Intercalation Compounds: Reversible Insertion of Molecules into Layered Structures
1.
2. Intercalation Compounds
• Intercalation is the reversible inclusion or
insertion of a molecule (or ion) into
compounds with layered structures.
Dr. Julekha Shaikh
16. MC8 (M = K, Rb, Cs) prep through no of stages
Dr. Julekha Shaikh
17. • Intercalation Compounds of oxo acids
• Intercalation compounds of oxo acids are formed by treating graphite with strong
acids in the presence of oxidizing agents. Graphite bisulfate, [C24]+[HSO4]−
lamellar graphite salts
• 48 C + 0.25 O2 + 3 H2SO4 → [C24]+[HSO4]−·2H2SO4 + 0.5 H2O
• Intercalation Compounds of metal halides
• A number of metal halides intercalate into graphite. The chloride derivatives
have been most extensively studied. Examples include MCl2 (M = Zn, Ni, Cu, Mn),
MCl3 (M = Al, Fe, Ga), MCl4 (M = Zr, Pt), etc.
• e.g. [C27]+[AlCl4]−·2AlCl3, [C10]+[FeCl4]−·5FeCl3
• Intercalation Compounds of halogens, oxides and sulphides
• Chlorine and bromine reversibly intercalate into graphite. Iodine does not.
Fluorine reacts irreversibly. In the case of bromine, the following stoichiometries
are known: CnBr for n = 8, 12, 14, 16, 20, and 28.
• Because it forms irreversibly, carbon monofluoride is often not classified as an
intercalation compound. It has the formula (CF)x. It is prepared by reaction of
gaseous fluorine with graphitic carbon at 215–230°C. The color is greyish, white,
or yellow. The bond between the carbon and fluorine atoms is covalent. Carbon
monofluoride is not electrically conductive. It has been studied as
a cathode material in one type of primary (non-rechargeable) lithium batteries.
• A number of oxides and sulphides also intercalate into graphite.
• SO3, N2O5, CrO3, MoO3, V2S3, Cr2S3, PdS, WS2, Sb2S3 etc. Dr. Julekha Shaikh
18. • Intercalation Compounds of Metal dichalcogenides
• Another well-known family of intercalation hosts are the
layered metal dichalcogenides such as titanium disulfide. These
materials are prepared by treating graphite with a strong
oxidant or a strong reducing agent: C + m X → CXm
• The reaction is reversible.The host (graphite) and the guest X
interact by charge transfer. A analogous process is the basis of
commercial lithium-ion batteries. LiS batteries.
• Intercalation of Li into a titanium disulfide cathode. The process involves swelling of one crystal
axis and charge transfer from Li to Ti. Dr. Julekha Shaikh
19. DNA intercalation
Intercalation induces structural
distortions.
Left: unchanged DNA strand.
Right: DNA strand intercalated
at three locations (black areas).
In biochemistry, intercalation is the
insertion of molecules between the planar
bases of DNA.
Intercalation occurs when ligands of an
appropriate size and chemical nature fit
themselves in between base pairs of DNA.
These ligands are mostly positively charged,
planar, polycyclic, aromatic compounds that
unwind the DNA double helix and insert
themselves between DNA base pairs.
Dr. Julekha Shaikh
20. Therapeutic applications
• metallo-intercalators can combat
cancerous tumor cells within the
body by targeting specific
mismatched DNA base pairs; the
ability to modify the ligands
bound to the metal center allows
for a high degree of specificity in
the binding interactions between
the metallo-intercalator and the
DNA sequence.
• DNA intercalators are used
in chemotherapeutic treatment to
inhibit DNA replication in rapidly
growing cancer cells. Examples
include doxorubicin (adriamycin)
and daunorubicin (both of which
are used in treatment of
Hodgkin's lymphoma), and
dactinomycin (used in Wilm's
tumour, Ewing's Sarcoma).
Dr. Julekha Shaikh
21. Properties and applications
• GICs exhibit diverse electronic and electrical properties.
• improves in-plane transport properties
• can change magnetic properties
• can produce superconductors (CaC6 exhibits the highest
critical temperature Tc = 11.5 K)
• Increases reactivity
• can dope other properties depending on electronic
mobility
intercalation is a powerful means of controlling physical
properties i. e obtain tailor made properties.
Dr. Julekha Shaikh