1
Chemical composition
Silica SiO2
Aluminosilicates Mx
I
AlxSi2-xO4 . nH2O
Aluminophosphates AlPO4 (isoelectronic with Si2O4)
Metallophosphates MPO4
Silicoaluminophosphates Mx
I
SixAlP1-x O4
Zeolites and Zeolitic Materials
Molecular sieves = highly organized matrices of tunable pore shape, size, and
polarity for separation, recognition, and organization of molecules with
precision of about 1 Å.
Macroporous > 50 nm
Mesoporous 250 nm
Microporous  2 nm
Ultramicroporous  0.7 nm
detergent builders, adsorbents, size-shape selective
catalysts, supramolecular chemistry, nanotechnology
Pores and Channels
2
ACO
AFI
SSY
UFI
STI
3
Zeolite Types
>60 naturally occurring zeolites - large deposits of analcime, chabazite,
clinoptilolite, erionite, mordenite and phillipsite
>232 zeolite framework types (IZA - 2017)
many hundreds of zeolite compounds
Nomenclature http://www.iza-structure.org/
Structure types - three capital letter codes
Most well known zeolite archetypes: SOD, LTA, FAU, MOR, MFI
Aluminium Cobalt Phosphate - 1 (One) = ACO
•Four-connected frameworks
•Interrupted frameworks (denoted by a hyphen: –CLO, cloverite)
Structure types do not depend on: chemical composition, element distribution,
cell dimensions, symmetry
Several zeolite compounds can belong to the same structure type:
FAU – faujasite, Linde X, Y, Beryllophosphate-X, SAPO-37, Zincophosphate-X
4
Zeolite Names
Names of zeolite materials:
•trivial names – Alpha, Beta, Rho
•chemical names – Gallogermanate-A
•mineral names – Chabazite, Mordenite, Stilbite, Sodalite
•codes – AlPO4-5, 8, 11, ..., 54, ZSM-4, 18, 57, ...
•brand names – Linde A, D, F, L, N, Q , R, T, W, X, Y
•university names
VPI-5 (Virginia Polytechnical Institute)
ULM (University Le Mans)
MU-n (Mulhouse, Université de Haute Alsace)
5
T
O
O
O
O
Zeolites Building Units
Isoelectronic relationship
(SiO2)2 [AlSiO4 ]- AlPO4
Primary building units:
Al(III)O4, P(V)O4 and Si(IV)O4 tetrahedra
6
3R 4R
6R
8R
D4R
D6R
D8R
spiro-5
5-1 5-2 5-3
2-6-2 6 1 (C6R)6-2
4-1
4=1 4-2
5R
4-4=1
Secondary (Structural) Building Units (SBU)
P
O
Al
O
Al
O
P
O
O
Al
O P
O
O
Al
O
O
P
O
O
R1
R2
R2
R1
R2
R1
R2
R1
Framework Type ACO
7
Polyhedral
composite
building units
8
Chain composite building units
(a) zig-zag unbranched single chain, periodicity of two
(b) sawtooth unbranched single chain, periodicity of three
(c) crankshaft unbranched single chain, periodicity of four
(d) natrolite branched single chain
(e) double crankshaft chain, an unbranched double chain
(f) narsarsukite chain, a branched double chain
(g) a pentasil chain
9
Sodalite Unit
Truncated octahedron
10
Sodalite Unit
Packing of the sodalite units:
SOD – bcc, sharing of 4-rings
LTA – sc, 4-rings connected through O bridges
FAU (faujasite) – cubic diamond, 6-rings connected through O bridges
EMT – hexagonal diamond, 6-rings connected through O bridges
11
Zeolite LTA
12
(a) [TO4] tetrahedra as BBU
(b) four-membered single rings
(c) lB fuenfer chains
(d) cubes [46]
(e) truncated octahedra [4668] (sodalite- or -cages)
(f) truncated cubeoctahedra [4126886] (-cavities)
Zeolite A
13
Pores in Zeolite A (LTA)
(a) the sodalite cage [4668]
(b) the -cavity [4126886]
(c) the 3-dimensional channel
system
(d) the 8-ring defining the 0.41
nm effective channel width
14
AFM growth studies of LTA
S. Sugiyama et. al. Microporous and Mesoporous Materials 28 (1999) 1–7
D4R
15
D4R
16
Zeolite A crystal in an amorphous gel particle after a synthesis time of 3 days at
room temperature
17
Zeolite FAU (X and Y) and EMT
18
Zeolite FAU (X and Y) and EMT
19
Molecular Sieves
