Katrine Svane

University of Bath | UB · Department of Chemistry

Vacancy lattice sites in the metal–organic framework UiO-66 are known to have a profound effect on the material properties. Here we use density functional theory to compare the energies of defect arrangements containing missing linkers and missing metal clusters for different choices of charge compensation. Our results show that the preference for...

Hybrid organic-inorganic perovskites represent a special class of metal-organic framework where a molecular cation is encased in an anionic cage. The molecule-cage interaction influences phase stability, phase transformations and the molecular dynamics. We examine the hydrogen bonding in four AmBX3 formate perovskites: [Am]Zn(HCOO)3, with Am⁺ = hyd...

Molecular conformational flexibility can play an important role in supramolecular self-assembly on surfaces, affecting not least chiral molecular assemblies. To explicitly and systematically investigate the role of molecular conformational flexibility in surface self-assembly, we synthesized a three-bit conformational switch where each of three swi...

The crystallography of mechanically soft materials such as hybrid organic-inorganic compounds often reveals large thermal displacement factors and partially occupied lattice sites, which can arise from static or dynamic disorder. A combination of ab initio lattice dynamics and molecular dynamics simulations reveals the origin of the giant thermal d...

To build on the success of other mineral systems employed in solar cells, including kesterites (Cu2ZnSnS4) and herzenbergite (SnS), and mineral-inspired systems such as lead halide perovskites (CH3NH3PbI3), we have searched for photoactive minerals with the additional constraint that a polar crystal structure is adopted. Macroscopic electric fields...

We report a comprehensive model surface science study, using scanning tunnelling microscopy (STM), of the regioselective and stereospecific complexation of a prochiral substrate molecule to a chiral modifier molecule on a metal surface. The system is chosen so as to compare the prochiral ratio (pr) measured directly by STM for the model system with...

Thin-film deposition of metal-organic frameworks (MOFs) is now possible, but little is known regarding the microscopic nature of hybrid hetero-interfaces. We first assess optimal substrate combinations for coherent epitaxy of MOFs based on a lattice matching procedure. We then perform a detailed quantum mechanical/molecular mechanical investigation...

Hybrid organic–inorganic materials are mechanically soft, leading to large thermoelastic effects which can affect properties such as electronic structure and ferroelectric ordering. Here we use a combination of ab initio lattice dynamics and molecular dynamics to study the finite temperature behavior of the hydrazinium and guanidinium formate perov...

Self-assembly of a molecule with many distinct conformational states, resulting in eight possible pairs of surface enantiomers, is investigated on a Au(111) surface under UHV conditions. The complex molecule is equipped with alkyl and carboxyl moieties to promote controlled self-assembly of lamellae structures. From statistical analysis of Scanning...

Entropy is a critical, but often overlooked, factor in determining the relative stabilities of crystal phases. The importance of entropy is most pronounced in softer materials, where small changes in free energy can drive phase transitions, which has recently been demonstrated in the case of organic-inorganic hybrid-formate perovskites. In this stu...

We report the development of a forcefield capable of reproducing accurate lattice dynamics of metal-organic frameworks. Phonon spectra, thermodynamic and mechanical properties, such as free energies, heat capacities and bulk moduli, are calculated using the quasi-harmonic approximation to account for anharmonic behaviour due to thermal expansion. C...

Metal-organic frameworks (MOFs) containing d0 metals such as NH2-MIL-125(Ti), NH2-UiO-66(Zr) and NH2-UiO-66(Hf) are among the most studied MOFs for photocatalytic applications. Despite structural similarities, we demonstrate that the electronic properties of these MOFs are markedly different. As revealed by quantum chemistry, EPR measurements and t...

The modelling of materials properties and processes from first principles is becoming sufficiently accurate as to facilitate the design and testing of new systems in silico. Computational materials science is both valuable and increasingly necessary for developing novel functional materials and composites that meet the requirements of next-generati...

We present a comprehensive theoretical investigation of the structures formed by self-assembly of tetrahydroxybenzene (THB)-derivatives on Cu(111). The THB molecule is known to dehydrogenate completely during annealing, forming a reactive radical which assembles into a close-packed structure or a porous metal-coordinated network depending on the co...

We report an investigation of the "missing-linker phenomenon" in the Zr-based metal-organic framework UiO-66 using atomistic forcefield and quantum chemical methods. For a vacant benzene dicarboxylate ligand, the lowest energy charge capping mechanism involves acetic acid or Cl-/H2O. The calculated defect free energy of formation is remarkably low,...

Magnetic interactions in hybrid materials are poorly understood compared to those in purely inorganic materials. The high flexibility of many metal-organic systems introduces a strong temperature dependence of the magnetic exchange interactions owing to changes in the crystal structure. Here, we study the cobalt adipate system, for which anisotropi...

Supra-molecular self-assembly on surfaces often involves molecular conformational flexibility which may act to enrich the variation and complexity of the structures formed. However, systematic and explicit investigations of how molecular conformational states are selected in surface self-assembly processes are relatively scarce. Here, we use a comb...

Proteins fold into three-dimensional structures, which determine their diverse functions. The conformation of the backbone of each structure is locally at each C(α) effectively described by conformational angles resulting in Ramachandran plots. These, however, do not describe the conformations around hydrogen bonds, which can be non-local along the...

Surface coordination networks formed by co-adsorption of metal atoms and organic ligands have interesting properties, for example regarding catalysis and data storage. Surface coordination networks studied to date have typically been based on single metal atom centers. The formation of a novel surface coordination network is now demonstrated that i...

Mittels Koadsorption von Metallatomen und organischen Liganden hergestellte Koordinationsnetzwerke haben interessante Eigenschaften, z. B. in der Katalyse oder für die Datenspeicherung. Bisher basierten solche Oberflächen-Netzwerke auf Koordination an einzelnen Metallatomen. Hier beschreiben wir hingegen die Bildung eines neuartigen Metall-organisc...

The reaction free energy for dehydrogenation of phenol, aniline, thiophenol, benzoic acid, and 1,4-benzenediol on the close packed copper, silver, and gold surfaces has been studied by density functional theory calculations. Dehydrogenation of thiophenol is found to be favourable on all three surfaces while aniline does not dehydrogenate on any of...

The formation of bimolecular complexes on metal surfaces through interaction between a single chemisorbed chiral molecule and a single chemisorbed prochiral substrate molecule can be considered as a preorganization step toward chirality transfer. In the case of asymmetric hydrogenation on chirally modified platinum catalysts, the metal surface diss...

Adsorption of tetrahydroxybenzene (THB) on Cu(111) and Au(111) surfaces is studied using a combination of STM, XPS, and DFT. THB is deposited intact, but on Cu(111) it undergoes gradual dehydrogenation of the hydroxyl groups as a function of substrate temperature, yielding a pure dihydroxy-benzoquinone phase at 370 K. Subtle changes to the adsorpti...