Functionalizing 2,2'-bipyridines at the 5-position for the synthesis of sulfate encapsulating receptors

ORGN 712

Peter V. Bonnesen, bonnesenpv@ornl.gov1, Radu Custelcean, custelceanr@ornl.gov2, Benjamin P. Hay, haybp@ornl.gov2, Jerome Bosano2, and Vilmos Kertesz2. (1) Center for Nanophase Materials Sciences and Chemical Sciences Division, Oak Ridge National Laboratory, Oak Ridge, TN 37831, (2) Chemical Sciences Division, Oak Ridge National Laboratory, PO Box 2008, Oak Ridge, TN 37831-6119
A series of 2,2'-bipyridines substituted at the 5-position with aminoalkyl or aminoaryl substituents was prepared as building blocks for the synthesis of novel 1,3-bis-bipyridyl-substituted urea ligands. Depending on the structure of the R-group linking the bipyridine to the urea, the ligands can self-assemble with transition-metal sulfates to form cage complexes of the type M4L6 in which the sulfate is encapsulated inside the cage, as determined by X-ray crystallography. The 5-substituted 2,2'-bipyridines were constructed using the Kröhnke cyclization, followed by the appropriate functionalization of the 5-substituent to obtain the desired 5-aminoalkyl or 5-aminoaryl bipyridine.