Differences in chemical properties and reactivity patterns of mono- and dioxomanganese(V) porphyrins as revealed by density functional theory

Recent experimental studies of Liu and Groves (J. Am. Chem. Soc. 2010; 132: 12847) on dioxomanganese(V) porphyrin complexes implicated substrate halogenation in good yield. Currently, little is known of this unique mechanism, therefore to gain understanding on the halogenation mechanism and the chemical features of this oxidant we decided to do a computational (density functional theory) study. We show that the dioxomanganese(V) complex has considerably different molecular (valence) orbitals as compared to monooxomanganese(V) porphyrin due to mixing of the metal 3d orbitals with 2p orbitals on both oxygen atoms. This results in a set of three pairs of orbitals of which the bonding and nonbonding pairs are doubly occupied and the antibonding orbitals are vacant. As a consequence, the bonding character along the Mn–O bond is less in dioxomanganese(V) as compared to monooxomanganese(V) complexes and therefore this bond can formally be described as a double bond rather than a triple bond. The differences in orbital interactions and orbital energies also affect the intrinsic chemical properties of the oxidants, such as the electron affinity and pKa values, which result in enhanced catalytic potential for dioxomanganese(V) porphyrin. Our calculations predict a halogenation mechanism in line with that proposed by experiment with an initial hydrogen atom abstraction followed by ligand exchange and halogen transfer.

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Nanostructures of Ionic Liquids Confined in Pores of SBA-15: Insights from Experimental Studies and Mean-Field Density Functional Theory

The Journal of Physical Chemistry C ◽

10.1021/acs.jpcc.1c06592 ◽

2021 ◽

Author(s):

Dmitry N. Lapshin ◽

Andrei V. Gromov ◽

Eleanor E. B. Campbell ◽

Lev Sarkisov

Keyword(s):

Density Functional Theory ◽

Ionic Liquids ◽

Density Functional ◽

Experimental Studies ◽

Mean Field ◽

Functional Theory ◽

Field Density

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A Free Aluminylene with Diverse σ-Donating and Doubly σ/π-Accepting Ligand Features for Transition Metals

10.33774/chemrxiv-2021-pk4xk-v2 ◽

2021 ◽

Author(s):

Xin Zhang ◽

Liu Leo Liu

Keyword(s):

Density Functional Theory ◽

Coordination Chemistry ◽

Transition Metals ◽

Electronic Structures ◽

Ligand Exchange ◽

Density Functional ◽

Reduction Reaction ◽

Functional Theory ◽

Metal Centers ◽

Coordination Behavior

We report herein the synthesis, characterization, and coordination chemistry of a free N-aluminylene, namely a carbazolylaluminylene 2b. This species is prepared via a reduction reaction of the corresponding carbazolyl aluminium diiodide. The coordination behavior of 2b towards transition metal centers (W, Cr) is shown to afford a series of novel aluminylene complexes 3-6 with diverse coordination modes. We demonstrate that the Al center in 2b can behave as: 1. a σ-donating and doubly π-accepting ligand; 2. a σ-donating, σ-accepting and π-accepting ligand; and 3. a σ-donating and doubly σ-accepting ligand. Additionally, we show ligand exchange at the aluminylene center providing access to the modulation of electronic properties of transition metals without changing the coordinated atoms. Investigations of 2b with IDippCuCl (IDipp = 1,3-bis(2,6-diisopropylphenyl)imidazol-2-ylidene) show an unprecedented aluminylene-alumanyl transformation leading to a rare terminal Cu-alumanyl complex 8. The electronic structures of such complexes and the mechanism of the aluminylene-alumanyl transformation are investigated through density functional theory (DFT) calculations.

