Projects: A

The concept of “philicity” is based on the idea of a competition between intermolecular interactions of different nature. The conventional terms “hydrophilic”, “hydrophobic”, “lipophilic”, “fluorophilic” and further flavors within this scheme can be understood as systems (mixtures of molecules) with outward-pointing sidegroups of type A and B leading to either of the following situations:

1. “A is B-phobic” (e.g. benzene =A is hydrophobic, water = B): Then, the intermolecular interactions of type A–A and B–B are enthalpically favorable compared to the interactions A–B, A–B, and this enthalpic advantage is not overcompensated by the genuine entropic advantage of the random spatial arrangement.

2. “A is B-philic” (e.g. methanol =A is hydrophilic, water = B): Then, the enthalpic difference between the interaction configurations (A–A, B–B) versus (A–B, A–B) is smaller than the corresponding entropic advantage.

We have recently discovered that small molecular building blocks with more than one interacting funtional group dynamically self assemble into non-trivial, non-random (thermal) structures in solution. This self-assembly into ionoids (as we termed them) takes place through a combination of preferential solvation, viscosity, van der Waals interactions together with long-range correlated electrostatics.

In this project in which two doctoral researchers will be supervised by Prof. Dr. Dariush Hinderberger and Prof. Dr. Daniel Sebastiani, we aim at deriving the full design principles that govern the formation of these dynamic structures from isotropic “clouds” of ions in solution through concepts of multiple non-covalent interactions.

Quasicrystalline packings have been detected in metal alloys by Nobel laureate D. Schechtmann. Meanwhile, quasicrystalline order was also found in block-copolymer morphologies, colloidal and nano-particle assemblies. Formation of quasiperiodic 2D nets is known in monomolecular layers on surfaces, which depend on the support by a surface lattice and the stabilization by surface interactions.

Quasicrystalline packings have been detected in metal alloys by Nobel laureate D. Schechtmann. Meanwhile, quasicrystalline order was also found in block-copolymer morphologies, colloidal and nano-particle assemblies. Formation of quasiperiodic 2D nets is known in monomolecular layers on surfaces, which depend on the support by a surface lattice and the stabilization by surface interactions.

Biological membranes are formed by a phospholipid bilayer matrix and separate the aqueous interior of cells or cellular compartments from the mostly aqueous outer environment. This separation, however, makes the transport of material and information through the membrane necessary – a task which is often carried out by proteins that reside in the membranes and interact with the surrounding lipids. The notion that these interactions bear functional importance has recently received increasing attention. Natural protein-lipid interactions are diverse and include hydrophobic as well as polar interactions. To study these polyphilic protein-lipid interactions, we will follow a multi-disciplinary approach. We will mostly employ native mass spectrometry, which allows maintaining the non-covalent interactions between proteins and their ligands.

The interaction and binding of enzymes to substrates is not a static procedure as suggested by the simple key-lock concept, but a dynamic process repeatedly referred to as “induced fit” that often utilizes amphiphilic and more interactions.

COFs are an emerging class of porous materials with high surface area and tunable pore sizes that have promising applications in gas storage, catalysis, and sensing. In this project, we aim to go beyond the traditional approach of tuning COFs’ hydrophobic and hydrophilic properties to explore other interactions that can be used to modify COFs’ structure and properties.

We will work on the design and synthesis of COFs with functional groups that can interact with other molecules beyond amphiphilic interactions. We use computational tools to design new COF structures with desired properties, and then synthesize them using organic synthesis techniques. We then characterize the resulting COFs using various techniques such as X-ray diffraction, Fourier transform infrared spectroscopy, and thermogravimetric analysis. We also evaluate their properties using gas adsorption measurements and solid state NMR. We will also work closely with other BEAM members to understand the fundamental principles that govern the behavior of COFs in various environments.