Solvation Effects in Organic Chemistry: A Short Historical Overview

Reichardt, Christian

doi:10.1021/acs.joc.1c01979

Cited by 55 publications

(41 citation statements)

References 196 publications

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“…Solvation has long been recognized as a key factor that determines the selectivity of many important chemical reactions. 5 Within the last century, rationales have been developed for the choice of the solvent, in terms of both bulk solvent properties such as polarity and specific solvent interactions such as hydrogen bonding. This provides chemists with an efficient toolbox to fine-tune chemical synthesis.…”

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confidence: 99%

Solvation Effects on Quantum Tunneling Reactions

et al. 2022

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Metrics & MoreArticle Recommendations * sı Supporting Information CONSPECTUS: A decisive factor for obtaining high yields and selectivities in organic synthesis is the choice of the proper solvent. Solvent selection is often guided by the intuitive understanding of transition state−solvent interactions. However, quantummechanical tunneling can significantly contribute to chemical reactions, circumventing the transition state and thus depriving chemists of their intuitive handle on the reaction kinetics. In this Account, we aim to provide rationales for the effects of solvation on tunneling reactions derived from experiments performed in cryogenic matrices.The tunneling reactions analyzed here cover a broad range of prototypical organic transformations that are subject to strong solvation effects. Examples are the hydrogen tunneling probability for the cis−trans isomerization of formic acid which is strongly reduced upon formation of hydrogen-bonded complexes and the [1,2]H-shift in methylhydroxycarbene where a change in product selectivity is predicted upon interaction with hydrogen bond acceptors. Not only hydrogen but also heavy atom tunneling can exhibit strong solvent effects. The direction of the nearly degenerate valence tautomerization between benzene oxide and oxepin was found to reverse upon formation of a halogen or hydrogen bond with ICF 3 or H 2 O. But even in the absence of strong noncovalent interactions such as hydrogen or halogen bonding, solvation can have a decisive effect on tunneling as evidenced by the Cope rearrangement of semibullvalenes via heavy-atom tunneling. Can quantum tunneling be catalyzed? The acceleration of the ring expansion of 1H-bicyclo[3.1.0.]-hexa-3,5-dien-2-one by complexation with Lewis acids provides a proof-of-concept for tunneling catalysis. Two concepts are central for the explanation and prediction of solvation effects on tunneling phenomena: a simple approach expands the Born−Oppenheimer approximation by separating nuclear degrees of freedom into intra-and intermolecular degrees. Intermolecular movements represent the slowest motions within molecular aggregates, thus effectively freezing the position of the solvent in relation to the reactant during the tunneling process. Another useful approach is to treat reactants and products by separate single-well potentials, where the intersection represents the transition state. Thus, stabilization of the reactants via solvation should result in an increase in barrier heights and widths which in turn lowers tunneling probabilities. These simple models can predict trends in tunneling kinetics and provide a rational basis for controlling tunneling reactions via solvation.

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confidence: 99%

Solvation Effects on Quantum Tunneling Reactions

et al. 2022

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“…However, their results showed that the achieved photoresist cannot be deactivated by the inhibition light, and thus subdiffraction manufacturing is an impossibility using such an approach. This might arise due to the “solvation effect” that somewhat alters the molecular energy levels of DETC. , So far, no reported cases have arisen for successful dip-in STED-TPL with subdiffraction resolution for opaque substrates, especially for a silicon wafer, which would be a key factor for any promotion of STED-TPL applications in silicon-based chip manufacturing. Therefore, it is important and quite urgent to invent an effective Rim-P for dip-in STED-TPL.…”

Section: Introductionmentioning

confidence: 99%

Dip-In Photoresist for Photoinhibited Two-Photon Lithography to Realize High-Precision Direct Laser Writing on Wafer

Cao

Qiu

Guan

et al. 2022

ACS Appl. Mater. Interfaces

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For decades, photoinhibited two-photon lithography (PI-TPL) has been continually developed and applied into versatile nanofabrication. However, ultrahigh precision fabrication on wafer by PI-TPL remains challenging, due to the lack of a refractive index (n) matched photoresist (Rim-P) with effective photoinhibition capacity for dip-in mode. In this paper, various Rim-P are developed and then screened for their applications in PI-TPL. In addition, different lithography methods (in terms of oil-mode and dip-in mode) are analyzed by use of optical simulations combined with experiments. Remarkably, one type of Rim-P (n = 1.518) shows effective photoinhibition capacity, which represents an outstanding breakthrough in the field of PI-TPL. In contrast to photoresist with an unsuitable refractive index, optical aberrations are almost completely eliminated in the dip-in mode by using the Rim-P. Consequently, features with a minimum critical dimension as small as 39 nm are successfully achieved on wafer by dip-in PI-TPL, which paves the way for subdiffraction silicon-based chip manufacturing by PI-TPL. Moreover, through a combination of the Rim-P and dip-in mode, the ability to achieve tall and high-precision three-dimensional nanostructures is no longer problematic.

