Pretražite po imenu i prezimenu autora, mentora, urednika, prevoditelja

Napredna pretraga

Pregled bibliografske jedinice broj: 532374

Ions can move a proton coupled electron transfer reaction into tunnelling regime


Jakobušić Brala, Cvijeta; Pilepić, Viktor; Sajenko, Ivana; Karković, Ana; Uršić, Stanko
Ions can move a proton coupled electron transfer reaction into tunnelling regime // Helvetica chimica acta, 94 (2011), 9; 1718-1731 doi:10.1002/hlca.201100035 (međunarodna recenzija, članak, znanstveni)


CROSBI ID: 532374 Za ispravke kontaktirajte CROSBI podršku putem web obrasca

Naslov
Ions can move a proton coupled electron transfer reaction into tunnelling regime

Autori
Jakobušić Brala, Cvijeta ; Pilepić, Viktor ; Sajenko, Ivana ; Karković, Ana ; Uršić, Stanko

Izvornik
Helvetica chimica acta (0018-019X) 94 (2011), 9; 1718-1731

Vrsta, podvrsta i kategorija rada
Radovi u časopisima, članak, znanstveni

Ključne riječi
proton-coupled electron transfer; cation; kinetic isotope effect; hydrogen tunnelling; ascorbate

Sažetak
The effects of charged species on proton-coupled electron-transfer (PCET) reaction should be of significance for understanding/application of important chemical and biological PCET systems. Such species can be found in proximity of activated complex in a PCET reaction, although they are not involved in the charge transfer process. Reported here is the first study of the above-mentioned effects. Here, the effects of Na+, K+, Li+, Ca2+, Mg2+, and Me4N+ observed in PCET reaction of ascorbate monoanions with hexacyanoferrate(III) ions in H2O reveal that, in presence of ions, this over-the-barrier reaction entered into tunneling regime. The observations are: a) dependence of the rate constant on the cation concentration, where the rate constant is 71 (at I = 0.0023), and 821 (at 0.5M K+), 847 (at 1.0M Na+), and 438 M−1 s−1 (at 0.011M Ca2+) ; b) changes of kinetic isotope effect (KIE) in the presence of ions, where kH/kD=4.6 (at I = 0.0023), and 3.4 (in the presence of 0.5M K+), 3.3 (at 1.0M Na+), 3.9 (at 0.001M Ca2+), and 3.9 (at 0.001M Mg2+), respectively ; c) the isotope effects on Arrhenius pre-factor where AH/AD=0.97 (0.15) in absence of ions, and 2.29 (0.60) (at 0.5M Na+), 1.77 (0.29) (at 1.0M Na+), 1.61 (0.25) (at 0.5M K+), 0.42 (0.16) (at 0.001M Ca2+) and 0.16 (0.19) (at 0.001M Mg2+) ; d) isotope differences in the enthalpies of activation in H2O and in D2O, where ΔΔH‡(D, H)=3.9 (0.4) kJ mol−1 in the absence of cations, 1.3 (0.6) at 0.5M Na+, 1.8 (0.4) at 0.5M K+, 1.5 (0.4) at 1.0M Na+, 5.5 (0.9) (at 0.001M Ca2+), and 7.9 (2.8) (at 0.001M Mg2+) kJ mol−1 ; e) nonlinear proton inventory in reaction. In the H2O/dioxane 1 : 1, the observed KIE is 7.8 and 4.4 in the absence and in the presence of 0.1M K+, respectively, and AH/AD=0.14 (0.03). The changes when cations are present in the reaction are explained in terms of termolecular encounter complex consisting of redox partners, and the cation where the cation can be found in a near proximity of the reaction-activated complex thus influencing the proton/electron double tunneling event in the PCET process. A molecule of H2O is involved in the transition state. The resulting ‘configuration’ is more ‘rigid’ and more appropriate for efficient tunneling with Na+ or K+ (extensive tunneling observed), i.e., there is more precise organized H transfer coordinate than in the case of Ca2+ and Mg2+ (moderate tunneling observed) in the reaction.

Izvorni jezik
Engleski

Znanstvena područja
Kemija



POVEZANOST RADA


Projekti:
006-0063082-0354 - Fizikalno kemijske interakcije biomedicinski važnih prirodnih antioksidansa (Pilepić, Viktor, MZOS ) ( POIROT)

Ustanove:
Farmaceutsko-biokemijski fakultet, Zagreb

Poveznice na cjeloviti tekst rada:

doi onlinelibrary.wiley.com

Citiraj ovu publikaciju:

Jakobušić Brala, Cvijeta; Pilepić, Viktor; Sajenko, Ivana; Karković, Ana; Uršić, Stanko
Ions can move a proton coupled electron transfer reaction into tunnelling regime // Helvetica chimica acta, 94 (2011), 9; 1718-1731 doi:10.1002/hlca.201100035 (međunarodna recenzija, članak, znanstveni)
Jakobušić Brala, C., Pilepić, V., Sajenko, I., Karković, A. & Uršić, S. (2011) Ions can move a proton coupled electron transfer reaction into tunnelling regime. Helvetica chimica acta, 94 (9), 1718-1731 doi:10.1002/hlca.201100035.
@article{article, author = {Jakobu\v{s}i\'{c} Brala, Cvijeta and Pilepi\'{c}, Viktor and Sajenko, Ivana and Karkovi\'{c}, Ana and Ur\v{s}i\'{c}, Stanko}, year = {2011}, pages = {1718-1731}, DOI = {10.1002/hlca.201100035}, keywords = {proton-coupled electron transfer, cation, kinetic isotope effect, hydrogen tunnelling, ascorbate}, journal = {Helvetica chimica acta}, doi = {10.1002/hlca.201100035}, volume = {94}, number = {9}, issn = {0018-019X}, title = {Ions can move a proton coupled electron transfer reaction into tunnelling regime}, keyword = {proton-coupled electron transfer, cation, kinetic isotope effect, hydrogen tunnelling, ascorbate} }
@article{article, author = {Jakobu\v{s}i\'{c} Brala, Cvijeta and Pilepi\'{c}, Viktor and Sajenko, Ivana and Karkovi\'{c}, Ana and Ur\v{s}i\'{c}, Stanko}, year = {2011}, pages = {1718-1731}, DOI = {10.1002/hlca.201100035}, keywords = {proton-coupled electron transfer, cation, kinetic isotope effect, hydrogen tunnelling, ascorbate}, journal = {Helvetica chimica acta}, doi = {10.1002/hlca.201100035}, volume = {94}, number = {9}, issn = {0018-019X}, title = {Ions can move a proton coupled electron transfer reaction into tunnelling regime}, keyword = {proton-coupled electron transfer, cation, kinetic isotope effect, hydrogen tunnelling, ascorbate} }

Časopis indeksira:


  • Current Contents Connect (CCC)
  • Web of Science Core Collection (WoSCC)
    • Science Citation Index Expanded (SCI-EXP)
    • SCI-EXP, SSCI i/ili A&HCI
  • Scopus


Uključenost u ostale bibliografske baze podataka::


  • CA Search (Chemical Abstracts)


Citati:





    Contrast
    Increase Font
    Decrease Font
    Dyslexic Font