traditional aqueous routes - is.muni.cz elimination ester elimination alkene elimination acetamide...
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Traditional Aqueous RoutesAdvantages
Simple EquipmentInexpensive MaterialsWell Studied
Disadvantages
Difficult control of hydrolysis and condensation ratesInhomogeneity introduced by homocondensationReversibility of condensation stepPhase Separation
M-O-M' + H-O-H M-OH + HO-M'
2 M-OH + 2 HO-M' M-O-M + M'-O-M' + 2 HOH
Nonaquoeus – Nonhydrolytic –Organometallic Methods
M-O-X + Z-M' X-Z + M-O-M'
Advantages
Inhomogeneity and phase separation prevented absence of water, volatile organic byproducts cannot cleave M-O-M’ bonds and cause homocondensation, irreversible condensation step
M = mononuclear, polynuclear clusters, building blocks
Chemical control of reactivity by selecting X, Z groups
Wide choice of solvents, medium polarity, reaction temperature
Simplified drying to aerogels, lower surface tension
Nonaquoeus – Nonhydrolytic –Organometallic Methods
Advantages
Synthesis of hybrid materials incorporation of water sensitive and water insoluble compounds: organometallics, coordination compounds, long aliphatic chains, clustershydrophobic hybrid materials
Template synthesesuse of water sensitive and water insoluble compounds, polymersmicroporous and mesoporous
Retention of lower coordination numbers (Al, TM), low-hydroxyl surfaces – catalysis
Nonaquoeus – Nonhydrolytic –Organometallic Methods
Disadvantages
- Elaborate procedures and expensive precursors
- Organic solvents
- Exclusion of moisture
- Ligand scrambling vs. elimination
Nonaquoeus – Nonhydrolytic –Organometallic Methods
Solid-state: solid-state thermolysis
Liquid-state: sol-gel, solventless, sonochemical reactions,
solution thermolysis
Gas-phase: CVD, pyrosol
Preparation of Oxides, Mixed Oxides, and Silicates
Alkylhalide Elimination
Ester Elimination
Alkene Elimination
Acetamide Elimination
Ether Elimination
Ketene Elimination
Ketimine Elimination
Alkylhalide Elimination ReactionsM = Si, Al, Ti, Zr, V, Nb, Mo, W, Fe
M-X + R-O-M' M-O-M' + R-X
M-O-M' + R-X
M-O-R + HX
M-X + R-O-R M-O-R + R-X
M-O-R + X-M'
M-X + H-O-R
M-O-R + X-M'
M-O-M' + R-X
Corriu, Vioux, Leclercq, Mutin, MontpellierHay et al., Surrey
Alkylhalide Elimination Reactions
MRO
OR
ROO M
O
RO OROR
MX
XX
- RXMX
X
X X
R MRO
OR
RO O
MX X
X X
R
C-O bond cleavage
MRO
OR
RO O
MX X
X X
R
MRO
OR
RO O
MX
X
XX
R
MRO
OR
RO O
MXX
X X
R
MRO
OR
RO O
MX X
X X
R
M
O
RO OROR
MX
XX
- RX
- RX
- RX
Alkylhalide Elimination Reactions
TiCl4 + Ti(OR)4 + TOPO
heptadecane 300 °C
TiO2 anatase10 nm
+ RClR = Me, Et, i-Pr, t-Bu
Colvin et al., J. Am. Chem. Soc., 1999, 121, 1613
Alkylhalide Elimination Reactions
AlCl3 + Si(OEt)4 + Et2O
CCl4, 110 °C
Al-O-Si gel
900 °C
3Al2O3. 2SiO2
mulliteJanackovic et al., NanoStructured Materials, 1999, 12, 147
Alkylhalide Elimination Reactions
H3C C
O
O Et
Cl
TiCl Cl
Cl AP-CVD 400 - 600 °C+ TiO2 anatase
Parkin I. et al., Chem. Mater., 2003, 15, 46
Ester Elimination Reactions: acetates + alkoxides
M = Zr, Si, Ti, Ba, Sn, Pb
SiO
O
R
MO
R'
MO
Si
O
O
RR'
++
Jansen, Guenther, Chem. Mater., 1995, 7, 2110
Hampden-Smith et al., Chem. Comm., 1995, 157
Ester Elimination Reactions: alkoxides + acid anhydrides
O
O
R'
O
MRO
OR
OROR
M'O
O
O
OM
O
O
O
O
O
R'R
R'
2 1/2
2
++
M = Si, M' = Ti
Fujiwara et al., Chem. Mater., 2002, 14, 4975
Ester Elimination Reactions: alkoxides + acid anhydrides
SiRO
OR
OROR
BO
O
OSi
O
O
O
O
BO
B
OB
RO OR
OR
ROB
OR
OR
R = Me, Et
+
+
acetone gel
600 °C
