Dr Damien Murphy - PhD CChem MRSC
The chemical reactivity and properties of molecules depends critically on their shape or structure. For example, molecular shapes govern everything from colour, odour and taste to whether a substance is a solid, liquid or gas. Scientists use different tools to study these shapes, and explore how one molecule reacts with another depending on shape. This is often difficult, particularly in solution and when the interactions are weak. Using Orientation Selective Electron Nuclear DOuble Resonance (ENDOR) spectroscopy, we can generate a 3-dimensional visualisation of weakly interacting molecules in solution, revealing the small changes in structure when chiral molecules interact with each other. In a sense, ENDOR experiments on single crystals with known three-dimensional structures can be regarded as complementary 1H crystallography. As shown in the example below, the coordinates and distances derived by 1H ENDOR spectroscopy are comparable to those computed using DFT structural models (in brackets). When combined with other Pulsed EPR techniques, a complete description of electron spin distributions can be obtained in radicals and paramagnetic systems.