A computational study of base-catalyzed reactions of cyclic 1,2-diones: cyclobutane-1,2-dione

Sultana, Nargis; Fabian, Walter M. F.

doi:10.3762/bjoc.9.64

Cited by 9 publications

(4 citation statements)

References 42 publications

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“…Our results only show the bond breaking of the pyrazole to the ethane backbone, but under all conditions used, we do not observe two pyrazole on one of the ethane carbon. 37 A point raised from this study is the difference in the ligands present in the structures of Cu 6 and Cu 16 which are prepared from Cu-nitrate and Cu-BF 4 , respectively, compared to that of Cu 8 obtained from Cuacetate. In the first two compounds, the central ligand is et with the coordinating Cu 6 cores looking identical, but for the latter, the inner ligands are the esters of et with the corresponding alkyl groups of the alcohol solvents.…”

Section: ■ Results and Discussionmentioning

confidence: 92%

“…However, we cannot crystallographically confirm the rearrangement, that is, the migration of the pyrazole from one ethane carbon to the other. Our results only show the bond breaking of the pyrazole to the ethane backbone, but under all conditions used, we do not observe two pyrazole on one of the ethane carbon . A point raised from this study is the difference in the ligands present in the structures of Cu 6 and Cu 16 which are prepared from Cu-nitrate and Cu-BF 4 , respectively, compared to that of Cu 8 obtained from Cu-acetate.…”

Section: Resultsmentioning

confidence: 99%

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Copper(II)-Assisted Ligand Fragmentation Leading to Three Families of Metallamacrocycle

Jagodič

et al. 2020

Inorg. Chem.

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We present an unprecedented copper(II)-assisted organic ligand fragmentation process under basic conditions leading to several ligands within three families of metallamacrocycle, Cu 6 , Cu 8 , and Cu 16 . The sequential multistep reaction include (i) the deprotonation of the starting alcohol, 1,2-bis(3,5-dimethyl-pyrazol-1-yl)ethane-1,2-diol (H 2 bdped) to its diolate bdped followed by complexation through six bonds (μ 6 ) to three copper atoms in a ring, (ii) the breaking of the ethane-pyrazole C−N bonds by the different solvent alcohols to form 1-(3,5-dimethyl-pyrazol-1-yl)-2-methoxyethane-1,2-diolate (dpmed) or 2-(3,5-dimethyl-pyrazol-1-yl)-2-hydroxyacetate (dpet), while retaining coordination to the copper centers and (iii) the final step to ethane-1,1,2,2-tetraolate, C 2 H 2 O 4 4− (et). Importantly, the latter product, only observed on two previous occasions, occupies the core of Cu 6 and Cu 16 through exceptionally eight coordination bonds (μ 8 ). Its alkyl esters, 2-alkoxyethane-1,1,2triolate (met, eet, and pet), also occupy the central parts of Cu 8 but forming six bonds (μ 6 ) instead. The other product, 3,5-dimethylpyrazolate (dp), acts as peripheral bridges (μ 2 ) but it is not involved in coordination if the starting salt is copper acetate, this may be a consequence of acetate being a better μ 2 -chelating ligand. In the presence of an oxidizing agent, K 2 Cr 2 O 7 , C 2 H 2 O 4 4− (et) is oxidized to oxalate, C 2 O 4 2− (ox). Thus, an additional μ 3hydroxide and μ 4 -oxalate in Cu 16 widen the complexity of the structures, not to mention the range of coordination geometries of the copper centers, though in the present cases they can be classed in only two types: distorted square-planar and square-pyramid. In addition to single-crystal crystallography, the results from different techniques such as IR, ESI-MS, optical UV−vis, and SQUID magnetometry help in the characterization of these rare metallamacrocycles made from unexpected and in situ generated ligands. We believe the results of the organic transformations are highly relevant to von Liebig's benzil−benzilic acid rearrangement.

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Section: ■ Results and Discussionmentioning

confidence: 92%

Section: Resultsmentioning

confidence: 99%

Copper(II)-Assisted Ligand Fragmentation Leading to Three Families of Metallamacrocycle

Jagodič

et al. 2020

Inorg. Chem.

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“…The base-catalyzed reaction of cyclobutane-1,2-dione was recently investigated by Sultana and Fabian with a variety of ab initio and density functional (M06-2Â) methods. 77 The authors examined three reaction pathways, whose products are 1-hydroxycyclopropane-1-carboxylate, a-oxobutanoate and g-oxobutanoate, respectively. Based on the activation and reaction energies computed with LPNO-CEPA, it was concluded that the formation of 1-hydroxycyclopropane-1-carboxylate via the benzilic acid rearrangement is the only feasible reaction pathway, in agreement with previous experimental observations.…”

Section: Organic Chemistrymentioning

confidence: 99%

“…Based on the activation and reaction energies computed with LPNO-CEPA, it was concluded that the formation of 1-hydroxycyclopropane-1-carboxylate via the benzilic acid rearrangement is the only feasible reaction pathway, in agreement with previous experimental observations. 77 Finally, in the validation of the DLPNO-CCSD(T) method, a benchmark dataset consisting of 51 reaction energies, for which accurate results have been recently published by Friedrich and Ha ¨nchen, 78 was considered. The database covers a large set of chemically interesting processes (e.g.…”

Section: Organic Chemistrymentioning

confidence: 99%

Chemical applications carried out by local pair natural orbital based coupled-cluster methods

2014

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The scope of this review is to provide a brief overview of the chemical applications carried out by local pair natural orbital coupled-electron pair and coupled-cluster methods. Benchmark tests reveal that these methods reproduce, with excellent accuracy, their canonical counterparts. At the same time, the speed up achieved by exploiting the locality of the electron correlation permits us to tackle chemical systems that, due to their size, would normally only be addressable with density functional theory. This review covers a broad variety of the chemical applications e.g. simulation of transition metal catalyzed reactions, estimation of weak interactions, and calculation of lattice properties in molecular crystals. This demonstrates that modern implementations of wavefunction-based correlated methods are playing an increasingly important role in applied computational chemistry.

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Direct Visualization of a Mechanochemically Induced Molecular Rearrangement

et al. 2020

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Recent progress in the field of mechanochemistry has expanded the discovery of mechanically induced chemical transformations to several areas of science. However, a general fundamental understanding of how mechanochemical reactions by ball milling occur has remained unreached. For this, we have now implemented in situ monitoring of a mechanochemically induced molecular rearrangement by synchrotron X‐ray powder diffraction, Raman spectroscopy, and real‐time temperature sensing. The results of this study demonstrate that molecular rearrangements can be accomplished in the solid state by ball milling and how in situ monitoring techniques enable the visualization of changes occurring at the exact instant of a molecular migration. The mechanochemical benzil–benzilic acid rearrangement is the focal point of the study.

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A computational study of base-catalyzed reactions of cyclic 1,2-diones: cyclobutane-1,2-dione

Cited by 9 publications

References 42 publications

Copper(II)-Assisted Ligand Fragmentation Leading to Three Families of Metallamacrocycle

Copper(II)-Assisted Ligand Fragmentation Leading to Three Families of Metallamacrocycle

Chemical applications carried out by local pair natural orbital based coupled-cluster methods

Direct Visualization of a Mechanochemically Induced Molecular Rearrangement

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