Multifunctional Logic Applications of a Single Molecule: A Molecular Photo‐Switch Performing as Simple and Complex Gates, Memory Element, and a Molecular Keypad Lock (original) (raw)
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Molecular logic gates:Recent advances and perspectives
The capacity and miniaturization of information storage and processing technology are rapidly approaching a limit. Alternative materials and operating principles for the elaboration and communication of data in electronic circuits and optical networks must be identified. Molecular level computing is predicted as the ultimate solution to overcome the present limitation of computing devices in terms of storage capacity and processing speed. Their attractive features are the miniaturized dimensions and the high degree of control on molecular design through chemical synthesis. In recent years a variety of molecules that respond to various chemical inputs have been synthesized and demonstrated as molecular logic gates. This review covers the recent developments and future perspectives of molecular logic gates with particular emphasis on fluorescent organic molecules.
Chemistry – A European Journal, 2011
Photochromic spiropyrans modified with fluorophores were investigated as molecular platforms for the realization of fluorescence switching through modulation of energy transfer. The dyads have been designed such that energy transfer is only observed for the open forms (merocyanine and protonated merocyanine) of the photochrome, while the closed spiropyran is inactive as energy acceptor. This was possible by intentionally choosing fluorophores (4-amino-1,8-naphthalimide, dansyl, and perylene), which lead to a zero spectral overlap with the spiro form and considerable overlap for the merocyanine forms. Based on the Förster theory, energy transfer is predicted to be highly efficient and in some cases of unit efficiency. The combined switching by photonic (light of λ > 530 nm) and chemical (base) inputs enabled the realization of a sequential logic device, which is the basic element of a keypad lock. Furthermore, in combination with an anthracene-based acidochromic fluorescence switch, a reversible logic device was designed. The latter enables the unambiguous coding of different input combinations through multicolour fluorescence signalling. All devices can be conveniently reset to their initial state and repeatedly cycled.
All-Photonic Multifunctional Molecular Logic Device
Journal of the American Chemical Society, 2011
Photochromes are photoswitchable, bistable chromophores which, like transistors, can implement binary logic operations. When several photochromes are combined in one molecule, interactions between them such as energy and electron transfer allow design of simple Boolean logic gates and more complex logic devices with all-photonic inputs and outputs. Selective isomerization of individual photochromes can be achieved using light of different wavelengths, and logic outputs can employ absorption and emission properties at different wavelengths, thus allowing a single molecular species to perform several different functions, even simultaneously. Here, we report a molecule consisting of three linked photochromes that can be configured as AND, XOR, INH, half-adder, half-subtractor, multiplexer, demultiplexer, encoder, decoder, keypad lock, and logically reversible transfer gate logic devices, all with a common initial state. The system demonstrates the advantages of light-responsive molecules as multifunctional, reconfigurable nanoscale logic devices that represent an approach to true molecular information processing units.
Nature Communications, 2019
Molecular-logic based computation (MLBC) has grown by accumulating many examples of combinational logic gates and a few sequential variants. In spite of many inspirations being available in biology, there are virtually no examples of MLBC in chemistry where sequential and combinational operations are integrated. Here we report a simple alcohol-ketone redox interconversion which switches a macrocycle between a large or small cavity, with erect aromatic walls which create a deep hydrophobic space or with collapsed walls respectively. Small aromatic guests can be captured or released in an all or none manner upon chemical command. During capture, the fluorescence of the alcohol macrocycle is quenched via fluorescent photoinduced electron transfer switching, meaning that its occupancy state is self-indicated. This represents a chemically-driven RS Flip-Flop, one of whose outputs is fed into an INHIBIT gate. Processing of outputs from memory stores is seen in the injection of packaged neurotransmitters into synaptic clefts for onward neural signalling. Overall, capture-release phenomena from discrete supermolecules now have a Boolean basis.
Biosystems, 2012
In this paper we detail experimental methods to implement registers, logic gates and logic circuits using populations of photochromic molecules exposed to sequences of light pulses. Photochromic molecules are molecules with two or more stable states that can be switched reversibly between states by illuminating with appropriate wavelengths of radiation. Registers are implemented by using the concentration of molecules in each state in a given sample to represent an integer value. The register's value can then be read using the intensity of a fluorescence signal from the sample. Logic gates have been implemented using a register with inputs in the form of light pulses to implement 1-input/1-output and 2-input/1output logic gates. A proof of concept logic circuit is also demonstrated; coupled with the software workflow describe the transition from a circuit design to the corresponding sequence of light pulses.
Complex molecular logic gates from simple molecules
RSC Advances, 2021
Herein we describe a protocol to mimic an electronic device. The MLG could function as a transmitter of information at a molecular level and this could be read using the variation of the magnetic field in the molecules.