Guest/host relationships in the synthesis of the novel cage-based zeolites SSZ-35, SSZ-36, and SSZ-39

Article abstract of DOI:10.1021/ja990722u

Here, we report the synthesis and structure of three high-silica molecular sieves, SSZ-35, SSZ-36, and SSZ-39, that are prepared from a library of 37 different cyclic and polycyclic quaternized amine molecules that are used as structure-directing agents (SDAs). The size and shape of the quaternized amine molecules are purposely designed in order to obtain novel zeolite structures, and the synthesis of these molecules is presented. The selectivity for the three molecular sieve phases is found to depend on both the SDA and the degree of heteroatom lattice substitution of Al³⁺ or B³⁺ in the silicate framework. Molecular modeling is utilized to probe the effects of the nonbonded SDA/zeolite-framework interaction energy on the selectivity for the observed molecular sieve phase. The Rietveld refinement of the powder X-ray data confirms the structure of the SSZ-39 zeolite to be isomorphous with the aluminophosphate molecular sieve, SAPO-18 (AEI). The structure of SSZ-36 is found to possess a range of fault probabilities between the two-dimensional channel system, end-member polymorphs, ITQ-3 and RUB-13 (International Zeolite Association Codes ITE and RTH, respectively). The SSZ-35 structure is reported to contain a one-dimensional pore system possessing stacked cages circumscribed by alternating rings of 10 and 18 tetrahedral atoms (10- and 18-membered rings).

Full text of DOI:10.1021/ja990722u

J. Am. Chem. Soc. 2000, 122, 263-273
263
Guest/Host Relationships in the Synthesis of the Novel Cage-Based
Zeolites SSZ-35, SSZ-36, and SSZ-39
,‡
Paul Wagner,† Yumi Nakagawa,‡,§ Greg S. Lee, Mark E. Davis,† Saleh Elomari,‡
Ronald C. Medrud,‡ and S. I. Zones*,‡
Contribution from the California Institute of Technology, Pasedena, California 91125, and CheVron
Research and Technology Company, Richmond, California 94802
ReceiVed March 5, 1999. ReVised Manuscript ReceiVed August 12, 1999
Abstract: Here, we report the synthesis and structure of three high-silica molecular sieves, SSZ-35, SSZ-36,
and SSZ-39, that are prepared from a library of 37 different cyclic and polycyclic quaternized amine molecules
that are used as structure-directing agents (SDAs). The size and shape of the quaternized amine molecules are
purposely designed in order to obtain novel zeolite structures, and the synthesis of these molecules is presented.
The selectivity for the three molecular sieve phases is found to depend on both the SDA and the degree of
heteroatom lattice substitution of Al3+ or B3+ in the silicate framework. Molecular modeling is utilized to
probe the effects of the nonbonded SDA/zeolite-framework interaction energy on the selectivity for the observed
molecular sieve phase. The Rietveld refinement of the powder X-ray data confirms the structure of the SSZ-
39 zeolite to be isomorphous with the aluminophosphate molecular sieve, SAPO-18 (AEI). The structure of
SSZ-36 is found to possess a range of fault probabilities between the two-dimensional channel system, end-
member polymorphs, ITQ-3 and RUB-13 (International Zeolite Association Codes ITE and RTH, respectively).
The SSZ-35 structure is reported to contain a one-dimensional pore system possessing stacked cages
circumscribed by alternating rings of 10 and 18 tetrahedral atoms (10- and 18-membered rings).
