Molecular Switching Framework Materials
Soft porous crystals, defined as porous solids that possess both a highly ordered network and structural transformability, offer a unique set of selective storage and separation functionality. Porous coordination polymers (PCPs) are a characteristic example of such systems as they are highly crystalline, soft and have tunable porous architectures. In ‘third generation’ PCPs, synergistic framework transformations occur in response to molecular guests resulting in guest- switchable bistability (i.e., ‘gated’ porous behaviour) and can lead to emergent porous properties. Importantly, aside from a purely structural transformation, other physical attributes, such as electron transfer and spin state can be perturbed in parallel with PCP flexing. These multi- functioning PCPs offer advanced capabilities, such as molecular sensing due to strong coupling between the host lattice and the guest.
Our research in the field of PCPs focuses on exploiting their structural flexibility to tailor the transition pathway and characteristics of spin crossover-active framework materials. Spin crossover (SCO) is a classic example of molecular switching, whereby two distinct states (high spin (HS) and low spin (LS)) can be accessed by external perturbation (e.g. T, P, light, guest exchange). We have shown that by integrating arrays of competing host-host and host-guest interactions into such frameworks, mixed spin state species (HSnLS1-n) can be stabilized. External perturbation on such species sees the emergence of multistep spin transition pathways which are sought after for higher order data storage applications and advancing our fundamental appreciation of lattice cooperativity. By this approach we have produced a diverse range of multi- stepped (two-,1 three-2 and four-stepped3), guest-modulated2,4 and ambient5 spin transitions. Suzanne M. Neville
- Y.M. Klein, N.F. Sciortino, F. Ragon, C.E. Housecroft, C.J. Kepert, S.M. Neville, Chem. Comm. 2014, 50, 3838-3840.
- M.J. Murphy, K.A. Zenere, F. Ragon, P.D. Southon, C.J. Kepert, S.M. Neville, J.Am. Chem. Soc. 2017, 139, 1330-1335.
- N.F. Sciortino, K.A. Zenere, M.E. Corrigan, G.J. Halder, G. Chastanet, J.-F. Letard, C.J. Kepert, S.M. Neville, Chem. Sci. 2017, 8, 701-707.
- F. Sciortino, F. Ragon, K.A. Zenere, P.D. Southon, G.J. Halder, K.W. Chapman, L.Piniero-Lopez, J.A. Real, C.J. Kepert, S.M. Neville, Inorg. Chem. 2016, 55, 10490-10498.
- K.A. Zenere, S.G. Duyker, E. Trzop, E. Collet, B. Chan, P.W. Doheny, C.J. Kepert, S.M. Neville Chem. Sci., 2018, 9, 5623-5629