The overhanging carboxylic acid strategy: an alternative route to the porphyrin core expansion/modification for the coordination of large metal ions

Gac, Stéphane Le; Boitrel, Bernard

doi:10.1142/s1088424612500514

Cited by 13 publications

(6 citation statements)

References 34 publications

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“…By doing so, several combinations of homo and heterobimetallic species would be virtually accessible, thus defining a dynamic library of metalloporphyrins. This strategy lies on recent results from our group obtained with bis-strap overhanging carboxylic acid(s) porphyrins. , We have indeed shown that two types of bimetallic complexes were accessible with such ditopic chelates (Figure ). On the one hand, “bridged” C 2 -symmetric homobimetallic species with the metal ions on opposite sides both bound to the porphyrin N-core and to a carboxylate of a strap (type I, lower part in Figure ) were observed with the C 2 -symmetric chelate 1 and Hg(II), Cd(II), Pb(II), and Bi(III) ions [ 1Hg 2 , 1Cd 2 , 1Pb 2 , and 1(BiOAc) 2 ] .…”

Section: Introductionmentioning

confidence: 96%

Heterobimetallic Porphyrin Complexes Displaying Triple Dynamics: Coupled Metal Motions Controlled by Constitutional Evolution

et al. 2014

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A bis-strap porphyrin ligand (1), with an overhanging carboxylic acid group on each side of the macrocycle, has been investigated toward the formation of dynamic libraries of bimetallic complexes with Hg(II), Cd(II), and Pb(II). Highly heteroselective metalation processes occurred in the presence of Pb(II), with Hg(II) or Cd(II) bound out-of-plane to the N-core and "PbOAc" bound to a carboxylate group of a strap on the opposite side. The resulting complexes, 1(Hg)·PbOAc and 1(Cd)·PbOAc, display three levels of dynamics. The first is strap-level (interactional dynamics), where the PbOAc moiety swings between the left and right side of the strap owing to a second sphere of coordination with lateral amide functions. The second is ligand-level (motional dynamics), where 1(Hg)·PbOAc and 1(Cd)·PbOAc exist as two degenerate states in equilibrium controlled by a chemical effector (AcO(-)). The process corresponds to a double translocation of the metal ions according to an intramolecular migration of Hg(II) or Cd(II) through the N-core, oscillating between the two equivalent overhanging carbonyl groups, coupled to an intermolecular pathway for PbOAc exchanging between the two equivalent overhanging carboxylate groups (N-core(up) ⇆ N-core(down) coupled to strap(down) ⇆ strap(up), i.e., coupled motion #1 in the abstract graphic). The third is library-level (constitutional dynamics), where a dynamic constitutional evolution of the system was achieved by the successive addition of two chemical effectors (DMAP and then AcO(-)). It allowed shifting equilibrium forward and backward between 1(Hg)·PbOAc and the corresponding homobimetallic complexes 1(Hg2)·DMAP and 1(Pb)·PbOAc. The latter displays a different ligand-level dynamics, in the form of an intraligand coupled migration of the Pb(II) ions (N-core(up) ⇆ strap(up) coupled to strap(down) ⇆ N-core(down), i.e., coupled motion #2 in the abstract graphic). In addition, the neutral "bridged" complexes 1HgPb and 1CdPb, with the metal ions on opposite sides both bound to the N-core and to a carboxylate of a strap, were structurally characterized. These results establish an unprecedented approach in supramolecular coordination chemistry, by considering the reversible interaction of a metal ion with the porphyrin N-core as a new source of self-organization processes. This work should provide new inspirations for the design of innovative adaptative materials and devices.