Introduction
or as “structure-directing agents” (SDAs).5 Clearly, part of the
challenge in synthesizing new zeolites is to develop candidate
guest molecules that have the potential to generate novel zeolite
structures. While the size and shape of the guest molecules often
correlate well with the void dimensions within the host, there
are still aspects of phase selectivity in zeolite synthesis that are
kinetically controlled. That is, the same organocation guest may
be capable of crystallizing more than one zeolitic phase.6 Thus,
while research becomes ever more sophisticated in molecular
modeling approaches toward developing favorable guest/host
interactions,7 the experimentalist is still faced with the question
of what controls “how to get there”.8
From the standpoint of empirical learning, we have divided
the field of high-silica zeolite formation into five domains that
are related by the extent of lattice substitution and the size of
the guest SDA molecule. With small SDA molecules and little
heteroatom lattice substitution, clathrates are the favored
product.9 Clathrates are cage-based structures in which the guest
molecule is surrounded by an inorganic lattice with portals too
small to allow any communication between cages. As the guest
molecules become larger, the second domain is observed in
which one-dimensional, parallel pore systems are found at the
There remains a keen interest in developing new, three-
dimensional, zeolitic silicate frameworks, as these materials have
found commercial use in hydrocarbon processing. Catalysts
based upon zeolites continue to proliferate in the extent of varied
uses in the modern refinery.1 New zeolite structures lend
themselves to the possibility of finding niches in processing
based upon shape-selective capabilities. This trend represents
a step change from much of the previous applications of Y
zeolites (FAU) that perform most of the large-scale catalyst work
in areas such as FCC and hydrocracking. Recent examples where
niche selectivities of zeolites have been exploited are in the
replacement of solvent extraction by shape-selective zeolites
capable of isomerization dewaxing2 in the pursuit of high-quality
lube oil base stocks and the introduction of zeolitic catalysts to
replace phosphoric acid on a silica support in the production of
cumene from benzene and propylene.3 Cumene is then oxidized
in a commercial process to produce both phenol and acetone.
Many of the novel silica-based zeolite structures are derived
from the use of organocations as guest molecules in the
crystallizing product; i.e., they effectively stabilize the void
regions within the inorganic structure. A popularization of this
guest activity has been to refer to them as “template” molecules4
(4) Lok, B. M.; Cannan, T. R.; Messina, C. A. Zeolites 1983, 3, 282.
(5) Lobo, R. F.; Zones, S. I.; Davis, M. E. In Inclusion Chemistry With
Zeolites, Nanoscale Materials by Design; Herron, N., Corbin, D., Eds.;
Kluwer Academic Publishers: Dordrecht, The Netherlands, 1995; Vol. 21,
pp 47-78.
(6) Wagner, P.; Yoshikawa, M.; Lovallo, M.; Tsuji, K.; Tsapatsis, M.;
Davis, M. E. J. Chem. Soc., Chem. Commun. 1997, 2179-80.
(7) Lewis, D. W.; Willock, D. J.; Catlow, C. R. A.; Thomas, J. M.;
Hutchings, G. J. Nature 1996, 382, p 604.
† California Institute of Technology.
‡ Chevron Research and Technology Co.
§ Current address: Chiron Technologies, Emeryville, California.
Current address: Lawrence Livermore National Laboratory, Livermore,
California.
(1) Absi-Halabi, A.; Stanislaus, A.; Qabazard, H. Hydrocarbon Process-
ing 1997, Feb, 45.
(2) Miller, S. J. Wax Isomerization for Improved Lube Oil Quality.
Presented at the AIChE Spring Meeting, New Orleans, LA, March, 1998
(see abstracts).
(8) Davis, M. E.; Zones, S. I. In Synthesis of Porous Materials; Occelli,
M. L., Kessler, H., Eds.; Marcel Dekker: New York, 1997; p 1.
(9) Gies, H. Inclusion Compounds; Academic Press: London, 1991; Vol.
5, pp 1-35.
(3) Innes, R. A.; Nacamuli, G.; Zones, S. I. U.S. Patent 4,891,458, 1990.
10.1021/ja990722u CCC: $19.00 © 2000 American Chemical Society
Published on Web 12/31/1999

264 J. Am. Chem. Soc., Vol. 122, No. 2, 2000
Wagner et al.
