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The rational design of high-performance fluorescent materials for cancer targeting in vivo is still challenging. A unique molecular design strategy is presented that involves tailoring aggregation-induced emission (AIE)-active organic molecules to realize preferable far-red and NIR fluorescence, well-controlled morphology (from rod-like to spherical), and also tumor-targeted bioimaging. The shape-tailored organic quinoline-malononitrile (QM) nanoprobes are biocompatible and highly desirable for cell-tracking applications. Impressively, the spherical shape of QM-5 nanoaggregates exhibits excellent tumor-targeted bioimaging performance after intravenously injection into mice, but not the rod-like aggregates of QM-2. [ABSTRACT FROM AUTHOR]

The rational design of high-performance fluorescent materials for cancer targeting in vivo is still challenging. A unique molecular design strategy is presented that involves tailoring aggregation-induced emission (AIE)-active organic molecules to realize preferable far-red and NIR fluorescence, well-controlled morphology (from rod-like to spherical), and also tumor-targeted bioimaging. The shape-tailored organic quinoline-malononitrile (QM) nanoprobes are biocompatible and highly desirable for cell-tracking applications. Impressively, the spherical shape of QM-5 nanoaggregates exhibits excellent tumor-targeted bioimaging performance after intravenously injection into mice, but not the rod-like aggregates of QM-2. [ABSTRACT FROM AUTHOR]

Using one ray of light to encode another ray of light is highly desirable because information in optical format can be directly transferred from one beam to another without converting back to the electronic format. One key medium to accomplish such an amazing task is photoswitchable molecules. Using bis(dithiazole)ethene that can be photoswitched between its ring‐open and ring‐closed states quantitatively with excellent fatigue resistance and high thermal stability, it is shown that quantitative photoreversibility allowed the photoswitching light to control other light travelling through the photoswitchable medium, a phenomenon of transferring information encoded in one light ray to others, thus imparting photo‐optical modulation on the orthogonal light beam. [ABSTRACT FROM AUTHOR]

Using one ray of light to encode another ray of light is highly desirable because information in optical format can be directly transferred from one beam to another without converting back to the electronic format. One key medium to accomplish such an amazing task is photoswitchable molecules. Using bis(dithiazole)ethene that can be photoswitched between its ring-open and ring-closed states quantitatively with excellent fatigue resistance and high thermal stability, it is shown that quantitative photoreversibility allowed the photoswitching light to control other light travelling through the photoswitchable medium, a phenomenon of transferring information encoded in one light ray to others, thus imparting photo-optical modulation on the orthogonal light beam. [ABSTRACT FROM AUTHOR]

Using one ray of light to encode another ray of light is highly desirable because information in optical format can be directly transferred from one beam to another without converting back to the electronic format. One key medium to accomplish such an amazing task is photoswitchable molecules. Using bis(dithiazole)ethene that can be photoswitched between its ring-open and ring-closed states quantitatively with excellent fatigue resistance and high thermal stability, it is shown that quantitative photoreversibility allowed the photoswitching light to control other light travelling through the photoswitchable medium, a phenomenon of transferring information encoded in one light ray to others, thus imparting photo-optical modulation on the orthogonal light beam. [ABSTRACT FROM AUTHOR]

Two complementary examples of porphyrin nanoarchitectonicsare presented. The fabrication of binary molecular monolayers usingtwo different porphyrin molecules, tetrakis(3,5-di-t-butyl-4-hydroxyphenyl)porphyrin (1) and tetrakis(4-pyridyl)porphyrin (2), by depositionin ultrahigh vacuum was demonstrated. Two unusual heteromolecularmonolayer structures were observed, with one exhibiting good separationof 1molecules within the monolayer. Also, a syntheticnanoarchitectonic approach was used to prepare self-assembled molecularnanowires at a mica substrate. The nanowires could be observed togrow using atomic force microscopy (AFM), and the network structuresof the nanowires could be influenced by manipulation using the AFMprobe tip. [ABSTRACT FROM AUTHOR]

Three photochromic compounds-2-butyl-5,6-bis[5-(4-methoxyphenyl)-2-methylthiophen-3-yl]-1 H-benzo[ de]isoquinoline-1,3(2 H)-dione (BTE-NA), 4,5-bis[5-(4-methoxyphenyl)-2-methylthiophen-3-yl]benzo[ c][1,2,5]thiadiazole (BTA), and BTTA, which contain naphthalimide, benzothiadiazole, and benzobisthiadiazole as six-membered ethene bridges with different aromaticities-were systematically studied in solution, sol-gel, and single-crystal states. They exhibit typical photochromic performance with considerably high cyclization quantum yields. BTE-NA, BTA, and BTTA form a typical donor-π-acceptor ( D-π-A) system with significant intramolecular charge transfer (ICT) between HOMO and LUMO upon excitation, thus realizing the fluorescence modulation by both photochromism and solvatochromism. The three ethene bridges with different degrees of aromaticity can provide a systematic comparison of the thermal stability evolution for their corresponding closed forms (c-BTE-NA, c-BTA, and c-BTTA). c-BTE-NA shows first-order decay in various solvents from cyclohexane to acetonitrile. c-BTA only shows first-order decay in polar solvents such as chloroform, whereas it is stable in nonpolar solvents like toluene. In contrast, the less aromatic property of BTTA gives rise to its unprecedented thermal stability in various solvents even at elevated temperatures in toluene (328 K). Moreover, the small energy barrier between the parallel and antiparallel conformers allows the full conversion from BTTA to c-BTTA. In well-ordered crystal states, all three compounds adopt a parallel conformation. Interestingly, BTTA forms a twin crystal of asymmetric nature with interactions between the electron-rich oxygen atom of the methoxy group and the carbon atom of the electron-deficient benzobisthiadiazole moiety. This work contributes to the understanding of aromaticity-controlled thermal stability of photochromic systems based on a six-membered ring as an ethene bridge, and a broadening of the novel building blocks for photochromic bisthienylethene systems. [ABSTRACT FROM AUTHOR]

