Structural Asymmetry and Chiral-Induced Spin Selectivity in Chiral Palladium-Halide Semiconductors.

Chiral Pb-free metal-halide semiconductors (MHSs) have attracted considerable attention in the field of spintronics due to various interesting spin-related properties and chiral-induced spin selectivity (CISS) effect. Despite their excellent chemical and structural tunability, the material scope and crystal structure of Pb-free chiral MHSs exhibiting the CISS effect are still limited; chiral MHSs that have metal-halide structures of octahedra and tetrahedra are only reported. Here, we report a new class of chiral MHSs, of which palladium (Pd)-halides are formed in 1D square-pyramidal structures or 0D square-planar structures, with a general formula of ((R/S-MBA)2PdBr4)1-x((R/S-MBA)2PdCl4)x (MBA = methylbenzylammonium; x = 0, 0.25, 0.5, 0.75, and 1) for the first time. The crystals adopt the 1D helical chain of Pd-halide square-pyramid (for x = 0, 0.25, 0.5, and 0.75) and 0D structure of Pd-halide square-plane (for x = 1). All the Pd-halides are distorted by the interaction between the halide and the chiral organic ammonium and arranged in a noncentrosymmetric position. Circular dichroism (CD) for ((R/S-MBA)2PdBr4)1-x((R/S-MBA)2PdCl4)x indicates that chirality was transferred from chiral organic ammonium to Pd-halide inorganics. ((R-MBA)2PdBr4)1-x((R-MBA)2PdCl4)x (x = 0, 0.25, 0.5, and 0.75) shows a distortion index of 0.127-0.128, which is the highest value among the previously reported chiral MHSs to the best of our knowledge. We also find that (R/S-MBA)2Pd(Br1-xClx)4 crystals grow along the out-of-plane direction during spin coating and have high c-axis orientation and crystallinity, and (R/S-MBA)2Pd(Br1-xClx)4 (x = 0 and 0.5) crystals exhibit a CISS effect in polycrystalline bulk films. These results demonstrate the possibility of a new metal-halide series with square-planar structures or square-pyramidal structures for future spintronic applications.

Solid-State [2+2] Photoreaction of Isostructural Cd(II) Metal Complexes and Solid-State Fluorescence.

A green method to synthesize cyclobutane derivatives has been developed over the past three decades in the form of solid-state [2+2] photochemical reactions. These solid-state reactions also play a major role in the structural transformation of hybrid materials. In this regard, crystal engineering has played a major role in designing photoreactive molecular systems. Here, we report three novel binuclear Cd(II) complexes with the molecular formula [Cd2(4spy)4L4], where 4spy = 4-styryl pyridine and L = p-toluate (1); 4-fluorobenzoate (2); and 3-fluorobenzoate (3). Although three different benzoates are used, all three complexes are isostructural, as corroborated through SCXRD experiments. Structural analysis also helped in identifying two potential photoreactions. These are both intra- and intermolecular in nature and are driven by the head-to-head (HH) and head-to-tail (HT) alignment of 4spy linkers within these metal complexes. 1H NMR spectroscopy studies showed evidence of a quantitative head-to-head photoreaction in all these three complexes, and SCXRD analysis of the recrystallization of the photoproducts also provided confirmation. TGA studies of these photoreactive complexes showed an increase in the thermal stability of the complexes due to the solid-state photoreaction. Photoluminescence studies of these complexes have been conducted, showing a blue shift in emission spectra across all three cases after the photoreaction.

Homo- and Heteromultinuclear Pseudocapsules Assembled from Calix[6]-mono-crown-5 and Alkali Metal Ions.

