Diphenylacetylene-Incorporating Octaphyrin: A Rigid Macrocycle with Readily Separable Conformational Isomers.

An expanded carbaporphyrinoid analogue, octaphyrin(2,1,1,1,2,1,1,1), containing two rigid diphenylacetylene moieties is reported. In contrast to traditional pyrrolic macrocycles where flexible conformers coexist in dynamic equilibrium, this macrocycle exists as two separable, conformationally stable stereoisomers, denoted as 1A and 1B. The conformational effect of both conformers, as well as their protonated forms, were thoroughly studied using NMR spectroscopy, UV/Vis, and single crystal X-ray diffraction analyses.

Resolution of Expanded Porphyrinoids: A Path to Persistent Chirality and Appealing Chiroptical Properties.

Chirality is a fundamental characteristic of nature. Expanded porphyrinoids and their analogues offer an attractive platform for delving into the intricacies of chirality. Expanded porphyrinoids comprise pyrrolic macrocycles and related heterocyclic systems.

Phenanthrene-Incorporated Isoamethyrin: A Near-Planar Macrocycle That Display Enhanced Aromaticity via Protonation-Triggered Conformation Changes.

Controlling the aromaticity in expanded porphyrins is a forefront research topic, and the strategy of using protonation-triggered conformational changes to fine-tune electronic properties and aromaticity has yet to be generalized in rigid and planar expanded porphyrins. Here, we synthesized phenanthrene-incorporated isoamethyrins that possess near-planar conformations and nonaromatic characters. However, when methanesulfonic acid (MSA) was added, geometric deformations occurred to minimize the unfavorable strain, resulting in macrocycles that were weakly aromatic as a whole.

Di-2,7-pyrenidecaphyrin(1.1.0.0.0.1.1.0.0.0) and Its Bis-Organopalladium Complexes: Synthesis and Chiroptical Properties.

A non-aromatic expanded carbaporphyrinoid, incorporating two built-in 2,7-pyrenylene moieties was synthesized. The intrinsically labile structure was demonstrated by proton-triggered conformational changes between the figure-of-eight and quasi-Möbius conformers. Upon treatment with Pd(OAc) , the reaction produces two bis-Pd complexes with distinct coordination modes.

Controlled assembly of a bicyclic porphyrinoid and its 3-dimensional boron difluoride arrays.

A fully conjugated cryptand-like bicyclic porphyrinoid ligand 4, incorporating three carbazole linkages and four dipyrrin moieties, was prepared the acid-catalysed condensation of an extended 2,2'-bipyrrole analogue containing a central carbazole moiety and 3,4-diethyl-2,5-diformylpyrrole in 79% isolated yield. This new cryptand-like system acts as an effective ligand and allows for complexation of BF (boron difluoride) subunits. Three BODIPY arrays, containing two, three, and four BF subunits, namely 4·2BF, 4·3BF and 4·4BF, could thus be isolated from the reaction of 4 with BF·EtO in the presence of triethylamine at 110 °C, albeit in relatively low yield.

Enhancing room-temperature phosphorescence intermolecular charge transfer in dopant-matrix systems.

Some specific organic dopants have been found to form intermolecular charge transfer complexes with phosphorescence-inactive organic matrices to mediate intersystem crossing of the organic matrices and thus activate room-temperature phosphorescence of the organic matrices. This method of boosting intersystem crossing paves the way for high-performance organic room-temperature phosphorescent materials.

3,6-Carbazoylene Octaphyrin (1.0.0.0.1.0.0.0) and Its Bis-BF Complex.

3,6-Carbazole precursors were used to prepare an octaphyrin. The conformation and electronic structure of the system could be modulated through trifluoroacetate (TFA) protonation and BF complexation. The resulting nonaromatic macrocyclic complexes, and , displayed noteworthy photophysical properties.

1,4-Phenylene-Incorporated Decaphyrin(1.0.1.0.0.1.0.1.0.0): Synthesis, Structure, and Topological Chirality.

Expanded porphyrins represent emerging structures in realizing topological chirality; however, their inherent flexibility has hampered the effective chiral resolution. Herein, we rationally designed a decaphyrin , which could be separated into its enantiomers in the free-base form. The enantiomers showed noteworthy chiroptical properties, e.