Abstract: A novel copper-containing enzyme named COI (catechol oxidase I) has been isolated and purified from tobacco by extracting acetone-emerged powder with phosphate buffer, centrifugation at low temperature, ammonium sulfate fractional precipitation, and column chromatography on DEAE-sephadex (A-50), sephadex (G-75), and DEAE-celluse (DE-52). PAGE, SDS-PAGE were used to detect the enzyme purity, and to determine its molecular weight. Then the secondary structures of COI at different pH, different temperatures and different concentrations of guanidine hydrochloride (GdnHCl) were studied by the FT-IR, Fourier self-deconvolution spectra, and circular dichroism (CD). At pH 2.0, the contents of both α-helix and anti-parallel β-sheet decrease, and that of random coil increases, while β-turn is unchanged compared with the neutral condition (pH 7.0). At pH 11.0, the results indicate that the contents of α-helix, anti-parallel β-sheet and β-turn decrease, while random coil structure increases. According to the CD measurements, the relative average fractions of α-helix, anti-parallel β-sheet, β-turn/parallel β-sheet, aromatic residues and disulfide bond, and random coil/γ-turn are 41.7%, 16.7%, 23.5%, 11.3%, and 6.8% at pH 7.0, respectively, while 7.2%, 7.7%, 15.2%, 10.7%, 59.2% at pH 2.0, and 20.6%, 9.5%, 15.2%, 10.5%, 44.2% at pH 11.0. Both α-helix and random coil decrease with temperature increasing, and anti-parallel β-sheet increases at the same time. After incubated in 6mol/L guanidine hydrochloride for 30min, the fraction of α-helix almost disappears (only 1.1% left), while random coil/γ-turn increases to 81.8%, which coincides well with the results obtained through enzymatic activity experiment. [Copyright &y& Elsevier]

A potentially heptadentate ligand H3L (N,N′-bis(2-hydroxybenzyl)-1,3-bis[(2-aminoethyl)amino]-2-propanol) and its two Ni(II) complexes, [Ni(H2L)H2O](H2O)3ClO4 (1) and [Ni(H2L)(H2O)](H2O)Cl (2) were prepared and characterized. X-ray structural analyses indicate that complex 1 has a distorted octahedral coordination geometry, with four amine N atoms of H2L- defining the equatorial plane, one aqua O atom and one phenoxo O atom of the ligand occupying two axial positions, respectively. The Ni(II) center of 2 has coordination geometry similar to that of 1. IR and electronic spectra of 1 and 2 are in agreement with their crystal structural features. Approximately along the ab plane, 2D supramolecular structure of 1 is assembled through multiple hydrogen bonds between hydroxy groups of the ligands, coordinated and crystal lattice H2O and π–π stacking interactions between adjacent phenyl rings of the ligands, while for that of 2, probably along the a axis, 1D chain structure is also formed by multiple hydrogen bonds, but lack of π–π stacking interactions. [Copyright &y& Elsevier]

Two Hg(II) halide complexes, [Hg2Cl4(TPA)2] (1) and [HgBr2(TPA)] (2) (TPA=tris(2-pyridyl)amine) have been synthesized. X-ray diffraction analyses reveal that 1 is binuclear, whereas, 2 is mononuclear. The binuclear structure of 1 is unsymmetrical: one Hg(II) atom is octahedrally coordinated, with the other Hg(II) tetrahedrally coordinated. Hg(II) atom in 2 has a distorted tetrahedral coordination environment. The coordination moieties of complexes 1 and 2 are connected to give 2D and 1D structures, respectively, by weak intermolecular interactions, namely, the multiple π–π interactions between the TPA pyridyl rings in complex 1, and the intermolecular Hg(II)⋯Br interactions in complex 2. 1H NMR, IR, and Raman results are discussed with reference to the crystal structures. [Copyright &y& Elsevier]

Two complexes of zinc (II) with mixed-ligand, [Zn2(phen)2(HL1)2] (ClO4)2 (1) and [Zn2(phen)2(HL2)2] (ClO4)2(2) (H2L1&z.dbnd6;N–(2-hydroxybenzyl) ethanolamine and H2L2=N–(2-hydroxybenzyl) propanolamine), and another zinc complex ZnL1 (3) were synthesized and characterized by elemental analysis, IR spectra, thermal analysis, fluorescence and 1H NMR. The crystal structure of (1) has a centrosymmetric di-phenoxo-bridged dizinc (II) core and each zinc center is laid in a slightly distorted trigonal bipyramidal geometry. A 2D supramolecular structure is formed approximately along bc plane in terms of the action of multiple N–H⋯O and O–H⋯O hydrogen bonds between the (HL1)− ligands and the π⋯π stacking interactions between the phenanthroline ligands. Thermal behavior, studied by TG and DTA in nitrogen atmosphere, indicates that phen is eliminated at higher temperature than (HL1)− and (HL2)−. Several possible mechanisms for the fluorescence quenching of the metal complexes are proposed. [Copyright &y& Elsevier]

Complex [Cu(2,2′-bpy)(H2L1)](ClO4)2 (1) has been self-assembled by the complexation of a potentially flexible tetradenate ligand 1,2-bis((2-hydroxyetheyl)amino)ethane (H2L1) and a chelating rigid ligand 2,2′-bipyridine (bpy) with Cu(II). Crystal analyses reveal that H2L1 acts as a tridenate ligand by the coordination of one alkoxyl O atom and two amino N atoms. Copper(II) coordinates additionally with the two N atoms of bipyridine, giving a distorted square pyramidal geometry. Each complex molecule is connected with four surrounding ones by hydrogen bonds along the ac plane, leading to 2D sheets constituted with 7.874×10.891 A˚ metallomacrocyclic rectangles. Each vertex of the rectangle is occupied by a copper atom. The four sides are comprised of multiple hydrogen bonds. Electronic spectra of complex 1 showed a band maximum at 661 nm; the EPR spectra of 1 in frozen DMF at 100 K showed an axial spectrum with four hyperfine peaks in the g∥ region, and g∥>g⊥, consistent with a distorted square pyramidal copper(II) coordination geometry. [Copyright &y& Elsevier]

Two copper(II) complexes [Cu4(L1)4] (1) and [Cu2(phen)2(HL2)2] (ClO4)2 (2) have been synthesized from two potentially tridentate ligands N-(2-hydroxybenzyl) propanolamine (H2L1) and N-(2-hydroxybenzyl) ethanolamine (H2L2). X-ray analyses revealed that 1 contains a Cu4O4 cubane core, with each two Cu(II) atoms bridged by a pair of alkoxides; 2 has a bis(μ2-phenoxo)-bridged dicopper(II) structure. Variable temperature magnetic measurements of 1 have revealed that the correlation between 2J and the bridge angles φ for 1 shows a very strong antiferromagnetic tendency, i.e. the ferromagnetic and antiferromagnetic interactions cross at the φ of 94.5°. The relatively weak antiferromagnetic interactions (2J=−226.8 cm−1) with respect to the bridge angles (φ=100.4°) for 2 have been ascribed to the pyramidal distortions at the phenoxide oxygen atoms in addition to the unfavorable overlaps of the magnetic orbitals for the highly distorted copper coordination polyhedra. [Copyright &y& Elsevier]

