Aluminium–ligand cooperation promotes selective dehydrogenation of formic acid to H2 and CO2

Selective conversion of formic acid to H2 and CO2 is catalysed by a molecular aluminum complex. Metal–ligand cooperative interactions stabilize a transition state for an outer-sphere β-hydride abstraction mechanism for catalysis.

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Hapticity of asymmetric rhodium-allyl compounds in the light of real-space bonding indicators

Zeitschrift für Kristallographie - Crystalline Materials ◽

10.1515/zkri-2017-2141 ◽

2018 ◽

Vol 233 (9-10) ◽

pp. 615-626

Author(s):

Stefan Mebs ◽

Sabrina Imke Kalläne ◽

Thomas Braun

Keyword(s):

Real Space ◽

Molecular Structures ◽

Dft Study ◽

Interaction Patterns ◽

Ligand Interaction ◽

Complex Metal ◽

Allyl Compounds ◽

Back Donation ◽

Metal Ligand

Abstract Rhodium boryl complexes are valuable catalysts for hydro- or diboration reactions of alkenes, but can also react with ketones (R2C=O) and imines (R2C=NR′) giving rise to insertion products having formally Rh–R2C–O/NR′–B linkages. The resulting molecular structures, however, may show complex metal–ligand and ligand–ligand interaction patterns with often unclear metal–ligand connectivities (hapticities, ηn). In order to assign the correct hapticity in a set of asymmetric rhodium-allyl compounds with molecular structures indicating η1−5 bonding, a comprehensive DFT study was conducted. The study comprises determination of a variety of real-space bonding indicators derived from computed electron and pair densities according to the AIM, ELI-D, NCI, and DORI topological and surface approaches, which uncover the metal–ligand connectivties and suggest an asymmetric ligand–metal donation/metal–ligand back-donation framework according to the Dewar–Chatt–Duncanson model.

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Decomposition of protonated formic acid: One transition state—Two product channels

Journal of the American Society for Mass Spectrometry ◽

10.1016/j.jasms.2004.04.028 ◽

2004 ◽

Vol 15 (7) ◽

pp. 982-988 ◽

Cited By ~ 11

Author(s):

Osamu Sekiguchi ◽

Vebjørn Bakken ◽

Einar Uggerud

Keyword(s):

Transition State ◽

Formic Acid

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ChemInform Abstract: THE TRANSITION STATE IN THE REDUCTION OF KETONES BY COMPLEX METAL HYDRIDES. REASSESSMENT AND LIMITED REINCARNATION OF THE CONCEPT OF PRODUCT DEVELOPMENT CONTROL

Chemischer Informationsdienst ◽

10.1002/chin.197939108 ◽

1979 ◽

Vol 10 (39) ◽

Author(s):

D. C. WIGFIELD ◽

F. W. GOWLAND

Keyword(s):

Product Development ◽

Transition State ◽

Metal Hydrides ◽

Development Control ◽

Complex Metal ◽

Reduction Of Ketones

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Transition state structure of the formic acid isomeric reaction in solution

Chemical Physics Letters ◽

10.1016/0009-2614(94)00413-7 ◽

1994 ◽

Vol 223 (1-2) ◽

pp. 23-26 ◽

Cited By ~ 4

Author(s):

José L. Andrés ◽

Agustí Lledós ◽

Juan Bertrán

Keyword(s):

Transition State ◽

Formic Acid ◽

State Structure ◽

Transition State Structure ◽

Reaction In Solution

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Outer Sphere Oxidations of Alcohols and Formic Acid by Charge Transfer Excited States of Iron(III) Species

Canadian Journal of Chemistry ◽

10.1139/v75-345 ◽

1975 ◽

Vol 53 (16) ◽

pp. 2436-2440 ◽

Cited By ~ 28

Author(s):

John H. Carey ◽

Cooper H. Langford

Keyword(s):

Charge Transfer ◽

Formic Acid ◽

Excited States ◽

Outer Sphere ◽

Butyl Alcohol ◽

Experimental Conditions ◽

Tert Butyl Alcohol ◽

Long Lifetime ◽

Resonance Relaxation ◽

Metal Charge Transfer

When methanol, 2-propanol, and formic acid are used as scavengers in the ligand to metal charge transfer (l.m.c.t.) photolysis of Fe(OH2)63+, Fe(OH2)5CI2+, Fe2(OH2)8(OH)24+, or FeEDTA, there is a linear relationship between quantum yield for Fe(II) production and scavenger concentration, [S], at higher [S] values. Extrapolation of the linear portions to [S] = 0 gives an intercept corresponding to the limiting yields observed for scavenging with tert-butyl alcohol. Butanol scavenging at the limit has been shown to give the primary free radical yields from photolysis of aquo iron(III) species. Nuclear magnetic resonance relaxation time studies show that alcohols do not coordinate to Fe(III) and calculations from known stability constants indicate that formic acid does not coordinate under the experimental conditions. The increase of Fe(II) yields with [S] is attributed to an outer sphere oxidation of noncoordinated organic species by the charge transfer excited states of Fe(III) species. There is no discrimination among the organic reductants. The results may be understood without postulating a long lifetime for the Fe(III) l.m.c.t. states if the reaction is assumed to occur only with organic molecules in encounter with the Fe(III) complex at the time of excitation. Organic products were formaldehyde from methanol oxidation and acetone from 2-propanol oxidation. The Fe(II): formaldehyde stoichiometry was 2:1.

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Unexpected chloro-functionalized ionic liquids-promoted selective conversion of cellulose into levulinic acid

BioResources ◽

10.15376/biores.15.4.9155-9165 ◽

2020 ◽

Vol 15 (4) ◽

pp. 9155-9165

Author(s):

Hao Ma ◽

Yanhui Qiao ◽

Junjiang Teng

Keyword(s):

Ionic Liquids ◽

Formic Acid ◽

Levulinic Acid ◽

Imidazolium Chloride ◽

Cellulose Conversion ◽

Selective Conversion

A series of chloro-functionalized ionic liquids (CFILs) with chlorine groups (–Cl) on cations and chloride anions (Cl-) were synthesized and used as the promotion reagents for the selective conversion of cellulose into levulinic acid (LA) with the co-product of formic acid (FA). The co-operation between cations and anions of CFILs was investigated intensively through the variation of the structure of cations and the addition of salts with different anions. 3-(3-chloropropyl)-1-methyl-imidazolium chloride (IL-3) was the most appropriate additive, achieving up to 4.2%, 52.6%, and 58.7% of glucose, LA, and FA yields at 83.5% of cellulose conversion, respectively.

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