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Studies of solvent effects on reacti...

Harris, Don Ahmasi.

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Studies of solvent effects on reaction dynamics using ultrafast transient absorption spectroscopy.

Record Type:	Language materials, printed : Monograph/item
Title/Author:	Studies of solvent effects on reaction dynamics using ultrafast transient absorption spectroscopy./
Author:	Harris, Don Ahmasi.
Description:	137 p.
Notes:	Adviser: Roseanne J. Sension.
Contained By:	Dissertation Abstracts International67-02B.
Subject:	Chemistry, Physical. -
Online resource:	http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3208297
ISBN:	9780542563393

Studies of solvent effects on reaction dynamics using ultrafast transient absorption spectroscopy.
Harris, Don Ahmasi.

Studies of solvent effects on reaction dynamics using ultrafast transient absorption spectroscopy. - 137 p.

Adviser: Roseanne J. Sension.

Thesis (Ph.D.)--University of Michigan, 2006.

Ultrafast transient absorption spectroscopy was used to investigate the solvent dependent reaction dynamics of two prototypical chemical systems: (1) The ring-opening reaction of 1,3-cyclohexadiene, the isolated chromophore in Provitamin D, and (2) The photolysis of various Vitamin B12 cofactors.

ISBN: 9780542563393Subjects--Topical Terms:

560527
Chemistry, Physical.

Studies of solvent effects on reaction dynamics using ultrafast transient absorption spectroscopy.
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005 20110915
008 110915s2006 eng d
020 $a 9780542563393
035 $a (UMI)AAI3208297
035 $a AAI3208297
040 $a UMI $c UMI
100 1 $a Harris, Don Ahmasi. $3 1291370
245 1 0 $a Studies of solvent effects on reaction dynamics using ultrafast transient absorption spectroscopy.
300 $a 137 p.
500 $a Adviser: Roseanne J. Sension.
500 $a Source: Dissertation Abstracts International, Volume: 67-02, Section: B, page: 0907.
502 $a Thesis (Ph.D.)--University of Michigan, 2006.
520 $a Ultrafast transient absorption spectroscopy was used to investigate the solvent dependent reaction dynamics of two prototypical chemical systems: (1) The ring-opening reaction of 1,3-cyclohexadiene, the isolated chromophore in Provitamin D, and (2) The photolysis of various Vitamin B12 cofactors.
520 $a We investigated the influence of solvent polarity on the ground state conformational relaxation of 1,3,5-cis hexatriene subsequent to the ring opening of 1,3-cyclohexadiene in methanol and 1-propanol solvents. Comparisons to the conformational relaxation in alkane solvents studied earlier demonstrated a surprising influence of solvent polarity on single bond isomerization. Temperature dependent transient absorption measurements were performed on 1,3,5-cis hexatriene in cyclohexane and 1-propanol to determine the effect of solvent polarity on the activation energy barrier for ground state single bond isomerization. These measurements conclude that the polar solvent lowers the energy barrier for single bond isomerization allowing conformational relaxation to proceed faster in alcohol solvents compared to alkane solvents. With no perceived polar transition state for single bond isomerization, this result disagrees with the conventional view of solvation and differentiates the single bond isomerization dynamics of polyenes from alkanes.
520 $a Transient absorption spectroscopy was also utilized to study the solvent effects in the photolysis of various B12 cofactors in different environments. We investigated the solvent dependent photolysis of adenosylcobalamin, methylcobalamin, and cyanocobalamin in water and ethylene glycol as a function of solvent temperature. In comparing the radical cage escape of adenosylcobalamin and cyanocobalamin, we determined a larger than expected hydrodynamic radii for the diffusing radicals in water compared to ethylene glycol, thus making necessary a revised perspective of solvent interaction with the diffusing radical. In addition, we investigated the role of the solvent environment in electronic internal conversion from the lowest electronic excited state to the ground state in cyanocobalamin and methylcobalamin. This study reveals the unique electronic nature of alkylcobalamins, which undergo photolysis, in comparison to non-alkylcobalamins that do not undergo photolysis. Finally, we examined the role of solvent environment on adenosylcoblamin bound to glutamate mutase, making comparisons to solvent effects on free adenosylcobalamin.
590 $a School code: 0127.
650 4 $a Chemistry, Physical. $3 560527
650 4 $a Physics, Molecular. $3 1018648
650 4 $a Physics, Optics. $3 1018756
690 $a 0494
690 $a 0609
690 $a 0752
710 2 0 $a University of Michigan. $3 777416
773 0 $t Dissertation Abstracts International $g 67-02B.
790 $a 0127
790 1 0 $a Sension, Roseanne J., $e advisor
791 $a Ph.D.
792 $a 2006
856 4 0 $u http://pqdd.sinica.edu.tw/twdaoapp/servlet/advanced?query=3208297