Simple Molecule-based Fluorescent Sensors For Vapor Detection Of Tnt

1,4-Diarylpentiptycenes (1a-e) were synthesized from 1,4-dichloro- or 1,4-difluoro-2,5-diarylbenzene derivatives by double base-promoted dehydrohalogenation to give corresponding arynes, which in the presence of anthracene undergo cycloaddition providing 1,4-diarylpentiptycenes in moderate overall yields. The resulting 1,4-diarylpentiptycenes show fluorescence modulated by the 1,4-aryl residues. The fluorescence is quenched in the presence of vapors of nitroaromatic compounds suggesting potential application in sensing of explosives

First Supramolecular Sensors for Phosphonate Anions

Fluorescent tripodal anion sensors with a 1,3,5-triethylbenzene core display a turn-on fluorescence response to phosphonate and phosphate anions and may be used as optical sensors. The properties of the receptors and sensors as well as their anion binding behavior were investigated both in solution and in solid state. The turn-on fluorescence response can be leveraged in sensing of phosphate anions and, most importantly, hydrolysis products of the nerve gas sarin, isopropyl methylphosphonate (IMP), and methylphosphonate (MP). The fluorescence signal amplification in the presence of anions allows for application of these molecules in a sensor microarray suitable for high-throughput screening.NSF CHE 0750303, EXP-LA 0731153BGSU (TIE Grant)Chemistr

Rational Design Of A Minimal Size Sensor Array For Metal Ion Detection

The focus of this study was to demonstrate that, in the luminescent sensors, the signal transduction may possibly be the most important part in the sensing process. Rational design of fluorescent sensor arrays for cations utilizing extended conjugated chromophores attached to 8-hydroxyquinoline is reported. All of the optical sensors utilized in the arrays comprise the same 8-hydroxyquinoline (8-HQ) receptor and various conjugated chromophores to yield a different response to various metal cations. This is because the conjugated chromophores attached to the receptor are partially quenched in their resting state, and upon the cation coordination by the 8-HQ, the resulting metalloquinolinolate complex displays a change in fluorescence. A delicate balance of conjugation, fluorescence enhancement, energy transfer, and a heavy metal quenching effect results in a fingerprint-like pattern of responses for each sensor-cation complex. Principal component analysis (PCA) and linear discriminant analysis (LDA) are used to demonstrate the contribution of individual sensors within the array, information that may be used to design sensor arrays with the smallest number of sensor elements. This approach allows discriminating between 10 cations by as few as two or even one sensor element. Examples of arrays comprising various numbers of sensor elements and their utility in qualitative identification of Ca2+, Mg2+, Cd2+, Hg2+, Co2+, Zn2+, CU2+, Ni2+, Al3+, and Ga3+ ions are presented. A two-member array was found to identify 11 analytes with 100% accuracy. Also the best two of the sensors were tested alone and both were found to be able to discriminate among the samples with 99% and 96% accuracy, respectively. To illustrate the utility of this approach to a real-world application, identification of enhanced soft drinks based on their Ca2+, Mg2+, and Zn2+ cation content was performed. The same approach to reducing array elements was used to construct three- and two-member arrays capable of identifying these complex analytes with 100% accuracy

Ultrafast Energy Transfer In Oligofluorene-aluminum Bis(8-hydroxyquinoline)acetylacetone Coordination Polymers

Understanding the excited-state dynamics in conjugated systems can lead to their better utilization in optical sensors, organic photovoltaics (OPVs), and organic light-emitting diodes (OLEDs). We present the synthesis of self-assembled coordination polymers comprising two types of fluorescent moieties: discrete fluorene oligomers of a well-defined length (n = 1-9) connected via aluminum(III) bis(8-quinolinolate)acetylacetone joints. Due to their well-defined structure, these materials allowed for a detailed study of energy migration processes within the materials. Thus, femtosecond transient spectroscopy was used to study the ultrafast energy transfer from the oligofluorene to the quinolinolate moieties, which was found to proceed at a rate of 10(11) s(-1). The experimental results were found to be in agreement with the behavior predicted according to the Beljonne\u27s improved Forster model of energy transfer. In addition, the solid-state and semiconductor properties of these coordination polymers allowed for the fabrication of OLEDs. Preliminary experiments with simple two- and three-layer devices fabricated by spin-coating yield bright yellow electroluminescence with maximum brightness of 6000 cd/m(2), with a turn-on voltage of similar to 6 V and a maximum external quantum efficiency of up to 1.2%, suggesting their potential for use in PLED applications

