Synthesis and exploring the excited-state PES of photochromic hydrogen bond-assembled [2]rotaxane based on 1,3-Diazabicyclo-[3.1.0]hex-3-enes

• Published in: Research on chemical intermediates Vol. 47; no. 6; pp. 2557 - 2572
• Main Authors: Fasihi-Ramandi, Mostafa, Mahmoodi, Nosrat O., Ghavidast, Atefeh, Shirini, Farhad, Taherpour Nahzomi, Hossein
• Format: Journal Article
• Language: English
• Published: Dordrecht Springer Netherlands 01.06.2021; Springer Nature B.V
• Subjects: Absorption spectra; Binding sites; Catalysis; Chemistry; Chemistry and Materials Science; Hydrogen bonds; Inorganic Chemistry; Molecular machines; Nitrogen dioxide; NMR; Nuclear magnetic resonance; Photochromism; Physical Chemistry; Rotaxanes; Switches; Synthesis; Ultraviolet radiation; Supramolecular; Photochromism; Hydrogen bonding; 1,3-Diazabicyclo[3.1.0]hex-3-ene; Rotaxane
• ISSN: 0922-6168; 1568-5675
• DOI: 10.1007/s11164-021-04425-7

Here, the synthesis of photochromic hydrogen bond-assembled [2]rotaxanes using bis-fumarate as a thread for the first time is reported. In fact, photochromic 1,3-diazabicyclo[3.1.0]hex-3-ene moieties were used as stoppers and two-atom spacers managed good binding sites for the tetralactam macrocycles in clipping reactions. Moreover, the yields of photochromic [2]rotaxanes highly depended on the NO 2 substituent stoppers. While the thread with a para –NO 2 substituent as stopper units was shown to be an excellent template for the synthesis of photochromic [2]rotaxanes. The structures of the [2]rotaxanes are established clearly in solution by chemical shifts of the 1 H 13 C NMR signals and UV–Vis spectra. A pronounced bathochromic shift was occurred in the excitation wavelength of photochoromic [2]rotaxanes compared with the absorption band of photochromic threads. Therefore, these organizations can be applied in light-driven molecular switches and motors. The reversible transformation of trans and cis geometric photoisomers under UV radiation was identified. In other efforts, the possibility of the process of trans to cis interconversion of the fumarate linker under UV irradiation has been examined computationally and it has appeared that it may cause the transverse of the bis-fumarate linker inside the tetralactam macrocycle to some extent.