A linear pentadentate ligand, N-(2-hydroxyethyl)-N″-(2-hydroxybenzyl)-diethylenetriamine (HL), and its zinc(II) complex were synthesized and characterized by IR spectra, 1H NMR spectra and elemental analyses. By pH potentiometric titration, protonation constants of HL and stability constants of Zn(II) complexation with HL have been determined at 25 ± 0.1°C and I = 0.1 mol/L (KNO3). The kinetics of 4-nitrophenyl acetate (NA) hydrolysis catalyzed by the complex was determined spectrophotometrically at 25 ± 0.1°C and I = 0.1 mol/L (KNO3) in CH3CN (10 % v/v) at pH 7.0–9.04 (50 mmol/L buffers), and the second-order rate constants kc for NA hydrolysis were obtained. The experimental results indicate that Zn···-OR (R = alkyl) is a better nucleophile than Zn···-OAr (Ar = aryl). A good catalysis was realized with a kc value of 8.5 × 10-2 mol-1 · L · s-1 at pH 9.04. [ABSTRACT FROM AUTHOR]

Di- and tripyrrin sensors D1–D4 exhibit CHEF-type fluorescence enhancement by factors up to 72 upon addition of 1 equiv. Zn2+, with tunable emission colours between green (D1) and red (D4). [ABSTRACT FROM AUTHOR]

Self-assembly and reassembly of high aspect ratio nanowires of trigeminal porphyrins and their manipulation using an atomic force microscope (AFM) is reported. [ABSTRACT FROM AUTHOR]

The combination of pyrrole and hemiquinone units produced a novel prototype of efficient colorimetric fluoride sensors, and the presence of the tautomerism effect provides additional means of modulating the sensing behavior. [ABSTRACT FROM AUTHOR]

Among other photovoltaic techniques including perovskite solar cells and organic solar cells, dye-sensitized solar cells (DSSCs) are considered to be a potential alternative to conventional silicon solar cells. Porphyrins are promising dyes with the properties of easy modification and superior light-harvesting capability. However, porphyrin dyes still suffer from a number of unfavorable aspects, which need to be addressed in order to improve the photovoltaic performance. This feature article briefly summarizes the recent progress in improving the Voc and Jsc of porphyrin-based DSSCs in terms of molecular engineering by modifying the porphyrin macrocycle, donor and acceptor moieties of the porphyrin dyes, coadsorption of the porphrin dyes with bulky coadsorbents like chenodeoxycholic acid (CDCA), and cosensitization of the porphyrin dyes with metal-free organic dyes. Notably, concerted companion (CC) dyes are described in detail, which have been constructed by linking a porphyrin dye subunit and a metal-free organic dye subunit with flexible alkoxy chains to achieve panchromatic absorption and concerted enhancement of Voc and Jsc. In one sentence, this article is expected to provide further insights into the development of high performance DSSCs through the design and syntheses of efficient porphyrin dyes and CC dyes in combination with device optimization to achieve simultaneously elevated Voc and Jsc, which may inspire and promote further progress in the commercialization of the DSSCs. [ABSTRACT FROM AUTHOR]

As a promising low-cost solar energy conversion technique, dye-sensitized solar cells have undergone spectacular development since 1991. For practical applications, improvement of power conversion efficiency has always been one of the major research topics. Porphyrins are outstanding sensitizers endowed with strong sunlight harvesting ability in the visible region and multiple reaction sites available for functionalization. However, judicious molecular design in consideration of light-harvest, energy levels, operational dynamics, adsorption geometry and suppression of back reactions is specifically required for achieving excellent photovoltaic performance. This feature article highlights some of the recently developed porphyrin sensitizers, especially focusing on the systematic dye structure optimization approach in combination with coadsorption and cosensitization methods in pursuing higher efficiencies. Herein, we expect to provide more insights into the structure–performance correlation and molecular engineering strategies in a stepwise manner. [ABSTRACT FROM AUTHOR]

Sensing of metal ions and anions is of great importance because of their widespread distribution in environmental systems and biological processes. Colorimetric and fluorescent chemosensors based on organic molecular species have been demonstrated to be effective for the detection of various ions and possess the significant advantages of low cost, high sensitivity, and convenient implementation. Of the available classes of organic molecules, porphyrin analogues possess inherently many advantageous features, making them suitable for the design of ion chemosensors, with the targeted sensing behavior achieved and easily modulated based on their following characteristics: (1) NH moieties properly disposed for binding of anions through cooperative hydrogen-bonding interactions; (2) multiple pyrrolic N atoms or other heteroatoms for selectively chelating metal ions; (3) variability of macrocycle size and peripheral substitution for modulation of ion selectivity and sensitivity; and (4) tunable near-infrared emission and good biocompatibility. In this Review, design strategies, sensing mechanisms, and sensing performance of ion chemosensors based on porphyrin analogues are described by use of extensive examples. Ion chemosensors based on normal porphyrins and linear oligopyrroles are also briefly described. This Review provides valuable information for researchers of related areas and thus may inspire the development of more practical and effective approaches for designing high-performance ion chemosensors based on porphyrin analogues and other relevant compounds. [ABSTRACT FROM AUTHOR]

Sapphyrin is a pentapyrrolic expanded porphyrin with a 22π aromatic character. Herein, we report the synthesis of a 20π antiaromatic sapphyrin isomer 1 by oxidative cyclization of a pentapyrrane precursor P5 with a terminal β‐linked pyrrole. The resulting isomer 1, containing a mis‐linked bipyrrole unit in the skeleton, exhibits a reactivity for further oxidation due to the distinct antiaromatic electronic structure, affording a fused macrocycle 2, possessing a spiro‐carbon‐containing [5.6.5.6]‐tetracyclic structure. Subsequent treatment with an acid afforded a weakly aromatic pyrrolone‐appended N‐confused corrole 3, and thermal fusion gave a [5.6.5.7]‐tetracyclic‐ring‐embedded 14π aromatic triphyrin(2.1.1) analog 4. The cyclization at the mis‐linked pyrrole moiety of P5 played a crucial role in synthesizing the antiaromatic porphyrinoid susceptible to facile transformation to novel porphyrinoids with variable aromaticity. [ABSTRACT FROM AUTHOR]

