Synthesis and optical resolution of a Cu(i) double-stranded helicate with ketimine-bridged tris(bipyridine) ligands

Furusho, Yoshio; Goto, Hidetoshi; Itomi, Ken; Katagiri, Hiroshi; Miyagawa, Takashi; Yashima, Eiji

doi:10.1039/c1cc13333k

Cited by 24 publications

(24 citation statements)

References 41 publications

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“…Thus acetonitrile leads to an acceleration of three orders of magnitude. As similar range was found for the inversion in a double-stranded helicate with ketimine-bridged tris(bipyridine) ligands [83]. The activation data in CD 2 Cl 2 were determined to DH à = 112 kJ mol À1 and DS à = 22.1 -J mol À1 K À1 along with k 303 = 3.61 Â 10 À6 s À1 (t½ = 53.5 h).…”

Section: Kinetics In Mononuclear Copper(i) Phenanthroline and Diiminesupporting

confidence: 69%

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Heteroleptic copper phenanthroline complexes in motion: From stand-alone devices to multi-component machinery

Goswami

Schmittel

2018

Coordination Chemistry Reviews

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a b s t r a c tTwo and a half decades of copper phenanthroline-based switches, devices and machines have illustrated the rich dynamic nature of these metal complexes. With an emphasis on the metal-ligand dissociation as the rate-determining step the present review summarizes not only spectacular examples of machinery, but also highlights rate data collected during a variety of investigations. Copper-ligand exchange reactions are mostly triggered by redox processes, addition of metal ions or addition of ligands. While the rate data spread over >8 orders of magnitude, individual effects of solvent, steric bulk, flexibility, r-basicity and the trajectory (intra-vs. intermolecular dissociation) have large impact. Unfortunately, in many cases the exact mechanism in the rate-determining step (nucleophile-induced vs. monomolecular metal-ligand dissociation) has not been determined, suggesting to invest further efforts in the physical (in)organic chemistry of such coordination-driven systems.

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Section: Kinetics In Mononuclear Copper(i) Phenanthroline and Diiminesupporting

confidence: 69%

“…It was argued that the unshielded phenanthroline in the thread is important for the high rate constant. This principle, somewhat modified, was used by the same authors to set up the fast shuttle [ [4] Cu (83)] + (see Fig. 38) [90].…”

Section: Topologically Controlled Switches Devices and Machinesmentioning

confidence: 99%

Heteroleptic copper phenanthroline complexes in motion: From stand-alone devices to multi-component machinery

Goswami

Schmittel

2018

Coordination Chemistry Reviews

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“…Recently double‐ and triple‐stranded helicates were reported by Furusho and Stephenson et al. from achiral bis‐bidendate building blocks, and trinuclear triple‐stranded homo‐ and heterometallic helicates were reported by Ghosh and co‐workers . Metallohelices exhibiting anticancer activity with nanomolar potency were reported by Kaner et al .…”

Section: Figurementioning

confidence: 98%

Luminescent Silver–Purine Double Helicate: Synthesis, Self‐Assembly and Antibacterial Action

et al. 2016

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How would you describe your research? We have designed al uminescent silver-purine helical coordination complex and studied its antibacterial activity against both Gram-positive and Gram-negative bacteria. The MIC values indicate that the complex exhibits significantly better activity against Gram-negative bacteria, especially against E. coli.L uminescent properties of this complex were used to study its bacterial cell uptake with the help of fluorescence and scanning electron microscopy methods. This study suggests that silver-purine double helical complexes could be used as potential antibacterial agents.

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“…The control of its handedness is of key importance for developing one-handed helicates with a specific functionality that involves separation 12 and sensing enantiomers 12–14 and asymmetric catalysis 15 as well as antimicrobial materials 16 . However, double-stranded helicates composed of achiral molecular strands assembled with labile metal ions, such as Cu(I) ions, mostly exist in an equal mixture of interconvertible right- ( P ) and left-handed ( M ) helices and their resolution into the enantiomers remains difficult except for one example 17 . A preferred-handed helicity can be biased in such kinetically labile double-stranded helicates using a chiral template 18 or chiral auxiliaries 19–21 , but the helicates likely lose their optical activities after removal of the chiral template or chiral auxiliaries due to irreversible racemization in solution.…”

Section: Introductionmentioning

confidence: 99%

Water-mediated deracemization of a bisporphyrin helicate assisted by diastereoselective encapsulation of chiral guests

et al. 2019

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Deracemization is a powerful method by which a racemic mixture can be transformed into an excess of one enantiomer with the aid of chiral auxiliaries, but has been applied only to small chiral molecular systems. Here we report a deracemization of a racemic double-stranded spiroborate helicate containing a bisporphyrin unit upon encapsulation of chiral aromatic guests between the bisporphyrin. The chiral guest-included helicate is kinetically stable, existing as a mixture of right- and left-handed double helices, which eventually undergo an inversion of the helicity triggered by water resulting from the water-mediated reversible diastereoselective B-O bond cleavage/reformation of the spiroborate groups, thus producing an optically-active helicate with a high enantioselectivity. Quantum chemical calculations suggest that the stereospecific CH-π interactions between the porphyrin hydrogen atoms of the helicate and an aromatic pendant group of the chiral guest play a key role in the enhancement of the helical handedness of the helicate.

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Synthesis and optical resolution of a Cu(i) double-stranded helicate with ketimine-bridged tris(bipyridine) ligands

Cited by 24 publications

References 41 publications

Heteroleptic copper phenanthroline complexes in motion: From stand-alone devices to multi-component machinery

Heteroleptic copper phenanthroline complexes in motion: From stand-alone devices to multi-component machinery

Luminescent Silver–Purine Double Helicate: Synthesis, Self‐Assembly and Antibacterial Action

Water-mediated deracemization of a bisporphyrin helicate assisted by diastereoselective encapsulation of chiral guests

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