The formation of pseudocapsule type homo- and heteromultinuclear complexes of calix[6]-mono-crown-5 (H4L) encapsulating from 4 to 6 alkali metal ions is reported. H4L reacts with KOH to yield a hexanuclear potassium(I) complex [K6(HL)2(CH3OH)2]·CHCl3 (1) in which two bowl-shaped tripotassium(I) complex units are linked in a rim-to-rim fashion via the interligand C-H···π interactions. In the same reaction condition, RbOH afforded a tetranuclear rubidium(I) complex [Rb4(H2L)2(CH3OH)2(µ-H2O)2]·6CHCl3 (2). In 2, again two bowl-shaped dirubidium(I) complex units are held together by two bridging water molecules and C-H···π interactions that act as a glue to generate such an elegant pseudocapsule. Interestingly, a mixture of KOH and RbOH yielded a heterotetranuclear complex [K2Rb2(H2L)2(CH3OH)2(µ-H2O)2]·6CHCl3 (3). Similarly, two heterodinuclear bowl units [KRb(H2L)] in 3 are held together by two bridging water molecules and C-H···π interactions to form a heteromultinuclear pseudocapsule. In each heterodinuclear K+/Rb+ bowl unit of 3, Rb+ occupies the center of the crown loop while K+ locates inside the calix rim. Consequently, the proposed host discriminates not only on the types and numbers of the metal ions but also on their positional preferences in forming pseudocapsules. Solution studies by nuclear magnetic resonance and electrospray ionization-mass support the heterometallic (K+/Rb+) complexation by showing the superior binding affinity of Rb+ over K+ toward the crown loop. These results demonstrate how the metal-driven pseudocapsules are formed and present a new perspective on the metallosupramolecules of the calixcrown scaffold.

Construction of Photoreactive Chiral Metal-Organic Frameworks and Their [2 + 2] Photocycloaddition Reactions.

Chiral metal-organic frameworks (CMOFs) and solid-state [2 + 2] photocyclization have been explored as independent areas in crystal engineering. We herein report the photoreactive CMOFs that undergo a [2 + 2] photocycloaddition reaction for the first time. Through the incorporation of a dipyridyl olefin ligand, 1,4-bis[2-(4-pyridyl)ethenyl]benzene, and d-camphoric acid or l-camphoric acid, we constructed a pair of homochiral Zn(II) CMOFs (d-1 or l-1) with a two-dimensional sql topology via a two-step procedure to avoid racemization. Both d-1 and l-1 were photoinert due to the large olefin bond separation. The removal of the solvent molecules between layers enabled them (d-1a and l-1a) to undergo [2 + 2] cycloaddition reactions; d-1a is more reactive (70%) than l-1a (20%) probably due to proper desolvation-induced rearrangement. The photoluminescence properties are also discussed. This work presents a new perspective on photoreactive homochiral network materials with diverse topologies and applications.

Solvent-Dependent Self-Assembly of a Pillar[5]arene-Based Poly-Pseudo-Rotaxane Linked and Threaded by Silver(I) Trifluoroacetate: A Double Role.

In the supramolecule area, the fabrication of a new concept called polyrotaxanes or poly-pseudo-rotaxanes remains challenging. We herein report the formation of a poly-pseudo-rotaxane in which the same salt-type guest serves both linking and threading in the resulting structure. The combination of A1/A2-thiopyridyl pillar[5]arene (L) and silver(I) trifluoroacetate in CHCl3/CH3OH afforded a one-dimensional (1D) poly-pseudo-rotaxane. In this structure, to our surprise, the AgCF3CO2 guest not only links the di-armed L ligands via an infinite -L-Ag-L-Ag- arrangement but also threads into a pillar[5]arene cavity in a dimer form, (AgCF3CO2)2. In contrast, the same reaction in CH2Cl2/CH3OH yielded a simple 1D coordination polymer because an included CH2Cl2 molecule in the pillar[5]arene cavity prevents the threading of the silver(I) trifluoroacetate guest. Comparative 1H- and 19F-NMR studies support the solvent-dependent poly-pseudo-rotaxane formation at a lower concentration of L.

Two-Dimensional Metal-Organic Framework Materials: Synthesis, Structures, Properties and Applications.

