supramolecular chemistry - ur · ∗ supramolecular chemistry-hosts: crown ethers, cryptands,...

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02.06.04 lcns04 – ch02 1 * Concepts of Bonding - Through-bond and through space interaction - Photoelectron spectroscopy - Intermolecular interactions: Forces and Systems * Supramolecular Chemistry - Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines - Host-guest systems: Cation binding, anion binding, van der Waals inclusion complexes - Hydrogen bonded systems - Artificial membranes * Self-assembling - Electron donor-acceptor complexes - catenanes * Natural Systems - DNA - Peptides, Proteins - Carbohydrates - Biological Membranes Supramolecular Chemistry SUP/NAN/MR

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Page 1: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 1

∗ Concepts of Bonding- Through-bond and through space interaction- Photoelectron spectroscopy- Intermolecular interactions: Forces and Systems

∗ Supramolecular Chemistry- Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes,

Siderophores, Cyclodextrines- Host-guest systems: Cation binding, anion binding, van der Waals

inclusion complexes- Hydrogen bonded systems- Artificial membranes

∗ Self-assembling- Electron donor-acceptor complexes - catenanes

∗ Natural Systems- DNA- Peptides, Proteins- Carbohydrates- Biological Membranes

Supramolecular Chemistry SUP/NAN/MR

Page 2: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 2

» P. D. Beer, P. A. Gale, D. K. Smith, Supramolecular Chemistry, Vol. 74,Oxford University Press Inc., New York, 1999.

» J. W. Steed, J. L. Atwood, Supramolecular Chemistry, J. Wiley,Chichester, 2000.

» J. L. Atwood, J.-M. Lehn, J. E. D. Davies, D. D. MacNicol, F. Voegtle,Comprehensive Supramolecular Chemistry, Pergamon, Oxford, UK,1996.

» F. Vögtle, Supramolekulare Chemie, B.G. Teubner, Stuttgart, 1992.

References - Supramolecular Chemistry SUP/REV

Page 3: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 3

Ø H.-H. Perkampus, Spektroskopie, VCH, Weinheim, 1993, S. 513

EOP/ANPhotoelectron spectroscopy

Page 4: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 4

Intramolecular interaction through space

Ø .

QUA/EOP

Ionization potentials• Norbornene 8.97 eV• (Z)-2-Butene 9.12 eV• Norbornadiene:

8.7 eV and 9.55 eV

Page 5: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 5

NAT/STR

The anomeric effect

Page 6: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 6

Intermolecular interaction SUP

» P. Atkins The Elements of Physical Chemistry; Oxford University Press: Oxford,2001

» J. W. Steed, J. L. Atwood Supramolecular Chemistry; J. Wiley: Chichester,2000.

Page 7: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 7

Ion-Ion interaction: Crystalline state SUP

Page 8: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 8

Solid state structure of benzene: ππ ππ-stacking

SUP

 

» J. W. Steed, J. L. Atwood, Supramolecular Chemistry, J.Wiley, Chichester, 2000.

Page 9: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 9

Helicates: Natural and synthetic systems SUP/CHI/MC

» Chem. Rev. 1997, 97, 2005.

Ø X-ray structures1: a double-stranded A-DNA2: trinuclear double-stranded helicate

Page 10: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 10

Nonnatural helicates by self-assembling SUP/CHI/MC

» Chem. Rev. 1997, 97, 2005.

Ø Metallosupramolecularhelicates

Ø Ligands: 2,2‘-bispyridinesØ Cu(I) ions form

pseudotetrahedral complexes

Page 11: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 11

Seminal work on supramolecular chemistry

SUP

Ø Crown ethers/corandsØ SpherandsØ Cryptands

O

OO

O

OO

NON

OO

O O

n

ROOR

OROR

RO

RO

dibenzo[18]crown-6 n = 2; [2.2.2]cryptand

spherand

"a cyclic hexa-meta-phenylene"

∗ Charles Pedersen∗ Donald Cram∗ Jean-Marie Lehn

Page 12: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 12

Supramolecular chemistry: Articles SUP

Ø Crown ethers/corandsØ SpherandsØ Cryptands

∗ Charles Pedersen∗ Donald Cram∗ Jean-Marie Lehn

» Die Entdeckung der Kronenether (Nobel-Vortrag), C. J. Pedersen,Angew. Chem. 1988, 100, 1053-1059.

» Von molekularen Wirten und Gästen und ihren Komplexen (Nobel-Vortrag), D. J. Cram, Angew. Chem. 1988, 100, 1041-1052.

