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Chiral molecular switches are attracting attention as they could pave the way to chiral molecular machines. Herein, we report on the design and synthesis of a single molecule chiral switch based on a cyclotriveratrylene scaffold, in which the chirality inversion is controlled by the solvent. Hemicryptophanes are built around a C3 cyclotriveratrylene chiral unit, with either M or P handedness, connected to another tripod and usually displaying an "out" configuration. Here, we demonstrate that solvents are able to control the "in" and "out" configurations of the CTV unit, creating a chiral molecular switch from (M/P)"in" to (P/M)"out" handedness. The full characterization of the "in" and "out" configurations and of the chirality switch were made possible by combining NMR, HPLC, ECD, DFT and molecular dynamics. Interestingly, bulky aromatic solvents such as 2‐t‐butylphenol favor the "in" configuration while polar aprotic solvents such as acetone favor the "out" configuration. This chiral switch was found to be fully reversible allowing the system to oscillate between two different M and P configurations several times upon the action of solvents stimuli. [ABSTRACT FROM AUTHOR]

Although some cyclotriveratrylene (CTV) liquid crystals had been reported, the CTV liquid crystal with high fluorescence in mesophase was not presented up to now. By introducing diphenylacrylonitrile units on CTV skeleton, two CTV derivatives with AIE units (7a and 7b) were prepared for the first time. Their structures and crown conformations were characterised by 1H NMR, 13C NMR, MALDI-MS spectra and elemental analysis. Samples 7a and 7b exhibited the reversible liquid crystalline behaviours with hexagonal columnar mesophase supported by the DSC, POM and XRD analysis. The studies on photophysical properties of samples 7a and 7b suggested the high fluorescence in solid state and mesophase. The absolute fluorescence quantum yield of 7b in mesophase was as high as 0.45. This work not only reported the first CTV liquid crystals with high fluorescence in aggregated state but also provided a good strategy for constructing the novel CTV liquid crystals with excellent fluorescence. [ABSTRACT FROM AUTHOR]

A new and innovative fluorescent structure was constructed on Cyclotriveratrylene affiliated to Dansyl chloride (DNSC) and was used to detect Cr (III) and Fe (III) among the various cations by using spectrofluorimetric method. The characterization of the new compound was carried out using the 1H-NMR, 13C-NMR, and ESI–MS techniques. The interaction and role of DNSC-CTV with cations was reviewed. A change in the spectra of absorption directed to the conclusion that there is substantial interaction of Cr (III) and Fe (III) with DNSC-CTV. Furthermore the interaction of the ligand DNSC-CTV with the metal ions Chromium (III) and Iron (III) showed quenching in the emission spectra. Quantum yield of the complexes were calculated and the stern volmer analysis was done to deduce the quenching mechanism of fluorescence to being either static or dynamic. The molecule DNSC-CTV was further studied with the help of computational methods such as molecular docking to study the binding interactions and properties of the molecule. [ABSTRACT FROM AUTHOR]

We describe here a controlled approach to C1‐symmetrical cyclotriveratrylenes (CTVs). In this approach dimers are synthesized through Barluenga boronic coupling (BBC) and after borylation, the last aromatic ring is introduced by a second BBC. After functional transformations of the trimers, the CTVs are formed using intramolecular SEAr. [ABSTRACT FROM AUTHOR]