Among the recent developments in metal-organic frameworks (MOFs), porous layered coordination polymers (CPs) have garnered attention due to their modular nature and tunable structures. These factors enable a number of properties and applications, including gas and guest sorption, storage and separation of gases and small molecules, catalysis, luminescence, sensing, magnetism, and energy storage and conversion. Among MOFs, two-dimensional (2D) compounds are also known as 2D CPs or 2D MOFs. Since the discovery of graphene in 2004, 2D materials have also been widely studied. Several 2D MOFs are suitable for exfoliation as ultrathin nanosheets similar to graphene and other 2D materials, making these layered structures useful and unique for various technological applications. Furthermore, these layered structures have fascinating topological networks and entanglements. This review provides an overview of different aspects of 2D MOF layered architectures such as topology, interpenetration, structural transformations, properties, and applications.

Metallosupramolecules of Pillar[5]arene with Two Flexible Thiopyridyl Arms: A Heterochiral Cyclic Dimer and Organic Guest-Assisted Homochiral Poly-Pseudo-Rotaxanes.

The formation of a cyclic dimer complex (1) and a poly-pseudo-rotaxane (2) of a racemic A1/A2-thiopyridyl pillar[5]arene (rac-L) with different chirality is reported. A one-pot reaction of rac-L with HgCl2 afforded a heterochiral cyclic dimer complex, [Hg2(pR-L)(pS-L)Cl4]·8CH2Cl2 (1), in which two Hg2+ atoms and one (pR-L)/(pS-L) enantiomeric pair form a [2:2] metallacycle via a metal coordination-based cyclization. Interestingly, the same reaction in the presence of the linear dinitrile guest, CN(CH2)8CN (G), yielded a one-dimensional poly-pseudo-rotaxane, {[Hg(G@pR-L)Cl2][Hg(G@pS-L)Cl2]}n (2), probably due to the rigidified ligand structure resulting from the dinitrile guest (G) threading. In 2, pR-L and pS-L generate two separated homochiral poly-pseudo-rotaxanes in a crystal. Both products are new members of the pillararene-derivative family. This study improves our understanding of self-assembly in nature and leads to this approach being an engineering tool for the construction of mechanically interlocked supramolecules.

Rapid Cs+ Capture via Multiple Supramolecular Interactions in Anionic Metal-Organic Framework Isomers.

Metal-organic frameworks (MOFs) provide an ideal platform for ion exchange due to their high porosity and structural designability; however, developing MOFs that have the essential characteristics for ion exchange remains a challenge. These crucial features include fast kinetics, selectivity, and stability. We present two anionic isomers, DGIST-2 (2D) and DGIST-3 (3D), comprising distinctly arranged 5-(1,8-naphthalimido)isophthalate ligands and In3+ cations. Interestingly, in protic solvents, DGIST-2 transforms into a hydrolytically stable crystalline phase, DGIST-2'. DGIST-2' and DGIST-3 exhibit rapid Cs+ adsorption kinetics, as well as high Cs+ affinity in the presence of competing cations. The mechanism for rapid and selective sorption is explored based on the results of single-crystal X-ray diffraction analysis of Cs+-incorporated DGIST-3. In Cs+-containing solutions, the loosely incorporated dimethylammonium countercation of the anionic framework is replaced by Cs+, which is held in the hydrophobic cavity by supramolecular ion-ion and cation-π interactions.

Unexpected Solvent-Dependent Self-Assembly of Alkali Metal Complexes of Calix[6]-mono-crown-4: Dinuclear Bowls, a Pseudo-Capsule, and a One-Dimensional Polymer.