Zeolite Cation Code Pore diameter
Zeolite A: Na 4A 0.42 nm
Ca 5A 0.48 nm
Na, K 3A 0.38 nm
Zeolite X: Na 13X 0.8-1.0 nm
Ca 10X 0.7 nm
Zeolite Y contains more Si
20
Framework Density
Framework density (FD)
Defined as the number of tetrahedral
atoms (T-atoms) per cubic nanometer
(1000 A3)
FD is related to the void volume of the
crystal: as the FD value decreases, the
void volume and capacity for
adsorption increases
FD < 20 are characteristic of
microporous structures
the minimum known FD is 12.5 with
the void occupying just over half of
the crystal volume
quartz
21
Pores
Various sizes (4 - 13 Å), shapes (circular, elliptical, cloverleaf-like),
and connectivity (1-3D)
The size of the rings formed by the TO4 tetrahedra ranges from 4 to
18 of the T-atoms and determines the pore aperture
Extraframework charge-balancing cations
Ion-exchangeable, size, charge, positions, distribution, ordering,
coordination number
Si-to-Al ratio
Influences cation content, hydro-phobicity/-philicity, acidity
Löwenstein rule:
absence of the Al-O-Al moieties, in aluminosilicates Si/Al > 1
Linde A (LTA) Si/Al = 1
ZK-4 (LTA) Si/Al = 2.5
ZSM-5 Si/Al = 20 - 
Pure SiO2 Si/Al = 
Pentasils
ZSM-5
Pores
22
2 nm
23
Synthesis - an empirical and heuristic process, new phases are
often discovered by serendipity
Aluminosilicates – high pH
 Mixing
NaAl(OH)4(aq) + Na2SiO3(aq) + NaOH(aq), 25 C,
condensation-polymerization, gel formation
 Ageing
Na(H2O)n
+
template effect  Naa(AlO2)b(SiO2)c.NaOH.H2O(gel) 
25-175 C
 Hydrothermal crystallization of amorphous gel, 60-200 C
Nax(AlO2)x(SiO2)y.zH2O(crystals)
 Separation of the solid product by filtration
 Calcination
- occluded water, removed by 25-500 C vacuum thermal
dehydration
-template removal – calcination in O2 at 400-900 C removes the
guest molecules from the framework without
altering it
– extraction (neutral templates)
Zeolite Synthesis
24
Zeolite Synthesis
Structure of the zeolite product depends on:
- Composition
- Concentrations and reactant ratios
- Order of mixing
- Temperature
- Ageing time (hours to weeks)
- Crystallization time (days to weeks,
kinetics of the structure-directing process is slow)
- pH
- Stirring/no stirring
- Pressure
- Seeding
- Reactor material (PTFE, glass, steel)
- Templates
Templates: Organic cationic quaternary alkylammonium salts, alkylamines,
aminoalcohols, crownethers,
structure-directing, space-filling, charge-balancing
Vary the template - discover new structures !
25
Zeolite Synthesis
26
Template or guest compounds
Three levels of the guest action with increasing structure-directing
specificity:
Space-filling - the least specific, observed, for example, in the
synthesis of AlPO4-5, 23 different, structurally unrelated
compounds, could be employed, they pack in the channels of the
structure thereby increasing its stability.
Structure-directing - a higher degree of specificity, only
tetramethylammonium hydroxide is effective in the synthesis of
AlPO4-20
-elongated molecules, such as linear diamines, initiate the formation
of channels
-nondirectional-shaped guests leads to the formation of cage-like
cavities, the size of these cavities correlates with the size of freely
rotating guests
True templating - very rare, it requires even more precise hostguest
fit which results in the cessation of the free guest-molecule
rotation
A curiosity: aluminophosphate VPI-5 does not require any guest for
its formation!
Templates
27
Templates
The ratio TO2/(C + N + O) is a measure of space-filling of the framework by the
guest molecules, characteristic for a specific guest and structure.
