Takeharu Haino
Hiroshima University, Chemistry, Faculty Member
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The helicity of the supramolecular porphyrin polymers was determined by the chirality of solvent molecules, which permitted the polymer chains to be used in chiral sensing.
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By utilizing a confined space inside a coordination capsule consisting of achiral components, we achieve trimeric structures composed of acetic acid and 2,3‐disubstituted tartaric acid derivatives. Steric and electronic interactions... more
By utilizing a confined space inside a coordination capsule consisting of achiral components, we achieve trimeric structures composed of acetic acid and 2,3‐disubstituted tartaric acid derivatives. Steric and electronic interactions between the substituents on the tartaric acid and 2,2′‐bipyridyl arms of the capsule permit the transfer of the chirality of the tartaric acid to the capsule, resulting in diastereoenrichment of the host‐guest complexes of up to 92 % de. The chiral templates can be washed away with diethyl ether, leaving an enantiomerically enriched capsule. The resulting capsule biases the dynamic axial chirality of a 4,4′‐diacetoxybiphenyl guest carrying benzothiadiazole units, demonstrating guest‐to‐capsule and capsule‐to‐guest chirality transfer. The induced chirality on the bound guest enables it to emit circularly polarized luminescence in the NIR region, demonstrating the application of induced chirality for confined spaces for the generation of chiroptical proper...
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Self‐assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular‐level devices. Herein, zinc porphyrin derivatives bearing a... more
Self‐assembly of porphyrins is a fascinating topic, not only for mimicking chlorophyll assemblies in photosynthetic organisms, but also for the potential of creating molecular‐level devices. Herein, zinc porphyrin derivatives bearing a meta‐pyridyl group at the meso position were prepared and their assemblies studied in chloroform. Among the porphyrins studied, one with a carbamoylpyridyl moiety gave a distinct 1H NMR spectrum in CDCl3, which allowed the supramolecular structure in solution to be probed in detail. Ring‐current‐induced chemical‐shift changes in the 1H NMR spectrum, together with vapor‐pressure osmometry and diffusion‐ordered NMR spectroscopy, among other evidence, suggested that the porphyrin molecules form a trimer with a triangular cone structure. Incorporation of a directly linked porphyrin–ferrocene dyad with the same assembling properties in the assemblies led to a rare example of a light‐harvesting/charge‐separation system in which an energy gradient is incorpo...
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Chemistry, Catalysis, Calixarene, Oligomer, CHEMICAL SCIENCES, and 4 moreDimer, Pyrogallol, Resorcinol, and trimer
A brand-new self-folding biscavitand was synthesized from a feet-to-feet-connected bisresorcinarene. The X-ray crystal structure of the biscaivtand showed that the two cavities are tightly connected with four butylene linkages. The... more
A brand-new self-folding biscavitand was synthesized from a feet-to-feet-connected bisresorcinarene. The X-ray crystal structure of the biscaivtand showed that the two cavities are tightly connected with four butylene linkages. The conformationally coupled two cavities accommodated two cationic guests, showing a homotropic negative cooperativity in nonpolar solvents (toluene and chloroform). A polar tetrahydrofuran solvent weakened the cyclic hydrogen bonding interactions of the biscavitand, which resulted in noncooperative guest binding.
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To date, supramolecular chemistry techniques have been applied to fullerene polymer synthesis, enabling the development of main-chain fullerene polymers whose primary structure is well regulated, including linear, dendritic, and net-like... more
To date, supramolecular chemistry techniques have been applied to fullerene polymer synthesis, enabling the development of main-chain fullerene polymers whose primary structure is well regulated, including linear, dendritic, and net-like fullerene arrays. These research achievements have led to an intriguing scientific challenge to create main-chain fullerene polymers with higher structural regulation. Here, we report the fabrication of a helically organized fullerene array based on the supramolecular polymerization of chiral ditopic tetrakiscalix[5]arene hosts and a dumbbell-shaped fullerene. The molecular association between the chiral hosts and the dumbbell-shaped fullerene resulted in sizable supramolecular polymers in solution, with the highest degree of polymerization of more than 32. The achiral dumbbell-shaped fullerene exhibited circular dichroism in the π-π* transition bands arising from the fullerene moieties through supramolecular polymerization. End-capping experiments of the supramolecular helical polymers showed that the chirally twisted conformation of the dumbbell-shaped fullerene was directed by supramolecular polymerization. Finally, the helical morphology of the supramolecular polymer chain was visualized by atomic force microscopy. The successful development of helical main-chain fullerene polymers would break new ground in fullerene chemistry.