Sapphyrin is a pentapyrrolic expanded porphyrin with a 22π aromatic character. Herein, we report the synthesis of a 20π antiaromatic sapphyrin isomer 1 by oxidative cyclization of a pentapyrrane precursor P5 with a terminal β‐linked pyrrole. The resulting isomer 1, containing a mis‐linked bipyrrole unit in the skeleton, exhibits a reactivity for further oxidation due to the distinct antiaromatic electronic structure, affording a fused macrocycle 2, possessing a spiro‐carbon‐containing [5.6.5.6]‐tetracyclic structure. Subsequent treatment with an acid afforded a weakly aromatic pyrrolone‐appended N‐confused corrole 3, and thermal fusion gave a [5.6.5.7]‐tetracyclic‐ring‐embedded 14π aromatic triphyrin(2.1.1) analog 4. The cyclization at the mis‐linked pyrrole moiety of P5 played a crucial role in synthesizing the antiaromatic porphyrinoid susceptible to facile transformation to novel porphyrinoids with variable aromaticity. [ABSTRACT FROM AUTHOR]

Porphyrinoids have attracted wide interest because of their vital roles in biological processes and fascinating structural and functional characters. In this work, a doubly N-confused pentapyrrane precursor N 2 C–P 5 has been synthesized with terminal pyrrole ring A and middle pyrrole C incorporated in the N-confused mode. On this basis, pentapyrrin 1 and sapphyrin 2 have been synthesized by oxidizing N 2 C–P 5 with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ). Both 1 and 2 possess a [5.5.5]-tricyclic fused ring involving pyrrole B and the neighboring confused pyrrole C. Meanwhile, the formation of 2 involves ring closure between the terminal rings A and E. Notably, 2 exists as a diradical showing a half-field signal in the electron paramagnetic resonance (EPR) spectrum and a singlet ground state with a negative singlet-triplet energy gap of −0.50 kcal/mol. Excellent thermal stability has been observed for 2 , which may be related to its large π-conjugated framework involving the fused structure. On this basis, 1 and 2 were treated with Cu(acac) 2 to afford Cu(II) complexes 3 and 4 , respectively. As a result, an acetylacetonyl moiety is attached at the terminal pyrrole ring E to afford an NNNO coordination environment for complex 3 , and the sapphyrin macrocycle of 2 has been cleaved between rings A and B to afford a fused pentapyrrin ligand, furnishing an NNNN coordination environment for complex 4 , in which a pentafluorophenyl-ketal group generated during the ring cleavage reaction is attached to ring A, and it can be hydrolyzed to the corresponding pentafluorobenzoyl substituent to afford complex 5. Compared with free bases 1 and 2 , complexes 3 − 5 show more intense low-energy near-infrared (NIR) absorption bands at ca. 791, 926 and 907 nm, respectively. This work provides an effective approach for the syntheses of linear and macrocyclic oligopyrroles with intriguing structures and properties by oxidizing oligopyrranes with precisely designed numbers and positions of N-confused pyrroles. [Display omitted] • Facile syntheses of stable N-fused sapphyrin diradical. • Cu(II) complexes of fused pentapyrrins with an acetylacetonyl, pentafluorophenyl-ketal and pentafluorobenzoyl substituent. • Tunable low-energy near-infrared (NIR) absorption bands up to 1151 nm. [ABSTRACT FROM AUTHOR]

To develop cosensitizers for fabricating dye-sensitized solar cells (DSSCs) based on porphyrin dyes, C2 and C3 have been synthesized using a diphenylamine donor, an anthracene based π-spacer and a benzoic acid acceptor on the basis of our previously reported cosensitizer C1. Thus, two hexyloxy chains have been introduced in the diphenylamine donor to synthesize C2 with the purpose of extending the absorption wavelength range and suppressing the charge recombination, and C3 has been synthesized by introducing two bulky 2,4-bis(hexyloxy)phenyl groups in the diphenylamine donor to effectively suppress dye aggregation and charge recombination between the injected electrons and the electrolyte. On this basis, DSSCs have been fabricated by using C1–C3 based on the cobalt electrolyte. As expected, an obviously higher Jsc of 13.03 mA cm−2 has been obtained for C2 relative to that of 11.92 mA cm−2 obtained for C1. As a result, C2 shows a slightly improved efficiency of 7.59%. On the other hand, the molecular structure of C3 has been further optimized with two bulky dihexyloxyphenyl units, and thus the suppressed interfacial back electron transfer improves the Jsc to 13.23 mA cm−2 and the superior anti-aggregation ability enhances the Voc to 857 mV. Finally, the highest PCE value of 8.95% is achieved for C3. On this basis, cosensitization with XW66 affords remarkable efficiencies of 9.06%, 9.89% and 10.22% for C1–C3, respectively. These results provide an effective approach for developing efficient cosensitizers for porphyrins by introducing suitable substituents into the donor unit. [ABSTRACT FROM AUTHOR]

In this work, a novel compound 2‐(3,5,6‐trichloro‐1,4‐benzoquinon‐2‐yl)‐neo‐fused hexaphyrin has been prepared from tetrachloroquinone and neo‐fused hexaphyrin through a substitution reaction. The chemical structure of the compound has been characterized by nuclear magnetic resonance (NMR), high‐resolution mass spectrum, UV–Vis spectrum, and X‐ray diffraction. The crystal structure reveals that the quinonyl unit is almost coplanar with the adjacent N‐confused pyrrole unit. Because of the cooperative effect of extended conjugation and the intramolecular charge transfer effect related to the strong electron‐withdrawing character of the quinonyl unit, the absorption of 2 is dramatically extended to ca. 1280 nm. [ABSTRACT FROM AUTHOR]

Tetracenequinone fused porphyrin Ni4TQ has been synthesized and the long tetracenequinone units at the vertices of porphyrin exhibit an intense π,π-interaction, which can be regulated by solvents to furnish different shapes of crystals or various uniform flower-shaped biomorphs. [ABSTRACT FROM AUTHOR]

The porphyrin macrocycle is one of the most frequently investigated functional molecular entities and can be incorporated into advanced functional nanomaterials upon formation of organized nanostructures. Thus, study of the science and technology of porphyrin assemblies has attracted many organic, biological and supramolecular chemists. A wide variety of nanostructures can be obtained by supramolecular self-assembly because the porphyrin moiety is amenable to chemical modifications through thoughtful synthetic design and moderate preparative effort. Some recent developments in porphyrin assembly, obtained through various supramolecular approaches, are briefly summarized. Topics described in this review are classified into four categories: (i) non-specific assemblies; (ii) specific assemblies; (iii) assemblies in organized films; (iv) molecular-level arrangement. We present examples in the order of structural precision of assemblies. [ABSTRACT FROM AUTHOR]

