Jena Subhrakant, Tulsiyan Kiran Devi, Rana Abhijit, Choudhury Shubhranshu S, Biswal Himansu S
School of Chemical Sciences, National Institute of Science Education and Research (NISER), PO-Bhimpur-Padanpur, Via-Jatni, District-Khurda, PIN-752050, Bhubaneswar, INDIA.
Homi Bhaba National Institute, Training School Complex, Anushakti Nagar, Mumbai, 400094, INDIA.
Chemphyschem. 2020 Aug 18;21(16):1826-1835. doi: 10.1002/cphc.202000386. Epub 2020 Jul 17.
The conceptual development of aromaticity is essential to rationalize and understand the structure and behavior of aromatic heterocycles. This work addresses for the first time, the interconnection between aromaticity and sulfur/selenium centered hydrogen bonds (S/SeCHBs) involved in representative heterocycle models of canonical nucleobases (2-Pyridone; 2PY) and its sulfur (2-Thiopyridone; 2TPY) and selenium (2-Selenopyridone; 2SePY) analogs. The nucleus-independent chemical shift (NICS) and gauge induced magnetic current density (GIMIC) values suggested significant reduction of aromaticity upon replacement of exocyclic carbonyl oxygen with sulfur and selenium. However, we observed two-fold (57 %) and three-fold (80 %) enhancement in the aromaticity for 2TPY dimer, and 2SePY dimer, respectively which are connected through S/SeCHBs. Aromaticity enhancement was also noticed in 1 : 1 H-bonded complexes (heterodimers), micro hydrated clusters and for bulk hydration. It is expected that exocyclic S and Se incorporation into heterocycles without compromising aromatic loss would definitely reinforce to design new supramolecular building blocks via S/SeCH-bonded complexes.
