Chiral dynamics in the excited state of a stereochemically labile metal complex. Enantiomer interconversion kinetics, enantioselective quenching, and chiroptical activity of Eu(cda) sub 3 sup 6 minus in H sub 2 O and D sub 2 O

Journal Article · Thu Sep 06 00:00:00 EDT 1990 · Journal of Physical Chemistry; (United States)

DOI:https://doi.org/10.1021/j100381a037· OSTI ID:5406840

Metcalf, D H; Snyder, S W; Demas, J N; Richardson, F S ^[1]

---

1. Univ. of Virginia, Charlottesville (USA)

Time-resolved chiroptical luminescence measurements are used to characterize the excited-state chiroptical activity and racemization kinetics of Eu(cda){sub 3}{sup 6{minus}} (cda {triple bond} chelidamate) in H{sub 2}O and D{sub 2}O solutions at temperatures between 293 and 353 K. Racemic Eu(cda){sub 3}{sup 6{minus}} is excited with circularly polarized light to create an enantiomeric excess of one optical (configurational) isomer in an excited electronic state, and then comparisons between time-resolved total luminescence and circularly polarized luminescence spectra are used to monitor the time dependence of the enantiomeric excess. Decay of the enantiomeric excess is related to interconversion of optical isomers (i.e., racemization) within the excited-state population of complexes, and rate constants are determined for the excited-state racemization of Eu(cda){sub 3}{sup 6{minus}} in both H{sub 2}O and D{sub 2}O over a 60{degree}C temperature range. Arrhenius parameters and thermodynamic activation parameters are derived from the temperature-dependent rate data, and the results obtained in H{sub 2}O and D{sub 2}O are compared and discussed.

• OSTI ID: 5406840
• Journal Information: Journal of Physical Chemistry; (United States), Vol. 94:18; ISSN 0022-3654
• Country of Publication: United States
• Language: English

Related Subjects

37 INORGANIC
ORGANIC
PHYSICAL AND ANALYTICAL CHEMISTRY
EUROPIUM COMPLEXES
OPTICAL ACTIVITY
ENANTIOMORPHS
EXCITED STATES
LUMINESCENCE
MEDIUM TEMPERATURE
RACEMIZATION
RARE EARTH COMPLEXES
SPECTROSCOPY
WATER
COMPLEXES
ENERGY LEVELS
HYDROGEN COMPOUNDS
OXYGEN COMPOUNDS
400201* - Chemical & Physicochemical Properties