Aromaticity monitoring during the donor-acceptor coordination of pyrosilicate, pyrophosphate, and pyrosulfate anions to a new designed anion receptor

The quantification of oxyanions is of increasing interest due to its relevance to metabolic processes and various diseases. However, the majority of the existing analytical methods often fall short in terms of on-site applicability, sensitivity, and user-friendliness. The ωB97XD/6-311++g(d,p) density functional method was utilized to study the anion affinities of a new designed organic anion receptor (1H-dipyrrolo[3,2-b:2′,3′-d]pyrrole-1,7(4H)-diyl) bis(boranecarbonitrile) (DPBB) in the gas phase for three oxyanions: pyrosilicate (Si₂O₇)⁶⁻, pyrophosphate (P₂O₇)⁴⁻, and pyrosulfate (S₂O₇)²⁻. The calculated anion affinities obtained were in the range of 348.12–1905.94 kJ mol⁻¹. The induced aromaticity by the studied anions on DPBB structure was monitored via the harmonic oscillator model of electron delocalization (HOMED), BIRD, and SHANNON indices. According to the obtained results, (P₂O₇)⁴⁻@DPBB complex showing 0.94, 0.65, 0.94 (HOMED), 73.35, 46.59, 73.17 (BIRD), and 0.0005033, 0.0026009, 0.0005033 (SHANNON) indices for the left, middle, and right side rings, respectively, demonstrated the highest induced aromaticity.