Zintl clusters, multifunctional ligands for homogeneous catalysts Oliver Townrow 1 , Andrew S. Weller 2 , Jose M. Goicoechea 1 1 University of Oxford, UK, 2 University of York, UK Zintl clusters are attractive supports for transition metal/ligand fragments. Such complexes can be viewed as molecular models for main group - transition metal alloys (TMMGAs) which have recently received significant attention as molten-state high temperature alkane dehydrogenation catalysts. 1 However, poor solubility and low yielding synthetic protocols have precluded the use of transition metal Zintl clusters in small molecule activation and catalysis. 2 We have recently reported the synthesis and reactivity of the first catalytically active Zintl cluster: Rh(COD) Ge 9 (Hyp) 3 ( 1 ) (COD = 1,5-cyclooctadiene; Hyp = Si(SiMe 3 ) 3 ) which is soluble in aliphatic hydrocarbons and can be isolated in high yields (>92%). 3 Complex 1 catalyzes the hydrogenation of COD and cis -cyclooctene. Ligand substitution of 1 gives access to clusters of form Rh(L)Ge 9 (Hyp) 3 , which feature coordinatively unsaturated rhodium centers and are active in H–H and C–H bond activation processes. 4 1 is also shown to accommodate multiple metal fragments, acting as a platform for the synthesis of homo- and hetero-multimetallic transition metal Zintl clusters. These results highlight that the [Ge 9 (Hyp) 3 ] − cage can act as a versatile, multifunctional ligand for constructing defined molecular models of TMMGAs.
Figure 1. Rh(COD)Ge9(Hyp)3(1) as a versatile, stable platform for catalysis and derivatisation. References 1. D. C. Upham, V. Agarwal, A. Khechfe, Z. R. Snodgrass, M. J. Gordon, H. Metiu and E. W. McFarland, Science , 2017, 358 , 917–921.R. 2. J. Wilson, B. Weinert and S. Dehnen, Dalton Trans. , 2018, 47 , 14861–14869. 3. O. P. E. Townrow, C. Chung, S. A. Macgregor, A. S. Weller and J. M. Goicoechea, J.Am. Chem. Soc. ,2020, 142 , 18330– 18335. 4. O. P. E. Townrow, S. B. Duckett, A. S. Weller and J. M. Goicoechea, Chem. Sci. , 2022, 13 ,7626–7633.
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