70152-65-7Relevant academic research and scientific papers
Electrolyte effects on the energetics and dynamics of intermolecular electron transfer reactions
Thompson, Peggy A.,Simon, John D.
, p. 5657 - 5664 (1993)
Picosecond absorption spectroscopy is to used to examine the effects of added electrolytes on the electron transfer reaction between the trans-stilbene radical cation and the radical anion of fumaronitrile in acetonitrile ethyl acetate solutions formed by photoexcitation of the corresponding ground state complex. The salts studied are LiClO4, NaClO4 and Bu4NClO4. Contrary to previous reports, the yield of ion-pair separation following photolysis of the ground state complex is small. Greater than 90% of the photogenerated ion-pairs undergo back electron transfer. The electron transfer rates are dependent on the particular electrolyte present in solution. Thus, the driving force of the reaction cannot be quantified by any general models which solely consider the concentration of dissolved salt. A model is proposed which parametrizes the energetics of the electron transfer reaction in terms of the photophysical behavior of 3-aminofluoren-9-one in the salt solutions studied. Using this approach, the dependence of the reaction rate on exothermicity is quantitatively determined. For the salt solutions studied, the driving force changes by ～ 15 kcal/mol. Excellent agreement between the experimental data and the predictions of the Marcus inverted region are observed. The influence that added salts have on the outer-sphere reorganization energy and solvent dynamic contributions.
Role of Contact and Solvent-Separated Radical Ion Pairs in the Diffusional Quenching of trans-Stilbene Excited Singlet State by Fumaronitrile
Peters, Kevin S.,Lee, Joseph
, p. 8941 - 8945 (2007/10/02)
Picosecond absorption spectroscopy is used to examine the question of wether contact radical ion pairs (CRIP) or solvent-separated radical ion pairs (SSRIP) are formed upon the quenching, by electron transfer, of the first excited singlet state of trans-stilbene (S1) by fumaronitrile (FN).Prior to these experiments, it was generally believed that for exothermic reactions in polar solvents, SSRIP are formed upon quenching by electron transfer.However the present experiments reveal that the quenching of S1 by FN in acetonitrile leads to the formation of CRIP.To establish the nature of the radical ion pair formed upon electron transfer, the kinetics for the decay of the CRIP and the SSRIP are established.
Intrinsic Rate of Electron Transfer in the Diffusional Quenching of trans-Stilbene S1 by Fumaronitrile
Angel, Stephen A.,Peters, Kevin S.
, p. 713 - 717 (2007/10/02)
The quenching of the first excited singlet state of trans-stilbene (S1) by fumaronitrile in acetonitrile has been examined by picosecond laser spectroscopy.From the time dependence of the rate constant for the quenching of S1, the intrinsic rate of the electron transfer can be separated from the diffusional contribution.The rate of electron transfer is ket = 1.9E12 M-1 s-1.From the time dependence of the formation of the resulting ion pair, it is concluded that the electron transfer occurs when the molecules are in contact.