Host Guest Complexes Of Pentiptycene Receptors Display Edge-to-face Interaction

The pentiptycene receptors form edge-to-face complexes with a variety of aromatic guests including nitroaromatics. X-ray diffractometry revealed that compounds 1, 2, and 3 form host-guest assemblies with a thienyl fragment (from a neightboring molecule of 1), benzene and nitrobenzene, respectively. X-ray studies of the three crystal structures reported here strongly suggest the edge-to-face to be a predominant binding mode between the aromatic guests and electron-rich faces of the pentiptycene aromatic cavity

Plant Coumarins with Anti-HIV Activity: Isolation and Mechanisms of Action

This review summarizes and systematizes the literature on the anti-HIV activity of plant coumarins with emphasis on isolation and the mechanism of their antiviral action. This review summarizes the information on the anti-HIV properties of simple coumarins as well as annulated furano- and pyranocoumarins and shows that coumarins of plant origin can act by several mechanisms: inhibition of HIV reverse transcriptase and integrase, inhibition of cellular factors that regulate HIV-1 replication, and transmission of viral particles from infected macrophages to healthy ones. It is important to note that some pyranocoumarins are able to act through several mechanisms or bind to several sites, which ensures the resistance of these compounds to HIV mutations. Here we review the last two decades of research on the anti-HIV activity of naturally occurring coumarins

Multiple molecular targets mediated antioxidant activity, molecular docking, ADMET, QSAR and bioactivity studies of halo substituted urea derivatives of α-Methyl-l-DOPA

A series of novel α-methyl-l-DOPA urea derivatives viz., 3-(3,4-dihydroxyphenyl)-2-methyl-2-(3-halo/trifluoromethyl substituted phenyl ureido)propanoic acids (6a-e) have been synthesized from the reaction of α-methyl-l-DOPA (3) with various aryl isocyanates (4a-e) by using triethylamine (5, TEA) as a base catalyst in THF at reflux conditions. The synthesized compounds are structurally characterized by spectral (IR, 1H & 13C NMR and MASS) and elemental analysis studies and screened for their in-vitro antioxidant activity against DPPH, NO and H2O2 free radical scavenging assays and identified compounds 6c & 6d as potential antioxidants. The acquired in vitro results were correlated with the results of molecular docking, ADMET, QSAR and bioactivity studies performed for them and predicted that the recorded in silico binding affinities are in good correlation with the in vitro antioxidant activity results. The molecular docking analysis has comprehended the strong hydrogen bonding interactions of 6a-e with 1CB4, 1N8Q, 3MNG, 1OG5, 1DNU, 3NRZ, 2CDU, 1HD2 and 2HCK proteins of their respective SOD, LO, PRXS5, CP450, MP, XO, NO, PRY5 and HCK enzymes. This has sustained the effective binding of 6a-e and resulted in functional inhibition of selective aminoacid residues to be pronounced as multiple molecular targets mediated antioxidant potent compounds. In addition, the evaluated toxicology risks of 6a-e are identified with in the potential limits of drug candidates. The conformational analysis of 6c & 6d prominently infers that urea moiety uniting α-methyl-l-DOPA with halo substituted aryl units into a distinctive orientation to comply good structure-activity to inhibit the proliferation of reactive oxygen species in vivo

(Mechano)synthesis of azomethine- and terpyridine-linked diketopyrrolopyrrole-based polymers

Three efficient synthetic approaches towards new azomethine- and terpyridine-containing 2,5-dihydropyrrolo[3,4-c]pyrrole-1,4-dione (diketopyrrolopyrrole, DPP) based polymers, such as P1 and P2, are reported. The first approach involves the Pd-catalyzed synthesis via two- or three-component Suzuki or Stille cross-coupling reaction in solution. The second approach involves Pd-catalyzed Suzuki cross-coupling reaction under ball-milling conditions. And, finally, the third approach involves Pd-free condensation reaction under ball-milling conditions. The newly obtained polymers exhibited absorbance around 700 nm and emission around 900 nm, and, thus, these polymers are considered to be NIR-fluorophores