Table 1. Substituted Monocyclic Quaternary Ammonium
Templatesa
Figure 1. Three guest molecules based upon extensions of the Diels-
Alder reaction and the types of zeolites generated as spatial features
change. (a) The norbornyl derivative is still small enough to generate
cage-centered clathrate structures such as nonasil (NON). (b) The
tricyclic derivatives with long, central axes produce one-dimensional,
large-pore zeolites. ZSM-12 (MTW structure) and SSZ-31 are two
different examples of this type of product. (c) The pseudo-propellane
developed in this guest leads away from one-dimensional larg-pore
zeolites and generates zeolites with cavities such as SSZ-35.
high-silica lattice content. A third case results as lattice
substitution increases, and multidimensional channel systems
possessing larger overall micropore volumes predominate. A
fourth domain is often observed at high lattice substitution, in
which the highly heteroatom-substituted zeolites contain cages
with smaller portals. The fifth domain arises from the use of
large guest molecules with strong nonbonded SDA/zeolite
interaction energy resulting in the stabilization of open-
framework zeolite lattices; in this case, due to the strong
interaction energy, the stabilized framework structure is formed
over the entire heteroatom lattice substitution range. The recent
report of a pure-phase MEL zeolite (ZSM-11) is an example of
this fifth case.10
To overcome the propensity for SDA molecules to form
clathrate structures, Nakagawa developed a designed organic
system that was based upon bringing together individual ring
structures in a Diels-Alder reaction to build candidate mol-
ecules leading to large-pore zeolites.11 The individual rings
themselves, if converted into charged ammonium compounds,
would generate clathrate products. Figure 1 shows three different
sized norbornane derivatives (based upon Diels-Alder chem-
istry) and the transition from clathrate to open-pore structure.
Many of the rigid, elongated SDA derivatives formed from
variations of cyclopentadiene reacting with maleimides produce
open-pore, one-dimensional zeolites such as MTW or SSZ-31
(shown in Figure 1). These two 12-ring zeolites possess different
configurations of the pore opening, with MTW containing a
somewhat puckered pore opening12 while SSZ-31 possesses a
very open but highly elliptical pore opening with dimensions
ranging from 8.8 to 5.5 Å.13
a Includes spirocyclic derivative 8 and 9.
Here, we describe our efforts to synthesize novel zeolite
structures by designing SDA molecules that both are too large
to fit into the cages of the clathrate-type silicates and possess a
spheroidal shape that precludes the formation of the straight
one-dimensional channel systems of zeolite structures that tend
to form when using rigid elongated SDA molecules, e.g., those
of Figure 1b. The initial success of this SDA design effort
resulted from a derivative of the camphor-type molecule (entry
9, Table 2) that led to the crystallization of the novel, open-
framework zeolites SSZ-35 and -36. Subsequently, numerous
other zeolite structure-directing molecules were discovered using
this design strategy (Tables 1-3), and we present a detailed
investigation into the guest/host relationship between these
organic SDA molecules and the resulting zeolite phases.
Experimental Section
(10) (a) Nakagawa, Y. WO 95/09812. (b) Terasaki, O.; Ohsuna, T.;
Sakuma, H.; Watanabe, D.; Nakagawa, Y.; Medrud, R. C. Chem. Mater.
1996, 8, 463. (c) Nijo, S. L.; Koegler, J. H.; van Koningsveld, H.; van de
Graaf, B. Microporous Mater. 1997, 8, 223-230.
Synthesis of Organocation Structure-Directing Agents (SDAs).
The syntheses of the 37 organocation SDAs that appear in Tables 1-3
are reported in the Supporting Information. Table 1 shows the
monocyclic organic directing molecules, Table 2 lists the bicyclic
organic directing molecules, and Table 3 presents the tri- and tetracyclic
organic directing molecules used in this study. The quaternary
ammonium guest molecules are used in their hydroxide form after ion-
exchanging the halide anion using Bio-Rad AG 1-X8 ion-exchange
resin. All reagents are from Aldrich Chemical Co. unless otherwise
stated.
(11) Nakagawa, Y.; Zones, S. I. In Molecular SieVes; Occelli, M. L.,
Robson, H. E., Eds.; Van Nostrand Reinhold: New York, 1992; Vol. 1, p
222.
(12) La Pierre, R. B.; Rohrman, A. C., Jr.; Schlenker, J. L.; Wood, J.
D.; Rubin, M. K.; Rohrbaugh, W. J. Zeolites 1985, 5, 346.
