Multifaceted activity of polyciclic MDR revertant agents in drug-resistant leukemic cells: Role of the spacer

A small library of derivatives carrying a polycyclic scaffold recently identified by us as a new privileged structure in medicinal chemistry was designed and synthesized, aiming at obtaining potent MDR reverting agents also endowed with antitumor properties. In particular, as a follow-up of our previous studies, attention was focused on the role of the spacer connecting the polycyclic core with a properly selected nitrogen-containing group. A relevant increase in reverting potency was observed, going from the previously employed but-2-ynyl- to a pent-3-ynylamino moiety, as in compounds 3d and 3e, while the introduction of a triazole ring proved to differently impact on the activity of the compounds. The docking results supported the data obtained by biological tests, showing, for the most active compounds, the ability to establish specific bonds with P-glycoprotein. Moreover, a multifaceted anticancer profile and dual in vitro activity was observed for all compounds, showing both revertant and antitumor effects on leukemic cells. In this respect, 3c emerged as a "triple-target" agent, endowed with a relevant reverting potency, a considerable antiproliferative activity and a collateral sensitivity profile.

Palladium-Catalysed Coupling Reactions En Route to Molecular Machines: Sterically Hindered Indenyl and Ferrocenyl Anthracenes and Triptycenes, and Biindenyls

Pd-catalysed Stille and Suzuki cross-couplings were used to prepare 9-(3-indenyl)-, 6, and 9-(2-indenyl)-anthracene, 7; addition of benzyne led to the 9-Indenyl-triptycenes, 8 and 9. In 6, [4 + 2] addition also occurred to the indenyl substituent. Reaction of 6 through 9 with Cr(CO)₆ or Re₂(CO)₁₀ gave their M(CO)₃ derivatives, where the Cr or Re was complexed to a six- or five-membered ring, respectively. In the 9-(2-indenyl)triptycene complexes, slowed rotation of the paddlewheel on the NMR time-scale was apparent in the η⁵-Re(CO)₃ case and, when the η⁶-Cr(CO)₃ was deprotonated, the resulting haptotropic shift of the metal tripod onto the five-membered ring also blocked paddlewheel rotation, thus functioning as an organometallic molecular brake. Suzuki coupling of ferrocenylboronic acid to mono- or dibromoanthracene yielded the ferrocenyl anthracenes en route to the corresponding triptycenes in which stepwise hindered rotations of the ferrocenyl groups behaved like molecular dials. CuCl₂-mediated coupling of methyl- and phenyl-indenes yielded their rac and meso 2,2′-biindenyls; surprisingly, however, the apparently sterically crowded rac 2,2′-Bis(9-triptycyl)biindenyl functioned as a freely rotating set of molecular gears. The predicted high rotation barrier in 9-phenylanthracene was experimentally validated via the Pd-catalysed syntheses of di(3-fluorophenyl)anthracene and 9-(1-naphthyl)-10-phenylanthracene.

An anthrone-based Kv7.2/7.3 channel blocker with improved properties for the investigation of psychiatric and neurodegenerative disorders

A set of novel Kv7.2/7.3 (KCNQ2/3) channel blockers was synthesized to address several liabilities of the known compounds XE991 (metabolic instability and CYP inhibition) and the clinical compound DMP 543 (acid instability, insolubility, and lipophilicity). Using the anthrone scaffold of the prior channel blockers, alternative heteroarylmethyl substituents were installed via enolate alkylation reactions. Incorporation of a pyridazine and a fluorinated pyridine gave an analog (compound 18, JDP-107) with a promising combination of potency (IC50 = 0.16 μM in a Kv7.2 thallium flux assay), efficacy in a Kv7.2/7.3 patch clamp assay, and drug-like properties.

