Synthesis and characterization of {[CuI3Sn2(OBut)6]+[CuII(hfac)3]−} – A heterometallic cluster with unique triangular copper(I) core

• Heterometallic Sn–Cu ionic compound contains copper atoms in two different oxidation states.
• Heterometallic cation features a triangular copper(I) core stabilized by cuprophilic interactions.
• Multinuclear NMR studies indicate the retention of heterometallic structure in solution.

New heterometallic Sn–Cu compound that contains copper atoms in two different oxidation states was obtained by the solid state reaction between Sn(OBut)2 (OBut = tert-butoxide) and Cu(hfac)2 (hfac = hexafluoroacetylacetonate). Single crystal X-ray diffraction study revealed the ionic structure of a compound that can be formulated as {[CuI3Sn2(OBut)6]+[CuII(hfac)3]−} (1) with no significant interactions between complex cation and anion. The anion is comprised of an octahedrally coordinated by three chelating β-diketonate ligands CuII atom that shows a typical tetragonal Jahn–Teller distortion of the polyhedron. The heterometallic [Cu3Sn2(OBut)6]+ cation features a CuI triangle capped by two Sn(OBut)3 units. All alkoxide ligands are μ2-bridging between Sn and Cu atoms providing a trigonal pyramidal geometry around tin that is consistent with lone pair SnII centers. An almost perfect triangular copper core is stabilized by cuprophilic interactions, similar to those in other polynuclear CuI compounds. The cation represents the first example of a CuI triangular arrangement that is not supported by μ3-centering atoms or by μ2-all-side bridging. Multinuclear NMR studies unambiguously confirm the retention of heterometallic cluster in solution as well as the absence of ligand redistribution between the anion and cation. The use of a mixed-ligand approach creates broad opportunities for designing new heterometallic complexes with unusual architectures that are not observed in homoleptic counterparts.

Synthesis and characterization of new heterometallic Sn–Cu ionic compound {[CuI3Sn2(OBut)6]+[CuII(hfac)3]−} is reported. The heterometallic cation features a CuI triangular core supported by cuprophilic interactions.Figure optionsDownload as PowerPoint slide