Two novel Cu(II) complexes, [Cu(H2tpda)(acac)](ClO4)0.5Cl0.5 · H2O, [Cu(H2tpda)(NO3)]ClO4 (2) (H2tpda = tripyridyldiamine) have been synthesized, and characterized by X-ray analyses, elemental analyses, IR, UV and ESR spectra. Single crystal X-ray diffraction revealed that the Cu atom in complex 1 is coordinated to three N atoms from H2tpda and two oxygen atoms from acac with an approximately trigonal bipyramidal geometry. The molecules are assembled through intermolecular hydrogen bonds and π-π stacking, affording a two dimensional network. In complex 2, the Cu atom is coordinated with three N atoms from H2tpda and two oxygen atoms from [image omitted] in addition to a weak coordination with one oxygen from [image omitted], resulting in an irregular octahedral environment, and the molecules are also connected by intermolecular hydrogen bonding and π-π stacking, affording a one dimensional structure. [ABSTRACT FROM AUTHOR]

PPO II is a novel enzyme that plays a key role in the plant defense system. PPO II has the active site of a pair of antiferromagnetic coppers with phenolate oxygen bridged at neutral pH medium. At low pH, the coordination ability of phenolate oxygen becomes weak and two H2O molecular replaces the phenolate oxygen bridge in the active center and the absorption of PPO II is changed to a novel state as that of mushroom PPO. A new PPO II active site is formed between pH 8.5 and 9.0 suddenly. The phenolate oxygen bridge has been broken, hydroxide coordination with one of coppers is formed. The other copper is still coordinated with the phenolate oxygen. The CD data shows at the pH 3.0 and pH 9.0 the second structure keeps stabile as the resting PPO II and is broken at high pH 10.0. [ABSTRACT FROM AUTHOR]

A facile synthetic strategy towards conformationally stable chiral chromophores based on dimeric porphyrinoids has been established. A peculiar class of face‐to‐face intramolecularly interlocked corrole dimers were formed by the oxidative C−C coupling linked at the inner carbon sites upon simple treatment of copper(II) ions. Their intrinsic electronic structures were modulated by the peripheral corrole ring annulations, which lead to distinct optical properties and redox profiles. The stereogenic carbon centers implemented in the confused corrole skeleton provided a rationale for designing novel chiral materials. [ABSTRACT FROM AUTHOR]

Oxidation of a thiophene‐hexapyrrane hybrid S‐P6 afforded a stable conjugated open‐chain thiaheptapyrrolic helix 1 with the terminal thiophene and confused pyrrole units lying at a long distance that is adverse for further cyclization. Chelation of 1 with copper(II) ion afforded 1‐Cu, which exhibits more distant terminal units. Interestingly, further oxidation of 1 triggered an intramolecular C−N fusion reaction to afford a unique 5,5,5‐tricyclic fused linear thiaheptapyrrin 2, with the two terminals positioned in proximity, which favors the oxidative ring‐closure reaction to give a unique 5,5,5‐tricyclic fused thiaheptaphyrin (1.1.1.1.1.1.0) 3 under air. The inner‐fusion strategy for positioning the reactive sites in proximity to promote oxidative cyclization offers a new approach for constructing large porphyrinoids through conjugated oligopyrrins without the assistance of metal ions. [ABSTRACT FROM AUTHOR]

An N‐confused phlorin isomer bearing a dipyrrin moiety at the α‐position of the confused pyrrole ring (1) was synthesized. PdII and BIII coordination at the peripheral prodigiosin‐like moiety of 1 afforded the corresponding complexes 2 and 3. Reflux of 2 in triethylamine (TEA) converted the meso‐phenyl into the PdII‐coordinating phenoxy group to afford 4. Under the same reaction conditions, TEA was linked to the α‐position of the dipyrrin unit in 3 as an N,N‐diethylaminovinyl group to afford 5. Furthermore, peripheral coordination of BIII in 3 and 5 improved the planarity of the phlorin macrocycle and thus facilitated the coordination of AgIII at the inner cavity to afford 3‐Ag and 5‐Ag, respectively. These results provide an effective approach for developing unique porphyrinoids through peripheral coordination. [ABSTRACT FROM AUTHOR]

An N‐confused phlorin isomer bearing a dipyrrin moiety at the α‐position of the confused pyrrole ring (1) was synthesized. PdII and BIII coordination at the peripheral prodigiosin‐like moiety of 1 afforded the corresponding complexes 2 and 3. Reflux of 2 in triethylamine (TEA) converted the meso‐phenyl into the PdII‐coordinating phenoxy group to afford 4. Under the same reaction conditions, TEA was linked to the α‐position of the dipyrrin unit in 3 as an N,N‐diethylaminovinyl group to afford 5. Furthermore, peripheral coordination of BIII in 3 and 5 improved the planarity of the phlorin macrocycle and thus facilitated the coordination of AgIII at the inner cavity to afford 3‐Ag and 5‐Ag, respectively. These results provide an effective approach for developing unique porphyrinoids through peripheral coordination. [ABSTRACT FROM AUTHOR]

A hybrid thia‐norhexaphyrin comprising a directly linked N‐confused pyrrole and thiophene unit (1) revealed unique macrocycle transformations to afford multiply inner‐annulated aromatic macrocycles. Oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone triggered a cleavage of the C−S bond of the thiophene unit, accompanied with skeletal rearrangement to afford unique π‐conjugated products: a thiopyrrolo‐pentaphyrin embedded with a pyrrolo[1,2]isothiazole (2), a sulfur‐free pentaphyrin incorporating an indolizine moiety (3), and a thiopyranyltriphyrinoid containing a 2H‐thiopyran unit (4). Furthermore, 2 underwent desulfurization reactions to afford a fused pentaphyrin containing a pyrrolizine moiety (5) under mild conditions. Using expanded porphyrin scaffolds, oxidative thiophene cleavage and desulfurization of the hitherto unknown N‐confused core‐modified macrocycles would be a practical approach for developing unique polypyrrolic aromatic macrocycles. Oxidation of a nonaromatic thia‐modified norhexaphyrin with directly linked N‐confused pyrrole and thiophene rings triggered cleavage of a C−S bond to afford three multiply annulated polypyrrolic aromatic macrocycles with global or local aromaticity. This approach is a path to porphyrinoids with tunable structures and aromaticity based on thiophene cleavage and desulfurization. [ABSTRACT FROM AUTHOR]