A symbiotic supramolecular approach to the design of novel amphiphiles with antibacterial properties against MSRA

Herein, we identify supramolecular self-associating amphiphiles (SSAs) as a novel class of antibacterials with activity towards methicillin-resistant Staphylococcus aureus. Structure-activity relationships have been identified in the solid, solution and gas phases. Finally, we show that when supplied in combination, SSAs exhibit increased antibacterial efficacy against these clinically relevant microbes.

Direct incorporation and extension of a fluorescent nucleotide through rolling circle DNA amplification for the detection of microRNA 24-3P

We designed and synthesized several fluorescent nucleotides from thiophene, anthracene and pyrene, which have different sizes, and screened their incorporation and extension capability during the rolling circle amplification of DNA. The thiophene-based fluorescent nucleotide (dUthioTP) could highly incorporate and extended into the rolling circle DNA product, while other fluorescent nucleotides (dUanthTP, and dUpyrTP) could not. This dUthioTP fluorescent nucleotide could be used for the detection of miRNA 24-3P, which is related PRRSV. This direct labeling system during rolling circle DNA amplification exhibited an increased fluorescence signal showing gel formation for the detection of miRNA 24-3P. This direct labeling system is a very simple and cost-efficient method for the detection miRNA 24-3P and also exhibited highly sensitive and selective detection properties.

Surface functionalization superparamagnetic nanoparticles conjugated with thermoresponsive poly(epsilon-lysine) dendrons tethered with carboxybetaine for the mild hyperthermia-controlled delivery of VEGF

Vascular endothelial growth factor (VEGF) is the growth factor responsible for the triggering of angiogenesis, the process of blood vessel formation supporting the long-term viability of any repaired or regenerated tissue. As the growth factor is effective only when concentration gradients are generated, new shuttles need to be developed that ensure both the control of gradients at the site of tissue repair and the release of VEGF at physiological levels. Magnetic hyperthermia is the production of heat induced by magnetic materials through their exposure to an external oscillating magnetic field. In this paper, magnetic nanoparticles capable of generating controllable hyperthermia were functionalised with hyperbranched poly(epsilon-lysine) peptides integrating in their core parallel thermoresponsive elastin-like peptide sequences and presenting an uppermost branching generation tethered by the zwitterionic amino acid carboxybetaine. The results show that these functionalised magnetic nanoparticles avidly bind VEGF and release it only upon generation of mild-hyperthermic pulses generated by oscillating magnetic filed. The VEGF release occurred in a temperature range at which the elastin-like peptides collapse. It is proposed that, through the application of an external magnetic field, these magnetic carriers could generated gradients of VEGF in vivo and allow its tuned delivery in a number of clinical applications.

STATEMENT OF SIGNIFICANCE

The present paper for the first time reveals the possibility to control the delivery of VEGF through mild hyperthermia stimuli generated by a oscillating magnetic field. To this purpose, magnetic nanoparticles of high size homogeneity and coated with a thin coating of poly(acrylic acid) were functionalised with a novel class of poly(epsilon lysine) dendrimers integrating in their structure a thermoresponsive amino acid sequence mimicking elastin and exposing at high density a zwitterionic modified amino acid, the carboxybetaine, known to be able to bind macromolecules. Physicochemical and biochemical characterisation elegantly show the link between the thermal properties of the nanoparticles and of the dendrimer change of conformation and how this enable the release of VEGF at temperature values compatible with the growth factor stability.

One-pot synthesis of 1,4-dihydroxy-2-((E)-1-hydroxy-4-phenylbut-3-enyl)anthracene-9,10-diones as novel shikonin analogs and evaluation of their antiproliferative activities

A series of shikonin analogs have been synthesized in a one-pot reaction of quinizarin with β,γ-unsaturated aldehydes in MeOH under mild conditions and investigated for their cytotoxicity against four cancer cell lines and one normal cell line. The synthesized compounds were found to be cytotoxic against HeLa cells with no apparent toxicity against normal cell line. Further modification led to the discovery of a novel tetracyclic anthraquinone (4b/4b') with potent cytotoxic activities against cervical, breast and pancreatic cancer cell lines with no significant effect on the growth of the control mammary epithelial cell line MCF-10. The good cytotoxicity and selectivity of compound 4b/4b' suggest that it could be a promising lead for further optimization.