borosilicate glassBecket et al., Chem. Comm., 2000, 1499
Ester Elimination Reactions
Ti(NO3)4 + Si(OEt)4 SiO2/TiO2 + 4 EtONO2
CVD , 300 - 535 °C
Gladfelter et al., Chem. Mater., 2000, 12, 2822
Alkene Elimination: tris(tert-butoxy)silanolates
SiO
O
O
OM
O
O
O
SiO
O
OOM M
Si
SiSi
Si
Si +
M = Ti, Zr, Hf, Al, Cr, Cu, Zn, Mo, W, V
Tilley et al., Berkely
Alkene Elimination: tris(tert-butoxy)silanolates
SiO
O
O
OM
CH3
CH3
H
HH
SiO
O
O
OHM
H3C CH3
H H
+
β-Hydrogen Elimination
Acetamide Elimination
Si
O
O OO
MO
OO
Si
AcO
AcO
AcO
O
O
CH3
AlMe2N
Me2N
Me2NNMe2
O
CH3Me2N
++
AlNMe2
NMe2
gel
950 °C
3Al2O3.2SiO2mullite
Pinkas J., Lobl J., Roesky H. W. unpublished
Ether Elimination
SiO
R
RRM M'
OM
RO
M'
++Si
O
R
RRR
Hampden-Smith et al.,
Ketene Elimination
+
H
OAl
R
O
O
H
Et
Bu
OHAl
R
OH
Bu
C
Et
C O
))))), 10 min
decanegel
γ-Al2O3 (10 nm)
Y3Al5O12
LaAlO3
700 - 900 °C
CN(Al) = 6
Ulman et al., J. Am. Chem. Soc., 2003, 125, 4010
Ketimine Elimination
Lindquist et al., Chem. Mater., 2003, 15, 51
H2N
AlNH2
Al
NH2
Al
Et Et
Et
Et
Et
Et O+
NH+ +EtH EtAlO
H2O
AlO(OH) high porosity
- EtH
Thermolysis of a single-source precursor
Ti
O
R2N
i-PrO
i-PrO
i-PrO TOPO 325 °CTiO2 anatase3 nm
Fischer et al., J. Mater. Chem. 2002, 12, 1625
Preparation of Phosphates and Phosphonates
Alkane/Hydrogen Elimination
Alkene Elimination
Alkylhalide Elimination
Alkylsilane Elimination
Aklylamine Elimination
Alcohol Elimination
Ether Elimination
Chlororsilane Elimination
Diketone/Ester Route
Alkane/Hydrogen Elimination
PO
OH
ROH
AlO
F
OP
O
OR
n
R = Me, Ph, n-Oct, n-Dodec
EtH+
AlO
Cl
OP
O
OR
nMe2Zn
H2AlCl(THF)2
+ H2
2 MeH+(RPO3)Zn
R = Me, Ph, thienyl, Me-thiophenyllayered
Et2AlF
Gerbier et al., J. Mater. Chem. 1999, 9, 2559
Knight et al., J. Organometal. Chem. 1999, 585, 162
Schmidt et al., J. Polym. Sci. A, 1968, 6, 3235
Alkene Elimination
PO
Al
OP
O
Al
O
X
X X
X
OO
O O X = Me, OiPr
AlPO4 + XH +
Tilley et al., J. Am. Chem. Soc. 2001, 123, 10133
X = Si(OtBu)3Al2P2Si3O14
Alkene Elimination: tris(tert-butoxy)silanolates
P
O
Al
O Al
O
PO
OAl O P
O
O
AlO
OP
O
O
O
Si
OtBu
OtBuButO
OSi
OtBuOtBu
OtBu
OSiButO
ButO
ButO
P
OAl
OAl
O
P
OO
Al
O
PO
O
Al
O
O
POO
P
O
Al
O Al
O
PO
OAl O P
O
O
AlO
OP
O
O
P O Al
O
Al O P
O
OAl
O
PO O Al
O
OPH
O
O
O
O
O
O
O
O
O
SiO2SiO2
O
SiO2
- H2O- isobutene
O
Pinkas J., Brlejova Z., Roesky H. W. unpublished
Alkene Elimination: tris(tert-butoxy)silanolates
isobutene + H2O
Alkylhalide EliminationNonhydrolytic synthesis of NASICONNa3Zr2Si2PO12 solid electrolyte, high Na+ ionic conductivity
- Solid state preparation: dissolved ZrO2
- Sol-gel from alkoxides: very slow hydrolysis necessary, different hydrolysis rates
- Nonhydrolytic route in CH3CN
OP(OnBu)3 + SiCl4 + Zr(OtBu)4 + NaOtBu → nBuCl + tBuCl +
Gel formationSolvent and byproduct evaporation under vacuumDrying at 120 °C for 15 hBall millingCalcination at 800 °C gives NASICON
O P O Si O Zr OO
O O
OCl
ClBu
Bu tBu
tBu
tBu
Di Vona et al., J. Sol-Gel Sci. Technol., 2000, 1/3, 463
Ether Elimination
O
AlO
P O
P
O
AlMe
Me
Me
Me
O
OMe3Si
SiMe3
O
O
Me3Si
SiMe3
O
AlO
P O
P
O
AlMe
Me
Me
Me
OH
HO
OH
OHCF3CH2OH
- CF3CH2OSiMe3
CH3-AlPO4 gelPinkas J., Moravec, Z., Roesky H. W. unpublished
Chlororsilane Elimination
AlCl3 + OP(OSiMe3)3THF, reflux
AlPO4 tridymite13% Si
gel AlPO4+ ClSiMe3
800 °C
Pinkas J., et al. Inorg. Chem. 1998, 37, 2450
Diketone/Ester Route
Daviero et al., J. Non-Cryst. Solids, 1992, 146, 279, Thin Solid Films, 1993, 226, 207
O
AlO
O O
O
O
O P
OR
OROR
+
pyrosol CVD processin ethanol, 300 – 400 °C
AlPO4 amorphous