Design and construction of high-efficiency electrochemical sensors for luteolin (LU) and quercetin (QCT) are greatly necessary for the detection of their excessive intake. In this work, a new metal-organic framework (MOF), [Zn 2 L(OH-bdc) 2 ]·2.5 H 2 O (1), was assembled with cyclotriveratrylene ligand (L), Zn(II) cation and 5-hydroxyisophthalic acid (OH-H 2 bdc). 1 featured a two-dimensional (2D) network structure. To improve the conductibility of 1 , typical carbon materials, such as multi-walled carbon nanotube (MWCNT), mesoporous carbon (MC) and reduced graphene oxide (RGO) were respectively combined with the sample of 1. Markedly, synergistic effects between 1 and RGO enabled the 1 @RGO(1:2) composite to exhibit efficient electrocatalytic performances for LU and QCT detection. Under the optimal condition, 1 @RGO(1:2)/GCE featured the relatively wide linear range (0.02–14 μM for LU and 0.02–14 μM for QCT) and low limits of determination (LODs) (0.0022 μM for LU and 0.0049 μM for QCT). Remarkably, 1 @RGO(1:2)/GCE showed good reproducibility, acceptable stability and satisfactory anti-interference. Importantly, the sensor was applied to detect LU and QCT in the natural samples with acceptable recoveries. [Display omitted] • A new cyclotriveratrylene-based metal–organic framework (1) was synthesized. • 1 @RGO was fabricated by combining 1 and reduced graphene oxide. • 1 @RGO featured high-efficiency quantitative detection for LU and QCT. • Synergistic effect between 1 and RGO was discussed during the sensing process. [ABSTRACT FROM AUTHOR]

[Display omitted] 1,4,6,9,11,14-Hexamethoxy-2,3,7,8,12,13-tris(methylene-dioxy)-10,15-dihydro-5H-tribenzo[ a,d,g ][9] annulene, a new representative of a cyclotriveratrylene family, was prepared in high yield by acid-catalyzed trimerization of 2,5-di-methoxy-3,4-(methylenedioxy)benzyl alcohol. Structure of the product was confirmed by X-ray diffraction. [ABSTRACT FROM AUTHOR]

Four diastereomeric molecular cages based on cyclotriveratrylene (CTV) and sucrose scaffolds, connected via p‐phenylene linkers, were synthesized in a few steps synthesis. The absolute configuration of these diastereoisomers was determined by advanced NMR and ECD spectroscopies supported by DFT calculations. The X‐Ray crystal structure of P‐4 b cage gave an insight into its unique structure. The binding properties of P‐4 a and M‐4 a cages towards small ammonium guests (1‐methylpyridinium and 1,3‐dimethylimidazolium salts) were investigated. [ABSTRACT FROM AUTHOR]

The scope of the trimerisation reaction of 3-substituted benzyl alcohols was explored. Several C3-symmetric cyclotribenzylene derivatives were obtained in preparative useful yields in one step and applied to the short synthesis (one or two steps) of two CTB derivatives, so far only accessible in six or seven linear steps. [ABSTRACT FROM AUTHOR]

The five‐steps synthesis of a hemicryptophane cage combining a benzene‐1,3,5‐tricarboxamide unit and a cyclotriveratrylene (CTV) moiety is described. Chiral high‐performance liquid chromatography (HPLC) was used to resolve the racemic mixture. The absolute configuration of the isolated enantiomers was assigned by comparison of the experimental electronic circular dichroism (ECD) spectra with the calculated ones. X‐ray molecular structures reveal that the capped benzene‐1,3,5‐tricarboxamide unit adopts a structurally chiral conformation in solid state: the chirality of CTV moiety controls the Λ or Δ orientation of the three amides. [ABSTRACT FROM AUTHOR]

Hemicryptophanes have recently emerged as an attractive class of cages due to their interesting applications as supramolecular receptors and catalysts. Over the last decade, substantial advances have been made regarding the preparation of enantiopure versions of these synthetic receptors. Enantiopure hemicryptophanes are commonly obtained through the separation of diastereomers by chromatography, or by resolution of racemic mixtures using chiral HPLC. This short review summarizes the existing methods to access to these chiral organic architectures and discusses the benefits and drawbacks of each approach. 1 Introduction 2 Enantiopure Hemicryptophanes Obtained by Introducing Additional Chiral Units and Separation of Diastereomers 2.1 Synthesis by Means of Intramolecular Macrocyclization Reactions 2.2 [1+1] Coupling of the CTV and the Southern Part 3 Enantiopure Hemicryptophanes Obtained by Means of Chiral HPLC Resolution of Enantiomers 3.1 Resolution of Hemicryptophane Racemates 3.2 Resolution of CTV-Based Precursor Racemates 4 Conclusion [ABSTRACT FROM AUTHOR]

