Molecular Recognition and Conductance in Crown Ethers

Abstract

Crown ethers have the remarkable property of recognizing and binding specific metal cations in complex mixtures. We propose to combine molecular recognition with molecular electric conductance. The question we address is: can the event of binding a cation be sensed by a change in conductance? Specifically, we study a short molecular wire (MW) containing a crown-6 molecule connected via sulfur atoms to two gold atomic wires acting as metallic leads. Upon binding a cation, the density of states of the system is only slightly affected. This reflects the fact that the cation binding is largely electrostatic in nature and is accompanied by little electronic reorganization. Yet, the cationic binding does significantly lower conductance. We also identify strong interference affecting the conductance. A striking feature is the insensitivity of conductance to the type of ligand with the exception of the proton.

Infrared spectroscopy of gas-phase hydrated K+:18-crown-6 complexes: Evidence for high energy conformer trapping using the argon tagging method

“…Recently, crown ethers have been used in molecular wires [1], in applications dealing with organic electrides [2], and as stabilizers of ionic compounds used to study aromaticity [3]. One of the most studied crown ethers, 18-crown-6 ether (18c6), has been shown to selectively bind K + in aqueous solution [4].…”

Electronic Diabatic Framework: Restrictions Due to Quantization of the Nonadiabatic Coupling Matrix

“…Non-Hermitian Hamiltonians are frequently applied in molecular dynamics (see, for instance, those that contain imaginary potentials to form absorbing boundary conditions [78][79][80][81][82][83][84][85][86][87][88][89] ); nevertheless, the results are practically correct. In any case, the final results are subject to convergence tests; therefore, to achieve convergence, we may need to vary p, as in any other scattering or spectroscopic crosssection calculation.…”

A quantum chemistry study of diethynylbenzene macrocycles: Structural and electronic properties

“…Incorporating the molecular recognition, this kind of molecules can potentially form various new types of molecular electronic devices [8]. Particular interest is the change in conductance as the cycle molecule binding and relinquishing an ion [9]. Such a chemical system could be used as a molecular transistor, switch, or sensor.…”