A theoretical study of hemiacetal formation from the reaction of methanol with derivatives of CX<sub>3</sub>CHO (X = H, F, Cl, Br and I)

Azofra, Luis Miguel; Alkorta, Ibón; Elguero, José

doi:10.1002/poc.3017

Cited by 8 publications

(11 citation statements)

References 61 publications

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“…The W 1 and W 2 quantities present similar values in percentage for all cases; however, mechanism (b) has a slightly higher activation energy due to electronic reordering (W 2 ): 24 versus 17% and 19% in (a) and (c), respectively, being the part associated with the geometric rearrangement (W 1 ) always higher than W 2 in all cases. This catalytic effect has also been observed in the mutarotation process of sugars [56,57] and in the reaction of formation of hemiacetals [58]. The reaction energies are always negative, that is, associated values of spontaneous processes, being smaller as more explicit H 2 O molecules are introduced.…”

Section: Reactant Propertiesmentioning

confidence: 61%

Ab initio study in the hydration process of metaphosphoric acid: the importance of the pnictogen interactions

2015

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known that the inorganic phosphorus oxoacids are one of the many systems which experiment such reaction (and its reverse one, dehydration) when transformed in the different oxoacid species. In the present paper, our efforts were concentrated on the study of the hydration reaction of metaphosphoric acid (HPO 3), a water-or moisture-absorbing reagent that, upon water absorption, evolves to orthophosphoric, also known as phosphoric acid (H 3 PO 4). The dehydration of H 3 PO 4 to HPO 3 in aqueous solution has been measured experimentally as 134 ± 8 kJ mol −1 [2]. Also, dehydration of the protonated phosphoric acid has been studied theoretically, and the proton affinity of HPO 3 has been calculated to be 712 kJ mol −1 at the G2(MP2) computational level [3]. In addition, hydrolysis of different phosphorus derivatives as phosphate anion [4], phosphate monoesters [5] and phosphate diesters and triesters [6] has been studied computationally. The protonation and dehydration of the protonated form of orthophosphoric acid have been studied experimentally and theoretically [3]. Finally, in 2002, Davies et al. estimated the pK a values of pentaoxyphosphoranes based on single bonds lengths [7], and more recently, the study of pnictogen (or pnicogen)-bonded complexes of the related PO 2 X (X = F, Cl and Br) compounds with electron donors reveals the great power of P as electron acceptor [8, 9]. In the present work, we will analyze the reaction mechanism of the hydration of metaphosphoric acid, focusing on the key role the number of explicit water molecules play as reactants or bridges in the assistance of the proton transfer, as well as the importance of the pnictogen interactions [1, 8-23], which are noncovalent forces [24] of electrostatic nature which favor bounded connections between negative entities with positive holes [25] (in their σ or π nature) located on the pnictogen atoms (N, P, As and Sb).

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Section: Reactant Propertiesmentioning

confidence: 61%

Ab initio study in the hydration process of metaphosphoric acid: the importance of the pnictogen interactions

2015

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“…The solid-state structural features of the hemiacetal form have been thoroughly probedb ys ingle-crystal X-ray diffractions tudies, and their solution-phase stability has been confirmed by detailed NMR and ESI-MSs tudies in av ariety of solvents. Compounds 1 and 2 are potential precursors and ideal buildingb locks for the eventual preparation of super structures such as MOFs andC OFs,f or which ap roof of concept has been already presented here through their reactions with aryl amines,y ielding corresponding tetra Schiff base decorated cubanes (5)(6)(7).…”

Section: Discussionmentioning

confidence: 99%

“…Similarly,h emiketals are formed when the carbonyl group is from ak etone functionality.A ne x-Scheme1.Reactionofa ldehyde with alcohol to produce hemiacetal and acetal. tensivet heoretical account on the formation and stabilization of hemiacetals in the presenceo fd ifferent alcohols has been recently reported by Azofra et al [5] Apart from hydrogen-bonding interactions, metal ions play an important role in stabilizing hemiacetal systems. Lehn and co-workersr eported the stabilization and dynamic nature of hemiacetalsb ased on ortho-derivatives of pyridyl aldehydes and various alcohols.…”

Section: Introductionmentioning

confidence: 95%

A Solvent Switch for the Stabilization of Multiple Hemiacetals on an Inorganic Platform: Role of Supramolecular Interactions

