1008780-64-0Relevant articles and documents
Strong intra- and intermolecular aurophilic interactions in a new series of brilliantly luminescent dinuclear cationic and neutral Au(I) benzimidazolethiolate complexes
Schneider, Jacob,Lee, Young-A.,Perez, Javier,Brennessel, William W.,Flaschenriem, Christine,Eisenberg, Richard
, p. 957 - 968 (2008/10/09)
The structural and photophysical properties of a new series of cationic and neutral Au(I) dinuclear compounds (1 and 2, respectively) bridged by bis(diphenylphosphino)methane (dppm) and substituted benzimidazolethiolate (X-BIT) ligands, where X = H (a), Me (b), OMe (c), and Cl (d), have been studied. Monocationic complexes, [Au2-(M-X-BIT)(μ-dppm)](CF 3CO2), were prepared by the reaction of [Au 2(μ-dppm)](CF3CO2)2 with 1 equiv of X-BIT in excellent yields. The cations 1a-1d possess similar molecular structures, each with a linear coordination geometry around the Au(I) nuclei, as well as relatively short intramolecular Au(I)...Au(I) separations ranging between 2.88907-(6) A for 1d and 2.90607(16) A for 1a indicative of strong aurophilic interactions. The cations are violet luminescent in CH 2Cl2 solution with a λemmax of ca. 365 nm, assigned as ligand-based or metal-centered (MC) transitions. Three of the cationic complexes, 1a, 1b, and 1d, exhibit unusual luminescence tribochromism in the solid-state, in which the photoemission is shifted significantly to higher energy upon gentle grinding of microcrystalline samples with ΔE = 1130 cm-1 for 1a, 670 cm-1 (1b), and 870 cm-1 (1d). The neutral dinuclear complexes, [Au2(μ-X- BIT)(μ-dppm)] (2a-2d) were formed in good yields by the treatment of a CH2Cl2 solution of cationic compounds (1) with NEt 3. 2a-2d aggregate to form dimers having substantial intra- and intermolecular aurophilic interactions with unsupported Au(I)...Au(I) intermolecular distances in the range of 2.8793(4)-2.9822(8) A, compared with intramolecular bridge-supported separations of 2.8597(3)-2.9162(3) A. 2a-2d exhibit brilliant luminescence in the solid-state and in DMSO solution with red-shifted λemmax energies in the range of 485-545 nm that are dependent on X-BIT and assigned as ligand-to-metal-metal charge transfer (LMMCT) states based in part on the extended Au...Au...Au...Au interactions.
