Optical activity studies of hydrogen-deuterium exchange

Miscellaneous · Mon Jan 01 00:00:00 EST 1990

OSTI ID:6108987

Hansen, L J

The potassium complexes of racemic and optically active forms of 1,2-propanediaminetriacetatoacetic acid nickel-ate (II) were prepared stoichiometrically by two different experimental procedures. The complexes were characterized by UV-VIS absorption spectroscopy, infrared spectroscopy, and thermal analysis. Circular dichroism and optical rotatory dispersion values were obtained on the optically active complexes. TGA and IR spectroscopy techniques suggest that {Delta}-K (Ni(R ({minus})HPDTA)) H{sub 2}O (1)and {Lambda}-K (Ni(S (+)HPDTA)) H{sub 2}O (2) have different configurations in solution than in the solid state. Solid complexes of (1) are theorized to have the nickel (II) ion bound pentadentate to the PDTA ligand and unidentate to a water molecule. The free carboxyl arm of the PDTA ligand is protonated. Dissolution of the complexes results in rotational changes which occur with time. The rate of rotational change has been kinetically measured, which results in three pH dependent rate constants. An isotope effect for such reactions in H{sub 2}O and D{sub 2}O has been measured. The base-catalyzed hydrogen-deuterium exchange of the out-of-plane glycinate rings of (1) and (2) complexes has been determined for three of the four glycinate protons by ORD. The rate of hydrogen-deuterium exchange is extremely slow and consecutive proton exchanges are not independent of one another over sufficiently long periods, such that measurement of {alpha}{sub {infinity}} are calculated by three differing mathematical models and applied to the calculation of the hydrogen-deuterium rate constants.

• Research Organization: Cleveland State Univ., OH (United States)
• OSTI ID: 6108987
• Resource Relation: Other Information: Thesis (Ph.D)
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
DEUTERIUM
ISOTOPIC EXCHANGE
POTASSIUM COMPLEXES
OPTICAL ACTIVITY
ABSORPTION SPECTROSCOPY
CHEMICAL REACTION KINETICS
DICHROISM
DISSOLUTION
HEAVY WATER
HYDROGEN
INFRARED RADIATION
ISOTOPE EFFECTS
LIGANDS
MATHEMATICAL MODELS
MOLECULAR STRUCTURE
NICKEL COMPLEXES
PH VALUE
PHYSICAL PROPERTIES
ROTATION
SAMPLE PREPARATION
THERMAL GRAVIMETRIC ANALYSIS
ULTRAVIOLET RADIATION
VISIBLE RADIATION
WATER
ALKALI METAL COMPLEXES
CHEMICAL ANALYSIS
COMPLEXES
ELECTROMAGNETIC RADIATION
ELEMENTS
GRAVIMETRIC ANALYSIS
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
ISOTOPES
KINETICS
LIGHT NUCLEI
MOTION
NONMETALS
NUCLEI
ODD-ODD NUCLEI
OXYGEN COMPOUNDS
QUANTITATIVE CHEMICAL ANALYSIS
RADIATIONS
REACTION KINETICS
SPECTROSCOPY
STABLE ISOTOPES
THERMAL ANALYSIS
TRANSITION ELEMENT COMPLEXES
400202* - Isotope Effects
Isotope Exchange
& Isotope Separation