We thank Prof. Maria José Calhorda, Universidade de Lisboa, and Prof. Luis Vieros, Universidade Técnica de Lisboa, for DFT calculations and Dr. Charles Harding, Open University (UK), for calculation of g values. Funding from the Irish Research Council for Science, Engineering and Technology (IRCSET), FNRS (FRFC 2.4508.08, 2.4537.12, IISN 4.4507.10), Fundação para a Ciência e a Technologia, Enterprise Ireland, and the ERA-Chemistry programme is gratefully acknowledged. Significant funding for a SQUID magnetometer by the Irish Higher Education Authority is also gratefully acknowledged, as is generous support from University College Dublin (to G.G.M. and B.G.). T.E.K. and T.L. acknowledge the Irish Government’s Programme for Research in Third Level Institutions, Cycle 4, Ireland’s EU Structural Funds Programmes 2007–2013 and Career Enhancement and Mobility Fellowship co-funded by Marie Curie Actions.