Bloch, W.M.Abe, Y.Holstein, J.J.Wandtke, C.M.Dittrich, B.Clever, G.H.2018-11-152018-11-152016Journal of the American Chemical Society, 2016; 138(41):13750-137550002-78631520-5126http://hdl.handle.net/2440/116075Due to the inherent difficulties in achieving a defined and exclusive formation of multicomponent assemblies against entropic predisposition, we present the rational assembly of a heteroleptic [Pd2LA2LB2]4+ coordination cage achieved through the geometric complementarity of two carefully designed ligands, LA and LB. With Pd(II) cations as rigid nodes, the pure distinctly angular components readily form homoleptic cages, a [Pd2LA4]4+ strained helical assembly and a [Pd4LB8]8+ box-like structure, both of which were characterized by X-ray analysis. Combined, however, the two ligands could be used to cleanly assemble a cis-[Pd2LA2LB2]4+ cage with a bent architecture. The same self-sorted product was also obtained by a quantitative cage-to-cage transformation upon mixing of the two homoleptic cages revealing the [Pd2LA2LB2]4+ assembly as the thermodynamic minimum. The structure of the heteroleptic cage was examined by ESI-MS, COSY, DOSY, and NOESY methods, the latter of which pointed toward a cis-conformation of ligands in the assembly. Indeed, DFT calculations revealed that the angular ligands and strict Pd(II) geometry strongly favor the cis-[Pd2LA2LB2]4+ species. The robust nature of the cis-[Pd2LA2LB2]4+ cage allowed us to probe the accessibility of its cavity, which could be utilized for shape recognition toward stereoisomeric guests. The ability to directly combine two different backbones in a controlled manner provides a powerful strategy for increasing complexity in the family of [Pd2L4] cages and opens up possibilities of introducing multiple functionalities into a single self-assembled architecture.en© 2016, American Chemical SocietyJournal article003007493210.1021/jacs.6b086940003859921000452-s2.0-84992188191368804Bloch, W.M. [0000-0003-1084-1287]