A functional polymerizable surfactant has been synthesized and used as a template to prepare MCM-41. Ozonolysis of the olefin functional group in the composite material generates a nonporous proton-conducting solid acid that has a conductivity of ca. 6 mS cm^(-1) at 95 °C and an activation energy of 14.2 kJ/mol

Alabi, Christopher A.

Davis, Mark E.

Caltech Authors - Main

Proton Conducting Solid Electrolyte via Ozonolysis of Cationic Ammonium 
Organoalkoxysilane Surfactant Templated MCM-41 
 
Supporting Information 
 
Synthetic Details 
 
Materials: All solvents were purified by fractional distillation from the appropriate 
drying agents or dried by filtration through the appropriate drying agents prior to use.  
 
Experimental: 
 
Synthesis of surfactant 8 
 
(E)-5-chloropent-1-enylboronic acid (2) 
Catecholborane (5.85 mmol, 0.7 g) was carefully added to neat chloropent-1-yne (4.9 
mmol, 0.5 g) under argon. The mixture was then heated to 100oC under vigorous stirring 
for 3 hours. The mixture was cooled to 70oC and quenched with (10 mL) water.  After 2 
hours of stirring, the mixture was further cooled to 0oC, and the resulting white 
precipitate was filtered over a buchner funnel, washed with cold water and recrystallized 
from hot water to give the desired product 2 in 60% yield.  
 
(E)-5-chloro-1-iodopent-1-ene (3) 
To a mixture of (E)-5-chloropent-1-enylboronic acid (4.9 mmol, 0.73g) in ether (5 mL) at 
0oC was added aqueous sodium hydroxide (15 mmol, 5 mL, 3N ) followed by elemental 
Iodine (5.85 mmol, 1.49g in 15 mL ether).  The mixture was stirred at 0oC for 30 minutes 
after which the excess Iodine was removed by adding a saturated solution of sodium 
thiosulfate until the dark color of Iodine is visibly removed. The ether layer was 
separated and washed with water and collected.  The resulting ether solution was dried 
over sodium sulfate, concentrated and distilled (95oC at 0.5 mmHg) to give 3 in 85% 
yield. 
 (E)-1-chlorotetradec-4-ene (5) 
To a flame dried flask under argon was added non-1-ene (0.48 mmol, 60.2 mg) and dry 
THF (0.3 mL).  9-borabicyclo[3.3.1] nonane (9-BBN) (0.5 M in THF, 0.477 mmol, 0.95 
mL) was slowly added to this mixture at 0oC and slowly warmed up to room temperature. 
After stirring for 6 hours, (E)-5-chloro-1-iodopent-1-ene (0.43 mmol, 100 mg), [1,1’-
bis(diphenylphosphino)-ferrocene]dichloropalladium (II) complex with dichloromethane 
(1:1) (3 mol%, 0.013, 10.6 mg), sodium hydroxide (1.3 mmol, 3M, 0.43 mL) and 
additional THF (1 mL) were added. The mixture was refluxed for 16 hours under 
vigorous stirring.  The resulting dark mixture was diluted with hexanes (3 mL), washed 
with brine, and dried over magnesium sulfate.  The crude mixture was purified over a 
column with hexanes to give desired product 5 in 75% yield.  
 
N,N-dimethyl-3-(trimethoxysilyl)propan-1-amine (7) 
Dimethylamine (2.0 M in methanol. 81.6 mmol, 40.8 mL) was added to neat (3-
chloropropyl)trimethoxysilane (10.88 mmol, 2 mL) and refluxed at 90oC for 24 hours. 
Excess dimethylamine and methanol were removed under vacuum to give a yellow solid 
which was washed with pet ether and filtered.  The filtrate was concentrated and distilled 
(95oC at 0.5 mmHg) to give the desired product 7 as a clear liquid in 40% yield.  
 
(E)-N,N-dimethyl-N-(3-(trimethoxysilyl)propyl)tetradec-4-en-1-ammonium chloride 
(8) 
Compound 7 (14.46 mmol, 3 g) was added to a solution of 5 (16 mmol, 3.67 g) stirring in 
methanol (6 mL) in a round bottom flask purged with argon.  The mixture was heated to 
reflux at 90oC for 3 days. The mixture was then concentrated under vacuum, washed 
twice with hexanes and then further dried under vacuum to give 8 in 51% yield.   
 
