title: Photophysical properties of quinones and their interaction with the photosynthetic reaction centre.
abstract: Photophysical properties of tetramethyl-1,4-benzoquinone (TMBQ) and 2,6-dimethoxy-1,4-benzoquinone (DMOBQ) in solution and their interactions with the photosynthetic reaction centre (RC) isolated from the photosynthetic bacterium Rhodobacter sphaeroides have been investigated in this work. For these two benzoquinone derivatives an efficient ISC process which leads to the population of the lowest triplet state of the molecules upon direct excitation was observed. The presence of RC does not alter the properties of the triplet state of DMOBQ suggesting that interactions are negligible; on the other side RC efficiently quenched the T1 state of TMBQ. The behavior is rationalized in terms of redox potentials of quinones and kinetic characteristics of their transients.
authors.affiliation: Chemistry Department, University of Perugia, via Elce di Sotto 8, 06123, Perugia, Italy.
authors.forename: Arianna
authors.initials: A
authors.lastname: Barbafina
authors.forename: Fausto
authors.initials: F
authors.lastname: Elisei
authors.forename: Loredana
authors.initials: L
authors.lastname: Latterini
authors.forename: Francesco
authors.initials: F
authors.lastname: Milano
authors.forename: Angela
authors.initials: A
authors.lastname: Agostiano
authors.forename: Massimo
authors.initials: M
authors.lastname: Trotta
mesh_terms: D018360:Crystallography, X-Ray; D008027:Light; D045322:Photosynthetic Reaction Center Complex Proteins / Q000737:chemistry / Q000187:drug effects* / Q000528:radiation effects; D011487:Protein Conformation; D011809:Quinones / Q000737:chemistry / Q000494:pharmacology*; D012242:Rhodobacter sphaeroides / Q000187:drug effects / Q000528:radiation effects
chemical_list: D045322:Photosynthetic Reaction Center Complex Proteins; D011809:Quinones