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“…Additionally, other methods rely on surface tension evaluation (1,6), differential scanning calorimetry (7) and accelerated ageing of the CSRP (8). This work shows an innovative approach in the evaluation and in the selection of the bonding agents based on the application of Reichardt's solvent polarity scale (9)(10)(11)(12)(13)(14) and other approaches. In particular, the Reichardt's empirical solvent polarity scale has already shown its effectiveness and usefulness in different fields and applications of chemistry as reported in ref.…”

Section: Introductionmentioning

confidence: 99%

“…In particular, the Reichardt's empirical solvent polarity scale has already shown its effectiveness and usefulness in different fields and applications of chemistry as reported in ref. (9)(10)(11)(12)(13)(14), including ionic liquids, solute-solvent interactions and relative solvatochromism (15), micellar systems ( 16) and so on. The Reichard's solvent polarity scale is based on the use of a dye called ET (30) which is characterized by a charge-separated zwitterionic structure and consists of 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenolate or 2,6-diphenyl-4-(2,4,6-triphenylpyridinio)phenolate (see chemical structure in Scheme 1) (9)(10)(11)(12)(13)(14).…”

Section: Introductionmentioning

confidence: 99%

“…(9)(10)(11)(12)(13)(14), including ionic liquids, solute-solvent interactions and relative solvatochromism (15), micellar systems ( 16) and so on. The Reichard's solvent polarity scale is based on the use of a dye called ET (30) which is characterized by a charge-separated zwitterionic structure and consists of 2,6-diphenyl-4-(2,4,6-triphenyl-1-pyridinio)phenolate or 2,6-diphenyl-4-(2,4,6-triphenylpyridinio)phenolate (see chemical structure in Scheme 1) (9)(10)(11)(12)(13)(14). The ET (30) dye acts as a molecular probe once dissolved in a solvent medium.…”

Section: Introductionmentioning

confidence: 99%

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Application of Reichardt’s Solvent Polarity Scale [E<sub>T</sub>(30)] in the Selection of Bonding Agents for Composite Solid Rocket Propellants

Cataldo¹

2022

Preprint

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Bonding agents (BA) are key compounding ingredients for the correct formulation of composite solid rocket propellants (CSRP). In particular, the addition of BA is essential to achieve suitable mechanical properties of CSRP in terms of adequate tensile strength and elongation at break. It is shown that the polarity of each conventional BA as well as new potential BA can be measured through the Reichardt’s ET(30) polarity scale. Using this criteria it was possible to find a substitute for MAPO (tris-(methylaziridinyl)-phosphine oxide), a conventional BA with the drawback of high toxicity and high reactivity, with TTPT (tris-(pyrrolidine)-phosphine oxide), a completely safe and effective BA. In this work, many other potential BA were evaluated through the Reichardt’s ET(30) polarity scale but only a selection of the potential BA were effectively tested in a standard CSRP. Particular interesting was the evaluation of TTPT vs MAPO showing the ability of the former BA to match the mechanical properties of the latter BA.

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Solvation Effects in Organic Chemistry: A Short Historical Overview

Abstract: This short overview describes the historical development of the physics and chemistry of organic solvents and solutions from the alchemist era until the present time based on some carefully selected examples that can be considered landmarks in the history of solution chemistry.

Cited by 55 publications

References 196 publications

Solvation Effects on Quantum Tunneling Reactions

Solvation Effects on Quantum Tunneling Reactions

Dip-In Photoresist for Photoinhibited Two-Photon Lithography to Realize High-Precision Direct Laser Writing on Wafer

Application of Reichardt’s Solvent Polarity Scale [E<sub>T</sub>(30)] in the Selection of Bonding Agents for Composite Solid Rocket Propellants

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