C-C cross-coupling reactions for the combinatorial synthesis of novel organic materials

To accelerate the development process to organic materials combinatorial strategies and screening methodologies have been representatively elaborated for coumarin dyes and oligothiophenes. Pd-catalyzed cross-couplings of Suzuki, Sonogashira-Hagihara and Heck type were utilized to substitute the coumarin scaffold. Optimized synthetic protocols were applied to construct in a parallel manner in solution diverse libraries of more than 150 coumarin derivatives. To evaluate the fluorophore ensemble, the coumarins were screened for optical properties and several library members with high fluorescence quantum yields were identified. Using solid-phase synthesis, a 256-membered library of quater(3-arylthiophene)s was generated by using both the parallel and the 'mix-and-split' technique. Suzuki type couplings were employed for the stepwise oligomer growth using diverse aryl substituted thiophene boronic esters as building blocks. The rapid screening for electrochemical properties was facilitated by using an automated screening device. The data analysis led to the development of structure-property relationships on which to base future material design. (C) 2002 Elsevier Science B.V. All rights reserved.