Perfluorinated ligands induce meridional metal stereochemistry to generate M8L12, M10L15 and M12L18 prisms
Journal of the American Chemical Society
American Chemical Society
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Kieffer, M., Pilgrim, B., Ronson, T., Roberts, D., Aleksanyan, M., & Nitschke, J. (2016). Perfluorinated ligands induce meridional metal stereochemistry to generate M8L12, M10L15 and M12L18 prisms. Journal of the American Chemical Society, 138 6813-6821. https://doi.org/10.1021/jacs.6b02445
Meridional (mer) coordination promotes the generation of larger and lower-symmetry prismatic metallosupramolecular structures, in contrast with the facial (fac) coordination common to smaller and higher-symmetry polyhedra. Here we describe a general route to the selective formation of large metallosupramolecular prisms that contain exclusively mer coordinated metal vertices. The use of 2-formylpyridine subcomponents that contain perfluorophenylene substituents at their 5-positions resulted in stereoselective formation of the iron(II) complexes from these subcomponents. Only mer vertices were observed, as opposed to the statistical fac/mer mixture otherwise generated. This mer-selective self-assembly could be used to prepare tetragonal (M_8L_12), pentagonal (M_10L_15) and hexagonal (M_12L_18) prisms, by taking advantage of the subtle selectivities imposed by the different anilines and counterions employed. The equilibrium between the tetragonal and pentagonal prism followed a linear free energy relationship, with the ratio between structures correlating with the Hammett σ_p^+ parameter of the incorporated aniline. The contrasting preferences of the fluorinated and non-fluorinated ligands to generate prisms and tetrahedra respectively were quantified energetically, with the destabilization increasing linearly for each “incorrect ligand” incorporated into either structure.
This project has received funding from the European Union's Horizon 2020 research and innovation programme under the Marie Sklodowska-Curie grant agreement No 642192 and was supported by the UK Engineering and Physical Sciences Research Council (EPSRC). The authors thank Diamond Light Source (UK) for synchrotron beamtime on I19 (MT8464 and MT11397), the Department of Chemistry NMR facility, University of Cambridge, and the EPSRC UK National Mass Spectrometry Facility at Swansea University. M.K. acknowledges the Cambridge Commonwealth, European and International Trust and the Frédéric Fontaine scholarship from Michelin SCA. B.S.P. acknowledges the Herchel Smith Research Fellowship from the University of Cambridge and a Fellowship from Corpus Christi College, Cambridge. D.A.R. acknowledges the Gates Cambridge Trust for Ph.D. funding.
European Commission (642192)
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External DOI: https://doi.org/10.1021/jacs.6b02445
This record's URL: https://www.repository.cam.ac.uk/handle/1810/256034