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A density functional theory study on the superacidity of sulfuric, fluorosulfuric, and triflic acid derivatives with two cyclopentadiene rings: ion pairs formation in the gas phase
Author(s) -
Valadbeigi Younes,
Vianello Robert
Publication year - 2019
Publication title -
journal of physical organic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.325
H-Index - 66
eISSN - 1099-1395
pISSN - 0894-3230
DOI - 10.1002/poc.3995
Subject(s) - chemistry , triflic acid , cyclopentadiene , protonation , deprotonation , moiety , density functional theory , delocalized electron , tautomer , medicinal chemistry , basis set , sulfuric acid , electronegativity , ion , gas phase , aromaticity , computational chemistry , stereochemistry , molecule , inorganic chemistry , organic chemistry , catalysis
The gas phase acidity of organosulfuric acid derivatives with two cyclopentadiene rings replacing the doubly‐bonded oxygen atoms was computationally assessed using the B3LYP DFT functional and 6–311++G(d,p) basis set. Introduced five‐membered rings increased the acidity through the delocalization of the excess negative charge in conjugates bases and by providing positions to accommodate electron withdrawing substituents such as F and CN. The calculated enthalpies of deprotonation (∆ H acid ) of polycyanated systems were as low as 227.8 to 263.2 kcal mol –1 indicating exceptional superacidity. Substitution of one OH moiety by F or CF 3 groups offered additional acidifying effect by preventing prototropic tautomerism in the neutral acids that acts towards lowering the acidity. The designed systems spontaneously protonated H 2 O and NH 3 in the gas phase and produced stable ion pair clusters.