Strong donor-acceptor chromophores for advanced materials applications

ORGN 41

François Diederich, diederich@org.chem.ethz.ch, Laboratorium für Organische Chemie, ETH Zürich, Hoenggerberg, HCI, Zürich, 8093, Switzerland
Cyanoethynylethenes (CEEs) and 1,1,4,4-tetracyanobutadienes (TCBDs) are introduced as new classes of powerful organic electron acceptors. Upon peripheral substitution with strong electron donors, such as N,N-dialkylanilino moieties, a variety of interesting advanced materials properties are generated. They include expectional electron uptake and storage capacity, electronic transitions extending into the near infrared, strong nonlinear optical properties, and efficient two-photon absorption cross-sections. The new chromophores are obtained by short, atom-economic synthesis and feature high thermal and environmental stabilities. Multiple 1,1,4,4-tetracyanobutadiene moieties are introduced into the branches of dendritic phenylacetylenes, resulting in chromophores that undergo up to twenty and more one-electron reductions in a narrow potential range between ca. –0.5 and –1.5 V versus ferrocene. Donor-acceptor molecules with a strong dipole moment show antiparallel stacking in the crystalline state, and this order is also maintained in thin films obtained by vapor phase deposition. First device applications are introduced.