Existence of primary and secondary units in a synthesis mixture
4R, 6R, 8R, D4R, D6R, 5-1, cubooctahedron
28
Zeolite Synthesis Mechanisms
(b) “in situ” rearrangement of the gel
(a) gel dissolution and solution mediated crystallization (SBU in solution)
29
Zeolite Synthesis Mechanisms
30
Zeolite Synthesis Mechanisms
Structure directing agents
31
Crystallization Mechanism
crystallization mechanism of FAU-type zeolite under ambient conditions
32
Zeolites and zeolitic materials
Wide range of solid state characterization methods for zeolites:
diffraction, microscopy, spectroscopy, thermal, adsorption and so forth
Zeolite post modification for controlling properties of zeolites
Tailoring channel, cage, window dimensions:
Cation choice (Ca2+ exchanged for Na+)
Larger Si/Al
decreases unit cell parametrs, window size
decreases number of cations, free space
increases hydrophobicity
Reaction temperature, higher T, larger pores
33
Stability Rules
Lőwenstein rule: never Al-O-Al
Dempsey rule: Al-O-Si-O-Si-O-Al
is more stable than
Al-O-Si-O-Al
NNN-principle
34
Production 1.6 million tons p.a. (about half that of natural zeolites)
Detergent - water softening by ion exchange (82%) - zeolites A and X
Catalysis (8%) - zeolite Y (faujasite, 96 wt.%), mordenite, ZSM-5, zeolite Beta
Desiccants/absorption (5%) - zeolites A, X, Y and mordenite
Host-guest inclusion, atoms, ions, molecules, radicals, organometallics, coordination
compounds, clusters, polymers (conducting, insulating)
Nanoreaction chambers
Advanced zeolite devices, electronic, optical, magnetic applications, nanoscale
materials, size tunable properties, QSEs
Mineral zeolites - odor control
Synthetic Zeolite Applications
Natural Mineral Zeolite Applications
35
Aquaculture
Ammonia filtration in fish hatcheries Biofilter media
Agriculture
Odor control Confined animal environmental control Livestock feed additives
Horticulture Nurseries, Greenhouses
Floriculture
Vegetables/herbs
Foliage
Tree and shrub transplanting
Turf grass soil amendment
Reclamation, revegetation, landscaping
Silviculture (forestry, tree plantations)
Medium for hydroponic growing
Household Products Household odor control Pet odor control
Industrial Products Absorbents for oil and spills Gas separations
Radioactive Waste Site remediation/decontamination
Water Treatment Water filtration Heavy metal removal Swimming pools
Wastewater Treatment Ammonia removal in municipal sludge/wastewater
Heavy metal removal Septic leach fields
36
Na Na
O
Si
O
Al
O
Si
O
Al
O
Si
O
O O O O O O O O O O
O
Si
O
Al
O
Si
O
Al
O
Si
O
O O O O O O O O O O
-Na+NH4
NH4 NH4
Ion Exchange
O
Si
O
Al
O
Si
O
Al
O
Si
O
O O O O O O O O O O
H H
O
Si
O
Al
O O O O
Si
O
Al
O
Si
O
O O O O O O
Heating -NH3
-H2OCalcination 600 oC
Bronsted acid
Lewis acid
Tuning Bronsted acidity:
• Ion exchange for NH4
+
• Pyrolysis to expel NH3
• Calcination to expel H2O
Solid acid for the hydrocarbon
cracking
The larger the Si/Al ratio, the
more acidic is the zeolite
Brønsted Acidity
450 °C
37
Strong Brønsted Acidity
Protonation of benzene
-complex Transition state for
H/D exchange
Low T High T
Not present in zeolites
38
39
Size-shape selective
catalysis, separations,
sensing
Selectivity at:
•Reactants
•Products
•Transition state
Size-Shape Selectivity
40
Separation of xylene isomers by pervaporation
through a MFI membrane
41
HRTEM
42
Isoelectronic relationship of AlPO4 to (SiO2)2
Ionic radius of Si4+ (0.26 Å) is very close to the average
of the ionic radii of Al3+ (0.39 Å) and P5+ (0.17 Å)
Many similarities between aluminosilicate and AlPO4
molecular sieves
Dense AlPO4 phases are isomorphic with the structural
forms of SiO2: quartz, tridymite, and cristobalite
Aluminosilicate framework charge balanced by
extraframework cations
Aluminophosphate frameworks neutral (AlO2
-)(PO2
+) =
AlPO4
Aluminophosphates
43
Aluminophosphates
Some AlPO4 structures are analogous to zeolites while other are novel
and unique to this class of molecular sieves.
Only even-number rings = the strict alternation of Al and P atoms
Incorporation of elements such as Si, Mg, Fe, Ti, Co, Zn, Mn, Ga, Ge,
Be, Li, As, and B into the tetrahedral sites of AlPO4 gives a vast number
of element-substituted molecular sieves (MeAPO, MeAPSO, SAPO)
important heterogeneous catalysts
M1+, M2+, and M3+ incorporate into the Al sites
M5+ elements incorporate into the P sites
This substitution introduces a negative charge on these frameworks.
Si4+, Ti4+, and Ge4+ can either replace P and introduce a negative charge
or a pair of these atoms can replace an Al/P pair and retain the charge
neutrality.
44
Aluminophosphates
45
Aluminophosphate Synthesis
Aluminophosphates prepared by the hydrothermal synthesis
Source of Al: pseudoboehmite, Al(O)(OH), Al(Oi-Pr)3
Mixing with aqueous H3PO4 in the equimolar ratio – low pH !