A new cyclotriveratrylene-based metal–organic framework 1 was combined with multi-walled carbon nanotubes to give a conductive 1@MWCNT sensor, which featured efficient detection of metronidazole. [Display omitted] • A new metal–organic framework [Cd 6 L 2 (cyclen) 2 (H 2 O) 2 ] (1) was designed. • 1 was dispersed in multi-walled carbon nanotubes to give conductive 1@MWCNT. • 1@MWCNT featured intense electrocatalytic activity for metronidazole detection. • The synergistic effect between 1 and MWCNT enhanced the sensing performances. Constructing a sensitive and efficient sensor for determination of metronidazole (MNZ) is crucial in food field. Herein, a new cyclotriveratrylene-based metal–organic framework (MOF), namely, [Cd 6 L 2 (cyclen) 2 (H 2 O) 2 ] (1), was constructed by self-assembly of functionalized 5,6,12,13,19,20-hexacarboxy-propoxy-cyclotriveratrylene (H 6 L), 1,4,7,10-tetraazacyclododecane (cyclen) and Cd(II) cation under solvothermal condition. In 1 , adjacent Cd(II) cations are linked by L6− to produce a 2D polymeric structure with carboxylate and phenolic oxygen atoms. To enhance conductivity of 1 , it was combined with conducting carbon materials, including mesoporous carbon (MC), reduced graphene oxide (RGO) and multi-walled carbon nanotubes (MWCNT), respectively, producing a series of composite materials. Remarkably, electrochemical tests showed that 1 @MWCNT(1:1) featured a much better electrochemical detection performance for metronidazole (MNZ) than 1 @MC and 1 @RGO. The linear range for the detection of MNZ is up to 0.4–500 μM and the limit of detection (LOD) for MNZ reached 0.25 μM. Importantly, the fabricated sensor 1 @MWCNT(1:1) was employed for the detection of MNZ in honey and egg with satisfactory result. High-performance liquid chromatography (HPLC) validated the high accuracy of the electrochemical method for the determination of honey and egg. [ABSTRACT FROM AUTHOR]

Chirabite‐AR was employed to differentiate enantiomers of the axially chiral cyclotriveratrylene (CTV)‐derived macrocyclic lactam with baseline separation of most of the proton NMR resonances enabling enantiomeric purity determination of this supramolecular scaffold. Attachment of menthyloxy acetic acid as a chiral auxiliary to the CTV‐Beckmann derived lactam afforded diastereomers that were enriched to a ratio of 87:13, as confirmed by both 1H NMR and single‐crystal X‐ray diffraction. Basic hydrolysis of the enriched diastereomeric mixture proceeded with rapid bowl inversion to yield racemic CTV‐lactam as confirmed by Chirabite‐AR NMR analysis. Density functional theory (DFT) calculations (M06 2X/6‐31G*) were performed on the crown and saddle conformers of the CTV‐lactam. [ABSTRACT FROM AUTHOR]

Trigonal bipyramidal metallo-cage species [Pd3(dppp)3(L)2]∙6OTf (where dppp = bis(diphenylphosphino)propane, OTf = triflate and L istris(iso-nicotinoyl)cyclotriguaiacylene (L1) ortris(fluoro-iso-nicotinoyl)cyclotriguaiacylene (FL1)) have been characterised in solution to exist predominantly as theanti-isomers. The crystal structure of [Pd3(dppp)3(FL1)2]∙6OTf, however, was found to be the achiralsyn-isomer. The complex [Pd3Cl3(L2)2] (where L2 = tris(methylbenzimidazolyl)cyclotriguaiacylene) is atrans-linked M3L2cage, observed by mass spectrometry and in the solid state as theanti-isomer. Ligand L2 also forms a 1:1 co-crystal with cyclotriguaiacylene. [ABSTRACT FROM AUTHOR]

