Yoav Eichen

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.

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 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. 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.

Photoinduced‐electron‐transfer (PET)‐based chemosensing is a very elegant way of reporting the presence of a guest species in solution. This method was successfully applied for the detection of different ionic species, such as cations, anions, and protons. Herein, we report on the application of the PET chemosensing concept for the efficient and selective detection of different alkylating agents. 2‐(2‐Dimethylaminoethyl)benzo[de]isoquinoline‐1,3‐dione (1) was found to be a highly selective and effective PET chemosensor that turns luminescent upon reacting with different alkylating agents. This PET‐based system detected even rather weak alkylating agents, such as dichloromethane. A PET‐based sensor that consists of 1 as the active component could detect rather low concentrations of alkylating agents in solution and in the gas phase.

Photo‐induced Energy Transfer (PET) based chemosensing is a very elegant way for reporting the presence of an analyte in solution. This method was successfully applied to the detection of many cationic species in solutions and already appears in interesting commercial applications. In this paper we report on the preparation and host–guest chemistry of 1,3‐di(2‐pyrrolyl)azulene (5), a new azulene‐based selective PET‐like chemosensor that turns fluorescent upon binding the fluoride anion. (© Wiley‐VCH Verlag GmbH & Co. KGaA, 69451 Weinheim, Germany, 2005)

A 1,3,5- alternate conformation of the pyrrole rings is adopted by the calix[6]pyrrole 1 in the crystal (see picture). Compound 1 was synthesized in a two-step process and although it crystallizes in the form of the adduct 1⋅3CH₃COCH₃⋅H₂O⋅CHCl₃, there are no solvent molecules in the cavity (cross section ca. 60Ų) of this macrocycle which possesses alternating dimethyl and diphenyl substitutents at the meso positions.