The Helicenes

“Helicene” is the name introduced by Newman in 1955, to describe the benzologues of phenanthrene in which the extra ortho-condensed rings give rise to a (regular) cylindrical helix. The pioneer work of Newman in this field cannot be overemphasized; his brillant synthesis and resolution of [6]helicene, achieved eighteen years ago, will remain as a landmark, for it opened the way to the study of a fascinating class of synthetic molecules. In the following review, an attempt is made to summarize the present state of our knowledge in this rapidly expanding field.     

Optisch aktive Ubergangsmetall-Komplexe XXI. Optisch aktive komplexe mit vier verschiedenen liganden am titanatom

Chiral C₅H₅(C₉H₇Ti(Cl)SCH(CH₃)₂ shows diastereotopic CH₃ resonances; the diasteroisomers of C₅H₅(CH₃C₅H₄Ti(Cl)OC₁₀H₁₉ could be separated by fractional crystallisation.     

Renormalization of non polynomial Lagrangians in Jaffe's class

It is shown how a renormalized perturbation series can be defined for a theory with strictly local, non-polynomial, interacting Lagrangian so as to preserve locality at every order.