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Reported herein is a multidisciplinary experiment for senior-level undergraduate teaching laboratories in the synthesis of the analytes acetaminophen and phenacetin; the fabrication of paper-based devices, using eyeliner, acrylic spray paint, or wax-printing, for sensing of those analytes; and the use of the newly fabricated devices for successful qualitative and quantitative analyte detection. This experiment includes elements of organic, analytical, and materials chemistry, as well as device engineering, and provides a strong pedagogical experience for the undergraduate student participants. The experiment was tested over two years in the Advanced Organic Laboratory, and 90% of students over the two years successfully completed all experimental objectives. The modular nature of the reported experiments and inexpensive costs of materials and instrumentation significantly enhance the practical applicability of this experiment and the likelihood of widespread adaptation.

Reported herein is a multidisciplinary laboratory experiment for advanced undergraduate students that includes elements of material synthesis, in the synthesis of cyclodextrin-containing metal-organic frameworks (CD-MOFs), and environmental chemistry, in the use of these MOFs for pollutant removal. This multiday laboratory experiment starts with the synthesis of cyclodextrin-containing metal-organic frameworks (CD-MOFs) using vapor diffusion crystal growth procedures, followed by the use of the CD-MOFs for a pollutant removal application. Specifically, the CD-MOFs were used for the removal of a methylene blue dye (a common mimic of aromatic pollutants) from an organic solution, with the monitoring of the success of the removal procedures using UV-vis spectroscopy. This experiment was implemented as part of a larger multiday unit, and undergraduate students were particularly engaged with and excited by the CD-MOF synthesis and methylene blue removal experimental modules. As a result, the decision was made to make these two components a stand-alone multidisciplinary laboratory experiment, the results of which are reported herein.

Covalent functionalization of cellulose with β‐cyclodextrin by succinic acid‐promoted cross‐linking leads to a dual‐function material that efficiently promotes proximity‐induced energy transfer from polycyclic aromatic hydrocarbons (PAHs) to squaraine fluorophores with high quantum yields, and removes PAHs from aqueous solution through non‐covalent binding. This material, which possesses a high functionalization density (0.17 μg/mm2 of cyclodextrin on cellulose), promotes energy transfer efficiencies as high as 58 % (for an anthracene donor in combination with a squaraine fluorophore acceptor), and leads to the removal of up to 91 % of a PAH (pyrene) from aqueous solution by mixing of the solution with the functionalized material. Overall, the high performance of this material in both proximity‐induced energy transfer and the removal of PAHs from water means that such a method has significant potential impact in a variety of real‐world environmental remediation scenarios. [ABSTRACT FROM AUTHOR]

The ability to bind and detect analytes with high levels of selectivity, sensitivity and broad applicability for a variety of analytes is an essential goal, with applications in public health and environmental remediation. Methods to achieve effective binding and detection include electrochemical, and spectroscopic methods. The use of supramolecular chemistry to accomplish such detection, by binding a target in a host and transducing that binding into a measurable signal, has advantages, including tunability of the sensor and the ability to rationally design hosts through an understanding of non-covalent interactions. Reported herein is the design and use of pillar[5]arenes to accomplish precisely such detection. Water-soluble pillar[5]arenes containing 10 cationic linker arms on their periphery bound toxicants in their hydrophobic cores with association constants of 105–106M−1. With the use of cationic exchange resins, the pillar[5]arene hosts were removed from solution with their encapsulated guests, allowing for effective toxicant removal. [ABSTRACT FROM AUTHOR]

Reported herein is the synthesis and application of three novel β‐cyclodextrin dimer hosts for the complexation of near infrared (NIR) squaraine dyes in aqueous solution. A series of eight different N‐substituted N‐methyl anilino squaraine dyes with variable terminal groups are investigated, with an optimal n‐hexyl‐substituted squaraine guest demonstrating binding constants orders of magnitude higher than the other squaraine–host combinations and comparable to literature‐reported systems. Moreover, hydrophobic complexation of the squaraine dyes with the β‐cyclodextrin dimer hosts causes drastic changes in the squaraine's photophysical properties, propensity for aggregation and susceptibility to hydrolytic decay. [ABSTRACT FROM AUTHOR]

Iron complexes containing pincer ligands that incorporate N-heterocyclic carbene (NHC) moieties are of significant interest in organometallic catalysis in order to generate more oxidatively robust complexes that may exhibit novel catalytic properties. In order to define the effect that introducing NHC moieties into pincer ligands has on electronic structure and bonding in iron(II)-pincer complexes, MCD and DFT studies of (iPrCDA)FeBr2, (iPrPDI)FeBr2, and (iPrCNC)FeBr2 were performed. These studies quantify the electronic structures and bonding interactions as a function of pincer ligand variation. They also demonstrate that the observed ligand fields (and, hence, spin states) directly correlate to the increased Fe-C bonding and pincer-donating abilities that result from introducing NHC moieties into the pincer ligand. However, the net donor abilities of the pincers and the strength of the Fe-pincer interaction do not directly correlate to the number of NHC moieties present, but instead are determined to be due to differences in Fe-C and overall Fe-pincer bonding as a result of the position of the NHC moieties in the pincer ligand and the overall geometric constraints of the pincer architecture. [ABSTRACT FROM AUTHOR]

