Judicially Designed Boranil Analogue as Multi-Stimuli Material Displaying Rewritable Behavior

In this paper, we report a systematic investigation related to the solid-state emission and mechanochromic properties by using a series of judicially designed boranil analogues. Interestingly, subtle chemical modification around the boranil and the attached appendage, thereby regulating the steric clash and/or rotational possibility have been found to play a vital role in governing the functional outcome. While smaller and closely connected appendages to the boranil moiety (B-Ph, B-Py, B-TPA, and B-p-Ph) were found to be mechanochromically inactive or insignificant changes were observed, the bulkier appendage with spacer (B-p-TPA and B-p-PY) have shown reversible mechanochromic behavior having spectra shift of 21 and 17 nm, respectively. Furthermore, the potential of B-p-TPA as rewritable material was investigated and reported. In-depth studies related to structural elucidation, solution/solid phase spectroscopy, as well as theoretical calculations; were performed to support the observations.