CAROTENOID TRIPLET STATES IN PHOTOSYNTHETIC BACTERIA

Abstract— The triplet state spectra of anaerobically grown cells of Rhodopseudomonas sphaeroides GIC and R. sphaeroides wild type and aerobically grown cells of R. sphaeroides wild type were examined under reducing and non-reducing conditions at 100 K. by electron paramagnetic resonance (EPR). Large differences in the zero field splitting parameters, |D| and |E| of the triplets are seen to arise in the different preparations. The spectra are assigned to the triplet states of carotenoids, some of which are closely associated with the reaction center and others are contained in the light harvesting complex. Taken together with the triplet state data on Rhodospirillum rubrum wild type previously published the trends in the zero field splitting parameters can be understood in terms of the extent of electron derealization in carotenoids of varying length.     

Simple evaluation of Franck–Condon factors and non‐Condon effects in the Morse potential

The calculation of Franck–Condon factors between different 1‐D Morse potential eigenstates using a formula derived from the Wigner function is discussed. Our numerical calculations using a simple program written in Mathematica are compared with other calculations. We show that our results have a similar accuracy as those calculations performed with more sophisticated methods. We discuss the extension of our method to include non‐Condon effects in the calculation. © 2002 Wiley Periodicals, Inc. Int J Quantum Chem 88: 280–295, 2002     

The class reconstruction number of maximal planar graphs

The reconstruction numberrn(G) of a graphG was introduced by Harary and Plantholt as the smallest number of vertex-deleted subgraphsG _i =G – v _i in the deck ofG which do not all appear in the deck of any other graph. For any graph theoretic propertyP, Harary defined theP-reconstruction number of a graph G P as the smallest number of theG _i in the deck ofG, which do not all appear in the deck of any other graph inP We now study the maximal planar graph reconstruction numberrn(G), proving that its value is either 1 or 2 and characterizing those with value 1.     

The aza-xylylene Diels-Alder approach for the synthesis of naturally occurring 2-alkyl tetrahydroquinolines

The recently discovered intramolecular aza-xylylene Diels-Alder reaction, based on a 1,4-dehydrohalogenation reaction, was extended in terms of substrates and leaving groups allowing the assembly of tetrahydroquinolines in two synthetic steps. Intramolecular cleavage of a thiocarbamate using triphenylphosphine and tetrachloromethane (Appel conditions) to give chloromethyl phenylisocyanate has been presented for the first time. The synthetic feasibility of this process was demonstrated in the first total syntheses of the alkaloids rac-Angustureine and 1-methyl-2-propyltetrahydroquinoline.