title: Canopied trans-chelating bis(N-heterocyclic carbene) ligand: synthesis, structure and catalysis.
abstract: The terphspan scaffold was employed to support a bis(N-heterocyclic carbene) ligand () that provides a m-terphenyl canopy over one side of its metal complexes. Single-crystal X-ray diffraction studies on a silver complex of {[Ag()]AgBr(2)}(2) revealed an unusual tetranuclear silver core with a Ag-Ag bond distance of 3.0241(8) A with as a trans-chelating ligand (C-Ag-C = 171 degrees ). A preliminary X-ray structure of pseudo-square planar [PdCl(2)()] showed a similar binding mode of (C-Pd-C = 177 degrees ). High yields were obtained in Suzuki-Miyaura coupling reactions utilizing [PdCl(2)()] as the procatalyst and the results were compared with analogous complexes of trans-spanning diphosphine () and diphosphinite () complexes. The diphosphinite complex, [PdCl(2)()], decomposes to [mu-ClPd(PPh(2)OH)(PPh(2)O)](2) at room temperature.
authors.affiliation: Department of Chemistry and Center for Optical Materials Science and Engineering Technologies (COMSET), Clemson University, Clemson, SC 29634, USA.
authors.forename: Brad P
authors.initials: BP
authors.lastname: Morgan
authors.forename: Gabriela A
authors.initials: GA
authors.lastname: Galdamez
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Gilliard
authors.forename: Rhett C
authors.initials: RC
authors.lastname: Smith