Stability of [2]pseudorotaxanes templated through second-sphere coordination.
A series of nine trans-dichlorobis(pyridine)palladium(II) complexes were prepared (2a-i), containing different 4-substituted pyridine co-ligands. The association constants between these Pd-complexes and 1 were measured, and their values plotted against corresponding sigma(p) degrees values. Measurement of the hydrogen bond acceptor capability of the chloride co-ligands revealed the presence of a linear free energy relationship between the electronic induction of a given 4-substituted pyridine co-ligand and the subsequent complexation strength in [2]pseudorotaxane formation. These trends also extended to trans-dibromobis(pyridine)palladium(II) (3a-e) and trans- dichlorobis(pyridine)platinum(II) complexes (5a-e) when plotted against sigma(p) degrees values. In addition, solid-state structures of three [2]pseudorotaxanes (1.2h, 1.2i, and 1.5e) were determined by single crystal X-ray diffraction further confirming the viability of this template in forming interpenetrated molecular architectures.
Blight
Barry A
BA
Department of Chemistry, The University of Western Ontario, 1151 Richmond Street, Chemistry Building, London, Ontario N6A 5B7, Canada.
Wisner
James A
JA
Jennings
Michael C
MC