(13) (a) Lobo, R. F.; Tsapatsis, M.; Freyhardt, C. C.; Chan, I. Y.; Chen,
C. Y.; Zones, S. I.; Davis, M. E. J. Am. Chem. Soc. 1997, 119, 3732. (b)
See: Treacy, M. M. J.; Deem, M. W.; Newsam, J. M. DIFFaX Version
1.801, 1995.

Synthesis of NoVel Cage-Based Zeolites
J. Am. Chem. Soc., Vol. 122, No. 2, 2000 265
Table 2. Substituted Bicyclic Quaternary Ammonium Templates
Zeolite Syntheses. The individual zeolite synthesis reactions are run
in Parr reactors of 23-mL capacity. The crystalline products are
generally collected on glass frits, washed with roughly 100 times the
amount of water as the initial reaction solution, and then air-dried before
XRD patterns are obtained on a Siemens D-500 instrument. The six
different zeolite syntheses run for the majority of the 37 guest molecules
reported here were recently described,14 and a representative procedure
for each synthesis is presented. The reactions are labeled as to starting
silica-to-alumina ratio (SAR) or, in one case, the corresponding ratio
for silica and borate. These reactions correspond to the entries found
in Table 4, in which the reaction product is presented.
is added as aluminum source, and finally 0.80 g of Cabosil-M5 is added.
This reaction is run like the one above but at 160 °C.
SAR ) 70: 3 mmol of the organic hydroxide is mixed with 0.76 g
of 1 N NaOH, and the total mass is brought to 7 g with water. Also,
0.25 g of Union Carbide’s LZ 210 (18% H2O) and 0.74 g of Cabosil-
M5 are added, and the reaction is run at 170 °C and 43 rpm.
SAR ) 100: 2.15 mmol of organic hydroxide and 1.50 mmol of 1
N NaOH are brought up to a mass of 11.75 g with water. Then, 0.03
g of Reheis F-2000 alumina (53 wt % Al2O3) is dissolved. Finally,
0.90 g of Cabosil-M5 is blended in, and the reaction is carried out at
170 °C with 43 rpm.
SAR ) 30: 2 mmol of the guest molecule hydroxide is mixed with
0.20 g of 1 N NaOH and the mass brought to 6 g with water. Then,
2.5 g of Banco “N” silicate is added (28 wt % SiO2, 8.9 wt % Na2O).
Also, 0.25 g of Union Carbide’s LZY-62 (25% H2O) is added as an
aluminum source. The reaction is heated at 135 °C and 43 rpm and is
checked every 3-4 days for a pH jump (from near 11.80 to 12.50).
SAR ) 40: 2.15 mmol of guest molecule hydroxide is mixed with
1.43 g of 1 N NaOH and the mass brought to 7.2 g with the addition
of water. Also, 0.25 g of Union Carbide’s LZY-52 (25% H2O) zeolite
SAR ) 300: In this reaction, Tosoh’s 390 HUA is used as the Si
and Al source.15 First, 2.25 mmol of organic hydroxide and 2.25 mmol
of 1 N NaOH are combined, and the mass is brought to 10 g with
water. Then, 0.90 g of Tosoh 390 HUA is added, and the reaction is
heated at 160 °C with 43 rpm tumbling.
SiO2/B2O3 ) 30: 2.25 mmol of organic hydroxide in 4.35 mL of
water is used to dissolve 0.095 g of sodium borate decahydrate. When
the solution is clear, 1.36 g of Dupont’s Ludox AS-30 (30% SiO2) is
added, and the reaction is heated at 160 °C without stirring. The
(14) Nakagawa, Y.; Lee, G. S.; Harris, T. V.; Yuen, L. T.; Zones, S. I.
Microporous Mesoporous Mater. 1998, 22, 69.
(15) Zones, S. I.; Nakagawa, Y. WO 96/29,284, 1996.

266 J. Am. Chem. Soc., Vol. 122, No. 2, 2000
Wagner et al.