A hybrid thia‐norhexaphyrin comprising a directly linked N‐confused pyrrole and thiophene unit (1) revealed unique macrocycle transformations to afford multiply inner‐annulated aromatic macrocycles. Oxidation with 2,3‐dichloro‐5,6‐dicyano‐1,4‐benzoquinone triggered a cleavage of the C−S bond of the thiophene unit, accompanied with skeletal rearrangement to afford unique π‐conjugated products: a thiopyrrolo‐pentaphyrin embedded with a pyrrolo[1,2]isothiazole (2), a sulfur‐free pentaphyrin incorporating an indolizine moiety (3), and a thiopyranyltriphyrinoid containing a 2H‐thiopyran unit (4). Furthermore, 2 underwent desulfurization reactions to afford a fused pentaphyrin containing a pyrrolizine moiety (5) under mild conditions. Using expanded porphyrin scaffolds, oxidative thiophene cleavage and desulfurization of the hitherto unknown N‐confused core‐modified macrocycles would be a practical approach for developing unique polypyrrolic aromatic macrocycles. [ABSTRACT FROM AUTHOR]

Dye-sensitized solar cells (DSSCs) have attracted intensive attention in developing photovoltaic devices for employing solar energy. For developing panchromatic and efficient porphyrin sensitizers, it has been demonstrated to be an effective approach to introduce an electron-withdrawing benzothiadiazole unit as an extra electron acceptor. In contrast, the structurally similar benzotriazole moiety remains relatively unknown in this respect. In this work, we have synthesized a novel porphyrin dye containing an extra electron acceptor of benzotriazole. Photophysical and electrochemical investigations revealed red-shifted absorption and a narrower band gap induced by the benzotriazole unit. Thus, a reasonable efficiency of 8.39% has been achieved with a J sc of 17.00 mA cm −2 and a V oc of 712 mV. On this basis, to investigate the effect of the dihedral angle between the benzotriazole and the adjacent phenylene ring, one or two methyl groups were attached to the ortho -positions of the phenylene ring. As a result, the enlarged torsion angles induce poor electronic coupling between the LUMO of the dyes and TiO 2 , resulting in lower efficiencies of 6.61% and 3.62%, respectively. With the purpose to further improve the efficiencies, coadsorption and cosensitization approaches were employed. And the efficiencies have been successfully elevated to 9.32%, 8.49% and 7.34%, respectively. These results demonstrate the effectiveness of incorporating an auxiliary benzotriazole acceptor into porphyrin dyes on achieving extended light-harvesting wavelength ranges and illustrate the importance of avoiding severe torsion within the acceptor part of the porphyrin dyes. In contrast to the commonly used cosensitizers with absorption peaks lying in the absorption valley between the Soret band and the Q bands of porphyrin dyes (500–600 nm), the utilization of an organic dye with broad absorption in this work has been demonstrated to be effective for improving the efficiencies despite the fact that its absorption peak at 450 nm largely overlaps with the Soret band of the porphyrin dyes. These results provide an alternative approach for developing cosensitizers for porphyrin dyes. [ABSTRACT FROM AUTHOR]

Biothiols, such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH), play essential roles in many physiological and pathological processes. In this work, three porphyrin derivatives, XQ1 , XQ2 and XQ3 , were synthesized by combining the porphyrin framework with nitroethylene, bis(methoxycarbonyl)ethylene and dicyanoethylene moieties, respectively. XQ1 was almost nonfluorescent, which could be utilized as a good starting point for developing fluorescence turn-on probes. Thus, XQ1 exhibits fast fluorescence enhancement and high selectivity towards the biothiols based on the Michael addition mechanism. It also exhibits high sensitivity towards the biothiols with the detection limits of 0.65–1.1 μM. In addition, XQ1 was successfully applied to cell imaging in living A549 cells for visualizing the biothiols. The results compose a good example of designing porphyrin derivatives for detecting biothiols, with the advantages of dramatic fluorescence enhancement in the NIR wavelength range, which exhibits good cell membrane permeability and practicability in detecting both exogenous and endogenous biothiols. [ABSTRACT FROM AUTHOR]

Biothiols such as cysteine (Cys), homocysteine (Hcy), and glutathione (GSH) play vital roles in various physiological and pathological processes. In this work, a BODIPY-based fluorescent probe XCN was synthesized from multi-step reactions. We first synthesized a BODIPY derivative with a cyano and a bromine moiety attached to the 8-diphenylaminophenyl substituent of BODIPY, followed by the reaction with p -aminothiophenol under basic condition. Interestingly, compound XCN was successfully obtained with the p -aminophenylthio moiety introduced into one of the α-positions of the pyrrolic units. This reaction may compose an efficient approach for synthesizing novel BODIPY derivatives with substituents attached to the pyrrolic unit without previously brominating it. XCN can be used as a fluorescence turn-on probe to selectively detect Cys and Hcy using the cyano group as the recognition site, with the p -aminophenylthio moiety left unreacted. XCN was found to be nearly nonfluorescent, and it exhibits only slight fluorescence enhancement when treated with GSH. However, upon interaction with Cys or Hcy, the fluorescence was enhanced by 1081 and 1126 folds, respectively. In addition, XCN exhibits good selectivity and sensitivity towards Cys and Hcy over GSH and other amino acids in a wide pH range from 2 to 10 in aqueous buffers. Furthermore, XCN was successfully used for imaging biothiols in living A549 lung cancer cells. [ABSTRACT FROM AUTHOR]

