Combination of suitable bis- or (poly) pyridine ligands with square planar palladium(II) centre has yielded an impressive range of discrete coordination cages and catenanes owing to their ease of formation and predictable ligand exchange dynamics.1 Coordination driven self-assembly has been one of the most effective approaches to rationally design a large assortment of discrete 2D and 3D architectures with control over their size and shape.2 These supramolecular cages having single cavities show many outstanding applications such as host guest chemistry, selective anion recognition, drug delivery and catalysis2 because of their interesting structures and internal cavities.
However, metallosupramolecular complexes containing two or more 2D-cavities within a single system have been well explored3 whereas coordination cages containing two or more 3D-cavities are extremely rare.4 To construct these architectures with distinguishable cavities two approaches have unfolded. The first approach has employed ligands that are known to generate single cavity cages and extends them in a lengthwise fashion to generate new rigid multidentate ligand and the second involves rational catenation of two (or more) discrete single cavity cages to attain multicavity architectures.5 Construction of discrete coordination architecture having multiple number of 3D-cavities is an interesting task. The objective of our work is to synthesis new unsymmetrical tridentate ligands and their respective multicavity cages which can be used for selective hetero guest encapsulation.
References: 1. N. B. Debata, D. Tripathy and D. K. Chand, Coord. Chem. Rev., 2012, 256, 1831. 2. W. M. Bloch and G. H. Clever, Chem. Commun., 2017, 53, 8056.
3. (a) S. Prusty, K. Yazaki, M. Yoshizawa and D. K. Chand, Chem. Eur. J., 2017, 23, 12456.
(b) M. Ruben, J. Rojo, F. J. Romeo-Salguero, L. H. Uppadine & J. -M. Lehn, Angew. Chem. Int. Ed., 2004, 43, 3644.
4. S. Samantray, S. Krishnaswamy and D. K. Chand, Nat. Commun., 2020, 11, 880.
5. R. A. S. Vasdev, D. Preston and J. D. Crowley, Chem. Asian J., 2017, 12, 2513.