» Supramolekulare Chemie - Moleküle, Übermoleküle undmolekulare Funktionseinheiten (Nobel-Vortrag), J.-M. Lehn, Angew.Chem. 1988, 100, 91-116.

Page 13: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 13

Host systems: Cation binding ligands SUP

Ø Coordination complexes of metal ionsØ MacrocylesØ Crown ethers/coronandsØ Lariat crown ethersØ Podands (acyclic hosts)Ø CryptandsØ SpherandsØ HelicatesØ CalixarenesØ Biological systems: Siderophores, Valinomycin

Page 14: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 14

Crown ether complexes SUP

 

∗ Ionic diameters: Li+, 1.20 Å; Na+, 1.80 Å; K+, 2.66 Å

Page 15: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 15

Formation of cryptates from cryptands andmetal ions (Mn+)

MR/SUP

 

[2.2.2.] cryptand cryptate a „metal complex“

Page 16: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 16

Calixarenes: p-tert-Butylcalix[4]arene SUP/MR

 

Page 17: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 17

Siderophores: Iron Sequestering

 

MR/SUP/BBM

enterobactin

complexation of Fe(III)

Page 18: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 18

Molecular cavities: Cyclodextrines MR/SUP

O

O

O

HO

HO

O

O

O

O O

O

OOH

HO

O

O

OOO

O

O

O

O

OH

OH

O

O

O

OO

O

O

OHO

OH

O

O

OO O

H

H H

H

H

H

H

H

H

H

H

H

H

H

H H

O

OO

O

O

O

O

O

O

O

HO

HO

HOOH

OH

OH

OOO

O

O

O

O

O

OO

O

O

O

OH

HH

H

H

H

HH

HH

H

H

O

HO

O

O

O

OO

O

O

HO

HO

OH

OOO

O

O

O

O

OH

O

O

O HO

OO

O

O O

O

OHO

O

O

O

H

HH

HH

H

H

H

H

H

H

H

H

H

α-cyclodextrin β-cyclodextrin γ-cyclodextrin

apolar cavity polar rim

Page 19: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 19

Binding constants (lg K) of crown ethers formetal ions

tms/SUP

 

[18]crown-6

• Na+, 4.32• K+, 6.10• Cs+, 4.62

[21]crown-7

• K+, 4.41• Cs+, 5.02

Page 20: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 20

Log K values for cryptands of different size

MR/SUP

 

Page 21: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 21

Calixarenes: Cationbinding

 

MR/SUP

Page 22: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 22

Calixarenes: Cation/Anion binding

 

MR/SUP

Page 23: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 23

Nitromethane inclusion complex with apyridinyl crown ether

tms/SUP

 

∗ Distances: C — H····N (2.21 Å); C—H····O (2.41 Å)

Ø E. Weber, S. Franken, H. Puff, J. Ahrendt, J. Chem. Soc.,Chem. Commun. 1986, 467.

Page 24: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 24

Van der Waals inclusion complex (X-raystructure): p-tert-butylcalix[4]arene andtoluene

SUP

 

Ø G. D. Andreetti, R. Ungaro, A. Pochini, J. Chem. Soc.,Chem. Commun. 1979, 1005.

Page 25: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 25

Problem: Sensing of Ammonium Ions

O

N

O

N

ON

oxazolin receptorfor ammonium ions

@ Fragen:∗ Wieso eignet sich der

Rezeptor 1 für dieBindung von Ammonium-Ionen?

∗ Welche Struktur hat derKomplex?

∗ Wie müssen Sie denRezeptor funktionalisieren,dass er chiraleAmmoniumsalzeunterscheiden kann?tripodal oxazoline receptor

» Organic Letters 2003, 5, 1419-1422.

Page 26: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 26

Hydrogen bondingSUP/QUA

Ø J. W. Steed, J. L. Atwood, Supramolecular Chemistry, J. Wiley,Chichester, 2000.

Page 27: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 27

Proton spongeSUP

Ø strong hydrogen bonds

N NMe

MeMeMe

H+

Page 28: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 28

Crystal structure of oxalic acidSUP

Page 29: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 29

Self-assembling via hydrogen bonding MR/SUP

NN

N OO

OHH

NN

N

N

NNHH

H HNN

N OO

OHH

self-assembling matrix

Cyanursäureamid

Isocyanursäure Isocyanursäure

N

NN

N

ZN

O

H

HN N

O

Z

N

H

H

H

N

NN

N

Z

NHH

N N

O

Z

Me

O

H

AT

GC

Page 30: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 30

Rosettes MR/SUP

cyanuric acid + melamine insoluble complex

Page 31: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 31

Problem: Flavin – receptor interaction MR/SUP

» G. Cooke, V. M. Rotello, Chem. Soc. Rev. 2002, 31, 275-286.