1,4-Bridged calix[6]-mono-crown-4 (H4L) capable of metal binding was employed, and the influence of solvent variations on the formation of alkali metal complexes (1-6) was investigated. In the crystal, the bowl-shaped H4L host contains one water molecule in a good-fit fashion via H-bonds. When the H4L host was reacted with alkali metal hydroxides (M = Na, K, Rb, and Cs) in chloroform/methanol (solvent A), anion-free dinuclear bowl-shaped complexes of type [M2(H2L)] were isolated regardless of the metal ions. In the dinuclear bowl complexes 1-4, two metal ions (M1 and M2) show different binding behaviors: one (M1) locates inside the pocket like an "egg-in-nest", and the other (M2) positions above the M1 interacting with the calix rim. When chloroform/acetonitrile (solvent B) was used in potassium(I) complexation, interestingly, an elegant pseudo-capsule-type quadrunuclear complex 5 was isolated. In 5, two dipotassium(I) bowls in a rim-to-rim arrangement are triply bridged by one water and two acetonitrile molecules like a magic glue. However, in dichloromethane/methanol (solvent C), cesium(I) yielded an infinite product 6 in which dicesium(I) bowls are linked by cation-π interactions, giving rise to a one-dimensional zigzag coordination polymer. Taken collectively, all products share a dinuclear bowl unit, some of which are further extended to the pseudo-capsule or polymeric array, depending on the solvents. The results suggest the solvent variation as a versatile engineering tool and present a perspective on the metallosupramolecules of calix[6]-mono-crowns with monomer, dimer (e.g., pseudo-capsule), and polymer topologies.

Pillar[5]-bis-trithiacrown: Influence of Host-Guest Interactions on the Formation of Coordination Networks.

A pillar[5]-bis-trithiacrown (L) capable of metal binding and organic guest threading simultaneously has been employed, and the influence of dinitrile guests [CN(CH2)nCN (n = 2-6: abbreviated C2-C6)] on the coordination behaviors has been investigated. When the ditopic ligand L was reacted with HgCl2 in the presence of the C2-C6 guests, the shorter guests C2 and C3 afforded a two-dimensional coordination polymer [Hg7Cl14(C2@L)2]n (1) and a one-dimensional coordination polymer [(Hg3Cl6)2(C3@L)2]n (2), respectively. In 1 and 2, each dinitrile guest threads into the pillararene cavity to form a C2@L or C3@L unit via the host-guest interaction. Further linking of these units by exocyclic Hg-S bonds and anion coordination lead to the formation of coordination products with different dimensionalities. While the use of the longer guests C4-C6 under the same reactions yielded a discrete dimercury(II) complex 3, [Hg2Cl4(CH3CN@L)] which contains one acetonitrile solvent molecule because the longer dinitriles do not serve as effective guests. In the NMR and UV-vis studies, the association constants (log K1:1) for the host-guest interactions of L with the dinitrile guests are C2 (4.75) > C3 (4.17) ≫ C4 (2.85) > C5 (2.45) > C6 (too small), indicating that the shorter guests C2 or C3 interact more strongly than longer ones due to the confined interior space of L. Taken collectively, the C2 and C3 guests with proper size-matching promote the formation of coordination polymers and vice versa, suggesting that the guest size could be a controlling factor.

Construction of 2D Interdigitated Polyrotaxane Layers and their Transformation to a 3D Polyrotaxane by a Photocycloaddition Reaction between Wheels.

Following the pioneering work of Sauvage and Stoddart on rotaxanes, construction of higher dimensional polyrotaxanes in metal-organic frameworks (MOFs) via a modified protocol is challenging. We present the formation of a two-dimensional (2D) polyrotaxane and its conversion to a three-dimensional (3D) polyrotaxane MOF via a photoreaction between interdigitated "olefin wheels". For this purpose, a 2-fold entangled 2D MOF [Pb2(bpp)(sdc)2] (1), showing a 2D + 2D → 2D polyrotaxane motif, has been synthesized from the solvothermal reaction of lead(II) nitrate, 3,3'-stilbenedicarboxylic acid (H2sdc) containing an olefin group, and 1,4-bis(4-pyridyl)piperazine (bpp). The single-crystal X-ray diffraction analysis of 1 revealed that the adjacent entangled 2D layers are interdigitated, with the separation of 3.72 Šbetween C═C bond pairs in adjacent layers satisfying Schmidt's criteria for the occurrence of a [2 + 2] photocycloaddition reaction. Irradiation of the single crystals of 1 under UV light resulted in formation of a 3D polyrotaxane, [Pb2(bpp)(rctt-tccb)]n (2), due to a [2 + 2] photocycloaddition reaction between two wheels via a single-crystal to single-crystal transformation. The photocycloaddition and partial thermal cleavage reaction between 1 and 2 were confirmed by 1H NMR and powder X-ray diffraction (PXRD) in solution and the solid state, respectively. The present approach could contribute to the understanding of the construction of higher dimensional polyrotaxanes which are not accessible by the traditional routes.