Kinetic trapping of a cobalt(ii) metallocage using a carbazole-containing expanded carbaporphyrinoid ligand.

The -unsubstituted expanded porphyrinoid 3, incorporating two carbazole moieties, acts as an effective ligand for Co(ii) and permits the isolation and X-ray diffraction-based characterization of a 6 : 3 metal-to-ligand metallocage complex that converts spontaneously to the constituent 2 : 1 metal-to-ligand metalloring species in chloroform solution. The discrete metalloring is formed directly when the Co(ii) complex is crystallized from supersaturated solutions, whereas crystallization from more dilute solutions favors the metallocage. Studies with two other test cations, Pd(ii) and Zn(ii), revealed exclusive formation of the monomeric metalloring complexes with no evidence of higher order species being formed.

Nickel-Catalyzed Reductive Cross-Coupling of Aryl Bromides with Vinyl Acetate in Dimethyl Isosorbide as a Sustainable Solvent.

A nickel-catalyzed reductive cross-coupling has been achieved using (hetero)aryl bromides and vinyl acetate as the coupling partners. This mild, applicable method provides a reliable access to a variety of vinyl arenes, heteroarenes, and benzoheterocycles, which should expand the chemical space of precursors to fine chemicals and polymers. Importantly, a sustainable solvent, dimethyl isosorbide, is used, making this protocol more attractive from the point of view of green chemistry.

Carbazole-Containing Carbadecaphyrins: Non-aromatic Expanded Porphyrins that Undergo Proton-Triggered Conformational Changes.

A pair of meso-unsubstituted expanded carbaporphyrins containing two carbazole moieties were prepared in high isolated yields (82 and 76 %, respectively). The two macrocycles, namely 3 and 4, differ with respect to their substitution at the carbazole N-atoms i. e.

Structural basis for the dimerization mechanism of human transcription factor E3.

The transcription factor for immunoglobulin heavy-chain enhancer 3 (TFE3) is a member of the microphthalmia (MiT/TFE) transcription factor family. Dysregulation of TFE3 due to chromosomal abnormalities is associated with a subset of human renal cell carcinoma. Little structural information of this key transcription factor has been reported.

Nickel-catalyzed asymmetric reductive arylation of α-chlorosulfones with aryl halides.

We report an asymmetric Ni-catalyzed reductive cross-coupling of aryl/heteroaryl halides with racemic α-chlorosulfones to afford enantioenriched sulfones. The reaction tolerates a variety of functional groups under mild reaction conditions, which complements the current methods. The utility of this work was demonstrated by facile late-stage functionalization of commercial drugs.

Controlled release of iodine from cross-linked cyclodextrin metal-organic frameworks for prolonged periodontal pocket therapy.

Effective therapeutic system to periodontitis was designed using cross-linked cyclodextrin metal-organic framework (COF) as carrier for iodine and further suspended in hydroxyethyl cellulose gel as I@COF-HEC hydrogel. Inclusion of iodine within the COF was demonstrated by SR-FTIR spectral and characteristic DSC and TGA changes. Molecular modelling identified the interaction of iodine with both COF central cavity and individual cyclodextrin moieties of COF.

Base-free oxidation of alcohols enabled by nickel(ii)-catalyzed transfer dehydrogenation.

An efficient nickel(ii)-catalyzed transfer dehydrogenation oxidation of alcohols is reported that relies on cyclohexanone as the formal oxidant and does not require the use of an external base. The synthetic utility of this protocol is demonstrated via the facile oxidation of structurally complicated natural products.

Metal catalyst-free photo-induced alkyl C-O bond borylation.

Metal catalyst free, blue visible light-induced C-O bond borylation of unactivated tertiary alkyl methyl oxalates has been developed to furnish tertiary alkyl boronates. From the secondary alcohols activated with imidazolylthionyl, moderate yields of boronates were attained under standard photo-induced conditions. Preliminary mechanistic studies confirmed the involvement of a (DMF)2-B2cat2 adduct that weakly absorbs light at 437 nm so as to initiate a Bcat radical.

