The Omary team has recently discovered a new type of chemical bonds between d10 metal centers, in particular a CuI-AuI bond in a hexanuclear cluster complex. Outer-shell s0/p0 orbital mixing with d10 orbitals and symmetry reduction upon cupriphication of trigonal-planar gold(I) complexes are found to sensitize ground-state Cu(I)-Au(I) covalent bonds in the heterobimetallic Au4Cu2 {[Au2(μ-C2,N3-EtIm)2Cu(µ-3,5-(CF3)2Pz)]2, (1)} and near-unity phosphorescence quantum yields in both 1 and the related trinuclear {[Au2(μ-C2,N3-MeIm)2Cu(µ-3,5-(CF3)2Pz)], (2)}. While the crystal structures of 2 reveals dimer-of-trimer units non-covalently packed via two Au(I)-Cu(I) metallophilic interactions, 1 exhibits a hexanuclear cluster structure wherein two monomer-of-trimer units are linked by two quanta of a genuine d10-d10 polar-covalent bond with ligand-unassisted Cu(I)-Au(I) distances of 2.875 Å each – the shortest such an intermolecular distance between any two d10 centers so as to deem it a “metal-metal bond” vis-à-vis “metallophilic interaction.” Density-functional calculations estimate 35-43 kcal/mol binding energy. FT-IR spectra of 1 show multiple far-IR bands within 65-200 cm-1, assignable to vCu-Au as validated by both the Harvey-Gray method of crystallographic-distance-to-force-constant correlation and dispersive DFT computations (Morse potential PES and Dunham analysis). The presentation will also present findings for other manifestations whereby such a new bond is discovered and generalized via both a priori and a posteriori approaches for [MM’(m-L)n]m d10 species.

Dawn rise of new M-M' bonds: An experimental/theoretical 21st-century approach to Alchemize gold en route to sensitizing genuine, ligand-unassisted d10-d10 covalent metal-metal bonds

254th National Meeting (2017)

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