Self-Powered Photodetector Using Two-Dimensional Ferroelectric Dion-Jacobson Hybrid Perovskites.

Dion-Jacobson (DJ) phase organic-inorganic hybrid perovskites (OIHPs) have emerged as promising alternatives to Ruddlesden-Poppers perovskites because of their chemical stability and ferroelectric phase. Here we fabricate a ferroelectricity-modulated photodetector based on the n = 2 homologue of the ferroelectric two-dimensional DJ-OIHP (AMP)(MA)Pb2I7 (DJPn=2, AMP = 4-(aminomethyl)piperidinium; MA = methylammonium), which shows an out-of-plane polarization and a saturated polarization (Ps) value of 3.7 µC/cm2. The coercive field of DJPn=2 (0.34 kV/cm) is lower than that for the n = 1 homologue (AMP)PbI4 (DJPn=1,0.4 kV/cm). DJPn=2 has a much longer carrier lifetime and absorption edge (580 nm, 2.13 eV) in comparison to DJPn=1 (523 nm, 2.37 eV); thus, DJPn=2 can be used for efficient photodetection in the visible range, in which a responsivity of 0.16 mA/W was achieved at 532 nm. The influence of remnant polarization on the direction and magnitude of the photocurrent was also demonstrated.

Mechanistic insights into heavy metal ion sensing by NOS2-macrocyclic fluorosensors via the structure-function relationship: influences of fluorophores, solvents and anions.

To obtain a mechanistic understanding of the effects derived from fluorophores, solvents and anions on heavy metal sensing, two NOS2-macrocycle-based fluorosensors with different fluorophores (L1: 9-methylanthracene, L2: benzothiazolyl) were synthesised. In this regard, particular attention was given to monitoring the cation-ligand, cation-anion and cation-solvent interactions from the detailed complexation processes in both the solution and solid states while considering the structure-function relationship. L1 showed turn-on type silver(i) selectivity over other metal ions, including mercury(ii), in ethanol. According to the complexation results obtained by titration (UV-vis, fluorescence and NMR), cold-spray ionization mass spectrometry and X-ray crystallography, the observed silver(i) sensing by L1 is mainly due to its 1 : 1 complexation with silver(i) via the Ag-Ntert bond and the strong solvation of mercury(ii). Thus, the turn-on sensing for silver(i) can be explained by the CHEF effect, in which the coordination of silver(i) to the receptor unit effectively prevents PET quenching. As a dual-probe (UV-vis and fluorescence) chemosensor, L2 showed fluorescence turn-off type selectivity for both silver(i) and mercury(ii) in ethanol. In acetonitrile, L2 showed improved fluorescence turn-off type selectivity for mercury(ii) with ClO4- and NO3-; however, no such responses were observed with other anions, such as Cl-, Br-, I-, SCN-, OAc- and SO42-. Together with the complexation results by titration, the crystal structures of an endocyclic mercury(ii) perchlorate complex and an exocyclic mercury(ii) iodide complex revealed that the anion-controlled mercury(ii) sensing by L2 arises from the endo- and exo-coordination modes depending on the anion coordinating ability, which induces either metal-receptor/fluorophore binding (Hg-Ntert and Hg-Nfl) or no binding. Taken collectively, the photophysical, thermodynamic and structural results of the complexations herein suggest that the sensing properties of heavy metal ions by macrocycle-based fluorosensors are very sensitive not only to the cation-receptor and cation-fluorophore interactions but also to the cation-anion (endo/exo-coordination modes) and/or cation-solvent interactions.