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Porphyrin–trimethyl‐β‐cyclodextrin (TMe‐β‐CDx) complexes have pseudorotaxane structures in which two meso‐phenyl and/or ‐pyridyl moieties penetrate the upper rim of two TMe‐β‐CDx molecules. Porphyrin derivatives with one to three pyridyl... more
Porphyrin–trimethyl‐β‐cyclodextrin (TMe‐β‐CDx) complexes have pseudorotaxane structures in which two meso‐phenyl and/or ‐pyridyl moieties penetrate the upper rim of two TMe‐β‐CDx molecules. Porphyrin derivatives with one to three pyridyl moieties at meso positions formed complexes with TMe‐β‐CDx in which the penetration of the upper rim of the two TMe‐β‐CDxs by the pyridyl moieties was minimized. In contrast, in TMe‐β‐CDx complexes formed with porphyrin derivatives bearing two 2‐methoxyphenyl moieties and two pyridyl moieties, the pyridyl moieties penetrate the upper rim of the two molecules because steric hindrance prevents penetration by the 2‐methoxyphenyl moieties.
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Nature precisely manipulates primary monomer sequences in biopolymers. In synthetic polymer sequences, this precision has been limited because of the lack of polymerization techniques for conventional polymer synthesis. Engineering the... more
Nature precisely manipulates primary monomer sequences in biopolymers. In synthetic polymer sequences, this precision has been limited because of the lack of polymerization techniques for conventional polymer synthesis. Engineering the primary monomer sequence of a polymer main chain represents a considerable challenge in polymer science. Here, we report the development of sequence-controlled supramolecular terpolymerization via a self-sorting behavior among three sets of monomers possessing mismatched host–guest pairs. Complementary biscalix[5]arene-C60, bisporphyrin-trinitrofluorenone (TNF), and Hamilton’s bis(acetamidopyridinyl)isophthalamide-barbiturate hydrogen-bonding host–guest complexes are separately incorporated into heteroditopic monomers that then generate an ABC sequence-controlled supramolecular terpolymer. The polymeric nature of the supramolecular terpolymer is confirmed in both solution and solid states. Our synthetic methodology may pave an avenue for constructing ...
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π-Stacked polymers, which consist of layered π-electron systems in a polymer, can be expected to molecular electronic devices. However, the construction of a stable π-stacked structure in a polymer is considerably challenging, because it... more
π-Stacked polymers, which consist of layered π-electron systems in a polymer, can be expected to molecular electronic devices. However, the construction of a stable π-stacked structure in a polymer is considerably challenging, because it requires sophisticated designs and precise synthetic methods. Herein, we present a novel π-stacked architecture based on poly(quinolylene-2,3-methylene), bearing alanine derivatives as the side chain, obtained through the living cyclocopolymerization of an o -allenylaryl isocyanide. In the resulting polymer, the neighboring quinoline rings of the main chain form a layered structure with π-π interactions, which is stabilized by intramolecular hydrogen bonds. The vicinal quinoline units form two independent helices and the whole molecule is a twisted tape structure. This structure is established on the basis of UV/CD spectra, theoretical calculations, and atomic force microscopy.
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The crystal structure of a bisporphyrin cleft molecule revealed that the head-to-head dimeric structure is directed by the intermolecular self-complementary hydrogen-bonding interactions of amide g...
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Circularly polarized luminescence (CPL) produced by achiral organic luminophores is described. Achiral organic luminophores can exhibit CPL by the chiral arrangement of the achiral luminophores. Chiral arrangement of achiral luminophores... more
Circularly polarized luminescence (CPL) produced by achiral organic luminophores is described. Achiral organic luminophores can exhibit CPL by the chiral arrangement of the achiral luminophores. Chiral arrangement of achiral luminophores can be constructed through a covalently linked chiral spacer like a binaphthyl moiety. A helical supramolecular assembly also provides chiral environment on an achiral luminophore. The helically stacked assemblies of achiral luminophores are excellent for realizing CPL of the achiral luminophore since the highly assembled structure in the helical assembly provides good CPL activity. The stimuli-responsivity of supramolecular systems provides stimuli-responsive CPL.
