The oxygen-atom transfer reactions of Mo-diselenolene biomimetic complexes: A computational investigation
TL;DR: In this paper, the aqueous Gibbs reaction and activation energies for the O-atom transfer mechanism of several Mo-bis(diselenolene) biomimetic complexes were investigated.
About: This article is published in Computational and Theoretical Chemistry.The article was published on 2018-09-01. It has received 3 citations till now. The article focuses on the topics: Ligand.
Citations
More filters
01 Jan 1994
TL;DR: In this article, the synthesis, structures, and redox properties of isomorphous Ni(I1) thiolato and selenolato complexes of the tridentate ligands bis(2-(hydrochalcogeno)ethyl)methylamines are reported.
Abstract: The syntheses, structures, and redox properties of isomorphous Ni(I1) thiolato and selenolato complexes of the tridentate ligands bis(2-(hydrochalcogeno)ethyl)methylamines are reported. Reaction of Ni(0Ac)z with bis(2mercaptoethy1)methylamine leads to the formation of a dimeric complex, bis{ [@-2-mercaptoethyl)(2-mercaptoethyl)methylaminato(2-)]nickel(II)}, [Ni(l)]2. This complex contains planar, diamagnetic Ni(I1) centers ligated by a tertiary amine N-donor atom, a terminal thiolate, and two thiolates that bridge to the second Ni center in the dimer. Crystals of [Ni(l)]2 form in orthorhombic space group h a 2 1 with cell dimensions a = 19.695(2) 8, b = 6.042(2) 8, c = 13.463(3) 8, V = 1602(1) A3, and Z = 4. Reaction of Ni(0Ac)p with bis(2-(hydroseleno)ethy1)methylamine results in the formation of a structurally analogous dimeric complex, bis([@-2-(hydroseleno)ethyl)(2-(hydroseleno)ethyl)methylaminato(2-)]nickel(II)}, [Ni(2)]2, where all of the chalcogenolate donors are selenolates. Crystals of [Ni(2)]2 are isomorphous with those of [Ni(l)]z, with a = 20.040(8) 8, b = 6.265(2) 8, c = 13.590(5) 8, and V = 1706(2) A3, One-electron oxidation of either dimeric complex leads to the formation of radical cations, which exhibit EPR spectra consistent with S = l/2 radicals. For [Ni(l)]2+ the g values observed (gx = 2.20, g, = 2.14, g, = 2.02) are essentially identical to those observed for a reduced and catalytically viable redox state of Fe,Ni hydrogenases (gx = 2.20, g, = 2.14, g, = 2.01). The substitution of Sefor S-donors in [Ni(2)]2 does not alter the observed g values much (gx = 2.23, g, = 2.14, g, = 2.05) but leads to the observation of 77Se hyperfine coupling (A, = 129 G) that indicates that the molecular orbital containing the unpaired spin is largely Se in character (54%). Reaction of either dimeric complex with CNleads to the formation of mononuclear trans-dichalcogenolate complexes, [Ni(l)CN]and [Ni(2)CN]-. Exposure of [Ni(l)CN]to 0 2 leads to the quantitative formation of a monosulfinato complex. In contrast, the selenolato complex does not react with 0 2 under the same conditions. The role of selenocysteinate ligation in Fe,Ni,Se hydrogenases is discussed in view of this chemistry.
37 citations
TL;DR: From the calculated thermodynamics, it appears that the Ni(SeNHC2(CN)2)2 complex is predicted to catalyze the production of H2 gas under mildly reducing conditions relative to the SHE, and may offer a means to improve the catalysts for H2 production.
Abstract: To reduce our carbon footprint, we must look at alternative non-carbon-containing fuels to prevent continued global climate change. One environmentally friendly alternative fuel is molecular hydrog...
4 citations
TL;DR: In this article , a review of the synthetic pathways leading to the different classes of homoleptic and heteroleptic metal complexes featuring 1,2-diselenolene ligands, discussing their structural features, properties, and main applications is presented.
1 citations
References
More filters
TL;DR: This work reports a gradient-corrected exchange-energy functional, containing only one parameter, that fits the exact Hartree-Fock exchange energies of a wide variety of atomic systems with remarkable accuracy, surpassing the performance of previous functionals containing two parameters or more.
Abstract: Current gradient-corrected density-functional approximations for the exchange energies of atomic and molecular systems fail to reproduce the correct 1/r asymptotic behavior of the exchange-energy density. Here we report a gradient-corrected exchange-energy functional with the proper asymptotic limit. Our functional, containing only one parameter, fits the exact Hartree-Fock exchange energies of a wide variety of atomic systems with remarkable accuracy, surpassing the performance of previous functionals containing two parameters or more.
45,683 citations
TL;DR: The revised DFT-D method is proposed as a general tool for the computation of the dispersion energy in molecules and solids of any kind with DFT and related (low-cost) electronic structure methods for large systems.