Porphyrin/Quinoidal-Bithiophene-Based Macrocycles and Their Dications: Template-Free Synthesis and Global Aromaticity.

We report the template-free synthesis and characterization of a new type of porphyrin/quinoidal-bithiophene-based conjugated macrocycle. X-ray crystallographic analysis of the dimer (2MC) revealed a cyclophane-like geometry with large dihedral angles between the porphyrin and the neighboring thiophene rings, and NMR measurements and theoretical calculations confirmed a localized aromatic character of the porphyrin/thiophene rings and quinoidal character of the bithiophene linkers. Restricted rotation of the thiophene rings linked to the porphyrin unit was observed by variable-temperature NMR measurements. The dication (2MC2+ ) adopts a chair-shaped conformation to facilitate π-electron delocalization around the whole macrocycle. As a result, the molecule is globally aromatic, with a dominant 54 π conjugation pathway. The trimer (3MC) also shows localized aromatic character of porphyrin rings and conformational flexibility, but its dication (3MC2+ ) is rigid and globally aromatic with a dominant 82 π conjugation pathway.

Divergent Chemistry Paths for 3D and 1D Metallo-Covalent Organic Frameworks (COFs).

The marriage of dynamic covalent chemistry (DCC) and coordination chemistry is a powerful tool for assembling complex architectures from simple building units. Recently, the synthesis of woven covalent organic frameworks (COFs) with topologically fascinating structures has been achieved using this approach. However, the scope is highly limited and there is a need to discover new pathways that can assemble covalently linked organic threads into crystalline frameworks. Herein, we have identified branching pathways leading to the assembly of three-dimensional (3D) woven COFs or one-dimensional (1D) metallo-COFs (mCOFs), where the mechanism is underpinned by the absence or presence of ligand exchange.

Giant Emission Enhancement of Solid-State Gold Nanoclusters by Surface Engineering.

Ligand-induced surface restructuring with heteroatomic doping is used to precisely modify the surface of a prototypical [Au25 (SR1 )18 ]- cluster (1) while maintaining its icosahedral Au13 core for the synthesis of a new bimetallic [Au19 Cd3 (SR2 )18 ]- cluster (2). Single-crystal X-ray diffraction studies reveal that six bidentate Au2 (SR1 )3 motifs (L2) attached to the Au13 core of 1 were replaced by three quadridentate Au2 Cd(SR2 )6 motifs (L4) to create a bimetallic cluster 2. Experimental and theoretical results demonstrate a stronger electronic interaction between the surface motifs (Au2 Cd(SR2 )6 ) and the Au13 core, attributed to a more compact cluster structure and a larger energy gap of 2 compared to that of 1. These factors dramatically enhance the photoluminescence quantum efficiency and lifetime of crystal of the cluster 2. This work provides a new route for the design of a wide range of bimetallic/alloy metal nanoclusters with superior optoelectronic properties and functionality.

Ferroelectricity and Rashba Effect in a Two-Dimensional Dion-Jacobson Hybrid Organic-Inorganic Perovskite.

Hybrid organic-inorganic perovskites (HOIPs) are a new generation of high-performance materials for solar cells and light emitting diodes. Beyond these applications, ferroelectricity and spin-related properties of HOIPs are increasingly attracting interests. The presence of strong spin-orbit coupling, allied with symmetry breaking ensured by remanent polarization, should give rise to Rashba-type splitting of electronic bands in HOIP. However, the report of both ferroelectricity and Rashba effect in HOIP is rare. Here we report the observation of robust ferroelectricity and Rashba effect in two-dimensional Dion-Jacobson perovskites.