Series of novel CTV derivatives with one, two and three triphenylene units were designed and synthesized via click reaction in 72–84% yields. The influences of the numbers of triphenylene units on mesomorphic behaviors were investigated. The results suggested that one triphenylene unit could not counteract the rigidity of CTV skeleton, resulting in no mesophase for CTV derivative 6 with one triphenylene unit. The strong induction of more triphenylene units leaded to the mesophase for CTV derivative 7 with two triphenylene units and 8 with three triphenylene units. The more triphenylene units decreased the phase transition temperatures. The XRD analysis suggested that compound 8 possessed higher ordered hexagonal columnar mesophase than compound 7 , implying that the more triphenylene units were favorable for improving the structural symmetry and produced the ordered columnar stacking. Compound 8 was the first example of high ordered hexagonal columnar liquid crystalline molecule based on CTV skeleton. [ABSTRACT FROM AUTHOR]

Series of cyclotriveratrylene (CTV) derivatives with triazole ring and three alkyl groups were prepared by one-pot click condensation in yield of 80-88%. The structures and crown conformations were confirmed by NMR and MS. Their liquid crystalline properties were investigated by DSC, POM and XRD analysis. The studies on mesomorphic properties suggested that the CTV derivatives with pentyl, hexyl or dodecyl groups show no mesophase but the one with octadecyl groups possesses ordered hexagonal columnar mesophase. In comparison with the reported columnar CTV liquid crystals with six alkyl chains at least, the CTV columnar CTV liquid crystal with three alkyl chains was reported for the first time. These results suggested a subtle balance between the number and length of alkyl chains for columnar CTV liquid crystalline behavior. [ABSTRACT FROM AUTHOR]

By using a cyclotriveratrylene-based ligand 5,12,19-trimethoxy-6,13,20-tricarboxy-methoxy-cyclotriveratrylene (H3L), four lanthanide-based compounds, Eu(L)(DMF)2 ( 1), Tb(L)(DMF)2 ( 2), Gd(L)(DMF)2 ( 3), and Yb(L)(DMF)(H2O) ( 4), have been constructed. Compounds 1- 3 are isostructural and show charming two-bowl interlocked chains linked by L3- anions and Ln3+ cations. The chains are further linked by C-H ···π interactions to form two-dimensional supramolecular layers, respectively. In 4, L3- anions bridge Yb3+ ions to yield a fascinating three-dimensional framework. The compounds are characterized by IR and powder X-ray diffraction. Their solid UV/Vis spectra and fluorescence properties are also studied. By fluorescence detection of metal cations, anions, and organic small molecules, compounds 1 and 2 exhibit high selectivity and sensitivity to Fe3+ ions, MnO4- anions, and nitromethane by quenching processes. [ABSTRACT FROM AUTHOR]

Mononuclear and trinuclear bis-cyclometallated IrIII complexes of the host ligands tris(4-[4′-methyl-2,2′-bipyridyl]methyl)cyclotriguaiacylene ( L1) and tris(4-(4′-methyl-2,2′- bipyridyl)carboxy)cyclotriguaiacylene ( L2) have been prepared. Complexes [{Ir(ppy)2}3( L1)](PF6)3 ( 1.1), [{Ir(ppy)2}( L1)](PF6)3 ( 1.2), [{Ir(ppy)2}3( L2)](PF6)3 ( 2.1) and [{Ir(ppy)2}( L2)](PF6)3 ( 2.2) (where ppy=phenylpyridinato) showed distinct photophysical properties depending on the L ligand. Complexes featuring the L1 ligand were comparatively blue-shifted in solution, with longer lifetimes and higher quantum yields. The mixed bis-cyclometallated IrIII complexes [{Ir(ppy)2}{Ir(dFppy)2}2( L1)](PF6)3 ( 1.3), [{Ir(ppy)2}{Ir(dFppy)2}2( L2)](PF6)3 ( 2.3), [{Ir(ppy)2}2{Ir(dFppy)2}( L1)](PF6)3 ( 1.4) and [{Ir(ppy)2}2{Ir(dFppy)2}( L2)](PF6)3 ( 2.4) (where dFppy=2,4-difluorophenylpyrinato) were also synthesised. Steady-state and time-resolved spectroscopy, along with electrochemical investigations, show that the Ir(III) chromophores within these mixed Ir-environment species behave as isolated centres, with no energy transfer or electronic communication between them. [ABSTRACT FROM AUTHOR]