Abstract: The method of dispersion correction as an add-on to standard Kohn-Sham density functional theory (DFT-D) has been refined regarding higher accuracy, broader range of applicability, and less empiricism. The main new ingredients are atom-pairwise specific dispersion coefficients and cutoff radii that are both computed from first principles. The coefficients for new eighth-order dispersion terms are computed using established recursion relations. System (geometry) dependent information is used for the first time in a DFT-D type approach by employing the new concept of fractional coordination numbers (CN). They are used to interpolate between dispersion coefficients of atoms in different chemical environments. The method only requires adjustment of two global parameters for each density functional, is asymptotically exact for a gas of weakly interacting neutral atoms, and easily allows the computation of atomic forces. Three-body nonadditivity terms are considered. The method has been assessed on standard benchmark sets for inter- and intramolecular noncovalent interactions with a particular emphasis on a consistent description of light and heavy element systems. The mean absolute deviations for the S22 benchmark set of noncovalent interactions for 11 standard density functionals decrease by 15%-40% compared to the previous (already accurate) DFT-D version. Spectacular improvements are found for a tripeptide-folding model and all tested metallic systems. The rectification of the long-range behavior and the use of more accurate C(6) coefficients also lead to a much better description of large (infinite) systems as shown for graphene sheets and the adsorption of benzene on an Ag(111) surface. For graphene it is found that the inclusion of three-body terms substantially (by about 10%) weakens the interlayer binding. We propose the revised DFT-D method as a general tool for the computation of the dispersion energy in molecules and solids of any kind with DFT and related (low-cost) electronic structure methods for large systems.
32,589 citations
TL;DR: Numerical results for atoms, positive ions, and surfaces are close to the exact correlation energies, with major improvements over the original LM approximation for the ions and surfaces.
Abstract: Langreth and Mehl (LM) and co-workers have developed a useful spin-density functional for the correlation energy of an electronic system. Here the LM functional is improved in two ways: (1) The natural separation between exchange and correlation is made, so that the density-gradient expansion of each is recovered in the slowly varying limit. (2) Uniform-gas and inhomogeneity effects beyond the randomphase approximation are built in. Numerical results for atoms, positive ions, and surfaces are close to the exact correlation energies, with major improvements over the original LM approximation for the ions and surfaces.
16,378 citations
TL;DR: It is shown by an extensive benchmark on molecular energy data that the mathematical form of the damping function in DFT‐D methods has only a minor impact on the quality of the results and BJ‐damping seems to provide a physically correct short‐range behavior of correlation/dispersion even with unmodified standard functionals.
Abstract: It is shown by an extensive benchmark on molecular energy data that the mathematical form of the damping function in DFT-D methods has only a minor impact on the quality of the results. For 12 different functionals, a standard "zero-damping" formula and rational damping to finite values for small interatomic distances according to Becke and Johnson (BJ-damping) has been tested. The same (DFT-D3) scheme for the computation of the dispersion coefficients is used. The BJ-damping requires one fit parameter more for each functional (three instead of two) but has the advantage of avoiding repulsive interatomic forces at shorter distances. With BJ-damping better results for nonbonded distances and more clear effects of intramolecular dispersion in four representative molecular structures are found. For the noncovalently-bonded structures in the S22 set, both schemes lead to very similar intermolecular distances. For noncovalent interaction energies BJ-damping performs slightly better but both variants can be recommended in general. The exception to this is Hartree-Fock that can be recommended only in the BJ-variant and which is then close to the accuracy of corrected GGAs for non-covalent interactions. According to the thermodynamic benchmarks BJ-damping is more accurate especially for medium-range electron correlation problems and only small and practically insignificant double-counting effects are observed. It seems to provide a physically correct short-range behavior of correlation/dispersion even with unmodified standard functionals. In any case, the differences between the two methods are much smaller than the overall dispersion effect and often also smaller than the influence of the underlying density functional.
14,151 citations
TL;DR: This paper presents a meta-modelling procedure called "Continuum Methods within MD and MC Simulations 3072", which automates the very labor-intensive and therefore time-heavy and expensive process of integrating discrete and continuous components into a discrete-time model.
Abstract: 6.2.2. Definition of Effective Properties 3064 6.3. Response Properties to Magnetic Fields 3066 6.3.1. Nuclear Shielding 3066 6.3.2. Indirect Spin−Spin Coupling 3067 6.3.3. EPR Parameters 3068 6.4. Properties of Chiral Systems 3069 6.4.1. Electronic Circular Dichroism (ECD) 3069 6.4.2. Optical Rotation (OR) 3069 6.4.3. VCD and VROA 3070 7. Continuum and Discrete Models 3071 7.1. Continuum Methods within MD and MC Simulations 3072
13,286 citations