Table 3. Tri- and Tetracyclic Quaternary Ammonium Templates
the synthesis reactions with silica-to-alumina ratios (SAR) )
30, 40, 70, 100, and >300 and also with boron lattice
substitution (silica-to-borate ratio, SBR ) 40). The three-letter
code entries in Table 4 are assigned by the International Zeolite
Association, and further information on these structures can be
found in ref 19. Zeolites that are referred to with an SSZ
designation in Table 4 have not yet been assigned structure
codes.
a. Observed Zeolite Formation Domains. Entry 2 in Table
4 provides an example of the first domain of zeolite synthesis
discussed in the Introduction in which small SDA molecules
tend to result in the formation of clathrates at low lattice
substitution. The clathrate NON results from the small-molecule
SDA, entry 2, over a range of low lattice substitutions (SAR )
70 f 300), as seen in Table 4. At very low lattice substitution
(SAR > 300), the small-molecule SDA, entry 3, is also seen to
direct for the clathrate NON. The results indicate that these small
SDA molecules effectively maximize the silica/SDA interaction
by stabilizing the small silica cages present in the clathrate
materials such as NON and DDR.
As the size of the SDA molecule is increased beyond the
small cage size of the clathrates, one-dimensional channel
system zeolites tend to form at low lattice substitution. Entry
4, Table 4 indicates that the N,N-diethylpiperidium derivative
molecule that possesses a pendent ethyl group off of the carbon
ring results in the crystallization of the one-dimensional channel
system zeolite SSZ-31 at SAR > 300. Increasing the lattice
substitution results in the formation of the multidimensional,
10-membered-ring (MR) zeolite MFI (SAR 40 and 70). This
SDA provides examples of the second and third domains of
zeolite formation.
At very high lattice substitution, the zeolitic phases denoted
SSZ-39 and CHA tend to crystallize from a number of the SDA
molecules in Tables 1-3. The most aluminum-rich reaction
described in the Experimental Section (SAR ) 30) is the best
reaction for selectively generating these zeolites. Compared with
the other five zeolite synthesis reactions described, the high
alumina syntheses also have a much higher OH/Si ratio in the
reactants. Zeolite synthesis mixtures containing high alumina
and high hydroxide concentrations are favorable for producing
cage-based zeolites, such as CHA, with small eight-ring pores
and structural subunits constructed of even-membered tetrahedral
atom rings.20 The structure solution of SSZ-39 outlined below
also reveals that this zeolite contains cages with eight-ring pores
and is composed entirely of four- and six-membered rings of
tetrahedral atoms similar to CHA. These even-membered-ring
zeolites tend to form at high lattice substitution because the strict
alternation of the silicon and aluminum in the framework avoids
the energetically unfavorable electrostatic interaction that arises
from two adjacently located negatively charged alumina tetra-
hedra. CHA and SSZ-39 are examples of the fourth zeolite
formation domain, in which high-alumina-containing zeolite
syntheses result in highly heteroatom-substituted, even-membered-
ring-containing zeolites that possess cages with smaller portals.
The tetracyclic Diels-Alder product, entry 29, Table 3 (also
shown in Figure 1c), is an example of a large rigid spheriodal
SDA that is designed to obtain novel, open-framework zeolites
by avoiding the crystallization of the commonly observed
clathrates and straight one-dimensional channel system zeolites.
completion of the reaction is determined by the transformation of the
uniform gel into a settled solid.
Sample Preparation for Synchrotron Data Collection. The
calcined silicate materials are loaded into 1-mm-diameter glass capil-
laries, heated to 350 °C under vacuum, and then sealed. The data
collected on the X7A synchrotron beamline at the National Synchrotron
Light Source at Brookhaven National Laboratory (Upton, NY) are
indexed16 and converted into a format compatible with GSAS17 for the
Rietveld refinement work.
Molecular Modeling. Monte Carlo simulations are conducted at 300
K with a fixed loading of one organic guest molecule per cage.18 The
sorption simulation probes 20 000 guest/host configurations, and the
lowest energy result is energy-minimized using the Burchart-Universal
force field. The framework atoms are fixed during the energy
minimization, and the cationic charge of the organocation is counterbal-
anced by averaging the negative charge over the framework atoms.