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Section: Introductionmentioning

confidence: 96%

Heterobimetallic Porphyrin Complexes Displaying Triple Dynamics: Coupled Metal Motions Controlled by Constitutional Evolution

et al. 2014

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“…In all of the above-mentioned examples, however, there was no specific design of the macrocycle, resulting in a lack of versatility. Conversely, appending a binding motif such as a carboxylic acid in the vicinity of the primary coordination site has proved to be a versatile strategy for the formation of bimetallic species with the period 6 main-group and late transition metals . Such an environment allows the stabilization of unique homodinuclear complexes with Pb(II) (e.g., 2Pb 2 in Figure a) and Hg(II) cations, in which each metal ion is bound to both the N core and a hanging carboxylate group.…”

Section: Introductionmentioning

confidence: 99%

Metal Migration Processes in Homo- and Heterobimetallic Bismuth(III)–Lead(II) Porphyrin Complexes: Emergence of Allosteric Newton’s Cradle-like Devices

et al. 2012

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Metal ion migration in a bis-strapped porphyrin ligand with overhanging carboxylate groups has been investigated in solution. Two types of homobimetallic complexes are generated with Pb(II) and Bi(III) cations, which stand on both sides of the macrocycle: (i) a dissymmetric complex with one cation bound to the porphyrin N core and the other cation hung over the N core through bonding with a carboxylate of a strap; (ii) a C(2)-symmetric complex with both cations coordinated to the N core and to the carboxylate groups of the straps. Variable-temperature NMR studies and 2D rotational Overhauser effect spectroscopy NMR experiments have shown that in the former dissymmetric complexes, the two cations undergo a coupled intramolecular migration resulting in exchange of their coordination modes. Such complexes constitute active states of Newton's cradle-like devices (NCDs), with the ion migration rate depending on the lability of the metal-ligand interactions [Pb(II) faster than Bi(III) NCDs]. On the other hand, the C(2)-symmetric complexes constitute either an inactive state [with Pb(II)] or a resting state [with Bi(III)] of an NCD, since they correspond respectively to a precursor or an intermediate in the motion of the cations. The NCDs are under both allosteric and acid-base control: (i) with Pb(II), the addition of an allosteric effector such as an acetate anion to the medium allows the conversion of the symmetric form to the dissymmetric one, thus triggering the Newton's cradle-like motion of the cations; (ii) with Bi(III), a lifted state was converted to a resting one by the addition of protons and then restored by the addition of a base. As an extension to nondegenerate systems, a heterobimetallic Bi(III)-Pb(II) complex was selectively obtained, and it constitutes a frozen lifted state of a dissymmetric NCD. All of these homo- and hetero-NCDs could be successively formed by selective metal ion exchange. These unique findings open the way to novel tristable devices.

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“… The substitution of the anisole moieties for phenol and quinone units strongly affects the kinetics of Zn II complexation in the following order: L Ome ≪ L OH < L Q (hours vs. minutes or less). Two factors can be invoked to explain this phenomenon: the decrease of steric crowding around the site of complexation (calixarene small rim) and the possible participation of the O ‐lone pairs as transient donors favoring approach and desolvation of the Zn II cation [54] . Indeed, these O ‐lone pairs differ strongly by their donor ability and orientation.…”

Section: Resultsmentioning

confidence: 99%

Selective Metal‐ion Complexation of a Biomimetic Calix[6]arene Funnel Cavity Functionalized with Phenol or Quinone

Aoun

Nyssen

Richard

et al. 2022

Chemistry A European J

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The overhanging carboxylic acid strategy: an alternative route to the porphyrin core expansion/modification for the coordination of large metal ions

Cited by 13 publications

References 34 publications

Heterobimetallic Porphyrin Complexes Displaying Triple Dynamics: Coupled Metal Motions Controlled by Constitutional Evolution

Heterobimetallic Porphyrin Complexes Displaying Triple Dynamics: Coupled Metal Motions Controlled by Constitutional Evolution

Metal Migration Processes in Homo- and Heterobimetallic Bismuth(III)–Lead(II) Porphyrin Complexes: Emergence of Allosteric Newton’s Cradle-like Devices

Selective Metal‐ion Complexation of a Biomimetic Calix[6]arene Funnel Cavity Functionalized with Phenol or Quinone

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