Downloaded 52 times
![Examples Pi-Pi STACKING
• A notable example of applying π–π interactions in
supramolecular assembly is the synthesis of catenane.
• [2]Catanene was synthesized by reacting bis(pyridinium)
(A), bisparaphenylene-34-crown-10 (B), and 1, 4-
bis(bromomethyl)benzene (C).
• The π–π interaction between A and B directed the
formation of an interlocked template intermediate that was
further cyclized by substitution reaction with
compound C to generate the [2]catenane product.
A dendritic polymeric micelle was
developed to improve micellar
stability and enhance
docetaxel(chemotherapy drug for
types of cancers.) retention through
Pi-Pi stacking.](https://image.slidesharecdn.com/supramolecularchemistry19march2020-200322120443/75/Supramolecular-chemistry-19-2048.jpg)
More Related Content
Similar to Supramolecular chemistry
Supramolecular chemistry
- 1. SUPRAMOLECULAR CHEMISTRY CHEMISTRY BEYOND MOLECULES BY JAYAMADHURI.P MNRPG COLLEGE, KUKATPALLY TELENGANA STATE, INDIA
- 2. What is supramolecularchemistry?? According to F. Vögtle: In contrast to molecular chemistry, which is predominantly based upon the covalent bonding of atoms, “supramolecular chemistry is based upon intermolecular interactions, i.e. on the association of two or more building blocks, which are held together by intermolecular bond.” Molecular chemistry : based on covalent bond formations Supramolecular chemistry: based on noncovalent interactions
- 3. Chemistry beyond themolecule NOBLE PRIZE-1987
- 4. Non covalent interactions insupramolecular chemistry 1. Hydrogen bonding 2. Ion-ion interaction 3. Ion-dipole interaction 4. Cation-pi interaction 5. Anion –pi interaction 6. Pi-Pi interaction 7. Van der walls interaction 8. Example: supramolecular
- 5. HYDROGEN BONDING Ahydrogen bond (often abbreviated H-bond) is electrostatic force of attraction between a hydrogen (H) atom which is covalently bound to a more electronegative atom or group, particularly the second-row elements nitrogen (N), oxygen (O), or fluorine (F) (HBD) The hydrogen acceptor (HBA), the neighboring electronegative ion or molecule, with lone electron pair in order to form a hydrogen bond.
- 6. Examples of hydrogenbonding a) CELLULOSE
- 7. Examples of hydrogenbonding b) PROTEINS
- 8. Examples of hydrogenbonding c) DNA Hydrogen bonding between guanine and cytosine, Adenine and Thymine base pairs in DNA.
- 9. Mater. Chem. Front.,2019,3, 2602-2616 H-bonding to man made molecules
- 10.
- 11. Example of ion-ioninteraction in protein
- 12.
- 13.
- 14. Anion-π Interaction Definition:non covalent forces between electron deficient aromatic systems and anions. These interactions are energetically favourable(~20-50kj/mol) Anion-p interactions relies on two effects: Electrostatic attraction Ion-induced polarization. Electron deficient arenes interact with anions more efficiently i.e. higher the electron deficiency in π system, greater the interaction Example: selective for fluoride ions
- 15. Examples of anion-πinteractions 1,3,5-triazine based π electron deficient system –selective for fluoride ions.
- 16. Cation-π Interaction Cation–πinteraction is a noncovalent molecular interaction between the face of an electron-rich π system (e.g. benzene, ethylene, acetylene) and an adjacent cation (e.g. Li+, Na+). cation–π interactions in molecular recognition is seen in the nicotinic acetylcholine receptor (nAChR) which binds its endogenous ligand, acetylcholine (a positively charged molecule), via a cation–π interaction to the quaternary ammonium.
- 17. Synthetic cation-π Thecation–π interaction involved looking at the interactions of charged, nitrogenous molecules in cyclophane host–guest chemistry.
- 18.
- 19. Examples Pi-Pi STACKING •A notable example of applying π–π interactions in supramolecular assembly is the synthesis of catenane. • [2]Catanene was synthesized by reacting bis(pyridinium) (A), bisparaphenylene-34-crown-10 (B), and 1, 4- bis(bromomethyl)benzene (C). • The π–π interaction between A and B directed the formation of an interlocked template intermediate that was further cyclized by substitution reaction with compound C to generate the [2]catenane product. A dendritic polymeric micelle was developed to improve micellar stability and enhance docetaxel(chemotherapy drug for types of cancers.) retention through Pi-Pi stacking.
- 20. Strength of noncovalentinteraction
- 21. Ionophores Ionophores functionas ion carriers. Ion carriers can transfer ions from a hydrophilic medium, such as water, into a hydrophobic medium, i.e. a biological membrane, where the ions typically would not be soluble. Importance: 1. Create electrochemical gradient 2. Oxidative phosphorylation 3. Cell signaling 4. Hormone action
- 22. Examples: examples ofionophores: the K+ ionophore valinomycin, the proton ionophore 2,4-dinitrophenol, the synthetic crown ether 18-crown-6, and the channel forming ionophore nystatin.
