A Highly Modular and Convergent Approach for the Synthesis of Stimulant-Responsive Heteroligated Cofacial Porphyrin Tweezer Complexes

Abstract

The synthesis of new hemilabile phosphine ligands and their reaction with [Rh(COE)2Cl]2 to form dissymmetric heteroligated tweezer complexes using a halide-induced ligand rearrangement reaction are reported. These complexes can undergo reactions with small-molecule ligands and elemental anions quantitatively in situ, which serve to regulate the porphyrin-porphyrin distances and interactions within the assembly.

An Allosterically Regulated, Four-State Macrocycle

“…WLA-based supramolecular systems are attractive because they offer (1) chemical access to multiple different states with tailorable selectivity and binding affinities, 16,17 (2) high functional group tolerance, 11,18 and (3) modularity, including access to structures with a wide variety of metal nodes and ligand types. 9,10,18 Many stimuli-responsive systems have been developed based on this platform, through the incorporation of catalytic, 19−23 redox-active, 24,25 and host− guest recognition sites 17 into the ligands in such a way that small-molecule-induced structural changes result in marked changes in the properties of these complexes.…”

“…The rational design of supramolecular systems, which undergo reversible structural changes, has been a long-standing goal of chemists because of the potential for developing technologically useful catalysts, switches, and sensors. , Coordination-driven supramolecular chemistry has emerged as a powerful means to assemble large and complex macrocycles, cages, and capsules, with general methods developed by several groups, − including our own, − for assembling such multicomponent structures. Among the different approaches to coordination-driven supramolecular constructs, the weak-link approach (WLA) has emerged as a powerful means for synthesizing complexes that can undergo reversible small-molecule-induced structural changes and therefore be toggled between “closed” rigid states and “open” flexible ones (Figure a–c). ,, Through the modular and convergent assembly of metal ions and hemilabile ligands, the WLA provides a platform for engineering molecular selectivity and stimuli-responsiveness with deliberate control.…”

“…Among the different approaches to coordination-driven supramolecular constructs, the weak-link approach (WLA) has emerged as a powerful means for synthesizing complexes that can undergo reversible small-molecule-induced structural changes and therefore be toggled between “closed” rigid states and “open” flexible ones (Figure a–c). ,, Through the modular and convergent assembly of metal ions and hemilabile ligands, the WLA provides a platform for engineering molecular selectivity and stimuli-responsiveness with deliberate control. WLA-based supramolecular systems are attractive because they offer (1) chemical access to multiple different states with tailorable selectivity and binding affinities, , (2) high functional group tolerance, , and (3) modularity, including access to structures with a wide variety of metal nodes and ligand types. ,, Many stimuli-responsive systems have been developed based on this platform, through the incorporation of catalytic, − redox-active, , and host–guest recognition sites into the ligands in such a way that small-molecule-induced structural changes result in marked changes in the properties of these complexes.…”

Box-like Heterometallic Macrocycles Derived from Bis-Terpyridine Metalloligands

“…Organometallic macrocycles have attracted increasing attention due to the aesthetic appeal of their triangles, squares, cages, and other polyhedra and great potential applications in the area of catalysis, selective recognition, and host–guest chemistry. − The incorporation of metal centers or organic linkers into these macrocycles could impart novel functionality and complexity to these systems. , Moreover, the design of molecular materials and devices based on multimetallic arrays supported by polydentate ligands has seen explosive growth, particularly in the formation of various heterometallic macrocycles derived from rich metalloligands. − Generally, substituted pyridines are prominent building blocks with rich coordination properties. − 4′-(4-Pyridyl)-2,2′:6′,2″-terpyridine (pyterpy) has been intensively explored due to its interesting properties and multifunctional coordination modes, and it has a strong ability to chelate metal centers to form ideal precursors [M(pyterpy) 2 ] n + …”

Enzymnachbildungen auf der Basis supramolekularer Koordinationschemie

“…[12d, 88,91] Die geschlossene und die offene Rhodium(I)-Zink(II)-Porphyrinstruktur 89 c bzw. 90 c (Abbildung 24) wurden synthetisiert und in Lösung spektroskopisch charakterisiert.…”