Chemical Patterning in Single Crystals of Metal-Organic Frameworks by [2+2] Cycloaddition Reaction.

Conventional chemical patterning involves films of polymeric materials. Herein, we demonstrate that the presence or absence of guest solvents in the crystal voids modulates the patterning of the cyclobutane rings in highly strained metal-organic frameworks (MOFs) under UV light. The olefin pairs of the spacer ligands, which resemble a ladder-like structure, in the MOF, undergo a [2+2] cycloaddition reaction in a single-crystal-to-single-crystal manner. For instance, a partial photoreaction in the MOFs in the absence of a guest solvent as well as with dimethylacetamide in the voids generated two different patterns of the cyclobutane rings. Surprisingly, the MOF with the lattice dimethylformamide undergoes 100 % photoreaction, but the photoproduct contains broken chains. Such chemical patterning at the molecular level represents a next step in crystal engineering.

Formation of a Pillar[5]arene-Based Two-Dimensional Poly-Pseudo-Rotaxane: Threading and Crosslinking by the Same Guest Molecules.

A one-pot reaction of the A1/A2-thiopyridyl pillar[5]arene L with silver(I) trifluoroacetate in the presence of the linear dinitrile guest C8, [CN(CH2 )n CN, n=8], afforded the first example of a two-dimensional (2D) poly-pseudo-rotaxane {[(µ4 -Ag)2 (C8@L)2 (µ-C8)](CF3 CO2 )2 }n . Surprisingly, in this structure the C8 guest not only threads into the pillar[5]arene unit but also crosslinks the 1D coordinative polymeric arrays. The formation of the 2D poly-pseudo-rotaxane is driven by an adaptive rearrangement of the components that minimizes the steric clashes not only between the threaded guests but also between the threaded and crosslinked guests where crosslinking occurs. A pathway for the formation of the 2D poly-pseudo-rotaxane is proposed.

pseudo[1]Catenane-Type Pillar[5]thiacrown Whose Planar Chiral Inversion is Triggered by Metal Cation and Controlled by Anion.

Chiral inversion of single molecules has been a challenging task because chirality information controls structures and functions of various molecules, artificial nanostructures, DNA, and proteins. Herein we present a pseudo[1]catenane-type molecule whose planar chiral inversion is driven by a metal ion under the control of anions for the first time. Considering an in-out equilibrium of a fused thiacrown and the soft metal binding, pillar[5]thiacrown ( rac-L) was synthesized. Two planar-chiral enantiomers of rac-L ( in-pS-L and in-pR-L) were isolated and the absolute configuration was determined by circular dichroism and single crystal X-ray analysis. The in-pS-L recognizes Hg2+ to trigger the chiral inversion to out-pR-L, to our surprise; it takes place only in the presence of ClO4- or NO3- among the anions used. In the mercury(II) perchlorate complex solution, anion-exchange from ClO4- to I- or removal of Hg2+ by addition of S2- makes the system reversible. The crystallographic approach reveals that the anions act as coordination mode-directing species ( endo- or exo-coordination) which play a decisive role on the chiral inversion. For instance, the week coordinating ClO4- allows Hg2+ to locate inside the thiacrown ( endo-coordination) which causes the chiral inversion from in-pS-L to out-pR-L due to the expansion of the thiacrown unit upon endo-mode complexation. Oppositely, the strong coordinating I- takes Hg2+ out of the thiacrown ( exo-coordination) without large conformational changes of the thiacrown, resulting in no chiral inversion. A series of experimental works was also accomplished with the other enantiomer in-pR-L, which afforded identical results. Consequently, the chiral inversion is governed by steric factors that arise from the coordination modes depending on the coordinating ability of anions. This work demonstrates the first chiral inversion induced by combination of metal ion and anion and presents a new perspective on the supramolecular coordination chemistry of pillar[ n]arenes.