Forms an AlPO4 gel, left to age
One equivalent of a guest compound = template
Crystallization in a reactor
Separated by filtration, washed with water
Calcination
Other zeolite materials
Oxide and non-oxide frameworks, sulfides, selenides
Coordination frameworks, supramolecular zeolites
The quest for larger and larger pore sizes
46
Cobalto-Aluminophosphate
ACP-1 (Co/Al 8.0)
bcc arrangement of the double 4-ring units (D4R)
Ethylenediamine molecules are located inside 8-ring channels
At the centre of each D4R, there is a water molecule, 2.31 Å away from four
metal sites
Al(O-iPr)3, CoCO3.H2O, 85% H3PO4, ethylene glycol, ethylenediamine, pH 8.4
Heated in a Teflon-coated steel autoclave at 180 °C for 4 d
47
Synthesis of Double 4-ring Units (D4R)
P
O
Al
O
Al
O
PO
O
Al
O P
O
O
Al
O
O
P
O
O
R1
R2
R2
R1
R2
R1
R2
R1
48
Metallo-Organic Framework (MOF) Structures
4000 structures known (2008), 1000 new per year
Porous coordination polymers (PCP)
Metal centers
• Coordiantive bonds
• Coordination numbers 3-6
• Bond angles
Polytopic Ligands
• Organic spacers
• Flexible – rigid
• Variable length
Reticular Chemistry
49
A building-block approach to the synthesis of nanostructured materials
Materials formed by a bottom-up self-assembly of building blocks (reticuli)
with predetermined symmetry
Targeted, predictable, and straightforward design and synthesis
Chemistry of the self-assembly and the design should not interact
Building blocks:
Discrete symmetry: C∞, C2, C3, C4, Td, …
Rigid, inert
Functional groups for linking
Suitable linking reaction
Discrete bonding direction
50
Polytopic Organic Linkers
51
Polytopic N-bound Organic Linkers
Cationic framework structures
Evacuation of guests within the pores usually results in collapse
of the host framework
52
53
Metallo-Organic Framework Structures
54
Polytopic carboxylate linkers
55
Polytopic Carboxylate Linkers
Aggregation of metal ions into M-O-C clusters
form more rigid frameworks
frameworks are neutral
no need for counterions
MOF Crystallization
56
Entropy-driven errors in self-assembly
Mechanism for error correction required
The reaction should be reversible to allow for thermodynamic control
No side-reactions should exist (loss of reagents, contamination)
The building block rigidity, symmetry and discrete bonding direction
decrease the incidence of errors
Solvothermal methods – control over p, T, μ to establish equilibrium
Low energy difference
(ΔH < –TΔS)
57
Zn4O(BDC)3.(DMF)8(C6H5Cl)
MOF-5
a primitive cubic lattice
Cavity diam. 18.5 Å
Nature, 1999, 402, 276
•Zn(NO3)2 + H2BDC in DMF/PhCl
•Addition of TEA: deprotonation of
H2BDC
•Addition of Zn2+
• Addition of H2O2: formation of O2- in
the cluster center Zn4O
58
MOF-5
Stable even after desolvation
at 300 °C in air
gas sorption isotherms for MOF-5
MOF-5
59
Interpenetration
MOF-9
60
Interpenetration
61
Metallo-Organic Framework Structures
62
Basic Nets
63
Inorganic and Metallo-Organic Quartz
64
MIL-100 and MIL-101
MIL-101 Record Surface area 5 900 m2/g
65
COF - Covalent Organic Frameworks
Linking reactions
produce covalent bonds
Covalent Organic Frameworks
66
Linking reactions
67
Covalent Organic Frameworks
COF-1
Solvents - reactants are poorly soluble
(to slow down the reversible condensation)
mesitylene-dioxane (1:1)
Sealed pyrex tubes, 110 °C, 72 h, minimize defects by self-
healing
COF-1 = microcrystalline, high yield, high structural
order by XRD
Solvent molecules are enclosed inside the pores, can be
removed at 200 ºC without collapse of the crystalline
structure
Surface area of 711 m2 g-1, pore size 0.7 nm
Interlayer spacing: 0.333 nm
Covalent Organic Frameworks
68
+ 23
COF-5
Surface area 1590 m2/g
Pore size: 2.7 nm
Interlayer spacing:
0.346 nm
Covalent Organic Frameworks
69
Covalent Organic Frameworks
70
Layer stackings: AA, AB, serrated and inclined
71
Covalent Organic Frameworks
3D frameworks
COF-102, COF-103, COF-105,
and COF-108
COF-108 - bor structure
two different types of pores
diameters of 15.2 and 29.6 Å.
density 0.17 g cm-3
surface area, m2 g-1
COF 102 3472
COF 103 4210
72
Borazine COFs
73
BET: 1178 m2/g
Pore size: 0.64 nm
Jackson K., Reich T., Chem. Commun., 2012, 48, 8823–8825