Commentary on the Models of Electronegativity

Accorinti, Hernán Lucas; Labarca, Martín

doi:10.1021/acs.jchemed.0c00512

Cited by 10 publications

(7 citation statements)

References 17 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The calculated Mayer bond orders (MBO) for the Mo≣Mo and Mo–M bonds provide an unambiguous display of the influence of the identity of the heterometal ion on the 3c/3e – metal–metal bond covalency. The leftmost and center plots in Figure show the calculated Mo≣Mo and Mo–M MBOs, respectively, plotted versus the heterometal electronegativity χ, which is directly proportional to Z eff . , The calculated Mo–Mo MBO values between 2 and 3 indicate a significant weakening from a true Mo≣Mo quadruple bond, and Mo–M MBO values < 1 but non-zero indicate partial σ bonding. Most importantly, we observe a concomitant decrease in the Mo≣Mo MBO and increase in the Mo 2 –M MBO with increasing χ of the heterometal ion.…”

Section: Resultsmentioning

confidence: 99%

Metal–Metal BondUmpolungin Heterometallic Extended Metal Atom Chains

et al. 2022

View full text Add to dashboard Cite

Understanding the fundamental properties governing metal− metal interactions is crucial to understanding the electronic structure and thereby applications of multimetallic systems in catalysis, material science, and magnetism. One such property that is relatively underexplored within multimetallic systems is metal−metal bond polarity, parameterized by the electronegativities (χ) of the metal atoms involved in the bond. In heterobimetallic systems, metal−metal bond polarity is a function of the donor−acceptor (Δχ) interactions of the two bonded metal atoms, with electropositive early transition metals acting as electron acceptors and electronegative late transition metals acting as electron donors. We show in this work, through the preparation and systematic study of a series of Mo 2 M(dpa) 4 (OTf) 2 (M = Cr, Mn, Fe, Co, and Ni; dpa = 2,2′dipyridylamide; OTf = trifluoromethanesulfonate) heterometallic extended metal atom chain (HEMAC) complexes that this expected trend in χ can be reversed. Physical characterization via single-crystal X-ray diffraction, magnetometry, and spectroscopic methods as well as electronic structure calculations supports the presence of a σ symmetry 3c/3e − bond that is delocalized across the entire metal-atom chain and forms the basis of the heterometallic Mo 2 −M interaction. The delocalized 3c/3e − interaction is discussed within the context of the analogous 3c/3e − π bonding in the vinoxy radical, CH 2 CHO. The vinoxy comparison establishes three predictions for the σ symmetry 3c/3e − bond in HEMACS: (1) an umpolung effect that causes the Mo−M interactions to become more covalent as Δχ increases, (2) distortion of the σ bonding and non-bonding orbitals to emphasize Mo−M bonding and de-emphasize Mo−Mo bonding, and (3) an increase in Mo spin population with increasing Mo−M covalency. In agreement with these predictions, we find that the Mo 2 •••M covalency increases with increasing Δχ of the Mo and M atoms (Δχ Mo−M increases as M = Cr < Mn < Fe < Co < Ni), an umpolung of the trend predicted in the absence of σ delocalization. We attribute the observed trend in covalency to the decreased energic differential (ΔE) between the heterometal d z 2 orbital and the σ bonding molecular orbital of the Mo 2 quadruple bond, which serves as an energetically stable, "ligand"-like electron-pair donor to the heterometal ion acceptor. As M is changed from Cr to Ni, the σ bonding and nonbonding orbitals do indeed distort as anticipated, and the spin population of the outer Mo group is increased by at least a factor of 2. These findings provide a predictive framework for multimetallic compounds and advance the current understanding of the electronic structures of molecular heteromultimetallic systems, which can be extrapolated to applications in the context of mixed-metal surface catalysis and multimetallic proteins.

show abstract

Section: Resultsmentioning

confidence: 99%

Metal–Metal BondUmpolungin Heterometallic Extended Metal Atom Chains

et al. 2022

View full text Add to dashboard Cite

show abstract

“…Electronegativity (EN) ,− is an extremely valuable concept in chemistry (the familiar Pauling X values are used) as a logical construct in partitioning charge in a chemical bond. Essentially defined as the ability of an atom or group of atoms to attract electrons toward itself within a bond, , it serves as a basis for chemical intuition to the budding chemist.…”

Section: The Tutorialmentioning

confidence: 99%

Elemental Aspects of Transition Metals Pertinent to Organometallic Chemistry: Properties, Periodicity, Curiosities, and Related Main Group Issues

Wolczanski

2024

Organometallics

View full text Add to dashboard Cite

This tutorial on transition metal chemistry�sans the lanthanides and actinides�is intended as preliminary information for a high-level undergraduate (UG) inorganic, organometallics, or a comparable first-year graduate (G) course. It features ionization energies (IEs) and comparative nd and (n+1)s orbital energies, electron affinities (EAs), electronegativities (ENs), and covalent radii (c r ). Redox properties of appropriate aquo complexes (ΔE°r ed = E°(red)) are also included due to their impact on critical properties and reactivity, as are pertinent aspects of the main group elements.

show abstract

“…Several scales have been built for EN with different modifications. [6][7][8][9] In 1978, Parr et al explained that electronegativity is the negative of chemical potential. [10] Recently, an approach to understanding a close qualitative relationship between the concept of electrophilicity and Pauling's and Mulliken's electronegativity has also been described within the context of density functional theory.…”

Section: Introductionmentioning

confidence: 99%

“…It is a well‐known indisputable truth in chemistry that different electronegativity values for an atom may be obtained depending on its valence state. Several scales have been built for EN with different modifications [6–9] . In 1978, Parr et al.…”

Section: Introductionmentioning

confidence: 99%

An FSGO based Electronegativity Scale invoking the Electrophilicity Index

et al. 2022

Self Cite

View full text Add to dashboard Cite

Electronegativity is an important chemical construct that plays a pivotal role to explain several chemical, biochemical and physicochemical phenomena. The study of this periodic descriptor is still considered an active domain of research, and a number of scientists are involved to propose different scales of electronegativity based on experimental findings and theoretical concepts. In this study, we have proposed a model to compute atomic electronegativity values of 103 elements based on the Floating Spherical Gaussian Orbital approach invoking the atomic electrophilicity index as a descriptor. The computed electronegativity scale observes the periodic trend and justifies many chemical phenomena. Molecular electronegativity values have also been computed using the computed atomic electronegativity data and utilized to justify the Electronegativity Equalization Principle. In order to validate our proposed model, internuclear bond distances for some molecules have been deduced in terms of our computed atomic electronegativity data. A strong correlation with experimental counterparts proves the efficacy of our proposed model.

show abstract

Commentary on the Models of Electronegativity

Cited by 10 publications

References 17 publications

Metal–Metal BondUmpolungin Heterometallic Extended Metal Atom Chains

Metal–Metal BondUmpolungin Heterometallic Extended Metal Atom Chains

Elemental Aspects of Transition Metals Pertinent to Organometallic Chemistry: Properties, Periodicity, Curiosities, and Related Main Group Issues

An FSGO based Electronegativity Scale invoking the Electrophilicity Index

Contact Info

Product

Resources

About