Ø Hydrogen bonding supported by ππ-stacking

Page 32: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 32

Multiple hydrogen bonding MR/SUP

» J. Am. Chem. Soc. 2002, 124, 11064-11072.

N

N N

N

O

O

H

NH

R

NHH

A

D

D

D

A

A

Page 33: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 33

Problem: Self assembling of theheterocyclic compound 1

MR/SUP

» J. Am. Chem. Soc. 2002, 124, 11064-11072.

Page 34: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 34

Problem: Nanotubes by self assembling MR/SUP/NAN

» J. Am. Chem. Soc. 2002, 124, 11064-11072.

Page 35: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 35

Structure of Phosphatidylcholin (L- α α-Lecithin)

NAT/BBM

Page 36: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 36

Schematic representation of a phospholipidmembrane (5-6 nm in width) BBM/MMA

Page 37: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 37

Surfactantstructuresin aqueoussolution

SUP/MMA/SAM

» E. Breitmaier, G. Jung, Organische Chemie:Grundlagen, Stoffklassen, Reaktionen, Konzepte,Molekülstruktur, 4th ed., Thieme, Stuttgart, 2001.

Page 38: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 38

Synthesis of a [2]Catenane MR/SUP

» F. M. Raymo, J. F.Stoddard, in B. L.Feringa (Ed.):MolecularSwitches, Wiley-VCH, Weinheim2001, p. 219.

Ø Charge transferinteraction – self-assembling –template synthesis

Page 39: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 39

Hydrogen bonded base pairing – DNANUC/SUP

NNN

N

Deoxyribose

NH

H

NN

O

O

Me

H

Deoxyribose

NNN

N

DeoxyriboseH

O

N HH

NN

N

O

H

Deoxyribose

HG = C

A = T

10.85 A

Page 40: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 40

Thymine, adenine base pairing and thesecondary structure of DNA: Major andminor groove

NUC

∗ vdW: van der Waals interaction∗ a and d: acceptor and donor hydrogen bonding

Ø Science 1998, 282, 111-115.

Page 41: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 41

NUC/ST

∗ A-T base pair (yellow); G-C base pair (blue)∗ identical positions of C1‘

Architecture of base-pair stacking

» L. Stryer, Biochemistry, W.H. Freeman, New York.

Page 42: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 42

Structure andcomplementary basepairing in DNA

NUC/SUP

∗ Purine, pyrimidine bases,phosphoric acid, deoxyribose(ribose): Nucleoside,nucleotide, nucleic acid

Page 43: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 43

NUC

∗ Watson-Crick –model

∗ The two strands arerunning in oppositedirection

Minorgroove

Majorgroove

Double stranded DNA molecule (B-form)

Page 44: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 44

NUC

» The quest for the chemical roots of life, N. Hall, ChemicalCommunications (Cambridge, United Kingdom) 2004, 1247-1252.

Interesting article to read

Page 45: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 45

A segment of a protein: right-handed helicalstructure (Myoglobin) BBM/SKE/NAT

Page 46: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 46

Secondary structure of proteins: ß-pleatedsheet BBM/SKE/NAT

Page 47: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 47

∗ Conformations of peptidic structures

Modulation of peptide nanostructures

Ø N. Voyer, in Topics in Current Chemistry, Vol. 184 (Ed.: F. P.Schmidtchen), Springer-Verlag, Berlin, 1996, pp. 1-37.

SKE/BBM

Page 48: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 48

Polysaccharides: Amylose, Amylopectine,Cellulose NAT/CL/BBM

Amylopectine:high molecular weightaround one million glucose units

α-1,6‘-glycosidic bond

α-1,4‘-glycosidic bond

β-1,4‘-glycosidic bond

Amylose forms a left-handed helix

Cellulose has a one-dimensional structure with aslight helical turn, enforced byintramolecular hydrogen bonding

Page 49: Supramolecular Chemistry - UR · ∗ Supramolecular Chemistry-Hosts: Crown Ethers, Cryptands, Spherands, Calixarenes, Siderophores, Cyclodextrines-Host-guest systems: Cation binding,

02.06.04 lcns04 – ch02 49

Representation of a biological membrane(„fluid mosaic model) BBM/BIO/MMA