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Influence of Varying Functionalization on the Peroxidase Activity of Nickel(II)–Pyridine Macrocycle Catalysts: Mechanistic Insights from Density Functional Theory

Computation ◽

10.3390/computation8020052 ◽

2020 ◽

Vol 8 (2) ◽

pp. 52

Author(s):

Jerwin Jay E. Taping ◽

Junie B. Billones ◽

Voltaire G. Organo

Keyword(s):

Density Functional Theory ◽

Proton Transfer ◽

Density Functional ◽

Experimental Studies ◽

Density Functional Theory Calculations ◽

Catalytic Performance ◽

Stoichiometric Ratio ◽

Functional Theory ◽

Pendant Arm ◽

Spin Singlet

Nickel(II) complexes of mono-functionalized pyridine-tetraazamacrocycles (PyMACs) are a new class of catalysts that possess promising activity similar to biological peroxidases. Experimental studies with ABTS (2,2′-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid), substrate) and H2O2 (oxidant) proposed that hydrogen-bonding and proton-transfer reactions facilitated by their pendant arm were responsible for their catalytic activity. In this work, density functional theory calculations were performed to unravel the influence of pendant arm functionalization on the catalytic performance of Ni(II)–PyMACs. Generated frontier orbitals suggested that Ni(II)–PyMACs activate H2O2 by satisfying two requirements: (1) the deprotonation of H2O2 to form the highly nucleophilic HOO−, and (2) the generation of low-spin, singlet state Ni(II)–PyMACs to allow the binding of HOO−. COSMO solvation-based energies revealed that the O–O Ni(II)–hydroperoxo bond, regardless of pendant arm type, ruptures favorably via heterolysis to produce high-spin (S = 1) [(L)Ni3+–O·]2+ and HO−. Aqueous solvation was found crucial in the stabilization of charged species, thereby favoring the heterolytic process over homolytic. The redox reaction of [(L)Ni3+–O·]2+ with ABTS obeyed a 1:2 stoichiometric ratio, followed by proton transfer to produce the final intermediate. The regeneration of Ni(II)–PyMACs at the final step involved the liberation of HO−, which was highly favorable when protons were readily available or when the pKa of the pendant arm was low.

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A Density Functional Theory Study of Coniferyl Alcohol Intermonomeric Cross Linkages in Lignin - Three-Dimensional Structures, Stabilities and the Thermodynamic Control Hypothesis

Holzforschung ◽

10.1515/hf.2003.024 ◽

2003 ◽

Vol 57 (2) ◽

pp. 150-164 ◽

Cited By ~ 25

Author(s):

B. Durbeej ◽

L.A. Eriksson

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Experimental Studies ◽

Three Dimensional ◽

Structural Features ◽

Density Functional Theory Study ◽

Thermodynamic Control ◽

Functional Theory ◽

Quantitative Correlation ◽

Control Hypothesis

Summary Density functional theory methods are utilized to investigate structural features and stabilities of the most common lignin dimerization products. It is found that intra-molecular hydrogen bonding acts as a stabilizing force in the lowest-energy conformer(s) of several different dimeric lignin structures. Furthermore, the calculations show that the hypothesis of thermodynamic control of monolignol dimerization accounts for some of the results obtained in experimental studies aimed at determining the ratios of intermonomeric linkages. A quantitative correlation between experimentally observed ratios and calculated relative energies cannot, however, be pointed out.

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The Influence of Ni(II) and Co(II) Adsorptions in the Anomalous Behavior of Co-Ni Alloys: Density Functional Theory and Experimental Studies

ChemistrySelect ◽

10.1002/slct.201601957 ◽

2017 ◽

Vol 2 (5) ◽

pp. 1826-1834 ◽

Cited By ~ 5

Author(s):

Jorge Vazquez-Arenas ◽

Guadalupe Ramos-Sanchez ◽

Rene H. Lara ◽

Issis Romero-Ibarra ◽

M. Eng. Francisco Almazan ◽

...

