Exploiting reduced-symmetry ligands with pyridyl and imidazole donors to construct a second-generation stimuli-responsive heterobimetallic [PdPtL₄]⁴⁺ cage

Abstract

A new sequential metalation strategy that enables the assembly of a new more robust reduced symmetry heterobimetallic [PdPtL4]4+ cage C is reported. By exploiting a low-symmetry ditopic ligand (L) that...

Diastereoselective Self‐Assembly of Low‐Symmetry PdnL2n Nanocages through Coordination‐Sphere Engineering**

“…The lack of bilateral symmetry in L4 Q induced a lowering of the symmetry of L2 H in both cage isomers, resulting in distinct signals for all 12 protons, corroborated by the 13 C NMR spectrum (Figure S211). Whilst analysis of the 1 H NMR spectrum was made challenging by significant signal overlap, 2D NMR techniques (COSY, HMBC and TOCSY) enabled assignment of all peaks for both isomers (Figure S205).…”

Heterometallic cages: synthesis and applications

“…Very recently Crowley and co-workers synthesized a second generation [PdPtL 4 ] 4+ cage. 164 Unlike the first-generation cage which was synthesised using a subcomponent self-assembly pathway, this new cage was generated using the stepwise metallo–ligand symmetry interaction approach. A low symmetry ligand ( L20 ) which featured both imidazole and pyridine units was developed.…”

Self-assembly of conformation-adaptive dihydrophenazine-based coordination cages

“…It is evident that the extension of the conjugation within these ligands leads to a gradual reduction of their oxidation potentials, which may explain why L2 and L3 are vulnerable to oxidation during the self-assembly process. 34 In comparison to the ligands, the oxidation potentials of Cage1 , Cage2 and Cage3 all increased, with values of 0.637 V, 0.112 V, and −0.012 V, respectively. Notably, the most twisted Cage1 displayed the most pronounced shift (0.624 V) in oxidation potential compared to its corresponding ligand L1 .…”

“…Therefore, based on these results we can conclude that Cage2 should be the most thermodynamically stable isomer which is also consistent with the reported results that the cis -cage is the most stable one among other isomers. 30–35 The structures of all the ligands and cages were characterized through NMR and mass spectrometry, and unambiguously confirmed by single-crystal X-ray diffraction analysis.…”