Design and Synthesis of a New Facile Ligand in a Dual Role: Mechanically Elastic Crystal and Selective Mitochondria Target

Herein we report the unique properties of a new Schiff base ligand (H2L), synthesized and characterized by Fourier transform infrared spectroscopy, 1H and 13C NMR, and liquid chromatography-mass spectrometry. Further, it has been authenticated by a single-crystal X-ray diffraction (XRD) study. In a solid state, H2L can bend upon an externally applied stress and rapidly reverts to its original shape upon relaxation, revealing highly flexible and elastic bending properties. Powder XRD and Raman studies indicate high retention of crystallinity and chemical bonds even under stress (bend) conditions, which implies that the bending in H2L is due to the intermolecular hydrogen bonding and C–H···π interactions. Moreover, in the solution state, H2L is fluorescent, non-cytotoxic, and selectively labels mitochondria of live cells and tumor spheroids.