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A charge-transfer complex ( CT complex ) or electron-donor-acceptor complex is an association of two or more molecules, or of different parts of one very large molecule, in which a fraction of electronic charge is transferred between the molecular entities.
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charge-transfer and complex
When iodine is dissolved in polar solvents which are strong donor solvents such as ketones, ethers, pyridine, the formation of charge-transfer complex leads to modification of the energy gap between the two molecular orbitals, thus different wavelengths were absorbed and iodine has different color in solvents with different polarity.
When the brown solution of iodine in strong donor solvents were heated, a color transition from brown to violet is observed as the weakly-bonded charge-transfer complex dissociates into to free solvent and iodine molecules.
An example is where a polymeric chain of the charge-transfer complex < sup > n +</ sup > exists in the compound.
In the 1950s, it was discovered that polycyclic aromatic compounds formed semi-conducting charge-transfer complex salts with halogens.
In the 1950s, researchers discovered that polycyclic aromatic compounds formed semi-conducting charge-transfer complex salts with halogens.
In 1972, researchers found metallic conductivity in the charge-transfer complex TTF-TCNQ.
The nature of the attraction in a charge-transfer complex is not a stable chemical bond, and is thus much weaker than covalent forces.
If the transfer occurs from the MO with ligand-like character to the metal-like one, the complex is called a ligand-to-metal charge-transfer ( LMCT ) complex.
If the electronic charge shifts from the MO with metal-like character to the ligand-like one, the complex is called a metal-to-ligand charge-transfer ( MLCT ) complex.
For example, the classic example of a charge-transfer complex is that between iodine and starch to form an intense purple color.
Hexamethylbenzene charge-transfer complex
In 1973 it was discovered that a combination of these components formed a strong charge-transfer complex, henceforth referred to as TTF-TCNQ.
In such chromophores, the charge-transfer ( CT ) transitions of the metal complex generally enhance metal-ligand stretching modes, as well as some of modes associated with the ligands alone.
charge-transfer and CT
These optical absorption bands are often referred to as charge-transfer bands ( CT bands ).
charge-transfer and is
In non-polar solvents such as hexane, no charge-transfer complexes is formed, and the solution appears violet ( λ < sub > max </ sub > = 520-540 nm ) since the energy gap in I < sub > 2 </ sub > in non-polar solvents is essentially the same as that in the gas phase.
UV / Vis CD is used to investigate charge-transfer transitions.
Optical spectroscopy is a powerful technique to characterize charge-transfer bands.
A well-known example is the blue charge-transfer band exhibited by iodine when combined with starch.
Resonance Raman Spectroscopy is also a powerful technique to assign and characterize charge-transfer bands in these complexes.
The intensity of charge-transfer bands in the absorbance spectrum is strongly dependent upon the degree ( equilibrium constant ) of this association reaction.
The color of charge-transfer bands, i. e., the charge-transfer transition energy, is characteristic of the specific type of donor and acceptor entities.
For charge-transfer complexes and conjugated systems the band width is determined by a variety of factors.
charge-transfer and association
The charge-transfer association occurs in a chemical equilibrium with the independent donor ( D ) and acceptor ( A ) molecules:
charge-transfer and one
In acquiring QRG, Atmel also inherited an ongoing patent lawsuit that QRG had filed against Apple Inc. in 2005 alleging infringement of one of its charge-transfer based patents in the iPod click-wheel ; the case was later settled.
Most of these electronic transitions are from one conjugated π-system molecular orbital ( MO ) with an even kind of symmetry to an other conjugated π-system MO with an odd kind of symmetry ( π to π < sup >*</ sup >), but electrons from other states can also be promoted to a π-system MO ( n to π < sup >*</ sup >) as often happens in charge-transfer complexes.
charge-transfer and electronic
Hence, in a biomolecule such as haemoglobin, tuning the laser to near the charge-transfer electronic transition of the iron center results in a spectrum reflecting only the stretching and bending modes associated with the tetrapyrrole-iron group.
charge-transfer and charge
The charge-transfer bands in transition metal complexes result from shift of charge density between molecular orbitals ( MO ) that are predominantly metal in character and those that are predominantly ligand in character.
charge-transfer and between
In inorganic chemistry, most charge-transfer complexes involve electron transfer between metal atoms and ligands.
charge-transfer and .
Most pigments are charge-transfer complexes, like transition metal compounds, with broad absorption bands that subtract most of the colors of the incident white light.
Together they may undergo charge-transfer reactions.
Pigments and dyes like these are charge-transfer complexes.
These are organic charge-transfer complexes and various linear-backbone conductive polymers derived from polyacetylene.
At least locally, charge-transfer complexes often exhibit similar conduction mechanisms to inorganic semiconductors.
Mainly due to low mobility, even unpaired electrons may be stable in charge-transfer complexes.
Superconductivity in charge-transfer complexes was first reported in the Bechgaard salt ( TMTSF )< sub > 2 </ sub > PF < sub > 6 </ sub > in 1980.
complex and CT
The cholera toxin ( CTX or CT ) is an oligomeric complex made up of six protein subunits: a single copy of the A subunit ( part A ), and five copies of the B subunit ( part B ), connected by a disulfide bond.
CT is often used to image complex fractures, especially ones around joints, because of its ability to reconstruct the area of interest in multiple planes.
The men's crew also uses the Red Top complex in Ledyard, CT, as their training camp for the annual Harvard-Yale Regatta.
A super specialty complex, CT scan, MRI scan, an artificial limb centre, Casualty ( Emergency Services ) complex, Samraksha Kendram, and Vishrama Kendram were later additions to the institution.
The molfile consists of some header information, the Connection Table ( CT ) containing atom info, then bond connections and types, followed by sections for more complex information.
complex and is
Accidental war is so sensitive a subject that most of the people who could become directly involved in one are told just enough so they can perform their portions of incredibly complex tasks.
I am suggesting that a case-history approach to the Oedipus complex is a blind alley for a storyteller.
It is most probable that Freud and the Oedipus complex never entered his head in the writing of this story.
The board's action shows what free enterprise is up against in our complex maze of regulatory laws.
The transportation system which serves the National Forests is a complex of highways and access roads and trails under various ownerships and jurisdictions.
But there is still the sometimes complex problem of helping campers choose the best equipment for their individual needs.
Perhaps the best way to indicate the versatility of design that characterizes the use of plastics in signs and displays would be to look at what is happening in only one of the areas in this complex field -- changeable signs.
Then in 2 we show that any line involution with the properties that ( A ) It has no complex of invariant lines, and ( B ) Its singular lines form a complex consisting exclusively of the lines which meet a twisted curve, is necessarily of the type discussed in 1.
Hence the totality of singular lines is the T order complex of lines which meet Aj.
Since the complex of singular lines is of order K and since there is no complex of invariant lines, it follows from the formula Af that the order of the involution is Af.
The most obvious of these is the quadratic complex of tangents to Q, each line of which is transformed into the entire pencil of lines tangent to Q at the image of the point of tangency of the given line.
We now observe that the case in which **zg is a Af curve on a quadric is impossible if the complex of singular lines consists exclusively of the lines which meet Aj.
However, if there is no additional complex of singular lines, the order of the image regulus of a pencil is precisely Af.
In societies like ours, however, its place is less clear and more complex.
This behavior is more `` veridical '' -- or true -- than other testing behavior for some types of evaluation, and so can give quick and accurate estimates of complex functioning.
Of all the possible forms of nonverbal expression, that which seems best to give release, and communicational expression, to complex and undifferentiated feelings is laughter.
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