Alkylating agents are simple and reactive molecules that are commonly used in many and diverse fields such as organic synthesis, medicine, and agriculture. Some highly reactive alkylating species are also being used as blister chemical-warfare agents. The detection and identification of alkylating agents is not a trivial issue because of their high reactivity and simple structure. Herein, we report on a new multispot luminescence-based approach to the detection and identification of alkylating agents. In order to demonstrate the potential of the approach, seven pi-conjugated oligomers and polymers bearing nucleophilic pyridine groups, 1-7, were adsorbed onto a solid support and exposed to vapors of alkylators 8-15. The alkylation-induced color-shift patterns of the seven-spot array allow clear discrimination of the different alkylators. The spots are sensitive to minute concentrations of alkylators and, because the detection is based on the formation of new covalent bonds, these spots saturate at about 50 ppb.

Sequence‐independent or “click” chemistry is applied for the preparation of a series of novel and structurally similar π‐conjugated oligomers. The new oligomers are prepared using Wittig–Horner chemistry from bifunctional building blocks that can be interconnected to one another at any desired sequence. The bifunctional building blocks consist of aromatic skeletons with acetal protected aldehyde groups on one side and a phosphonic acid diethyl ester group para to the aldehyde functionality. The first step in the arylenevinylene formation is a Wittig–Horner coupling of a functionalized aldehyde with the methyl phosphonate ester ylide of a bifunctional monomer. A stepwise protection–deprotection process is applied for the preparation of structurally similar π‐conjugated oligo‐phenylene vinylenes. New di‐, tri‐, penta‐, and hepta‐phenylenevinylenes are prepared and characterized. Selected penta‐arylenevinylenes are incorporated as the semiconductor channel in organic field‐effect transistors.

highly specialized ink-jet printer that can print 1 μm dots with excellent alignment; [ 10 ] however, to contact single crystals that are randomly oriented would require too complex mapping and aligning methods. This complexity, in fi nding a suitable method to use single crystals in a simple fabrication process, is probably part of the reason that there is very little synthetic effort devoted to fi nding better crystal-forming molecular structures, not to mention their implementation in devices through a printing process.Here, we propose to arrive at highperformance materials by making the crystal-forming molecules relevant through the use of a dedicated transistor architecture that is designed to accommodate the features of the crystal-forming organic materials. In ref. [ 11 ] the authors developed a method for contacting nanowires that is based on forming highly dense and aligned nanowires such that the deposition of the contacts did not need to be aligned to a single nanowire. However, aligning the nanowires was a must and to capture nanowires between source and drain electrodes it was required to maintain few microns resolution, which was achieved through photolithography. Here we report a transistor architecture where the fabrication of the source and drain contacts and the contacting of the crystals are implemented separately. This introduces another degree of freedom in the device design which can be used to easily accommodate organic crystals in an FET structure. After discussing the new transistor structure and its mode of operation we demonstrate its high performance. We fi rst demonstrate a P-type transistor having a 100 μm channel length which is based on multiple, primarily isolated and randomly oriented, single crystals having the size of ≈10 μm. We fi nd that the transistors' effective mobility is at least 50% of that found for a single crystal. We then move to showing the generality of the structure by demonstrating also N-type and varying crystallites morphologies. Results and Discussion The Statistical FETThe concept of the statistical FET (SFET) structure is shown in Figure 1 a-c, which also illustrates the specifi c implementation process adapted here. Figure 1 a shows a top view of the gate and gate dielectric onto which many crystallites were deposited at a number density such that they form a discontinuous polycrystalline layer.

Solution processable p-and n-type organic semiconductors are candidates for low-cost, large-area, and roll-to-roll printing of inexpensive mass-production electronics. In these organic semiconductors, it is the π-conjugated backbone that plays the major role in chargecarrier transport across the channel. In order to achieve better device performance, it is required to have better packing/crystallinity to minimize defects and avoid deep traps, so that effective transfer of charge carriers can take place in the solid state. Excellent results have been reported by blending crystal-forming organic semiconductors with amorphous polymers that serve as binders or passivating agents. We show that, for some molecular structures and processing conditions, mixtures of stereoisomers can separate and self-arrange into a thin amorphous layer covered by a polycrystalline layer. In this work, we focus on two families of constitutional isomers that differ only in the position of the pyridine groups on the π-skeleton and study the effect of the structure on the physical and electrical properties using absorption spectroscopy, AFM, X-ray, and organic field-effect transistor current−voltage response.

Alkylating agents are reactive, often simple, molecules that are frequently used in diverse fields such as medicine, agriculture, and organic synthesis. For over a century, some highly reactive alkylating agents are also being used as blister chemical warfare agents. The detection and identification of such alkylating agents is not a simple task because of their high reactivity and often simple structure. Here we report on a new approach for the detection and identification of such alkylating agents using a simple luminescence based array sensor that mimics the olfactory system. In order to demonstrate the potential of the approach, seven π‐conjugated oligomers and polymers bearing nucleophilic pyridine groups, 1‐7, were adsorbed onto a solid support and exposed to vapors of alkylators 8‐15. Applying principal component analysis to the alkylation induced color shift patterns of the seven‐spot array results with a clear discrimination of the different alkylators. The comparison of the data obtained from the sensor array with known response patterns allows the clear identification of the specific alkylator. The spots are sensitive to minute concentrations of alkylators and since the detection is based on the formation of new covalent bonds these spots saturate, within seconds even at about 50 ppb. Copyright © 2010 John Wiley & Sons, Ltd.