The selective and sensitive detection of zinc ions has been an important research topic because of the vital role played by zinc ions in numerous physiological activities, and fluorescent probes have emerged as effective and powerful tools for zinc detection because of their simplicity andcereal-time monitoring nature. In this work, with the purpose to improve the binding affinities and sensitivities of dipyrrin based fluorescent Zn 2+ probes, strongly coordinating pyridyl moieties were introduced into dipyrrins. Aroylation of 5-pentafluorophenyl and 5-unsubstituted dipyrromethanes with picolinoyl chloride afforded two corresponding dipicolinoyl dipyrromethanes, which were further oxidized with 2,3-dichloro-5,6-dicyano-1,4-benzoquinone (DDQ) to afford the expected 5-pentafluorophenyl-substituted dipicolinoyl dipyrrin and a unique unexpected dipicolinoyl dipyrrolyl ketone, respectively. Both of these compounds exhibited noticeable fluorescence “turn-on” responses specifically to Zn 2+ over other metal cations, with fluorescence enhancements of 87 fold and 119 fold, respectively. However, because of the different substituents at the 5 positions and the different conjugation frameworks, distinct Zn 2+ sensing behavior was observed. For the 5-pentafluorophenyl-substituted dipicolinoyl dipyrrin, the sensing of Zn 2+ induced a color change from light orange to pink accompanied with enhanced red fluorescence. Whereas, the sensing of Zn 2+ by the dipicolinoyl dipyrrolyl ketone induced the color change from nearly colorless to bright yellow and enhanced green fluorescence. Based on high binding affinities and the dramatic spectral responses, both of the probes exhibit high sensitivities towards Zn 2+ with detection limits of 9.8 nM and 6.3 nM, respectively. In addition, fast responses within 10 s and wide applicable pH ranges are indicative of their potential applications as promising zinc probes. Finally, the 5-pentafluorophenyl dipicolinoyl dipyrrin was successfully applied to cell imaging in Hela cells, demonstrating its practical applicability. It is noteworthy that the single crystal structure of a Zn 2+ complex of the dipicolinoyl dipyrrolyl ketone was successfully analyzed by X-ray diffraction, which revealed an interesting tetranuclear Zn 2+ coordination structure. These results provide further insights into the design of highly sensitive Zn 2+ probes by introducing pyridyl moieties into dipyrrin platforms. [ABSTRACT FROM AUTHOR]

With the purpose to develop efficient dye-sensitized solar cells (DSSCs), a series of push-pull porphyrin dyes have been designed and optimized by introducing additional electron-donating diphenylamino and electron-withdrawing benzothiadiazole moieties. Electrochemical, photophysical and photovoltaic investigations indicate that the introduction of additional donors and acceptors can effectively extend the absorption spectra, resulting in better sunlight harvesting. However, the HOMO levels of the dyes are elevated by the additional donors, resulting in decreased driving forces for dye regeneration and decreased cell efficiencies. Upon coadsorption with 5 mM chenodeoxycholic acid (CDCA), the cell efficiencies can be elevated from 1.37% - 5.01% to 1.70% - 6.97%. Furthermore, based on the subtle absorption characteristics of the porphyrin dyes, we delicately designed a cocktail co-sensitization strategy using the solutions containing two of the porphyrin dyes as well as CDCA. Finally, a high photovoltaic efficiency of 8.6% was successfully achieved at an optimized molar ratio of 10:1 for the two porphyrin dyes. [ABSTRACT FROM AUTHOR]

A bidipyrrin nickel complex was synthesized in a high yield by oxidatively coupling between the ligands in the corresponding 2:1 (L:M) type of dipyrrin nickel complex, and further demetallation afforded the free bidipyrrin ligand. Interestingly, when treating the bidipyrrin nickel complex or the free bidipyrrin with FeCl 3 in CH 2 Cl 2 /MeOH, the symmetric di- α -methoxy bidipyrrin could be synthesized in a high yield, with two methoxy groups attached to the terminal pyrrolic α -positions. Moreover, the coordination of the unsubstituted and disubstituted bidipyrrins with Zn(OAc) 2 ·2H 2 O afforded two similar M 2 L 2 type of bidipyrrin helical complexes with different ligand conformations and different Zn⋯Zn distances of 5.353 and 3.357 Å, respectively. The difference in the conformations may be related to the electrostatic repulsions between the methoxy substituents. These results indicate that the dyes based on helical bidipyrrin zinc complexes with tunable structures and photophysical properties may be developed simply by modulating the terminal α -substituents. [ABSTRACT FROM AUTHOR]

Four alkoxy-wrapped push-pull porphyrin dyes containing the phenothiazine derived donor and the ethynylbenzoic acid acceptor have been designed, synthesized and used as sensitizers for fabricating efficient dye-sensitized solar cells (DSSCs). Branched or linear alkoxy chains were introduced to the ortho -positions of the meso- phenyl moieties to suppress the dye aggregation and charge recombination. The effect of alkoxy chains were investigated in the absence and presence of an additional electron-withdrawing benzothiadiazole unit. In the former cases, almost identical photovoltaic efficiencies of ∼8.3% were achieved for both the branched and the linear alkoxy chains, while in the latter cases, the planar benzothiadiazole unit induces serious dye aggregation and charge recombination, resulting in lower efficiencies of 6.46% and 7.50% for the linear and branched chains, respectively, even though broader absorption was achieved. The relatively higher efficiency achieved for the dyes with branched chains may be related to the better effect of suppressing the dye aggregation and charge recombination. Furthermore, the coadsorption approach was employed, and a highest efficiency of 9.62% was achieved for the dye that features branched chains and the benzothiadiazole unit. These results compose a novel approach for developing efficient DSSCs by combining the coadsorbent with a porphyrin dye containing both the additional benzothiadiazole acceptor and branched alkoxy chains. [ABSTRACT FROM AUTHOR]

From the simple one-pot Vilsmeier formylation of 9-diphenylaminoanthracence, mono-, di- and tri-formyl products were successfully synthesized and the yields for the individual products can be optimized by varying the equivalents of the Vilsmeier reagent and changing the reaction temperature. The four obtained aldehydes exhibit distinct optical properties, with the emission maxima varying in a large wavelength range of 455–593 nm, despite their similar structures. The intramolecular charge transfer effect can be effectively modulated by varying the numbers and positions of the formyl groups, resulting in the observed distinct optical properties. Based on the aldehydes, the corresponding boron-dipyrromethenes were also synthesized. Similarly, the intramolecular charge transfer effect and the optical properties can be effectively modulated by the numbers and positions of the boron-dipyrromethene moieties. To further modulate the intramolecular charge transfer effect and red shift the emission, the dimethoxy-substituted 9-diphenylaminoanthracence was also used for synthesizing the corresponding aldehyde and boron-dipyrromethene. Thus, full color emissions within the wavelength range of 455–704 nm were successfully achieved based on modulating the intramolecular charge transfer. [ABSTRACT FROM AUTHOR]