- 23. MOLECULAR RECEPTORS ENDORECEPTORS Accordingto Lehn’s , Host molecules that have binding sites inside their molecular structures are called Endoreceptors. In natural system Enzymes are the endo receptors which binds the substrate in its cavity. In synthetic system, cyclic hosts like crown ethers, cryptands, cyclophanes, calixarenes, can trap the guest molecules inside their cavities. EXORECEPTORS According to Lehn’s , Host molecules that have binding sites on their surfaces are called Exoreceptors. In natural system antibodies recognises antigens on their terminal surface. In synthetic system, molecular clefts, cyclodextrins and its derivatives. Molecular receptors are the chemical entities which can binds the target molecules i.e. host-guest ; enzyme-substrate. Molecular receptors can be ENDORECEPTORS and EXORECEPTORS.
- 24. ENZYME-SUBSTRATE COMPLEX CROWN ETHERS–METAL ION COMPLEX KEMP’S-TRIACID –CYCLO-l-LEUCINE-l-LEUCINE
- 25. HOST GUEST CHEMISTRY LOCK AND KEY ANALOGY:
- 26.
- 27. SUPRAMOLECULAR STRUCTURES CARCERANDS CALIXARENES CRYPTANDS SPHERANDSCYCLOPHANES CYCLODEXTRINS
- 28.
- 29.
- 30. SPHERANDS A macrocyclicligand consisting of meta-bridged phenols. Spherands are complex cryptands, having an almost spherical structure, and can form complexes by enveloping the metal cations.
- 31.
- 32.
- 33.
- 34.
- 35. CYCLOPHANES Cyclophanes arestrained organic molecules which contain aromatic ring(s) as well as aliphatic unit(s). The aromatic rings provide rigidity to their structure, whereas the aliphatic unit(s) form bridge(s) between the aromatic rings and provide flexibility to the overall structure. Cyclophanes play an important role in “host–guest” chemistry and supramolecular assembly. “Phane”-containing molecules show interactions with π-systems, and they can also bind to many cations, anions, and neutral molecules. Cyclophanes are widely used in materials science and molecular recognition processes.
- 36.
- 37. Natural cyclophanes The cyclophaneskeleton is a core structural unit in many biologically active natural products such as macrocidin A and B, nostocyclyne A , and in the turriane family of natural products. Cyclophanes are also applied in research areas such as pharmaceuticals , catalysis and supramolecular chemistry
- 38. Cyclophanes are alsoapplied in research areas such as pharmaceuticals , catalysis and supramolecular chemistry Cyclophanes possess a defined cavity size and are efficient in encapsulating and stabilising guest molecules inside the cavity through various non-covalent interactions. This unique property of the cyclophanes has been widely exploited for the development of selective probes for a variety of guest molecules cyclophane architectures for the sensitive and selective optical recognition of important biomolecules.
- 39.
- 40.
- 41.
- 42. SELF ASSEMBLIES –COMPLIMENTARY HYDROGEN BONDING Cyanuric acid and melamine
- 43.
- 44.
- 45. Molecular necklace- α-cyclodextrin with polyethylene glycol (PEG)
- 46.
- 47. Three point contactmodel
- 48.
- 49. Chiral recognition bycrown ethers Crown ether with axis- chiral binaphthyl groups.
- 50. Cram demonstratedthe chiral recognition of an ammonium guest using a crown ether with axis-chiral binaphthyl groups.(Figure 2.7 shows top views of the complex formed.) When the (S,S)-host binds to a chiral guest (S- and R-α phenylethyl ammonium ions), the complexes formed are thermodynamically different. When the ammonium group attaches to the host crown ether, the spatial orientations of the phenyl group, the methyl group and the hydrogen atom change in an isomer- dependent way. This results in these complexes having different stabilities The crown ether is divided in two by the two binaphthyl groups. Different regions of the cycle then interact with a large site (L), a medium site (M) and a small site (S) on the guest. Which sites interact with which regions of the host cycle depends on the stereochemistry of the host cycle and the guest. Binding of the R-guest to the (S,S)-host satisfies steric requirements, because the phenyl group, the methyl group and the hydrogen can occupy the L, M, and S sites, respectively. This complex should be stable. In contrast, the S-guest cannot fill the sites in this desirable manner due to its different stereochemistry. The R-guest is therefore selectively recognized by the host.
- 51. Chiral receptor derivedfrom Kemp’s triacid- Rebek’s group In which amide and lactam functions coverage within cleft like cavity. It shows very high enantioselective recognition with diketopiperazines. In the complex ,four hydrogen bonds are formed. The R- group pointing outwards causing no steric interactions. In case of any mismatched fit best of three hydrogen bonds are formed.
- 52. Kemp’s triacid receptor NH NH O O CH3 CH3 CH3 CH3 cycloL- leu-L- leu diketopiperazines
- 53. KEMP’S TRIACID Kemp's triacid(a), on example of Rebek's receptors (b) and guests.
- 54.
- 55. CHIRAL RECEPTOR FOR DIACYLTARTARIC ACID The receptor has two acyl aminopyridine units linked through the chiral 1,1- binaphthyl spacer. The two anti carboxyl groups binds to the two acyloxy groups, which are opposite faces of binding cavity. The acyloxy groups hanging outwards forms complex with L(+) derivative tartaric acid ,sterically favored. In D(-)-derivative, the acyloxy groups are pushed upwards.
- 56.