A DFT study on trapping of nitric oxide by 1,3,2,5-diazadiborinine, a frustrated Lewis pair

Department of Chemistry and Center for Theoretical Studies, Indian Institute of Technology Kharagpur, Kharagpur-721 302, West Bengal, India E-mail: pkc@chem.iitkgp.ac.in Manuscript received 23 July 2018, accepted 10 August 2018 Nitric oxide (NO) can be trapped by a “frustrated Lewis pair” (FLP) containing two ambiphilic boron centers as shown through the results from a DFT based computation. There are three possible ways in which NO can bind to the FLP. Among the three possible paths only two are thermodynamically favorable with respect to enthalpy as well as free energy changes. However, all the products are kinetically favorable as explained by lower values of free energy barriers (less than 15.0 kcal/mol). The favorable orbital interactions between the HOMO of FLP and LUMO of NO play a crucial role in giving these three possible products as revealed by molecular orbital analysis, which is further confirmed by NBO analysis, where the net gain of elec­tron density is shown to take place on the NO segment. On the other hand, the WBI values along with the AIM analysis re­veal that all the newly formed B-N and B-O bonds are partially covalent in nature