Kalita

Gupta

Murugavel

2016

Chemistry A European J

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Reaction of Zn(OAc)2 ⋅2 H2 O with 2,6-diisopropylphenyl phosphate (dippH2 ) in the presence of pyridine-4-carboxaldehyde (Py-4-CHO) in methanol resulted in the isolation of a tetrameric zinc phosphate cluster [Zn(dipp)(Py-4-CH(OH)(OMe))]4 ⋅4 MeOH (1) with four hemiacetal moieties stabilized on the double-4-ring inorganic cubane cluster. The change of solvent from methanol to acetonitrile leads to the formation of [Zn(dipp)(Py-4-CHO)]4 (2), in which the coordinated Py-4-CHO retains its aldehydic form. Dissolution of 1 in CD3 CN readily converts it to the aldehydic form and yields 2. Similarly 2, which exists in the aldehyde form in CD3 CN, readily converts to the hemiacetal form in CD3 OD/CH3 OH. Compound 1 is an unprecedented example in which four hemiacetals have been stabilized on a single molecule in the solid state retaining its stability in solution as revealed by its (1) H NMR spectrum in CD3 OD. The solution stability of 1 and 2 has further been confirmed by ESI-MS studies. To generalize the stabilization of multiple hemiacetals on a single double-four-ring platform, pyridine-2-carboxaldehyde (Py-2-CHO) was used as the auxiliary ligand in the reaction between zinc acetate and dippH2 , leading to isolation of [Zn(dipp)(Py-2-CH(OH)(OMe))]4 (3). Understandably, recrystallization of 3 from acetonitrile yields the parent aldehydic form, [Zn(dipp)(Py-2-CHO)]4 (4). Single-crystal X-ray diffraction studies reveal that supramolecular bonding, aided by hydrogen-bonding interactions involving the hemiacetal functionalities (C-OH, C-OMe, and C-H), are responsible for the observed stabilization. The hemiacetal/aldehyde groups in 1 and 2 readily react with p-toluidine, 2,6-dimethylaniline, and 4-bromoaniline to yield the corresponding tetra-Schiff base ligands, [Zn(dipp)(L)]4 (L=4-methyl-N-(pyridin-4-ylmethylidene)aniline (5), 2,6-dimethyl-N-(pyridin-4-ylmethylene)-aniline (6), and 4-bromo-N-(pyridin-4-ylmethylene)aniline (7)). Isolation of 5-7 opens up further possibilities of using 1 and 2 as new supramolecular synthons and ligands.

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“…This reaction is characterized by two chemical events that occur simultaneously: (1) the oxygen atom of the hydroxyl group of methanol attacks the carbonyl carbon of the aldehyde and (2) the hydrogen atom of the hydroxyl group is donated to the carbonyl oxygen forming the final hemiacetal structure. This class of reactions has been studied extensively in the literature; − a computational study specifically investigating the substituent effects comparing acetaldehyde (X = H) with fluoral (X = F), chloral (X = Cl), and bromal (X = Br) group was carried out by Azofra et al Their results showed the smallest energy barrier for fluoral, followed by chloral, bromal, and then acetaldehyde group. They rationalize this by establishing a linear correlation between the relative nucleophilicity of the carbonyl carbon atom and the activation energy barrier.…”

Section: Introductionmentioning

confidence: 99%

Symmetry-Adapted Perturbation Theory Decomposition of the Reaction Force: Insights into Substituent Effects Involved in Hemiacetal Formation Mechanisms

Derricotte

2019

J. Phys. Chem. A

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The decomposition of the reaction force based on symmetry-adapted perturbation theory (SAPT) has been proposed. This approach was used to investigate the substituent effects along the reaction coordinate pathway for the hemiacetal formation mechanism between methanol and substituted aldehydes of the form CX3CHO (X = H, F, Cl, and Br), providing a quantitative evaluation of the reaction-driving and reaction-retarding force components. Our results highlight the importance of more favorable electrostatic and induction effects in the reactions involving halogenated aldehydes that leads to lower activation energy barriers. These substituent effects are further elucidated by applying the functional-group partition of symmetry-adapted perturbation theory (F-SAPT). The results show that the reaction is largely driven by favorable direct noncovalent interactions between the CX3 group on the aldehyde and the OH group on methanol.

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A theoretical study of hemiacetal formation from the reaction of methanol with derivatives of CX₃CHO (X = H, F, Cl, Br and I)

Cited by 8 publications

References 61 publications

Ab initio study in the hydration process of metaphosphoric acid: the importance of the pnictogen interactions

Ab initio study in the hydration process of metaphosphoric acid: the importance of the pnictogen interactions

A Solvent Switch for the Stabilization of Multiple Hemiacetals on an Inorganic Platform: Role of Supramolecular Interactions

Symmetry-Adapted Perturbation Theory Decomposition of the Reaction Force: Insights into Substituent Effects Involved in Hemiacetal Formation Mechanisms

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A theoretical study of hemiacetal formation from the reaction of methanol with derivatives of CX3CHO (X = H, F, Cl, Br and I)

Cited by 8 publications

References 61 publications

Ab initio study in the hydration process of metaphosphoric acid: the importance of the pnictogen interactions

Ab initio study in the hydration process of metaphosphoric acid: the importance of the pnictogen interactions

A Solvent Switch for the Stabilization of Multiple Hemiacetals on an Inorganic Platform: Role of Supramolecular Interactions

Symmetry-Adapted Perturbation Theory Decomposition of the Reaction Force: Insights into Substituent Effects Involved in Hemiacetal Formation Mechanisms

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A theoretical study of hemiacetal formation from the reaction of methanol with derivatives of CX₃CHO (X = H, F, Cl, Br and I)