A series of [4]pseudorotaxanes composed of three-way axle threads based on the cyclotriguaiacylene family of crown-shaped cavitands and three threaded macrocyclic components has been achieved. These exploit the strong affinity for electron-poor alkyl-pyridinium units to reside within the electron-rich cavity of macrocycles, in this case dimethoxypillar[5]arene (DMP). The branched [4]pseudorotaxane assemblies {(DMP)3∙L}3+,whereL = N-alkylated derivatives of the host molecule (±)-tris-(isonicotinoyl)cyclotriguaiacylene, were characterised by NMR spectroscopy and mass spectrometry, and an energy-minimised structure of {(DMP)3∙(tris-(N-propyl-isonicotinoyl)cyclotriguaiacylene)}3+was calculated. Crystal structures ofN-ethyl-isonicotinoyl)cyclotriguaiacylene hexafluorophosphate andN-propyl-isonicotinoyl)cyclotriguaiacylene hexafluorophosphate each show ‘hand-shake’ self-inclusion motifs occurring between the individual cavitands. [ABSTRACT FROM AUTHOR]

Hemicryptophanes have been designed to include endohedral functionalities in the cavity, giving molecular receptors and catalysts. In this study, a tri-aromatic amide hemicryptophane was synthesized. The host–guest interactions with various types of tetraalkylammonium salts were investigated. The structure of the partial inclusion complex in which an acetylcholine molecule was encapsulated within the hemicryptophane was characterized by NMR, X-ray crystal structure, and ESI-MS analysis. [ABSTRACT FROM AUTHOR]

Cyclotriveratrylene-oxime (CTV-oxime) derivatives that terminate with a dithiolate linker were synthesized enabling the supramolecular scaffold to adhere to gold nanoparticles (AuNPs) with the bowl-shaped cavity of the CTV scaffold exposed for utilization in host–guest chemistry. Exposure of these CTV functionalized AuNPs to varying concentrations of di- and trivalent metal cations resulted in the formation of large CTV-AuNP polymeric clusters and an accompanying a shift in the plasmon resonance. These interactions between the CTV-AuNPs and the metal cations in solution provides proof-of-concept that supramolecular functionalized AuNPs can be used as a simple and straightforward, on-site detection system for toxic metal cations in solution. The order of binding affinity of the metals studied based on observed K d values is Cu 2+ > Zn 2+ > Pb 2+ > Hg 2+ > Eu 3+ > Cd 2+ . [ABSTRACT FROM AUTHOR]

Five organic complexes are prepared by cocrystallization of tri-[( N-methyl-2-imidazoly)methoxy]cyclotriguiacylene (TMIM-CTG) with corresponding acids. While hydrogen bonds are the basic interactions in the five complexes, the homo-included motifs with CH···π interactions also control the molecular arrangement except for complex 5. In complex 1, the two dimensional networks contain 1D zigzag chains formed by hydrogen bonding and 1D chains of homo-included CTG motifs. Complex 2 has 2D 4·82 hydrogen bonding networks, and the chains of homomeric inclusion extend the 2D structure to a 3D framework. Complex 3 contains four-membered rings through hydrogen bonds, and the chains of homo-inclusion link the rings to a novel 2D network. In complex 4, hydrogen bonds construct a novel double-layer 2D network, which is extended to a 3D framework by "hand-shake" dimeric homomeric inclusion interactions. Interestingly, there is no homomeric inclusion phenomenon in complex 5 and hydrogen bonds solely connect two components to a chiral (6,3) 2D network. [ABSTRACT FROM AUTHOR]