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The title complex is a triple-stranded metallohelicate organized by the self-assembly of 5,17-difunctionalized calix[4]arenes and metal cations with octahedral coordination geometry. Due to hydrophilic triethylene glycol chains on the... more
The title complex is a triple-stranded metallohelicate organized by the self-assembly of 5,17-difunctionalized calix[4]arenes and metal cations with octahedral coordination geometry. Due to hydrophilic triethylene glycol chains on the lower rim of the calix[4]arene, the metallohelicate can encapsulate cationic guests in water. NMR and UV-vis titration experiments reveal that the metallohelicate captures a pyridinium guest with an alanine derivative to form a host-guest complex with a host-guest ratio of 1:1. CD spectroscopy confirms the bias of the P - and M -helical sense of the metallohelicate by the captured guest. The metallohelicate captures two molecules of dicationic N , N' -dimethyl-DABCO and monocationic N -methyl quinuclidine, exhibiting a positive allosteric effect. 1 H NMR titration experiments indicate that the bound guests are in close proximately to the aromatic rings of the ligands. Molecular mechanics calculations based on the UV-vis and NMR observations suggest that the first guest preorganizes the conformation of the metallohelicate to facilitate access of the second guest to the cavity.
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Ureido-pyrimidinone (UPy)-appended tris(phenylisoxazolyl)benzenes were synthesized. The UPy moieties of the tris(phenylisoxazolyl)benzenes stably formed self-complementary dimers in solution. The dimers self-assembled to form helically... more
Ureido-pyrimidinone (UPy)-appended tris(phenylisoxazolyl)benzenes were synthesized. The UPy moieties of the tris(phenylisoxazolyl)benzenes stably formed self-complementary dimers in solution. The dimers self-assembled to form helically twisted stacking constructs in a process driven by π-π stacking interactions of UPy dimer moieties and dipole-dipole interactions of isoxazole units. Strong association affinity was seen within the stacking constructs compared with the previously reported isoxazole derivatives owing to the auxiliary π-π stacking interaction. Notably, tris(phenylisoxazolyl)benzenes showed an environmentally responsive nature. The absorption bands, emission intensities, and sizes of ensembles depended significantly on the mixing ratio of CHCl3 and methylcyclohexane (MCH). Additionally, sharp on-off switching phenomena were seen in their circular dichroism (CD) and circularly polarized luminescence (CPL) spectra in response to the mixing ratio of CHCl3 and MCH. CD and CP...
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Herein, we describe self-sorting supramolecular polymerization that uses chiral calix[5]arene hosts and a dumbbell-shaped fullerene guest.
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A calix[5]arene appended monomer molecule was subjected to polymerization reaction to yield corresponding methacrylate polymers. The calix[5]arene appended polymers showed excellent encapsulation capability for fullerene molecules.
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Suitably decorated small aromatic systems can organize stacked structures that display interesting properties arising from their unique morphologies. Although nanographenes produced by top-down methods have graphitic domains and can in... more
Suitably decorated small aromatic systems can organize stacked structures that display interesting properties arising from their unique morphologies. Although nanographenes produced by top-down methods have graphitic domains and can in principle be applied for such supramolecular systems, to the best of our knowledge, no such example has been reported thus far. This is partly because of their limited solubility in organic solvents and partly because of their wide lateral size distribution. To realize nanographene-based supramolecular aggregates, nanographenes carrying alkyl chains with narrow lateral size distributions are employed. We find that the nanographenes undergo self-assembly and that self-assembly is regulated by concentration, solvent polarity, temperature, and sonication. Optical measurements and AFM images indicate that stacked structures are possible candidates for aggregates. A molecular mechanics calculation suggests that graphitic domains inside the nanographenes can contact those of the nearest neighbors in the aggregates, while graphitic domains near the edge are difficult to make contact due to steric congestion. This model can rationalize a unique PL response to temperature. The nanographenes showed concentration-dependent morphologies on mica, stacked structures at low concentrations and polymer-like network structures on mica at higher concentrations.
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Neutral platinum complexes that possess chiral triethylene glycol (TEG) moieties were synthesized. The complexes formed chiral micellar aggregates in THF/water mixture.
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Trisresorcinarene is an interesting class of macrocyclic host. Its unique structure and insolubility allow to function as a amorphous solid absorbent capable of absorbing various aromatic and aliphatic hydrocarbons.
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A dual redox-responsive supramolecular polymer driven by molecular recognition between bisporphyrin (bisPor) and trinitrofluorenone (TNF) has been developed.
