ELECTRON-TRANSFER REACTIONS BETWEEN NUCLEIC-ACID BASES AND TETRACYANOETHYLENE IN ACETONITRILE

The electron transfer reactions between pyrimidines, e.g. thymine (Thy), uracil (Ura) and cytosine (Cyt), and tetracyanoethylene (TCNE) in acetonitrile were studied using nanosecond laser flash photolysis techniques. Laser photolysis of a mixed solution of TCNE and pyrimidines led to the formation of the anion radical of TCNE, which has an absorption band at 350-500 nm (lambda(max)A=430 nm) and decays following second-order kinetics. The electron transfer reaction occurs through the excited triplet states of the pyrimidines, and the bimolecular quenching rate constants are 7.6X10(9) dm(3) mol(-1) s(-1) for thymine and 1.7X10(10) dm(3) mol(-1) s(-1) for uracil. However, a ground state complex between cytosine and TCNE was found. This complex has an absorption band with lambda(max) at 419, 444 and 472 nm. The photoinduced electron transfer between cytosine and TCNE was not observed on a nanosecond time scale during laser photolysis.http://gateway.webofknowledge.com/gateway/Gateway.cgi?GWVersion=2&SrcApp=PARTNER_APP&SrcAuth=LinksAMR&KeyUT=WOS:A1995QB80100010&DestLinkType=FullRecord&DestApp=ALL_WOS&UsrCustomerID=8e1609b174ce4e31116a60747a720701Chemistry, PhysicalSCI(E)6ARTICLE1-285-888