Low-valent iron complexes bearing bis(amidine)pyrimidylidene (or carbenodiamidine, CDA) ligands have been synthesized and characterized by X-ray crystallography, Mössbauer spectroscopy, infrared spectroscopy, EPR spectroscopy, and DFT calculations. One electron reduction of (CDA)FeCl2(1) resulted in the formation of (CDA)FeCl (2), which demonstrated an unusual metal−N-heterocyclic carbene (NHC) interaction where a redox non-innocent NHC participates in a one electronπ-interaction with the metal center. This interaction renders the complex best described as a low-spin iron(II) complex that is antiferromagnetically coupled to a singly reduced CDA ligand. Two electron reduction of1under an atmosphere of carbon monoxide resulted in the formation of the diamagnetic complex (CDA)Fe(CO)2(3). Complex3demonstrated significantly lower CO stretching frequencies compared to previously reported bis(imino)pyridine and even bis(N-heterocyclic carbene)pyridine iron complexes, which reflects the significantσ-donating capabilities of the CDA ligands. [ABSTRACT FROM AUTHOR]

Fluorescent organic polymers are used in a wide range of applications, including explosive sensing, clean energy technologies, and biological detection schemes. However, such polymers are rarely synthesized in an undergraduate organic teaching laboratory due to their air and moisture sensitivity. The synthesis of a fluorescent organic polymer, poly[2-methoxy-5-(2-ethylhexyloxy)-1,4-phenylenevinylene] (MEH-PPV), is described for the upper-division undergraduate organic laboratory. This polymerization is accomplished using straightforward procedures to exclude air and moisture, without requiring the use of a glovebox or strict inert-atmosphere conditions. Once synthesized, the polymer is used for two applications, the fabrication of fluorescent thin films and the formation of organic conjugated nanoparticles, and leads to a number of pedagogical opportunities about polymerization, organic fluorescence, solid-state properties, and hydrophobic nanoparticle formation. [ABSTRACT FROM AUTHOR]

A second, monoclinic, polymorph of the title compound, C14H8Cl2, has been found. In addition to the structure of this monoclinic form, the structure of the previously described orthorhombic form [Desvergne, Chekpo & Bouas-Laurent (1978). J. Chem. Soc. Perkin Trans. 2, pp. 84-87; Benites, Maverick & Fronczek (1996). Acta Cryst. C 52, 647-648] has been redetermined at low temperature and using modern methods. The low-temperature structure of the orthorhombic form is of significantly higher quality than the previously published structure and additional details can be derived. A comparison of the crystal packing of the two forms with a focus on weak intermolecular C-H...Cl interactions shows the monoclinic structure to have one such interaction linking the molecules into infinite ribbons, while two crystallographically independent C-H...Cl interactions give rise to an interesting infinite three-dimensional network in the orthorhombic crystal form. [ABSTRACT FROM AUTHOR]

Reported herein is a new method for the detection of polycyclic aromatic hydrocarbons (PAHs) which relies on energy transfer from the PAH to a near-infrared emitting squaraine fluorophore. This energy transfer occurs inside the γ-cyclodextrin cavity, with up to 35% emission observed from energy transfer compared with exciting the squaraine directly. [ABSTRACT FROM PUBLISHER]

Herein we report a robust and easy method for detecting cesium metal ion (Cs+) in partially aqueous solutions using the fluorescence quenching of 2,4-bis[4-(N,N-dihydroxyethylamino)phenyl]squaraine. This squaraine dye was found to be both highly sensitive (low limits of detection) and selective (limited response to other metals) for cesium ion detection. The detection is likely based on the metal complexing to the dihydroxyethanolamine moieties, which disrupts the donor–acceptor–donor architecture and leads to efficient quenching. [ABSTRACT FROM AUTHOR]

High concentrations of certain nutrients, including phosphate, are known to lead to undesired algal growth and low dissolved oxygen levels, creating deadly conditions for organisms in marine ecosystems. The rapid and robust detection of these nutrients using a colorimetric, paper-based system that can be applied on-site is of high interest to individuals monitoring marine environments and others affected by marine ecosystem health. Several techniques for detecting phosphate have been reported previously, yet these techniques often suffer from high detection limits, reagent instability, and the need of the user to handle toxic reagents. In order to develop improved phosphate detection methods, the commonly used molybdenum blue reagents were incorporated into a paper-based, colorimetric detection system. This system benefited from improved stabilization of the molybdenum blue reagent as well as minimal user contact with toxic reagents. The colorimetric readout from the paper-based devices was analyzed and quantified using RGB analyses (via ImageJ), and resulted in the detection of phosphate at detection limits between 1.3 and 2.8 ppm in various aqueous media, including real seawater. [ABSTRACT FROM AUTHOR]

Reported herein is the immobilization of N -(1-naphthyl)ethylenediamine (NED) on cellulose via an epichlorohydrin (ECH)-based covalent attachment and the implementation of the functionalized cellulose into an ultrasensitive, paper-based device for nitrite detection. The reported functionalization procedure resulted in a 12.9-fold higher functionalization density than the density that results from the previously reported procedures, and the subsequent device allows for nitrite detection limits in synthetic freshwater and real seawater of 0.26 and 0.22 μM, respectively. The sensor is efficient in a wide range of temperature, humidity, turbidity, and salinity conditions and has been successfully applied for nitrite detection in real water samples.