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Nanographenes (NGs) have recently emerged as new carbon materials. Their nanoscale size results in a size-dependent quantum confinement effect, opening the band gap by a few eV. This energy gap allows NGs to be applied as optical... more
Nanographenes (NGs) have recently emerged as new carbon materials. Their nanoscale size results in a size-dependent quantum confinement effect, opening the band gap by a few eV. This energy gap allows NGs to be applied as optical materials. This property has attracted researchers across multiple scientific fields. The photophysical properties of NGs can be manipulated by introducing organic groups onto their basal planes and/or into their edges. In addition, the integration of organic functional groups into NGs results in NG-based hybrid materials. These features make the postsynthetic modification of NGs an active research area. Since obtainable information on chemically functionalized NGs is limited due to their nonstoichiometry and structural uncertainty, their structural characterization requires a combination of multiple spectroscopic methods. Therefore, information on the characterization procedures of recently published chemically functionalized NGs is of value for advancing the field of NG-based hybrid materials. The present review focuses on the structural characterization of chemically functionalized NGs. We hope this review will help to advance this field.
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The repeating guest units of poly-( R )- 2 were selectively encapsulated by the self-assembled capsule poly- 1 possessing the eight polymer side chains to form the supramolecular graft polymer (poly- 1 ) n •poly-( R )- 2 . The... more
The repeating guest units of poly-( R )- 2 were selectively encapsulated by the self-assembled capsule poly- 1 possessing the eight polymer side chains to form the supramolecular graft polymer (poly- 1 ) n •poly-( R )- 2 . The encapsulation of the guest units was confirmed by 1 H NMR spectroscopy and DOSY technique. The hydrodynamic radius of the graft polymer structure was greatly increased upon the complexation of poly- 1 . The supramolecular graft polymer (poly- 1 ) n •poly-( R )- 2 was stably formed in the 1:1 host-guest ratio, which increased the glass transition temperature more than 10 °C compared to that of poly- 1 . AFM visualized that (poly- 1 ) n •poly-( R )- 2 formed the networked structure on mica. The (poly- 1 ) n •poly-( R )- 2 gelled in 1,1,2,2-tetrachloroethane, which fabricated the distinct viscoelastic materials that demonstrated the self-healing behaviors in tensile test.
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NORIA is a synthetic macrocycle consisting of twelve resorcinol rings. By cocrystallization of NORIA with benzene, NORIA organized one-dimensional array.
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The dynamic helix interconversion of the C60-appended polyacetylene was directed by the molecular recognition of a chiral biscalix[5]arene.
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Nanographenes (NGs), also known as graphene quantum dots, have recently been developed as nanoscale graphene fragments. These nanocarbon species can be excited with UV light and emit light from the UV-to-visible region. This photoemission... more
Nanographenes (NGs), also known as graphene quantum dots, have recently been developed as nanoscale graphene fragments. These nanocarbon species can be excited with UV light and emit light from the UV-to-visible region. This photoemission has received great attraction across multiple scientific fields. NGs can be produced by cutting off carbon sources or fusing small organic molecules to grow graphitic structures. Furthermore, the organic synthesis of NGs has been intensely studied. Recently, the number of research papers on postsynthetic modifications of NGs has gradually increased. Installed organic groups can tune the properties of NGs and provide new functionalities, opening the door for the development of sophisticated carbon-based functional materials. This review sheds light on recent progress in the postsynthetic modification of NGs and provides a brief summary of their production methods.
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An octaiodobiscavitand was synthesized via an aromatic Finkelstein iodination reaction in good yield. An octa-functionalized biscavitand self-assembled to form a supramolecular polymer in the solid state.
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Covalent organic capsules, such as carcerands and hemi-carcerands, constitute an interesting class of molecular hosts. These container molecules have confined spaces capable of hosting small molecules, although the size of the inner... more
Covalent organic capsules, such as carcerands and hemi-carcerands, constitute an interesting class of molecular hosts. These container molecules have confined spaces capable of hosting small molecules, although the size of the inner cavities cannot be changed substantially, limiting the scope of the applications. The title covalently linked container is produced by metal-directed dimerization of a resorcinarene-based cavitand possessing four 2,2'-bipyridyl arms on the wide rim followed by olefin metathesis at the vertexes of the resulting capsule with a second-generation Grubbs catalyst. The covalently linked bipyridyl arms permit expansion of the inner cavity by demetalation. This structural change influences the molecular recognition properties; the metal-coordinated capsule recognizes only 4,4'-diacetoxybiphenyl, while a metal-free counterpart can encapsulate not only 4,4'-diacetoxybiphenyl but also 2,5-disubstituted-1,4-bis(4-acetoxyphenylethynyl)benzene, which is 9.4 Å longer than the former guest. Molecular mechanics calculations predict that the capsule expands the internal cavity to encapsulate the long guest by unfolding the folded conformation of the alkyl chains, demonstrating the flexible and regulable nature of the cavity. The guest competition experiments show that the preferred guest can be switched by metalation and demetalation.