Synthesis of 9-Substituted Triptycene Building Blocks for Solid-Phase Diversification and Nucleic Acid Junction Targeting

Triptycenes have been shown to bind nucleic acid three-way junctions, but rapid and efficient methods to diversify the triptycene core are lacking. An efficient synthesis of a 9-substituted triptycene scaffold is reported that can be used as a building block for solid-phase peptide synthesis and rapid diversification. The triptycene building block was diversified to produce a new class of tripeptide-triptycenes, and their binding abilities toward d(CAG)·(CTG) repeat junctions were investigated.

Synthesis and high-throughput characterization of structural analogues of molecular glassformers: 1,3,5-trisarylbenzenes

We report the synthesis and characterization of an analogous series of small organic molecules derived from a well-known glass former, 1,3-bis(1-naphthyl)-5-(2-naphthyl)benzene (α,α,β-TNB). Synthesized molecules include α,α,β-TNB, 3,5-di(naphthalen-1-yl)-1-phenylbenzene (α,α-P), 9-(3,5-di(naphthalen-1-yl)phenyl)anthracene (α,α-A), 9,9'-(5-(naphthalen-2-yl)-1,3-phenylene)dianthracene (β-AA) and 3,3',5,5'-tetra(naphthalen-1-yl)-1,1'-biphenyl (α,α,α,α-TNBP). The design of molecules was based on increasing molecular weight with varied π-π interactions in one or more substituents. The synthesis is based on Suzuki cross-coupling of 1-bromo-3-chloro-5-iodobenzene with arylboronic acids, which allows attachment of various substituents to tailor the chemical structure. The bulk compounds were characterized using NMR spectroscopy and differential scanning calorimetry (DSC). Thin films of these compounds were produced using physical vapor deposition and were subsequently annealed above the glass transition temperatures (Tg). For each molecular glass, cooling rate-dependent glass transition temperature measurements (CR-Tg) were performed using ellipsometry as a high-throughput method to characterize thin film properties. CR-Tg allows rapid characterization of glassy properties, such as Tg, apparent thermal expansion coefficients, apparent activation energy at Tg and fragility. DSC measurements confirmed the general trend that increasing molecular weight leads to increasing melting point (Tm) and Tg. Furthermore, CR-Tg provided evidence that the introduction of stronger π-interacting substituents in the chosen set of structural analogues increases fragility and decreases the ability to form glasses, such that β-AA has the largest fragility and highest tendency to crystallize among all the compounds. These strong interactions also significantly elevate Tg and promote more harmonic intermolecular potentials, as observed by decreasing value of the apparent thermal expansion coefficient.

A New-Anthracene Derivative Containing t-Butyl Group for Solution Process Organic Light-Emitting Diodes

4-(10-(3',5'-diphenylbiphenyl-4-yl)anthracen-9-yl)-N,N-diphenylaniline [TATa] and a new anthracene derivative of 4-(2 or 3-tert-butyl-10-(3',5'-diphenylbiphenyl-4-yl)anthracen-9-yl)-N,N-diphenylaniline [T-TATa] isomer by introduced t-butyl group were synthesized. OLED devices of TATa and T-TATa were fabricated by solution process. Its physical properties such as optical, electrochemical, and electroluminescent properties were also investigated. Two compounds were used as emitting layer (EML) in OLED device: ITO/PEDOT (40 nm)/synthesized materials (60 nm)/TPBi (20 nm)/LiF (1 nm)/Al (200 nm). The luminance efficiency of the synthesized compounds at 10 mA/cm2 were measured 0.85 cd/A for TATa and 1.49 cd/A for T-TATa, respectively. Moreover, the power efficiency of T-TATa is 1.08 lm/W. Its value is almost two times higher than 0.56 lm/W of TATa. As a result, more improved efficiency was shown with the device in a compound including t-butyl group to TATa core part, when the deivces were prepared by solution process.

