Special Issue "Photochemistry in Organic Synthesis"

Guest Editor
Dr. Joaquim Luís Faria
Laboratory of Catalysis and Materials, Department of Chemical Engineering, Faculty of Engineering, University of Porto, Rua Doutor Roberto Frias s/n, 4200-465 Porto, Portugal
E-Mail:
Interests: photochemistry and photocatalysis: photoinduced electron and energy transfer processes; heterogeneous photocatalysis and photocatalytic reactor engineering; photocatalytic processes (homogeneous and heterogeneous); catalysis and kinetics: selective hydrogenation in liquid phase; catalytic wet air oxidation; advanced oxidation processes for air and water treatments; spectroscopy: time resolved analysis of short lived intermediates; materials characterization; surface reactions; interface analysis by non-linear spectroscopy

Dear Colleagues,

Photochemistry in Organic Synthesis concerns any type of useful chemical reaction that can by initiated by one electronic excited state of an organic molecule, generated after irradiation of a suitable system in the UV or visible region. In our days, because of environmental concerns, conversion to a highly functional compound by a photochemical useful reaction needs to be encompassed with a high selectivity to minimize waste. Thus, in this issue in addition to the traditional fields of electronic excited state reactivity and conventional photoinduced electron transfer activation, attention will be given to the enormous potential of photocatalysis as a tool for sustainable organic synthesis. Since radiation sources, optical materials and spectroscopic analytical tools are rapidly evolving, technological aspects as photochemical reactor engineering will be also covered.

Dr. Joaquim Luís Faria
Guest Editor

Submission

• electronic photo-excited states
• energy transfer
• photocatalysis
• photochemical organic synthesis
• photochemistry
• photoinduced electron transfer
• selective photo-oxidation
• selective photo-reduction
• semiconductor photocatalysis

Manuscript ID: Molecules-photochem-20091111-jp-Sakai
Type of Paper: Article
Title: Syntheses, Characterization and Photo-Hydrogen-Evolving Properties of tris(2,2'-bipyridine)ruthenium(II) Derivatives Tethered to a (2-phenylpyridinato)platinum(II) Unit
Authors: Masayuki Kobayashi, Shigeyuki Masaoka and Ken Sakai; E-Mails: ksakai@chem.kyushu-univ.jp, masaoka@chem.kyushu-univ.jp, mkoba@chem.kyushu-univ.jp
Abstract: With the aim of developing new molecular devices having higher
photo-hydrogen-evolving activity, Pt(ppy)(L)Cl units (ppy = 2-phenylpyridinato, L = Cl- or DMSO; DMSO = dimethylsulfoxide) have been employed as an H₂-evolving site for the reported Ru(II)Pt(II) devices, since the catalytic activity of [Pt(ppy)Cl₂]- was confirmed to be higher than those of other mononuclear platinum(II) complexes. In the present study, two new heterodinuclear Ru(II)Pt(II) complexes, given as a condensation product of [Ru(bpy)₂(5-amino-phen)]²⁺ (bpy = 2,2'-bipyridine, phen = 1,10-phenanthroline) with either Pt(cppy)Cl₂ or Pt(cppy)(DMSO)Cl (cppy = 9-carboxy-phenylpyridinato), have been prepared and their photo-hydrogen-evolving activities have been evaluated in detail. The ineffectiveness of these systems as photo-hydrogen-evolving molecular devices are discussed in terms of the driving force for the photoinduced electron transfer from the triplet MLCT excited state of the Ru chromophore to the pai*(cppy) orbital of the catalyst moiety.

Manuscript ID: Molecules-photochem-20091113-Poizat-fr
Type of Paper: Article
Title: Probing the Dynamics of Solvation and Structure of the OH-ion in Aqueous Solution from Picosecond Transient Absorption Measurements
Authors: Olivier Poizat and Guy Buntinx; E-Mail: olivier.poizat@univ-lille1.fr
Abstract: The reaction of intracomplex proton transfer (44BPY^-...HO-H) → 44BPYH + OH^- that follows the photoreduction of 4,4’-bipyridine (44BPY) into its anion radical 44BPY^- in the presence of 1,4-diazabicyclo[2.2.2]octane (DABCO) is investigated in acetonitrile-water mixtures by using picosecond transient absorption. The dependence of the appearance kinetics of the 44BPYH. radical on the water content reveals a highly diffusional proton transfer process that is controlled by the dynamics of solvation of the released hydroxide ion. The results are interpreted on the basis of a two-step mechanism where an intermediate solvation complex (44BPYH.)OH^-(H₂O)₃ is formed first before evolving toward a final four-water hydration structure OH^-(H₂O)₄.

Title: Photochemical Oxidative Cyclisation of Stilbenes and Stilbenoids – The Mallory-Reaction.
Author: Kåre B. Jørgensen
Affiliation: Faculty of Science and Technology, University of Stavanger, 4036 Stavanger, Norway; E-Mail: kare.b.jorgensen@uis.no
Abstract: After Mallory in 1964 described the use of iodine as catalyst for photochemical cyclisation of stilbenes, this reaction has proven its effectiveness in the synthesis of phenanthrenes, other PAHs and Phenacenes with a surprisingly large selection of substituents. The “early age” of the reaction was reviewed by Mallory in a huge chapter in Organic Reactions in 1984. But the development has continued. Alternative conditions accommodate more sensitive substituents, and isomers can be favoured by sacrificial substituents. Here the further developments and applications of this reaction after 1984 are discussed and summarized.