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Experimental Studies ◽

Anomalous Behavior ◽

Functional Theory ◽

Ni Alloys

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Catalytic investigation of Pd(II) complexes over Heck-Mizoroki reaction: Tailored synthesis, characterization and density functional theory

Journal of the Serbian Chemical Society ◽

10.2298/jsc200902075s ◽

2020 ◽

pp. 75-75

Author(s):

Satyendra Shukla ◽

Pratiksha Gaur ◽

Sanjay Bagri ◽

Ripul Mehrotra ◽

Bhaskar Chaurasia

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Electronic Spectroscopy ◽

Molar Conductance ◽

Basis Set ◽

Chemical Parameters ◽

Schiff Base Ligands ◽

Functional Theory ◽

Catalytic Potential ◽

Ft Ir

Tailored reaction of Schiff base ligands with palladium(II) chloride and imidazole afford three complexes of formula [Pd(II)(L)(imdz)2]Cl; where L = 2-((E)-(p-lylimino)methyl)-6-methoxyphenol (complex 1); 2-methoxy-6- -((E)-(phenylimine)methyl)phenol (complex 2); and 2-((E)-(4-chlorophenyl-imino)methyl)-6-methoxyphenol (complex 3). Compounds were characterized with elemental analysis, molar conductance, electronic spectroscopy, ESI-MS, FT-IR, TGA, 1H-NMR and 13C-NMR. Molecular structure and different quan-tum chemical parameters were calculated using the B3LYP basis set of density functional theory with the standard 6-311+G (d, 2p) level. The catalytic potential of 1-3 was examined over Heck-Mizoroki reaction and found in order of 1 > 2 > 3.

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Density Functional Theory Study on the Adsorption Mechanism of Sulphide Gas Molecules on α-Fe2O3(001) Surface

Inorganics ◽

10.3390/inorganics9110080 ◽

2021 ◽

Vol 9 (11) ◽

pp. 80

Author(s):

Li Zhou ◽

Huadong Zhu ◽

Wen Zeng

Keyword(s):

Density Functional Theory ◽

Density Functional ◽

Molecular Form ◽

Population Analysis ◽

Chemical Properties ◽

Vacancy Defect ◽

Mulliken Charge ◽

Functional Theory ◽

Differential Density ◽

Gas Molecules

Sulphide gas is an impurity that affects the quality of natural gas, which needs reasonable storage and transportation. In this work, we investigated the adsorption structure and electronic behavior of hydrogen sulfide (H2S), carbonyl sulfur (COS), and methyl mercaptan (CH3SH) on sulphide gas molecules on pure and vacant α-Fe2O3(001) surfaces by density functional theory with geometrical relaxations. The results show that H2S and CH3SH are mainly adsorbed in the form of molecules on the pure Fe2O3(001) surface. On the vacant α-Fe2O3(001) surface, they can be adsorbed on Fe atoms in molecular form and by dissociation. The absolute value of the adsorption energy of H2S and CH3SH on the vacancy defect α-Fe2O3 surface is larger, and the density of states show that the electron orbital hybridization is more significant, and the adsorption is stronger. The charge differential density and Mulliken charge population analysis show that the charge is rearranged and chemical bonds are formed. The affinity of H2S to the vacancy α-Fe2O3(001) surface is slightly higher than that of CH3SH, while COS molecules basically do not adsorb on the α-Fe2O3(001) surface, which may be related to the stable chemical properties of the molecules themselves.

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Application of Density Functional Theory in Coordination Chemistry: A Case Study of Group 13 Monohalide as a Ligand

10.5772/intechopen.99790 ◽

2021 ◽

Author(s):

Thayalaraj Christopher Jeyakumar ◽

Francisxavier Paularokiadoss

Keyword(s):

Density Functional Theory ◽

Coordination Chemistry ◽

Density Functional ◽

Experimental Studies ◽

Theoretical Studies ◽

Dft Methods ◽

Functional Theory ◽

Group 13 ◽

Metal Bonding

The chemistry of Group 13 Monohalide is of great interest due to its isoelectronic relationship with carbon monoxide and dinitrogen. In recent years, theoretical and experimental studies have been evolved on the group-13 atom-based diatomic molecules as a ligand. The synthetic, characterisation and reactivity of various metal complexes have been well discussed in recent reviews. The nature of the metal bonding of these ligands of various types has been explained in addition by the variety of theoretical studies (using DFT methods) such as FMO and EDA. This chapter has a comprehensive experimental and theoretical study of group 13 monohalides as a ligand in coordination chemistry.

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