 
 
 
 
Electrochemical Impedance Spectroscopy 
Electrochemical impedance was measured in the frequency range from 1 Hz to 1 MHz at 
an a.c. measuring voltage of 100 mV with a potentiostat/galvanostat and frequency 
response analyzer (Solatron 1287/1260).  The setup used for the proton conductivity 
measurements is shown in Figure S1. The measurements were performed by sandwiching 
the sample in the sample holder (made of Torlon plastic) between two Pt/Ir (80:20) 
electrodes.  Measurements were made initially under 100% R.H. at room temperature and 
then also at variable temperature. The temperature range between 25oC and 95oC was 
explored by using a digital temperature controller (Watlow) hooked up to Kapton heaters 
sandwiched between brass coolers and the main brass block as shown in Figure S-1. The 
temperature was measured with an accuracy greater than +/- 0.1oC. The membrane 
conductivity was calculated using Eq. (1) 
σ = l /RS   (1) 
where σ is the ionic conductivity, l the distance between the two electrodes (i.e. the 
thickness of the pellet) measured with a digital micrometer at a constant torque of 46 
inch-ounce, R is the resistance of the membrane and S the cross-sectional area of the 
pellet i.e. the electrode area.  
  
Figure S-1 
 
 
  
 
 
 
 
 
 
 
 
 
 
 
 
Figure S-2: XRD patterns of MCM-41 before (a) and after ozonolysis (b) 
 
Figure S-3: 13C MAS NMR of liquid phase in CDCl3 and solid phase of 8 
 Figure S-4: TGA of MCM-41-C(4)-acid.  Loading assuming full condensation = 2.53 
mmol/g. Loading assuming one uncondensed methoxy group = 2.21 mmol/g. 
 
Figure S-5: 29Si CP NMR of MCM-41-C(4)-acid.  
T2 
T3 
Q3 
Q4 
Q2 
 Figure S-6: N2 Adsorption/Desorption Isotherm of MCM-41-C(4)-acid. 
N
O
N
O
N
OHO
HO
OH
Ozone
OxidationN
N
N
MCM-41-C4 Olefin
Straight-Chain  model
= Open Pore
 
Figure S-7: Schematic diagram illustrating straight chain mechanism 
 
Si
OMe
N O
OH3
N(MeO)3Si
Cl
N(MeO)3Si
Cl
10
MCM-41
10 Si
OMe
N
3
O3
CHOOH
H2O2
PhMe
Reflux
9
7
 
Scheme S-1: Preparation of grafted material 
 
(E)-N,N-dimethyl-N-(3-(trimethoxysilyl)propyl)hex-4-en-1-ammonium chloride (10) 
 
Compound 7 (38.4 mmol, 7.97 g) was added to a solution of 9 (40 mmol, 4.78 g) stirring 
in methanol (8 mL) in a round bottom flask purged with argon.  The mixture was heated 
to reflux at 95oC for 3 days. The mixture was then concentrated under vacuum, washed 
twice with hexanes and then further dried under vacuum to give 10 in 60% yield.   
 
Grafting and Ozonolysis procedure for the C(4)-acid grafted material 
Compound 10 (1.84 mmol, 0.6 g) was dissolved in toluene (90 mL) and added to calcined 
mesoporous MCM-41.  The mixture was heated to reflux for 24 hours under vigorous 
stirring.  After cooling down to room temperature, the mixture was filtered, washed with 
acetone and extracted using a soxhlet apparatus in dichloromethane overnight.  The 
resulting powder was then dried overnight. 
Ozonolysis was carried out by bubbling ozone (84 µg/mL) through a suspension of the 
grafted MCM-41 (1 g) material in dichloromethane (60 mL) at -780C.  After 7 hours, the 
solution was purged with argon while warming to room temperature, filtered and washed 
with acetone and water.  Oxidation of the ozone treated solid was carried out with formic 
acid (5 mL) and hydrogen peroxide (2.5 mL) in water (2.5 mL) at 50oC for 1 hour 
followed by a 1N hydrochloric acid (10 mL) post treatment for another hour to give the 
corresponding carboxylic acid groups.  The solids were then washed with acidic ethanol 
at 50oC to remove any  adsorbed species. 


Proton-Conducting Solid Electrolyte via Ozonolysis of Cationic Ammonium Organoalkoxysilane Surfactant-Templated MCM-41

https://authors.library.caltech.edu/73948/2/cm061722dsi20060926_112722.pdf

Proton-Conducting Solid Electrolyte via Ozonolysis of Cationic Ammonium Organoalkoxysilane Surfactant-Templated MCM-41

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