[Display omitted] This review focuses on synthetic examples of cyclotriveratrylene (CTV) derivatives with different numbers of substituents on the cavity rims, where the number of substituents on aromatic units ranges from zero to four. The synthesis of hydrocarbon cyclotribenzylene with the unsubstituted aromatic unit was initially and briefly introduced, and then the synthetic routes of hydrocarbon cyclotribenzylene with monosubstituted, disubstituted, and trisubstituted aromatic hydrocarbon unit, respectively, were also described. Among them, the optimization of the synthetic routes of C 3 - or C 1 -symmetry CTV derivatives with disubstituted aromatic units were especially emphasized. Finally, the synthesis of CTV analogues with the tetrasubstituted aromatic unit, cyclotrixylohydroquinene (CTX), was discussed, which was conducted by commercially available tetrasubstituted o-xylohydroquinone as a starting material. Besides the synthetic progress of CTV derivatives, this review also provides some insights into their host–guest research and potential applications. [ABSTRACT FROM AUTHOR]

Hemicryptophanes are covalent molecular cages, constructed from a cyclotriveratrylene-based host unit and a functional unit linked by covalent spacers, which have been designed to accommodate endohedral functionalities in the cavity. In this study, the synthesis and characterization of the rigid, biphenyl-linked hemicryptophane 1 were investigated by NMR, ESI-MS, and X-ray crystallography. The structure of the inclusion complex, in which a dichloromethane molecule was constructed encapsulated within 1 , was characterized by X-ray crystallography. An endohedral, cobalt(II) hemicryptophane complex 2 was also synthesized and characterized ESI-MS and X-ray crystallography. The X-ray crystal structure of 2 showed that the biphenyl-linked hemicryptophane had three components—a molecule each of chloroform and acetonitrile, and a cobalt(II) ion—within its cavity. [ABSTRACT FROM AUTHOR]

Abstract: The synthesis of four 3,4-di(alkylsulfanyl)benzyl alcohol derivatives is described, in five steps from methyl 3,4-di(hydroxy)benzoate via a Newman–Kwart rearrangement. Incubation of these derivatives in formic acid affords 2,3,7,8,12,13-hexakis(alkylsulfanyl)-10,15-dihydro-5H-tribenzo[a,d,g]cyclononene products, which are hexa-sulfanyl analogues of the well-known supramolecular cavitand host, cyclotriveratrylene (CTV). The yield of this cyclization depends strongly on the alkylsulfanyl substituents present, in the order SMe>SEt≈SiPr≫SBn. A crystal structure determination of one of the cyclotrimers shows a mode of self-association that is commonly exhibited by CTV itself. [Copyright &y& Elsevier]

Abstract: C 1-symmetric cyclotriveratrylene analogues 2–8 with various functional groups at one benzene moiety were prepared starting from the selectively demethylated compound 1. Through the chemical resolution, a pair of enantiomers of C 1-symmeric compound 1 could be separated with gram scale. Compound 8, which possessed an N-linked imidazolium unit at the upper rim of the macrocyclic skeleton through a methylene linker, was successfully applied to 1,4-Michael addition reaction of alcohol to unsaturated aryl ketone. Its supramolecular catalytic activity as an NHC precursor was demonstrated by the chem-selectivity to aromatic alcohol than alkyl alcohol. [Copyright &y& Elsevier]

Two rigid macrocyclic CTV-based porous organic polymers, Click-POP-1 and Click-POP-2, have been synthesized by Click reaction of a cyclotriveratrylene analogue with alkyne groups and aromatic azides in one pot. FTIR, solid 13C NMR and elemental analysis confirmed the formation of the polymers. Both of them possess high thermo-stability which is up to 410 and 900°C, respectively, and moderate hydrogen storage properties with 0.46 wt% at 77 K. Their nitrogen uptake showed type-I isotherm with BET surface areas up to 342 and 317 m2·g−1. [ABSTRACT FROM AUTHOR]