title: Cd(II), Zn(II), and Pd(II) complexes of an isoindoline pincer ligand: consequences of steric crowding.
abstract: The sterically crowded isoindoline pincer ligand, 6'-MeLH, prepared by condensation of 4-methyl-2-aminopyridine and phthalonitrile, exhibits very different reaction chemistry with Cd2+, Zn2+, and Pd2+. Three different ligand coordination modes are reported, each dependent upon choice of metal ion. This isoindoline binds to Cd2+ as a charge-neutral, zwitterionic, bidentate ligand using imine and pyridine nitrogen atoms to form the eight-coordinate fluxional complex, Cd(6'-MeLH)2(NO3)2. In the presence of Zn2+, however, loss of a pyridine arm occurs through solvolysis and tetrahedrally coordinated complexes are formed with coordination of pyrrole and pyridine nitrogen atoms. Reaction with Pd2+ produces the highly distorted, square planar complex Pd(6'-MeL)Cl in which a deprotonated isoindoline anion coordinates as a tridentate pyridinium NNC pincer ligand.
authors.affiliation: Department of Chemistry, Western Washington University, Bellingham, Washington 98225, USA.
authors.forename: Brandon L
authors.initials: BL
authors.lastname: Dietrich
authors.forename: Jonathan
authors.initials: J
authors.lastname: Egbert
authors.forename: Aimee M
authors.initials: AM
authors.lastname: Morris
authors.forename: Mark
authors.initials: M
authors.lastname: Wicholas
authors.forename: Oren P
authors.initials: OP
authors.lastname: Anderson
authors.forename: Susie M
authors.initials: SM
authors.lastname: Miller
mesh_terms: D002104:Cadmium / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
chemical_list: D008024:Ligands; D002104:Cadmium; D010165:Palladium; D015032:Zinc