Photochemistry of Nucleic Acid Bases and Their Thio- and Aza-Analogues in Solution

Part of the Topics in Current Chemistry book series (TOPCURRCHEM, volume 355)


The steady-state and time-resolved photochemistry of the natural nucleic acid bases and their sulfur- and nitrogen-substituted analogues in solution is reviewed. Emphasis is given to the experimental studies performed over the last 3–5 years that showcase topical areas of scientific inquiry and those that require further scrutiny. Significant progress has been made toward mapping the radiative and nonradiative decay pathways of nucleic acid bases. There is a consensus that ultrafast internal conversion to the ground state is the primary relaxation pathway in the nucleic acid bases, whereas the mechanism of this relaxation and the level of participation of the 1πσ*, 1 nπ*, and 3ππ* states are still matters of debate. Although impressive research has been performed in recent years, the microscopic mechanism(s) by which the nucleic acid bases dissipate excess vibrational energy to their environment, and the role of the N-glycosidic group in this and in other nonradiative decay pathways, are still poorly understood. The simple replacement of a single atom in a nucleobase with a sulfur or nitrogen atom severely restricts access to the conical intersections responsible for the intrinsic internal conversion pathways to the ground state in the nucleic acid bases. It also enhances access to ultrafast and efficient intersystem crossing pathways that populate the triplet manifold in yields close to unity. Determining the coupled nuclear and electronic pathways responsible for the significantly different photochemistry in these nucleic acid base analogues serves as a convenient platform to examine the current state of knowledge regarding the photodynamic properties of the DNA and RNA bases from both experimental and computational perspectives. Further investigations should also aid in forecasting the prospective use of sulfur- and nitrogen-substituted base analogues in photochemotherapeutic applications.


Azabases DNA and RNA analogues DNA and RNA monomers Excited singlet and triplet states Excited-state dynamics Femtochemistry Fluorescence up-conversion Photochemistry Pump-probe transient absorption Quantum-chemical calculations Thiobases 









2-Thiothymidine (ribose)


















































2′-3′-5′-Tri-O-acetylated ribose








Adenosine 5′-monophosphate


5-Bromo-4-thiouridine (2′-3′-5′-tri-O-acetylated ribose)


Complete Active Space Perturbation Theory


Complete Active Space Self-Consistent Field




Configuration Interaction Singles


5-Chloro-4-thiouridine (2′-3′-5′-tri-O-acetylated ribose)


Cytidine 5′-monophosphate


COnductor-like Screening MOdel


Conductor-like Polarizable Continuum Model








2′-Deoxyadenosine 5′-monophosphate




2′-Deoxycytidine 5′-monophosphate




2′-Deoxyguanosine 5′-monophosphate








2′-Deoxythymidine 5′-monophosphate










Equation Of Motion Coupled Cluster


5-Fluoro-4-thiouridine (2′-3′-5′-tri-O-acetylated ribose)




Fluorescence Up-conversion


Guanosine 5′-monophosphate






5-Iodo-4-thiouridine (2′-3′-5′-tri-O-acetylated ribose)




Laser-Induced OptoAcoustic Spectroscopy


MultiReference Configuration Interaction






Phosphate Buffer Solution


















Transient Absorption Spectroscopy


Time-Correlated Single Photon Counting


Time-Dependent Density Functional Theory


Thymidine (ribonucleoside)






Thymidine 5′-monophosphate (ribonucleotide)


Two-Quanta Photolysis


Time-Resolved Fluorescence


Tris(hydroxymethyl)aminomethane buffer


Time-Resolved Luminescence


Time-Resolved PhotoElectron Spectroscopy


Time-Resolved Thermal Lensing






UltraViolet, electromagnetic radiation subtype A (400 to 315 nm)


UltraViolet, electromagnetic radiation subtype C (280 to 100 nm)



The authors acknowledge the CAREER program of the National Science Foundation (Grant.No.CHE-1255084) for financial support. LMF acknowledges the financial support of MICINN for a FPU grant and the Project No.CTQ2012-35513-C02-01.

Authors' noteSpace limitations preclude a comprehensive review, and it is unfitting to include all references to relevant work from many research groups working in this area (particularly in Sect. 2). We apologize for any unintentional omissions.


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Copyright information

© Springer-Verlag Berlin Heidelberg 2014

Authors and Affiliations

  1. 1.Department of Chemistry and Center for Chemical DynamicsCase Western Reserve UniversityClevelandUSA
  2. 2.Departamento de QuímicaUniversidad Autónoma de MadridMadridSpain

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