Distance Measurement of a Noncovalently Bound Y@C82 Pair with Double Electron Electron Resonance Spectroscopy

We thank the EPSRC (EP/I035536/1; EP/J015067/1), The Royal Society (University Research Fellowship to JEL) and Wellcome Trust (099149/Z/12/Z) for funding and the EPSRC UK National Mass Spectrometry Facility at Swansea University for mass spectra. Paramagnetic endohedral fullerenes with long spin coherence times, such as N@C60 and Y@C82, are being explored as potential spin quantum bits (qubits). Their use for quantum information processing requires a ways to hold them in fixed spatial arrangements. Here we report the synthesis of a porphyrin-based two-site receptor 1 , offering a rigid structure that binds spin-active fullerenes (Y@C82) at a center-to-center distance of 5.0 nm, predicted from molecular simulations. The spin-spin dipolar coupling was measured with the pulsed EPR spectroscopy technique of double electron electron resonance (DEER) and analysed to give a distance of 4.87 nm with a small distribution of distances. Postprint