Synthesis, crystal structure, spectroscopic and density functional theory (DFT) study of N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine

N-[3-anthracen-9-yl-1-(4-bromo-phenyl)-allylidene]-N-benzenesulfonohydrazine has been synthesized and characterized by various spectroscopic techniques including FT-IR, UV-vis, (1)H-NMR, (13)C-NMR spectroscopy, and the structure was unequivocally confirmed by single crystal X-ray diffraction studies. The compound crystallized in monoclinic system with P21/n space group, and adopted cis-geometry around the azomethine CN double bond. The X-ray crystal structure revealed that the intermolecular packing was stabilized by C-H⋯O type hydrogen bonding interaction, whereas NH was not involved in hydrogen bonding due to steric hindrance. Absorption wavelength was studied by scanning UV-vis. absorption spectrum in different solvents to explore excited state stability of the molecule in polar solvent. Density functional theory calculations were performed at B3LYP/6-31G (d, p) level in order to compare the experimental results with the theoretical results. The simulated molecular electrostatic potential (MEP), Mulliken charges and NPA (natural population analysis) also confirmed the presence of specific intermolecular hydrogen bonding (C-H⋯O). In addition natural bond orbital (NBO) analysis (intra and inter molecular bonding and interaction among bonds), frontier molecular orbital analysis (electronic properties) and first hyperpolarizability analysis (nonlinear optical response) were simulated at B3LYP/6-31G (d, p) level of theory.

On the use of metal purine derivatives (M=Ir, Rh) for the selective labeling of nucleosides and nucleotides

The reactions of neutral or cationic IrIII and RhIII derivatives of phenyl purine nucleobases with unsymmetrical alkynes produce new metallacycles in a predictable manner, which allows for the incorporation of either photoactive (anthracene or pyrene) or electroactive (ferrocene) labels in the nucleotide or nucleoside moiety. The reported methodology (metalation of the purine derivative and subsequent marker insertion) could be used for the postfunctionalization and unambiguous labeling of oligonucleotides.

Formation of nitroanthracene and anthraquinone from the heterogeneous reaction between NO2 and anthracene adsorbed on NaCl particles

Oxidative derivatives of polycyclic aromatic hydrocarbons (PAHs), that is, nitro-PAHs and quinones, are classed as hazardous semivolatile organic compounds but their formation mechanism from the heterogeneous reactions of PAHs adsorbed on atmospheric particles is not well understood. The heterogeneous reaction of NO2 with anthracene adsorbed on NaCl particles under different relative humidity (RH 0-60%) was investigated under dark conditions at 298 K. The formation of the major products, 9,10-anthraquinone (9,10-AQ) and 9-nitroanthracene (9-NANT), were determined to be second-order reactions with respect to NO2 concentration. The rate of formation of 9,10-AQ under low RH (0-20%) increased as the RH increased but decreased when the RH was further increased in high RH (40-60%). In contrast, the rate of formation of 9-NANT across the whole RH range (0-60%) decreased significantly with increasing RH. Two different reaction pathways are discussed for the formation of 9,10-AQ and 9-NANT, respectively, and both are considered to be coupled to the predominant reaction of NO2 with the NaCl substrate. These results suggest that relative humidity, which controls the amount of surface adsorbed water on NaCl particles, plays an important role in the heterogeneous reaction of NO2 with adsorbed PAHs.

