NHC-Au(i) complexes bearing trispyrazolyl borate (Tp) ligands: efficient platforms for bimetallic species

Treatment of NHC-AuCl (NHC = IPr and IMes) complexes with equimolar amounts of KTpR2 (R = Me, H) salts in tetrahydrofuran produces in high yields the heteroleptic complexes 3-6 with the general formula NHC-Au-TpR2. As the TpR ligand in complexes 3-6 features a k1-N type coordination toward the gold(i) center, the subsequent addition of group 10 and 11 metal precursors (NiII, PtII, CuII) results in the isolation of heterobimetallic Au/M complexes supported by TpR platforms. All new metal complexes have been fully characterized by elemental analysis and NMR spectroscopy, and in the case of 3, 4 and 6 by X-ray crystallography.

Hydroxyl-functionalized triazolylidene-based PEPPSI complexes: metallacycle formation effect on the Suzuki coupling reaction

We report the preparation and full characterization of a series of hydroxyl functionalized 1,2,3-triazolylidene-based PEPPSI complexes 2a-c and their catalytic application in the Suzuki cross coupling reaction of aryl chlorides/amides with boronic acids. Under basic reaction conditions, complexes 2a-c show a notable increase in their catalytic efficiency compared with two ether-wingtip functionalized PEPPSI analogues (3 and 4) and a commercially available NHC-Pd complex (5). The catalytic results suggest that deprotonation of the hydroxyl group in complexes 2a-c plays an important role in the overall process. Deprotonation of the alcohol moiety of complexes 2a-b with sodium tert-butoxide allows for the isolation of metallacycles 6a-b, which are proposed as the active species of cross coupling reactions.

Chrysin functionalized NHC–Au(i) complexes: synthesis, characterization and effects on the nematode Caenorhabditis elegans

The synthesis and biological effects on the nematodeCaenorhabditis elegansof chrysin functionalized Au(i)–NHC complexes are reported.