Determination of ribavirin by molecularly imprinted electrochemical sensors using pyrro-1-propionyl-alaninoyl-chitooligosaccharide and pyrrole as bifunctional monomers on Prussian blue-gold nanocomposite films.

Herein, we developed a highly sensitive imprinted electrochemical sensor for the trace detection of ribavirin (RBV) using pyrrole (PYR) and pyrro-1-propionyl-alaninoyl-chitooligosaccharides (PPACO) as bifunctional monomers on Prussian blue-gold nanocomposite films. PPACO had strong molecular effect on RBV molecule and was selected by quantitative calculations. After the deposition of the Prussian blue-gold nanocomposite on a glassy carbon electrode (GCE) surface, a 4-aminothiophenol layer successfully self-assembled on the surface. Subsequently, the molecularly imprinted membrane (MIM) was subjected to electrochemical polymerization on the electrode surface using RBV as the template and PPACO and PYR as the two monomers. After eluting the RBV molecules from the MIM, the fabricated RBV-MIM/Fn-Au-PB/GCE exhibited the specific adsorption of RBV. Under optimal conditions, differential pulse voltammetry (DPV) was used to measure the performance of the synthesized sensor, which exhibited a linear relationship between the decreasing peak current and RBV concentration from 0.015 to 3.5 µM with a low detection limit of 3 nM (S/N = 3). As a proof of concept, RBV-MIM/Fn-Au-PB/GCE was also applied to monitor the RBV content in RBV granules. It showed a satisfactory recovery (96.5-99.2%) with a relative standard deviation of less than 3.5% (n = 5), and thus, we believe it has potential for practical applications.

Synthesis and fluorescence properties of two dendritic molecules based on naphthalimide and triphenylamine.

Artificial light-harvesting systems have attracted great interest in biological photosynthesis and photo-voltaic devices areas due to their unique structures, easy purification, low-cost, and convenient processing abilities. Here, two dendritic molecules based on triphenylamine and naphthalimide have been designed and synthesized, their structures were confirmed by 1 H NMR, ESI-MS, and high resolution mass spectrometry. In these molecules, triphenylamine units perform as the electron donor moiety, and naphthalimide units perform as the electron acceptor. The obvious quenched fluorescence intensity and considerably shortened lifetime of the dendritic molecules combined with the molecular frontier orbital energy levels proved that the dendritic molecules not only are good candidates as hole-transporting materials but also are two excellent photo-induced electron transfer materials. Therefore, it is believed that these dendritic molecules have potential application value in photo-voltaic devices.

Rapid and visual detection for hypochlorite of an AIE enhanced fluorescence probe.

In this paper, a new 'turn-on' fluorescence probe for the rapid, sensitive, and visual detection of hypochlorite is reported. The push-pull type trianiline-tricyanofuran-based fluorescent probe was prepared using a condensation reaction between tricyanofuran and the thiophene-trianiline derivative that had high quantum yields and showed aggregation-induced emission enhanced properties. Upon exposure to hypochlorite, prominent fluorescence enhancement of the probe was observed via the release of the fluorophore from the probe. The probe showed a ratiometric absorption change at 315 nm and 575 nm. Importantly, the probe showed an excellent detection limit for hypochlorite at 1.2 × 10-7  M in solution and it was successfully applied for monitoring hypochlorite in waste water by test strip. This work reports a new fluorescence analytical sensing method for hypochlorite that has potential practical value in environmental monitoring and biological discrimination.

Two-channel near-infrared fluorescence Ag+ ion sensing of a new star-shaped dendrimer.

A new near-infrared fluorescence sensor PDI-PD for Ag+ ions was successfully prepared and its structure characterized by 1 H nuclear magnetic resonance (NMR), 13 C NMR and high-resolution mass spectrometry; matrix-assisted laser desorption/ionization time-of-flight mass spectrometry (HRMS MALDI-TOF). The probe exhibited rapid, sensitive, and selective two-channel fluorescence responses towards Ag+ ions and protons. The probe has a marked high binding affinity and high sensitivity for Ag+ , with a detection limit of 1.4 × 10-6  M. An approximately five-fold enhanced core emission at 784 nm was attributed to fluorescence resonance energy transfer (FRET). The enhanced core emission of the probe with Ag+ ions based on photo-induced electron transfer and FRET is discussed. In addition, the probe presented a visible colour change. All experimental results demonstrated that PDI-PD is an efficient tool for the selective, sensitive and rapid detection of Ag+ ions and protons using two-channel fluorescence responses.

Two Fe3(µ3-S)2(CO)8 clusters with terminal N-heterocyclic carbenes.

The title compounds with terminal N-heterocyclic carbenes, namely octacarbonyl(imidazolidinylidene-κC(2))di-µ3-sulfido-triiron(II)(2 Fe-Fe), [Fe3(C3H6N2)(µ3-S)2(CO)8], (I), and octacarbonyl(1-methylimidazo[1,5-a]pyridin-3-ylidene-κC(3))di-µ3-sulfido-triiron(II)(2 Fe-Fe), [Fe3(C8H8N2)(µ3-S)2(CO)8], (II), have been synthesized. Each compound contains two Fe-Fe bonds and two S atoms above and below a triiron triangle. One of the eight carbonyl ligands deviates significantly from linearity. In (I), dimers generated by an N-H···S hydrogen bond are linked into [001] double chains by a second N-H···S hydrogen bond. These chains are packed by a C-H···O hydrogen bond to yield [101] sheets. In (II), dimers generated by an N-H···S hydrogen bond are linked by C-H···O hydrogen bonds to form [111] double chains.

A novel hexairon cluster with one disulfide and two Ph2PCS(3-) ligands.

The title compound, hexadecacarbonylbis{µ3-[(diphenylphosphanyl)methanediidyl]sulfanido}-µ4-disulfido(2-)-hexairon(4 Fe-Fe), [Fe6(C13H10PS)2(S2)(CO)16], contains two inversion-related [Fe3(Ph2PCS)(CO)8] subclusters linked by an equatorial disulfide bond [S-S = 2.1490 (9) Å]. Each Ph2PCS(3-) ligand is coordinated to a triiron core in a µ3-κP:κ(2)C:κ(2)S fashion.

µ(4)-Orthothio-carbonato-tetra-kis-[tri-carbonyl-iron(I)](2 Fe-Fe).

The fused bis-butterfly-shaped title compound, [Fe(4)(CS(4))(CO)(12)], possesses an orthothio-carbonate (CS(4) (4-)) ligand that acts as a bridge between two Fe(2)(CO)(6) units. A short intra-molecular S⋯S contact [2.6984 (8) and 2.6977 (8) Å] occurs in each S(2)Fe(2)(CO)(6) fragment.