Excitonically Coupled Cyclic BF Arrays of Calix[8]- and Calix[16]phyrin as Near-IR-Chromophores.

Two giant calix[n]phyrin derivatives namely calix[8]- (4) and calix[16]phyrin (5), involving two and four BF units, respectively, were prepared through the condensation of the bis-naphthobipyrrolylmethene-BF complex (3) with pentafluorobenzaldehyde. Calix[n]phyrins 4 and 5 display extremely high extinction coefficients (3.67 and 4.

Intramolecular Aromatic C-H Acyloxylation Enabled by Iron Photocatalysis.

A mild and efficient protocol for the intramolecular aromatic C-H oxygenation of 2-biphenylcarboxylic acids has been achieved via iron photocatalysis. The 2-biphenylcarboxylic acids with a diverse array of substituents at both phenyl rings could furnish the oxygenation products in good to excellent yields. We speculate that the aryl carboxylate-iron(III) complexes should generate the aroyloxy radicals and iron(II) upon visible light irradiation.

Self-Assembled Cagelike Receptor That Binds Biologically Relevant Dicarboxylic Acids via Proton-Coupled Anion Recognition.

We report here a fully organic, self-assembled dimeric receptor, constructed from acyclic naphthyridyl-polypyrrolic building blocks. The cagelike dimer is stable in the solid state, in solution, and in gas phase, as inferred from X-ray diffraction and spectroscopic analyses. This system acts as a receptor for oxalic acid, maleic acid, and malonic acid in the solid state and in THF solution.

Diastereo- and Enantioselective Synthesis of Quaternary α-Amino Acid Precursors by Copper-Catalyzed Propargylation.

A diastereo- and enantioselective propargylic substitution reaction between propargylic carbonates and α-substituted nitroacetates catalyzed by a Cu-pybox complex is described. This method allows the preparation of a series of non-proteinogenic quaternary α-amino acid precursors featuring two contiguous stereogenic centers and a terminal alkyne moiety in high yields with good to excellent diastereo- and enantioselectivities in most cases. The propargylated adducts were elaborated into a diverse set of quaternary α-amino acid derivatives.

Cesium Carbonate Catalyzed Esterification of -Benzyl--Boc-amides under Ambient Conditions.

We report a general activated amide to ester transformation catalyzed by CsCO. Using this approach, esterification proceeds under relatively mild conditions and without the need for a transition metal catalyst. This method exhibits broad substrate scope and represents a practical alternative to existing esterification strategies.

Arylation of Aldehydes To Directly Form Ketones via Tandem Nickel Catalysis.

A nickel-catalyzed arylation of both aliphatic and aromatic aldehydes proceeds with air-stable (hetero)arylboronic acids, with an exceptionally wide substrate scope. The neutral condition tolerates acidic hydrogen and sensitive polar groups and also preserves α-stereocenters of some chiral aldehydes. Interestingly, this nickel(0) catalysis does not follow common 1,2-insertion of arylmetal species to aldehydes and β-hydrogen elimination.

Shape-persistent pyrrole-based covalent organic cages: synthesis, structure and selective gas adsorption properties.

Two cryptand-like, shape persistent [2+3] imine cages (1 and 2) derived from oligopyrrolic precursors (diformyl dipyrrylpyridine 3 and diformyl bipyrrole 4) were prepared. These cages contain open cavities as inferred from solid state structural analyses and act as selective CO2 gas adsorbing materials in the solid state.

Nickel-Catalyzed Direct Synthesis of Aryl Olefins from Ketones and Organoboron Reagents under Neutral Conditions.

Nickel-catalyzed addition of arylboron reagents to ketones results in aryl olefins directly. The neutral condition allows acidic protons of alcohols, phenols, and malonates to be present, and fragile structures are also tolerated.

Palladium-Catalyzed Arylation of Ketones and Acetonitrile with Ortho Alkylation of Aryl Rings: De Novo Synthesis of Tetralines and Benzocycloheptenes.

Palladium-catalyzed α-arylation reactions of ketones with simultaneous ortho alkylation offer 1,2,3-substituted arenes. The reactions of 1,ω-dihaloalkanes also allow facile construction of medicinally important tetralines and benzocycloheptenes.