Cd(II), Zn(II), and Pd(II) complexes of an isoindoline pincer ligand: consequences of steric crowding.
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.
Dietrich
Brandon L
BL
Department of Chemistry, Western Washington University, Bellingham, Washington 98225, USA.
Egbert
Jonathan
J
Morris
Aimee M
AM
Wicholas
Mark
M
Anderson
Oren P
OP
Miller
Susie M
SM
D002104:Cadmium / Q000737:chemistry*; D008024:Ligands; D008956:Models, Chemical; D008958:Models, Molecular; D015394:Molecular Structure; D010165:Palladium / Q000737:chemistry*; D015032:Zinc / Q000737:chemistry*
D008024:Ligands; D002104:Cadmium; D010165:Palladium; D015032:Zinc