A reversible dual mode chemodosimeter for the detection of cyanide ions in natural sources

Herein, we report the synthesis of two indolium probes 1 and 2 based on anthracene and pyrene derivatives and their interactions with various anions. Of these probes, the pyrene conjugate 2 acts as a dual colorimetric and fluorescent chemodosimeter for the selective and sensitive detection of cyanide ions. The detection limit of probe 2 for CN(-) ions was found to be 10 ppb (30 nM). The nature of interaction has been thoroughly studied through various techniques such as (1)H NMR and IR spectroscopy, HRMS, and isothermal calorimetric (ITC) studies. These studies confirm that probe 2 forms a 1,2-adduct in the presence of CN(-) ions. Kinetic studies using probe 2 showed the completion of the reaction within 15 s with a rate constant of k' = 0.522±0.063 s(-1). This probe can be coated on a solid surface (dipstick) and a polymer matrix for the on-site analysis and quantification of endogenous cyanide ions in natural sources such as Indian almonds.

[Synthesis of 11-[(2-pyridyl)amino]- and 11-[(9-anthracenylcarbonyl)amino]undecyl phosphate and investigation of their acceptor properties in the enzymic reaction catalyzed by galactosylphosphotransferases from Salmonella]

11-[(2-Pyridyl)amino]undecyl phosphate and 11-[(9-anthracenylcarbonyl)amino]undecyl phosphate were chemically synthesized. The abiliy of these new fluorescent derivatives of undecyl phosphate to serve as acceptor substrate of galactosyl phosphate residue in the enzymic reaction catalyzed by galactosylphosphotransferase from Salmonella anatum or Salmonella newport membrane preparation was demonstrated.

Design and application of anthracene derivative with aggregation-induced emission charateristics for visualization and monitoring of erythropoietin unfolding

Erythropoietin (EPO) is an attractive protein-unfolding/folding model because of its high degree of unfolding and folding reversibility and intermediate size. Due to its function for regulating red blood cell production by stimulating late erythroid precursor cells, EPO presents obvious values to biological research. A nonemissive anthracene derivative, that is 9,10-bis[4-(3-sulfonatopropoxyl)-styryl]anthracene sodium salt (BSPSA), with aggregation-induced emission (AIE) charateristics shows a novel phenomenon of AIE when EPO is added. The AIE biosensor for EPO shows the limit of detection is 1 × 10(-9) M. Utilizing the AIE feature of BSPSA, the unfolding process of EPO using guanidine hydrochloride is monitored, which indicates three steps for the folding structures of EPO to transform to random coil. Computational modeling suggests that the BSPSA luminogens prefer docking in the hydrophobic cavity in the EPO folding structures, and the assembly of BSPSA in this cavity makes the AIE available, making the monitoring of unfolding of EPO possible.

Fe(3+)-selective fluorescent probe based on aminoantipyrine in aqueous solution

A novel and simple Schiff base composed with 9-anthraldehyde and 4-aminoantipyrine was synthesized and characterized as a fluorescent probe. In the presence of Fe(3+), the fluorescent intensity has a dramatic enhancement over other examined metal ions in aqueous solution. The method of Job's plot indicated the formation of 1:1 complex between probe and Fe(3+), and the possible binding mode of the system was also proposed. Moreover, other examined metal ions had no effect on the detection of Fe(3+).

Self-assembled monolayers made of 6-(5-((6-((5-hexylthiophen-2-yl)ethynyl)-9,10-bis(phenylethynyl)anthracen-2-yl)ethynyl)thiophen-2-yl)hexyl 3-(triethoxysilyl)propylcarbamate for ultrathin film transistors

