molecular gates

7/29/2019 Molecular Gates

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Molecular gates

Submitted by:

Harmanjot kaurGEC 103368


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Molecular gate

a molecular gateis amolecule that performs logic

operations with one or more than one physical or

chemical and one output.


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Scientists in Europe and the US have designed a molecule that

can be manipulated using light to carry out multiple and

distinct logic functions. The multifunctional molecule, which

can be reconfigured by light, could be used in data storage

devices and biomedicine, including nanoparticle tracking anddrug delivery.

Although molecular logic devices are not new, most have only

ever managed to carry out single logic operations. Therefore,

many different molecules, and different logic devices basedon these, would have to be used and coordinated to carry out

a set of logic manipulations. Furthermore, most molecular

logic devices require some form of chemical input to

function. Devens Gust of Arizona State University in Tempe, US, and

colleagues in Sweden and Spain, created a molecule which

can perform 13 different logic operations. Some of these

operations can work in unison and the whole process is

controlled entirely by different wavelengths of light.


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The FG-DTE molecule comprises three covalently linked photochromicchromophores: a dithienylethene (DTE) and two identical fulgimides (FG).Shining different wavelengths of light on the molecule causesphotoisomerisation of the three chromophores, thus making it possible toswitch each of them into open and closed isomeric forms.

To test the system, the team used standard laboratoryspectrophotometers and light sources and found that it could performbinary arithmetic using AND, XOR and IHN gates, and decoder andencoder functions required for storing digital information.

'Although these functionalities have been individually obtained withspecific systems in the past few years, this work is the first to integrate all

of them in the same molecular platform,' says Alberto Credi, whoinvestigates light operated molecules at the University of Bologna, Italy.'Achieving a large degree of functional integration is a key objective formolecular logic because, unlike the elements of electronic circuits,molecular logic gates are difficult to connect together.'

'In principle, suitable photochromic molecules could be used to build

computers or other data processing devices. In practice, such systems maynever replace electronic materials,' Gust says. 'However, a molecular logicdevice operated by light may find applications in nanotechnology andbiomedicine where relatively simple logic processing may be needed atvery small scale


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AND GATE

A B OUTPUT

0 0 0

Ca2+ 0 0

0 H+ 0

Ca2+ H+ Fluroscence

This compound contains

tertiary amino group i.e

capable of binding to protons.

Fluoroscence wiil be onlydue prescence of both

cations, thus acts as AND gate.


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X-NOR gate

A B OUTPUT

0(NO I/P) O(NO I/P) Max.absorbance.

Ca 2+ 0 BLUE SHIFT

0 H+ RED SHIFT

Ca2+ H+ Max.

absorbance

Compound shown is olefin which acts

as molecular X-NOR molecular gate.

Input is given as addition of either H+

and Ca2+.Output depends on the absorption in

UV spectroscopy.


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X-OR gate

XOR is obtained through a psedo rotaxane.

Added tertiary amine or trifloro

methanedethreaded the complex and

results in increased emission at 343 nm.

But if both are added the process getsreverted.

A B OUTPUT

0 0 O

TERTIARYAMINE 0 INCREASEDEMISSIO

0 TRIFLORO

METHANE

INCREASED

EMMISSION

TERTIARY

AMINE

TRIFLORO

METHANE

0


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NOT gate

A OUTPUT state

Zn+ 0


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OR gate

A B OUTPUT STATE

0 0 0

Mg 0 1

0 Ca 1

Mg Ca 1

molecular gates

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