A density functional study of the spin state energetics of polypyrazolylborato complexes of first-row transition metals

Gruden, Maja; Stepanović, Srdjan; Perić, Marko; Güell, Mireia; Swart, Marcel

doi:10.1039/c3cp55488k

Cited by 20 publications

(27 citation statements)

References 76 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Steric bulk at the periphery of the ligand sphere can promote the low-spin state if it inhibits expansion of the metal coordination sphere, or the high-spin state if it leads to distortion of the ligandÑmetal dative interaction. These effects can be reliably understood or predicted in individual compounds computationally [43,50,92] or using molecular models.…”

Section: Discussionmentioning

confidence: 99%

The Effect of Ligand Design on Metal Ion Spin State—Lessons from Spin Crossover Complexes

2016

View full text Add to dashboard Cite

Abstract:The relationship between chemical structure and spin state in a transition metal complex has an important bearing on mechanistic bioinorganic chemistry, catalysis by base metals, and the design of spin crossover materials. The latter provide an ideal testbed for this question, since small changes in spin state energetics can be easily detected from shifts in the spin crossover equilibrium temperature. Published structure-function relationships relating ligand design and spin state from the spin crossover literature give varied results. A sterically crowded ligand sphere favors the expanded metal-ligand bonds associated with the high-spin state. However, steric clashes at the molecular periphery can stabilize either the high-spin or the low-spin state in a predictable way, depending on their effect on ligand conformation. In the absence of steric influences, the picture is less clear since electron-withdrawing ligand substituents are reported to favor the low-spin or the high-spin state in different series of compounds. A recent study has shed light on this conundrum, showing that the electronic influence of a substituent on a coordinated metal ion depends on its position on the ligand framework. Finally, hydrogen bonding to complexes containing peripheral N-H groups consistently stabilizes the low-spin state, where this has been quantified.

show abstract

Section: Discussionmentioning

confidence: 99%

The Effect of Ligand Design on Metal Ion Spin State—Lessons from Spin Crossover Complexes

2016

View full text Add to dashboard Cite

show abstract

“…A small deviation of < S 2 > from the ideal value confirms the good performance of the S12g functional for studying spin states of transition metal complexes. 32,38 The results of the Mulliken population analysis for various atoms at the CO−Pt n /PAH complexes are shown in Table 4. Comparing the orbital populations of the supported Pt atom and dimer and the CO molecule before and after adsorption, gives us the characteristic features of bonding between the CO molecule and the supported Pt atom and dimers.…”

Section: Co Adsorption On Carbon-supported Pt Atom and Dimermentioning

confidence: 99%

“…37 Its performance for spin states of transition metal complexes is well documented. 18,32,38 The relativistic effects are taken into account at the all-electron level with the zero-orderregular approximation (ZORA) approach. [39][40][41][42][43][44] The molecular orbitals (MOs) were expanded in an uncontracted set of Slater-type orbitals (STO), based on a basis set study.…”

Section: Computational Detailsmentioning

confidence: 99%

Influence of Carbon Support on Electronic Structure and Catalytic Activity of Pt Catalysts: Binding to the CO Molecule

2016

View full text Add to dashboard Cite

Single-atom catalysts, especially with single Pt atoms, exhibit potentially improved catalytic activity as compared to metal clusters and metal surfaces. Here, the atop and bridged bondings of the CO molecule on the Pt/C system are studied. Vibrational frequencies, Mulliken populations, charge transfer, charge density differences and density of states are examined to determine the influence of the carbon support on electronic properties and catalytic activity of the Pt adatom and dimer. Comparing orbital populations and the amount of electron transfer to/from the CO molecule show that the net amount of electron transfer to the anti-bonding 2π * orbitals of the CO molecule is higher for the supported Pt dimer than for the substrate-free Pt dimer which leads to a lower vibrational frequency and a larger C−O bond distance. The hybridization between the π orbitals of the polycyclic aromatic hydrocarbons surface and the d orbitals of the Pt adatoms is responsible for enhancing the back donation of electrons to the 2π * orbitals of the CO molecule which results in a larger peak below the Fermi level for the 2π * states of the CO molecule in the corresponding density of state analysis. Therefore, it can be concluded that the carbon support significantly enhances the catalytic activity of the Pt atoms in contact with the surface for activating the CO molecule. The calculated C−O vibrational stretching frequencies provide valuable guidance for experiments considering the use of atom-type catalyst as building blocks for designing new catalysts.

show abstract

“…96 To check the effect of the electronic structure on Co-PAH interactions, several spin states for the Co n -PAH (n = 1, 2) complex are studied with the S12g functional, which has been demonstrated to be successful for describing spin states of transition-metal complexes. 83,87 Many standard density functionals fail to predict the spin ground-state of transitionmetal complexes 97 and the S12g functional was specifically designed to do well in this respect. 83 The spin state is denoted with the spin multiplicity, 2S + 1, which is for example, 1 for a singlet state, 2 for a doublet state and 3 for a triplet state and so on.…”

Section: Computational Detailsmentioning

confidence: 99%

“…86 Its performance for spin states of transition metal complexes is well documented. 83,87 For comparison, the Perdew-Burke-Ernzerhof (PBE) functional 88 has also been employed in our study. The molecular orbitals (MOs) are expanded in an uncontracted set of Slater-type orbitals (STOs) and Slater-type functions are substantially more diffuse than a corresponding Gaussian type basis set and give consistent and rapidly converging results, which may be related to the cusp at the nuclei that is correctly described by STOs.…”

Section: Computational Detailsmentioning

confidence: 99%

Chemical Bonding and Electronic Properties of the Co Adatom and Dimer Interacting with Polyaromatic Hydrocarbons

2015

View full text Add to dashboard Cite

The density functional calculations presented here elucidate the nature of the interaction between the Co atom and dimer with a polyaromatic hydrocarbon (PAH). The results are analyzed in terms of structural, electronic and magnetic properties. The bonding character of the Co atom and dimer adsorbed on the PAH exhibits a strong covalent bonding, arising from a hybridization between the d orbitals of Co and the p z orbitals of the carbon atoms, which cause an in-plane distortion in the PAHs. A small charge transfer takes place from the Co atom and dimer to the PAH surface, which creates a positive charge on the metal atoms and thereby change their catalytic activity. Upon adsorption, the magnetic moment of the Co adatom is reduced depending on the adsorption site. For the perpendicular Co dimer to the PAH plane, the projected magnetic moment of the Co atom further from the PAH is increased, which is due to antiferromagnetic coupling between the Co atoms in this configuration. Density of state analysis shows that the main contribution of magnetic moment reduction is due to promotion of electrons from the 4s states to the 3d states of the Co adatom upon adsorption.

show abstract

A density functional study of the spin state energetics of polypyrazolylborato complexes of first-row transition metals

Cited by 20 publications

References 76 publications

The Effect of Ligand Design on Metal Ion Spin State—Lessons from Spin Crossover Complexes

The Effect of Ligand Design on Metal Ion Spin State—Lessons from Spin Crossover Complexes

Influence of Carbon Support on Electronic Structure and Catalytic Activity of Pt Catalysts: Binding to the CO Molecule

Chemical Bonding and Electronic Properties of the Co Adatom and Dimer Interacting with Polyaromatic Hydrocarbons

Contact Info

Product

Resources

About