A new functionalized triethoxysilane bearing an X-shaped, anthracene-based semiconducting molecule on one arm was designed and synthesized as a precursor for the preparation of a self-assembled monolayer (SAM) on a SiO(2) substrate. 3-Isocyanatopropyl triethoxysilane was reacted with a monohydroxyl-terminated X-shaped, anthracene-based semiconducting molecule in the presence of tin catalyst. The 6-(5-((6-((5-hexylthiophen-2-yl)ethynyl)-9,10-bis(phenylethynyl)anthracen-2-yl)ethynyl)thiophen-2-yl)hexyl 3-(triethoxysilyl)propylcarbamate (BATHT-TEOS) was found to be stable and sufficiently reactive to form organic monolayers on hydroxylated SiO(2) surfaces. The structures and properties of these SAMs were investigated using X-ray photoelectron spectroscopy, UV-vis absorption spectroscopy, photoluminescence (PL) spectroscopy, laser scanning confocal microscopy-PL spectrometry, and spectroscopic ellipsometry. In this work, BATHT-SAM was employed as an interfacial layer on SiO(2) to fabricate ultrathin film transistors (UTFTs, active layer thickness ∼ 16.09 nm). The device UTFT-I, made of 0.06 wt % 5,5'-(9,10-bis(phenylethynyl)anthracene-2,6-diyl)bis(ethyne-2,1-diyl)bis(2-hexylthiophene) (BATHT) solution on an n-octyltrichlorosilane-SAM/SiO(2) layer, showed no gate effect for the carrier transport behavior; however, the device UTFT-II, fabricated on BATHT-SAM/SiO(2), exhibited field effect mobilities of 0.04 cm(2) V(-1) s(-1) (I(on/off) ∼ 6.3 × 10(3) to 1.0 × 10(4)). This can be attributed to the effect of BATHT-SAM inducing uniform coverage and ordering of BATHT molecules as an upper layer.

Convergent synthesis of the potent P2Y receptor antagonist MG 50-3-1 based on a regioselective Ullmann coupling reaction

MG 50-3-1 (3, trisodium 1-amino-4-{4-[4-chloro-6-(2-sulfophenylamino)-1,3,5-triazin-2-ylamino]-2-sulfophenylamino}-9,10-dioxo-9,10-dihydroanthracene 2-sulfonate) is the most potent and selective antagonist (IC₅₀ 4.6 nM) for "P2Y₁-like" nucleotide-activated membrane receptors in guinea-pig taenia coli responsible for smooth muscle relaxation. Full characterization of the compound, however, e.g., at the human P2Y₁ receptor, which is a novel potential target for antithrombotic drugs, as well as other P2 receptor subtypes, has been hampered due to difficulties in synthesizing the compound in sufficient quantity. MG 50-3-1 would be highly useful as a biological tool for detailed investigation of signal transduction in the gut. We have now developed a convenient, fast, mild, and efficient convergent synthesis of 3 based on retrosynthetic analysis. A new, regioselective Ullmann coupling reaction under microwave irradiation was successfully developed to obtain 1-amino-4-(4-amino-2-sulfophenylamino)-9,10-dioxo-9,10-dihydro-anthracene 2-sulfonate (8). Four different copper catalysts (Cu, CuCl, CuCl₂, and CuSO₄) were investigated at different pH values of sodium phosphate buffer, and in water in the absence or presence of base. Results showed that CuSO₄ in water in the presence of triethylamine provided the best conditions for the regioselective Ullmann coupling reaction yielding the key intermediate compound 8. A new synthon (sodium 2-(4,6-dichloro-1,3,5-triazin-2-ylamino)benzenesulfonate, 13) which can easily be obtained on a gram scale was prepared, and 13 was successfully coupled with 8 yielding the target compound 3.

Photoligation of self-assembled DNA constructs containing anthracene-functionalized 2'-amino-LNA monomers

Efficient synthesis of a novel anthracene-functionalized 2'-amino-LNA phosphoramidite derivative is described together with its incorporation into oligodeoxynucleotides. Two DNA strands with the novel 2'-N-anthracenylmethyl-2'-amino-LNA monomers can be effectively cross-linked by photoligation at 366 nm in various types of DNA constructs. Successful application of three differently functionalized 2'-amino-LNA monomers in self-assembled higher ordered structures for simultaneous cross-linking and monitoring of assembly formation is furthermore demonstrated.

