Chemistry-- Properties of Radioactive Materials
ACTINIDE COMPLEXES
ACTIVATION ENERGY
AROMATICS
CHEMICAL REACTION KINETICS
CHEMICAL REACTIONS
CHLORINATED ALIPHATIC HYDROCARBONS
CHLORINATED AROMATIC HYDROCARBONS
CHLOROFORM
CHROMATOGRAPHY
COMPLEXES
DEUTERIUM COMPOUNDS
DIOXANE
DIPOLE MOMENTS
DISPERSIONS
ENERGY
ENERGY LEVELS
ENTHALPY
ENTROPY
FREE ENERGY
HALOGENATED ALIPHATIC HYDROCARBONS
HALOGENATED AROMATIC HYDROCARBONS
HETEROCYCLIC COMPOUNDS
HYDROGEN COMPOUNDS
ISOMERIZATION
ISOMERS
KINETICS
LOW TEMPERATURE
MAGNETIC RESONANCE
MIXED SOLVENTS
MIXTURES
MOLECULAR STRUCTURE
NUCLEAR MAGNETIC RESONANCE
ORGANIC CHLORINE COMPOUNDS
ORGANIC COMPOUNDS
ORGANIC HALOGEN COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
ORGANOMETALLIC COMPOUNDS
OVERHAUSER EFFECT
PALLADIUM COMPLEXES
PHYSICAL PROPERTIES
REACTION KINETICS
RESONANCE
SEPARATION PROCESSES
SOLVENTS
STEREOCHEMISTRY
STRUCTURAL CHEMICAL ANALYSIS
TEMPERATURE DEPENDENCE
THERMODYNAMIC PROPERTIES
TRANSITION ELEMENT COMPLEXES
URANIUM COMPLEXES
ZIRCONIUM COMPLEXES