Premium
An Objective Alternative to IUPAC's Approach To Assign Oxidation States
Author(s) -
Postils Verònica,
DelgadoAlonso Carlos,
Luis Josep M.,
Salvador Pedro
Publication year - 2018
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201802745
Subject(s) - chemical nomenclature , electronegativity , context (archaeology) , oxidation state , aromaticity , computer science , state (computer science) , stability (learning theory) , ionic bonding , chemistry , computational chemistry , term (time) , algorithm , physics , molecule , quantum mechanics , organic chemistry , ion , machine learning , paleontology , biology , catalysis
The IUPAC has recently clarified the term oxidation state (OS), and provided algorithms for its determination based on the ionic approximation (IA) of the bonds supported by atomic electronegativities (EN). Unfortunately, there are a number of exceptions and ambiguities in IUPAC's algorithms when it comes to practical applications. Our comprehensive study reveals the critical role of the chemical environment on establishing the OS, which cannot always be properly predicted using fix atomic EN values. By identifying what we define here as subsystems of enhanced stability within the molecular system, the OS can be safely assigned in many cases without invoking exceptions. New insights about the effect of local aromaticity upon OS are revealed. Moreover, we prove that there are intrinsic limitations of the IA that cannot be overcome. In this context, the effective oxidation state (EOS) analysis arises as a robust and general scheme to derive an OS without any external guidance.