Towards single-crystal-to-single-crystal transformations in organometallic chemistry via copper(i) complexes Chloe Johnson, Matthew R. Gyton,Andrew S. Weller, Simon B. Duckett University of York, UK Solid-state molecular organometallic (SMOM) chemistry uses organometallic complexes in single-crystal to single-crystal (SC-SC) transformations to provide unique synthetic and catalytic opportunities.1 For example, highly reactive σ-alkane complexes, that bind via 3c-2e interactions, cannot be isolated via traditional solution- state methods.2 However, application of SMOM techniques has allowed a variety of σ-alkane complexes to be isolated which are shown to be relatively stable in the solid-state.3 For example, the solid-gas SC-SC hydrogenation of [Rh(Cy2PCH2CH2PCy2)(NBD)][BArF4] (NBD = norbornadiene, ArF=3,5-(CF3)2C6H3) leads to the σ-alkane complex, [Rh(Cy2PCH2CH2PCy2)(η2η2-NBA)][BArF4] (NBA = norbornane).4 This imparted stability is due to the octahedral arrangement of the [BArF4]– anions which form a well-defined cavity, encapsulating and stabilising the reactive metal centre via non-covalent interactions.5 This arrangement of [BArF4]– anions also promotes the retention of crystallinity during subsequent SC-SC transformations, allowing substrates to reversibly access the metal center through resulting hydrophobic [BArF4]– channels. Previously, SMOM has concentrated on diphosphine complexes of group 9 metals, especially rhodium. This research project aims to expand the chemical space to group 11, as M(I) (M = Cu, Ag, Au) complexes are versatile, with a wide range of oxidation states and coordination geometries. M(I) is also d10, providing a labile coordination sphere for potential SC-SC reactivity, however SC-SC reactions of copper in the solid-state remain relatively underexplored.6,7 Herein, we report the synthesis and characterisation of novel copper(I) diphosphines, [Cu(R2P(CH2)nPR2) (MeCN)][BArF4] (R = Cy, tBu; n = 1, 4, 5) (Figure 1), wherein acetonitrile may act as a labile ligand to be substituted in subsequent SC-SC reactions. The SC-SC reactivity of these complexes is probed with gaseous substrates such as CO, C2H4 and NH3. References 1. Martínez-Martínez et al., ACS Catal., 2020, 10, 1984–1992. 2. b) Martínez-Martínez et al., Angew. Chemie Int. Ed., 2019, 58, 16873–16877.
3. Bernskoetter et al., Science, 2009, 326, 553–556. 4. a) Pike et al., Science, 2012, 337, 1648–1651. 5. Chadwick et al., Angew. Chemie, 2016, 128, 3741–3745. 6. c) Martínez-Martínez et al., J. Am. Chem. Soc., 2018, 140, 14958–14970. 7. Pike et al., J. Am. Chem. Soc., 2015, 137, 820–833. 8. Furfari et al., Chem. – A Eur. J., 2021, 27, 3177–3183. 9. Peralta et al., Inorg. Chem., 2021, 60, 11775–11783. 10. Chen et al., Angew. Chemie Int. Ed., 2021, 60, 27184-27188.
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