A combination of aggregation-induced emission and intramolecular charge transfer was achieved by using a triphenylamine analogue and a dicyanovinyl moiety as the electron donating and accepting units, respectively. Hence, we designed and synthesized a probe with a D-π-A framework as a near-infrared fluorescence turn-on probe for biothiols (cysteine and homocysteine). Owing to the remarkable intramolecular charge transfer effect as well as intramolecular rotations associated with the donor moiety, the probe exhibits extremely weak fluorescence, which becomes a good starting point for developing fluorescence “turn-on” probes. Upon reaction with cysteine or homocysteine utilizing the dicyanovinyl moiety, the intramolecular charge transfer character was weakened, and the reacting products were observed to aggregate in aqueous solutions, resulting in the aggregation-induced emission effect with red fluorescence at 651 and 656 nm, respectively. Hence, the probe could be used as a fluorescence “turn-on” sensor for cysteine and homocysteine, with the sensing time of less than 4 min and the detection limits of 8.4 μM and 5.7 μM towards cysteine and homocysteine, respectively. The probe could distinguish cysteine and homocysteine from glutathione. The sensing mechanism was systematically investigated by employing high resolution mass spectrometry, 1 H NMR and density functional theory calculations as well as checking the solvent viscosity dependent fluorescence, and thus the nucleophilic addition products, the intramolecular charge transfer character, and the aggregation-induced emission behaviour were clearly elucidated. It is noteworthy that the low cytotoxicity, the intrinsic aggregation-induced emission nature and near-infrared emissions enable the application of the probe in living cell imaging. [ABSTRACT FROM AUTHOR]

A rational and effective approach for synthesizing linear π-conjugated hexa-, hepta- and octapyrrins through the regioselective oxidative coupling of monoacylated tripyrrane and bilane is described. Depending upon the numbers of pyrrolic units, the geometry and properties of bis-copper(ii) complexes could be systematically modulated. [ABSTRACT FROM AUTHOR]

Three kinds of fused porphyrinoids, L2- L4, possessing different types of corrole-based frameworks were synthesized from a pyrrole-substituted corrole isomer (norrole L1). Oxidation of L1 afforded a unique N-Cmeso-fused pyrrolyl isonorrole L2, involving the fusion of an auxiliary pyrrolic NH moiety with a meso-sp3-hybridized carbon atom. Subsequently, L2 underwent macrocycle transformations to give singly and doubly N-CAr-fused N-confused corroles, L3 and L4, respectively. L3 and L4 contain fused [5.7.6.5]-tetra- and [5.6.7.7.6.5]-hexacyclic structures, respectively, prepared through lateral annulation. These skeletal transformation reactions from norrole to its isomer isonorrole and finally to N-confused corrole indicate that multiply fused porphyrinoids could be readily synthesized from pyrrole-appended confused porphyrinoids. [ABSTRACT FROM AUTHOR]

Three kinds of fused porphyrinoids, L2- L4, possessing different types of corrole-based frameworks were synthesized from a pyrrole-substituted corrole isomer (norrole L1). Oxidation of L1 afforded a unique N-Cmeso-fused pyrrolyl isonorrole L2, involving the fusion of an auxiliary pyrrolic NH moiety with a meso-sp3-hybridized carbon atom. Subsequently, L2 underwent macrocycle transformations to give singly and doubly N-CAr-fused N-confused corroles, L3 and L4, respectively. L3 and L4 contain fused [5.7.6.5]-tetra- and [5.6.7.7.6.5]-hexacyclic structures, respectively, prepared through lateral annulation. These skeletal transformation reactions from norrole to its isomer isonorrole and finally to N-confused corrole indicate that multiply fused porphyrinoids could be readily synthesized from pyrrole-appended confused porphyrinoids. [ABSTRACT FROM AUTHOR]

Light-driven transcription, replication and enzyme catalysis are critically dependent upon a delicate transfer between molecular and supramolecular chirality. Chemists have well realized the impressive stereospecificity over many thermally accessible cycloaddition with chiral catalysts, but making light work in the enantiomer control of diarylethene photocyclization has proved to be more challenging. Here, we report a unique sterically hindered diarylethene (BBTE) system with absolute enantiospecific photocyclization and cycloreversion. Moreover, we have fully separated all the five thermally stable isomers, consisting of one achiral parallel conformer, one pair of anti-parallel ring-open enantiomers, and another pair of ring-closed enantiomers, whose absolute chiral configurations are entirely elucidated by single X-ray crystallographic analyses. The photo-responsive feature exhibits a reversible, complete enantio-control transformation without racemism, offering an unrivaled unimolecular enantiospecific platform for potential applications as bistable chiroptical switches and all-photonic photomemories with optical rotation as non-destructive readout. [ABSTRACT FROM AUTHOR]

Metal ions and anions play important roles in many industrial and biochemical processes, and thus it is highly desired to detect them in the relevant systems. Small organic molecule based sensors for selective and sensitive detection of target ions show the advantages of low cost, high sensitivity and convenient implementation. In this area, pyrrole has incomparable advantages. It can be easily incorporated into linear and macrocyclic conjugated structures such as dipyrrins, porphyrins, and N-confused porphyrins, which may utilize the imino N and amino NH moieties for binding metal ions and anions, respectively. In this tutorial review, we focus on representative examples to describe the design, syntheses, sensing mechanisms, and applications of the conjugated oligopyrroles. These compounds could be used as colorimetric or fluorescent ion probes, with the advantages of vivid colour and fluorescence changes, easy structural modification and functionalization, and tunable emission wavelengths. Compared with normal porphyrins, simple di- and tripyrrins, as well as some porphyrinoids are more suitable for designing fluorescence “turn-on” metal probes, because they may exhibit flexible confirmations, and metal coordination will improve the rigidity, resulting in vivid fluorescence enhancement. It is noteworthy that the oligopyrrolic moieties may simultaneously act as the binding unit as well as the reporting moiety, which simplifies the design and syntheses of the probes. [ABSTRACT FROM AUTHOR]

The acylation of 5-aryl dipyrromethanes afforded products with interestingly rich substitution modes, i.e. , α- and β-monoacylated (modes a and b ), and α, α′-, α, β′- and β, β′-diacylated (modes c – e ). Especially, the β- and β, β′-acylation modes are unprecedented. And most of these products can be synthesized at a gram scale. The anisoyl substituted 5-(4-cyanophenyl) dipyrromethanes ( 1a – 1e ) were oxidized with DDQ. Thus, 1a and 1b afforded the corresponding dipyrrins 1a-DPR , and 1b-DPR . More interestingly, the diacylated ones 1c – 1e could not be oxidized by DDQ. Instead, 1c-OH – 1e-OH were obtained with a hydroxyl group attached to the 5-position. 1a-DPR – 1e-OH were further developed as fluorescence turn-on Zn 2+ probes. 1d-OH showed the highest sensitivity, with a detection limit of 1.5 × 10 −8 M, and it was successfully applied in Zn 2+ imaging in Hela cells. Furthermore, single crystals of two Zn 2+ complexes were obtained and analyzed by X-ray diffraction. [ABSTRACT FROM AUTHOR]