Elongation of the molecular probe DDNP with phenylethynylidene or phenyldiazenylidene spacers

In this work, we report the synthesis, X-ray structures, and optical properties of two DDNP analogs containing an unsaturated spacer inserted between the donor N,N-dimethylamino group and the naphthalene ring. The new compounds have longer distances between the donor and acceptor groups and are intended to serve as molecular probes for the assessment of spatial and polarity requirements for binding to protein aggregates found in the central nervous system (CNS) of patients with neurodegenerative diseases.