Identifikation von Weißweinen durch ionische Poly(para-phenylen- ethinylene) und ihre Komplexe

Narrowly-Distributed Conjugated Polymers Synthesized through Suzuki Polymerization with Palladium(II) N-Heterocyclic Carbene Complex Confined in Dendritic Mesoporous Silica Nanoparticles

A catalytic heterogenous Suzuki polymerization method was developed by confining the Pd(II)-catalyzed cross coupling reactions to take place exclusively in the nanochannels of dendritic mesoporous silica nanoparticles. Conjugated polymers with various monomer combinations, including donor-acceptor structures, were obtained in high yields. The molecular weights of the obtained polymers were well controlled with narrow molecular weight distributions (PDI value down to 1.13). All the polymeric products were highly soluble in common organic solvents, granting them with high processability. All the features of this confined Suzuki polymerization method endow the conjugated polymers great potential in optoelectronic applications.

Communication of Bichromophore Emission upon Aggregation - Aroyl-S,N-ketene Acetals as Multifunctional Sensor Merocyanines

Aroyl-S,N-ketene acetal-based bichromophores can be readily synthesized in a consecutive three-component synthesis in good to excellent yields by condensation of aroyl chlorides and an N-(p-bromobenzyl) 2-methyl benzothiazolium salt followed by a Suzuki coupling, yielding a library of 31 bichromophoric fluorophores with substitution pattern-tunable emission properties. Varying both chromophores enables different communication pathways between the chromophores, exploiting aggregation-induced emission (AIE) and energy transfer (ET) properties, and thus, furnishing aggregation-based fluorescence switches. Possible applications range from fluorometric analysis of alcoholic beverages to pH sensors.

Supramolecular Sensor for Astringent Procyanidin C1: Fluorescent Artificial Tongue for Wine Components

An artificial tongue that detects astringent components for a comprehensive evaluation of taste has not been established to date. Herein, we first propose fluorescent polythiophene (PT) derivatives (S1-S3) modified with 3-pyridinium boronic acid as supramolecular chemosensors for wine components including astringent procyanidin C1. After numerous attempts for the synthetic conditions, more than 95 mol % of the PT unit was modified with the pyridinium boronic acid moiety. To evaluate the PT derivatives as chemosensors of the artificial tongue, qualitative and quantitative analyses were performed with four types of wine components (i.e., sweet, sour, bitter, and astringent tastes) in combination with pattern recognition models. Notably, procyanidin C1 in the actual wine sample was successfully detected in a quantitative manner. In other words, we have established an authentic artificial tongue using PT based supramolecular chemosensors.

Sensor Array Based Determination of Edman Degradated Amino Acids Using Poly(p-phenyleneethynylene)s

A cross‐reactive optical sensor array based on poly(p‐phenyleneethynylene)s (PPEs) determines Edman degraded amino acids. We report a sensor array composed of three anionic PPEs P1–P3, and their electrostatic complexes with metal ions (Fe²⁺, Cu²⁺, Co²⁺). We recorded distinct fluorescence intensity response patterns as “fingerprints” of this chemical tongue toward standard phenylthiohydantoin (PTH) amino acids—degradation products of the Edman process. These “fingerprints” were converted into canonical scores by linear discrimination analysis (LDA), which differentiates all of the PTH‐amino acids. This array discriminates PTH‐amino acid residues degraded from an oligopeptide through Edman sequencing. This approach is complementary to chromatography approaches which rely on mass spectrometry; our array offers the advantage of simplicity.

Detecting Counterfeit Brandies

A hypothesis-free sensor array (optoelectronic tongue) composed of an anionic, a cationic and two neutral poly(para-aryleneethynylene)s (PAE) at pH 3, 7 and 13 discriminate more than 30 spirits (including brandy, Branntwein, Cognac, Spirituose, and Weinbrand). Counterfeits (made by mixing of low-quality spirits and caramel colour) and different batches of identical brands of brandies are discriminated. The sensor array works without sample preparation or great instrumental cost, and is superior to conventional methods with respect to sample need (10-20 μL), time and effort. The discrimination stems from differential fluorescence quenching of the PAE-array by the complex mixture of the beverages' colourants, from the oak barrels or added caramel colour. The collected quenching data were analysed by linear discriminant analysis (LDA) and principal component analysis (PCA) to achieve successful discrimination.

Immobilized Poly(aryleneethynylene) pH Strips Discriminate Different Brands of Cola

Fluorescent, water-soluble poly(p-aryleneethynylene)s (PAE) were immobilized on commercially available nylon membranes by using a slot plotter, creating fluorescent, barcode-like sensor strips. Digital imaging by using a standard digital camera, before and after immersion of the strips in buffers of different pH, displays a unique color for each pH value. Statistical evaluation, multivariate analysis of variance (MANOVA) and principal component analysis (PCA), of the acquired data revealed that the immobilized PAEs are superior to the identical fluorophores when dissolved. The pH sensor array discriminates 20 different brands of commercial-cola soft drinks through differences in pH and colorant-PAE interactions.

A Simple Optoelectronic Tongue Discriminates Amino Acids

A self-assembled nine-element optoelectronic tongue consisting of a positively charged water-soluble poly(para-phenyleneethynylene) and three metal ions (Fe²⁺ , Co²⁺ , and Cu²⁺ ) at three different pH values (7, 10, and 13) discriminates all of the 20 natural amino acids in water. Unknown identification was not ideal. Addition of a highly positively charged green fluorescent protein in the presence of Fe²⁺ , Co²⁺ , and Cu²⁺ increased the unknown identification to above 86 %. Linear discriminant analysis (LDA) orders the responses according to the amino acid type, that is, hydrophobic, polar, anionic, or cationic.