title: A rigid trans-spanning dinitrile ligand.
abstract: A rigid dinitrile ligand was synthesized from two xanthene units condensed to a naphthalene-1,4,5,8-diimide spacer. The rigidity and C shape of the ligand gave exclusively trans complexes with Pd(II), Ag(I), and Au(I). Evidence for complexation, coordination geometry, and stoichiometry was provided by a combination of 1H NMR, 19F NMR, and IR spectroscopy. The AuBF4 and PdCl2 complexes were shown to have a 1:1 (metal-to-ligand) stoichiometry and the AgBF4 complex was shown to have a 1:2 stoichiometry in solution. The preorganization of the dinitrile ligand resulted in complexes much more stable than their monodentate counterparts.
authors.affiliation: Department of Chemistry, Massachusetts Institute of Technology, Cambridge 02138, USA.
authors.forename: K D
authors.initials: KD
authors.lastname: Shimizu
authors.forename: J
authors.initials: J
authors.lastname: Rebek
mesh_terms: D006046:Gold; D007202:Indicators and Reagents; D007536:Isomerism; D007700:Kinetics; D008024:Ligands; D009682:Magnetic Resonance Spectroscopy; D008670:Metals; D015394:Molecular Structure; D009570:Nitriles / Q000138:chemical synthesis / Q000737:chemistry*; D010165:Palladium; D012834:Silver; D013055:Spectrophotometry, Infrared; D014966:Xanthenes / Q000138:chemical synthesis / Q000737:chemistry*
chemical_list: D007202:Indicators and Reagents; D008024:Ligands; D008670:Metals; C099462:N,N'-bis(2,7-di(tert-butyl)-5-cyano-9,9-dimethyl-9H-xanthen-4-yl)-1,4,5,8-naphthalenetetracarboxylic-1,8(4,5)-diimide; D009570:Nitriles; D014966:Xanthenes; D012834:Silver; D010165:Palladium; D006046:Gold