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The macrocyclization of resorcinol and odd-numbered bisdioxolanes under acidic conditions produced feet-to-feet connected trisresorcinarenes possessing three resorcinarene units linked with odd-numbered alkyl chains. The formation of... more
The macrocyclization of resorcinol and odd-numbered bisdioxolanes under acidic conditions produced feet-to-feet connected trisresorcinarenes possessing three resorcinarene units linked with odd-numbered alkyl chains. The formation of trisresorcinarenes was confirmed using high-resolution mass spectrometry and NMR spectroscopy. The trisresorcinarenes were isolated as protected forms in moderate yields. The protected trisresorcinarenes exhibited D3h symmetry in conformation in solution. Crystal structure analysis revealed that the protected trisresorcinarenes possess large inner spaces surrounded by three resorcinarene units.
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An increased interest in the use of platinum complex based luminescent micelles for imaging biological tissues has emerged in recent years due to their low cytotoxicity, synthetic flexibility, photostability, and...
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Uncommon entropy-driven cooperativity is reported in the guest binding of an octaphosphonate biscavitand. Isothermal titration calorimetry analysis determined the thermodynamic parameters for the 1:2 host-guest binding of biscavitands... more
Uncommon entropy-driven cooperativity is reported in the guest binding of an octaphosphonate biscavitand. Isothermal titration calorimetry analysis determined the thermodynamic parameters for the 1:2 host-guest binding of biscavitands with ammonium guests in methanol, ethanol, isopropanol, and chloroform. Chloroform drove uncommon entropy-driven cooperative binding, whereas the alcohols resulted in enthalpy-driven noncooperative binding. 1 H NMR studies revealed that each cavity possessed six water molecules in chloroform, which were liberated upon the guest binding. The enthalpy-entropy compensation relationship produced a large positive intrinsic entropy in chloroform, which implies that water desolvation causes a considerable entropic gain by paying an enthalpic penalty due to breaking the hydrogen bonding networks of the water clusters.
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Top-down methods are convenient preparative methods for nanographenes, although the products consist of graphene fragments with a broad size distribution. We developed a simple protocol for size separation of nanographenes.
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The homopolymeric sequence formed by the head-to-head association of tetrakisporphyrin 1 is completely dissociated by the competitive association of the ditopic guest G2, resulting in the supramolecular copolymer poly-1⋅G2 with an... more
The homopolymeric sequence formed by the head-to-head association of tetrakisporphyrin 1 is completely dissociated by the competitive association of the ditopic guest G2, resulting in the supramolecular copolymer poly-1⋅G2 with an alternatingly repeating host-guest sequence. The 1:1 stoichiometry of 1 and G2 is confirmed by a Job plot using UV/Vis titration and diffusion-ordered NMR spectroscopy (DOSY). The solution viscometry for poly-1 and poly-1⋅G2 suggests that the supramolecular chain of poly-1 behaves like a rod, whereas the supramolecular copolymer chain of poly-1⋅G2 behaves like a swelled fat chain, which is entangled in the semi-dilute regime. Atomic force microscopy shows that the supramolecular polymer poly-1⋅G2 is highly oriented through the interdigitation of the long alkyl chains.
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The quantum-size effect, which enables nanographenes to emit photoluminescence (PL) in the UV to visible region, has inspired intense research. However, the control of the PL properties of nanographenes through manipulation of their... more
The quantum-size effect, which enables nanographenes to emit photoluminescence (PL) in the UV to visible region, has inspired intense research. However, the control of the PL properties of nanographenes through manipulation of their π-system by post-modifications is not well developed. By utilizing a ring-closure reaction between an aromatic 1,2-dicarboxylic acid and a 1,8-naphthalenediamine derivative, which produces a perimidine framework, nitrogen-doped nanographenes were realized. Two nanographenes produced by a one-pot reaction of edge-oxidized nanographene (GQD-2) with 1,8-naphthalenediamine derivatives (GQD-1 a and GQD-1 b) displayed an absorption band extending to >1000 nm; furthermore, the PL wavelength of GQD-1 a was significantly red-shifted into the near-infrared (NIR) region in which it can be used for bioimaging. Time-dependent DFT calculations of model nanographenes showed that the functional groups narrow the HOMO-LUMO gap, realizing the NIR-emitting nanographenes.
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Correction for ‘Substituent-controlled racemization of dissymmetric coordination capsules’ by Kentaro Harada et al., Org. Biomol. Chem., 2019, DOI: 10.1039/c9ob00388f.