Synthesis of uniformly 13C-labeled polycyclic aromatic hydrocarbons

Convergent synthetic pathways were devised for efficient synthesis of a series of uniformly (13)C labeled polycyclic aromatic hydrocarbons de novo from U-(13)C-benzene and other simple commercially-available (13)C-starting compounds. All target products were obtained in excellent yields, including the alternant PAH U-(13)C-naphthalene, U-(13)C-phenanthrene, U-(13)C-anthracene, U-(13)C-benz[a]anthracene, U-(13)C-pyrene and the nonalternant PAH U-(13)C-fluoranthene.

Fluorescent nanoparticles of chitosan complex for real-time monitoring drug release

New types of fluorescent nanoparticles (FNPs) were prepared through ionic self-assembly of anthracene derivative and chitosan for applications as drug delivery carriers with real-time monitoring of the process of drug release. Because of the presence of the hydrophilic groups, these FNPs showed excellent dispersion and stability in aqueous solution. The structure and properties of the FNPs were investigated by using means of (1)H NMR, FTIR, SEM, dynamic light scattering (DLS), and so on. The potential practical applications as drug delivery carriers for real-time detection of the drug release process were demonstrated using Nicardipine as a model drug. Upon loading the drug, the strong blue fluorescence of FNPs was quenched due to electron transfer and fluorescence resonance energy transfer (FRET). With release of drug in vitro, the fluorescence was recovered again. The relationship between the accumulative drug release of FNPs and the recovered fluorescence intensity has been established. Such FNPs may open up new perspectives for designing a new class of detection system for monitoring drug release.

Synthesis and photophysical processes of an anthracene derivative containing hole transfer groups

A novel luminescent compound 9,10-di-(N-carbazovinylene)anthracene (DCVA) was synthesized by Heck reaction of 9,10-dibromoanthracene and N-vinylcarbazole. The structure was characterized by MS, 1H NMR and Elemental analysis. The photoluminescent properties of DCVA have been carefully investigated by UV-vis absorption and fluorescence emission spectra. The results showed that the luminescent quantum yield of DCVA was 0.73 in THF and it emitted blue-light with the band gap of 3.60 eV estimated from the onset absorption. In addition, the light-emission of DCVA can be quenched by electron acceptor (dimethyl terephthalate), however, the fluorescent intensities of DCVA were slowly increased with the addition of electron donor (N,N-dimethylaniline). Furthermore, the molecular interactions of DCVA with fullerene (C60) and carbon nanotubes (CNTs) were also investigated, which indicated the organic luminescent compound can be used as new fluorescent probe.

Novel fluorescent pH sensors and a biological probe based on anthracene derivatives with aggregation-induced emission characteristics

Three functionalized 9,10-distyrylanthracene (DSA) derivatives, namely, 9,10-bis(4-hydroxystyryl)anthracene (2), 9,10-bis{4-[2-(diethylamino)ethoxy]styryl}anthracene (4), and 9,10-bis{4-[2-(N,N,N-triethylammonium)ethoxy]styryl}anthracene dibromide (5), were synthesized and their fluorescence properties were investigated. The three DSA derivatives possess a typical aggregation-induced emission (AIE) property (i.e., they are nonluminescent in dilute solutions but are efficiently fluorescent as induced by molecular aggregation). Different AIE properties were tuned through molecular structure control. Dye 2 is a phenol-moiety-containing compound, which shows aggregation at pH values smaller than 10, resulting in a high fluorescence intensity. Thus, dye 2 has a pK(a) of 9.94. 4 is an amine-containing compound that starts to aggregate at slightly basic conditions, resulting in a pK(a) of 6.90. Dye 5 is an ammonium-salt-containing compound. Because it is very soluble in water, this compound has no AIE phenomenon but can interact strongly with protein or DNA to amplify its emission. Therefore, 5 is a fluorescent turn "on" biological probe for protein and DNA detection and it is also selective, which works for native BSA and ct DNA but not their denatured forms. Therefore, we not only developed a few new compounds showing the AIE phenomena but also controlled the AIE through environmental stimulation and demonstrated that the new AIE molecules are suitable for pH and biomacromolecule sensing.