339:. Basic bonding and steric effects are at times insufficient to explain many structures, properties, and reactivity. Thus, steric effects are often contrasted and complemented by electronic effects, implying the influence of effects such as induction, conjunction, orbital symmetry, electrostatic interactions, and spin state. There are more esoteric electronic effects but these are among the most important when considering chemical structure and reactivity.
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is important when dealing with orbitals that contain directional components like p and d. An example of such an effect is square planar low-spin d transition metal complexes. These complexes exist as square planar complexes due to the directionality of the metal center's d orbitals despite fewer
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include both attractive and repulsive forces associated with the build-up of charge in a molecule. Electrostatic interactions are generally too weak to be considered traditional bonds or are prevented from forming a traditional bond, possibly by a steric effect. A bond is usually defined as two
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as well as high-spin and low-spin configuration. For example, a low-spin d transition metal complex is usually square planar substitutionally inert with no unpaired electrons. In contrast, a high-spin d transition metal complex is usually octahedral, substitutionally labile, with two unpaired
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borders on being an actual "bond" and an electrostatic interaction. While an attractive electrostatic interaction is considered a "bond" if it gets too strong, a repulsive electrostatic interaction is always an electrostatic effect regardless of strength. An example of a repulsive effect is a
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electronic ground state will undergo a geometrical distortion that removes that degeneracy. This has the effect of lowering the overall energy. The Jahn–Teller distortion is especially common in certain transition metal complexes; for example, copper(II) complexes with 9 d electrons.
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in quantum mechanics. This is the major reasons there is a very high reaction barrier for the extremely thermodynamically favorable reaction of singlet organic molecules with triplet oxygen. This kinetic barrier prevents life from bursting into flames at room temperature.
420:
Ananikov, V. P.; Musaev, D. G.; Morokuma, K. (2007). "Critical Effect of
Phosphane Ligands on the Mechanism of Carbon–Carbon Bond Formation Involving Palladium(II) Complexes: A Theoretical Investigation of Reductive Elimination from Square-Planar and T-Shaped Species".
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is the influence that a ligand in a square or octahedral complex has on the bond to the ligand trans to it. It is caused by electronic effects, and manifests itself as the lengthening of the trans bonds and as an effect on the overall energy of the complex.
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anion, the presence of the electron-withdrawing substituent has a stabilizing effect. Similarly, an electron-releasing group (ERG) or electron-donating group (EDG) releases electrons into a reaction center and as such stabilizes electron deficient
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is a redistribution of electron density similar to induction but transmitted through interconnected pi-bonds. Conjugation is not only affected by electronegativity of the connected atoms but also affected by the position of
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that make up the majority of life have no unpaired electrons even when charged. Such molecules are called singlet molecules, since their paired electrons have only one spin state. In contrast,
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Special computational procedure was developed to separate steric and electronic effects of an arbitrary group in the molecule and to reveal their influence on structure and reactivity.
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In the context of electronic redistribution, an electron-withdrawing group (EWG) draws electrons away from a reaction center. When this center is an electron rich
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with respect to the pi-system. Electronic effects can be transmitted throughout a pi-system allowing their influence to extend further than induction.
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is sometimes used to refer to electronic effects, but also may have the more narrow definition of effects resulting from non-conjugated substituents.
162:. Resonance electron-releasing groups are classed as activating, while Resonance electron-withdrawing groups are classed as deactivating.
335:, and other forms of bonding. This bonding supplies a basic molecular skeleton that is modified by repulsive forces generally considered
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This article is about the influences on the chemical structure, reactivity, or properties of a molecule. For electric audio effects, see
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steric congestion in a tetrahedral geometric structure. This is simple one example of many varied examples, including aspects of
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of the atoms involved. The inductive effect drops across every sigma bond involved limiting its effect to only a few bonds.
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The structure, properties, and reactivity of a molecule are dependent on straightforward bonding interactions including
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that increases the stability of the system. Hyperconjugation can be used to explain phenomena such as the
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at it simplest describes the number of unpaired electrons in a molecule. Most molecules including the
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285:. To understand the reactivity of transition metals, it is essential to understand the concept of
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G. L. Miessler and D. A. Tarr “Inorganic
Chemistry” 3rd Ed, Pearson/Prentice Hall publisher,
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Influences on a molecule's properties not due to bonds or geometry
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under certain situations. Any non-linear molecule with a
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under ambient conditions has two unpaired electrons.
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or an antibonding sigma orbital to give an extended
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226:atoms approaching closer than the sum of their
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281:Electronic spin states are more complex for
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239:interactions of atoms that hold like
235:molecule contorting to minimize the
148:electrophilic aromatic substitution
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152:nucleophilic aromatic substitution
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296:is the geometrical distortion of
154:, substituents are divided into
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319:Comparison with steric effects
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112:structure according to the
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455:Physical organic chemistry
223:Electrostatic interactions
166:Non-redistributive effects
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403:John McMurry 2nd edition
104:is the redistribution of
287:d electron configuration
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71:stereoelectronic effect
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108:through a traditional
97:Redistributive effects
247:Electronic spin state
217:Diels-Alder reaction
213:pericyclic reactions
423:Eur. J. Inorg. Chem
160:deactivating groups
125:electron lone pairs
294:Jahn–Teller effect
228:Van der Waal radii
18:Electronic effects
429:(34): 5390–5399.
401:Organic chemistry
283:transition metals
194:molecular orbital
156:activating groups
114:electronegativity
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86:polar effect
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32:Effects unit
329:ionic bonds
290:electrons.
187:antibonding
120:Conjugation
69:, the term
387:2024-02-06
346:References
305:degenerate
298:non-linear
179:sigma bond
51:properties
47:reactivity
301:molecules
237:coulombic
190:Ď€ orbital
183:p-orbital
175:electrons
132:carbanion
102:Induction
84:The term
43:structure
449:Category
267:Dioxygen
263:dioxygen
251:proteins
136:alkoxide
75:geometry
55:molecule
383:. IUPAC
241:charges
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259:lipids
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134:or an
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