The reported stabilization energies represent only the nonbonded van
der Waals interactions between the silicate framework and the organic
guest.
Results and Discussion
1. Synthesis. Table 4 presents the products that result from
each of the 37 structure-directing molecules (Tables 1-3) in
(16) Werner, P. E.; Erikson, L.; Westdahl, M. J. J. Appl. Crystallogr.
1985, 18, 367.
(17) Larson, A. C.; Von Dreele, R. B. GSASsGeneral Structure Analysis
System; Los Alamos National Laboratory Report, LA-UR 86-748; LANL:
Los Alamos, NM, 1986.
(18) CERIUS 2, Version 3.5; Molecular Simulations Inc.: Cambridge,
UK 1996.
(19) Meier, W. M.; Olson, D. H.; Baerlocher, Ch. Atlas of Zeolite
Structure Types, 4th ed.; Elseveir: London, 1996.
(20) (a) Zones, S. I.; Van Nordstrand, R. A. NoVel Materials in
Heterogeneous Catalysis; ACS Symposium Series 437; Baker, R. T. K.,
Murrell, L. L., Eds.; American Chemical Society: Washington, DC, 1990;
p 14. (b) Zones, S. I.; van Nordstrand, R. A. Zeolites 1989, 9, 458.

Synthesis of NoVel Cage-Based Zeolites
J. Am. Chem. Soc., Vol. 122, No. 2, 2000 267
Table 4. List of Zeolite Reactions and Products

268 J. Am. Chem. Soc., Vol. 122, No. 2, 2000
Table 4. (Cont’d)
Wagner et al.
These products result when either small or rigid elongated
molecules are employed as SDAs. As can be seen from entry
29 of Table 4, this tetracyclic Diels-Alder SDA molecule is
found to have a very high selectivity for the novel zeolite phase
denoted SSZ-35 over the entire lattice substitution range from
fairly aluminum rich (SAR ) 30)21 to pure silica. The diffraction
pattern of SSZ-35 is presented in Figure 2. The strong
nonbonded SDA/zeolite interaction energy between entry 29
and SSZ-35 accounts for the high phase selectivity (as will be
discussed in more detail in Section 3); replacing just one
N-methyl group with ethyl prevents the crystallization of SSZ-
35. Entry 29 successfully achieves the design goals for generat-
ing new zeolite topologies and provides an example of the fifth
domain of zeolite formation, in which strong nonbonded SDA/
zeolite interactions stabilize a particular zeolite structure over
a wide range of lattice substitution.
The extensions of methyl groups off the bicyclic ring system
of entry 9 (Table 2) also creates a bulky spheriodal SDA that
satisfies the design strategy; however, the phase specificity in
this case is much weaker than that in the previous case. The
use of organocation 9 (Table 2) in zeolite synthesis reactions
with silica-to-alumina ratios (SAR) of 100 also results in the
formation of SSZ-35 (entry 9, Table 4). Increasing the alumina
or borate content in zeolite synthesis reactions containing entry
9 (Table 2) results in the novel zeolitic phase denoted SSZ-36
(entry 9, Table 4). A diffraction pattern for SSZ-36 is shown in
Figure 3a. Clearly, entry 9 has a weaker selectivity for SSZ-35
than entry 29 and illustrates the competing influences of the
kinetic control of the inorganic gel composition with the
(21) Zones, S. I.; Nakagawa, Y. U.S. Patent 5,785,947, 1998.

Synthesis of NoVel Cage-Based Zeolites
J. Am. Chem. Soc., Vol. 122, No. 2, 2000 269
Figure 2. X-ray powder diffraction pattern for SSZ-35.
Figure 3. Two examples of X-ray powder diffraction patterns for SSZ-36: (a) from a synthesis using entry 9 and (b) from entry 18.
thermodynamic influences of the organic/inorganic interactions
in the zeolite formation, and this will be explored more
thoroughly in Section 3.
b. Summary of SSZ-35, SSZ-36, and SSZ-39 Syntheses.
A number of zeolite synthesis trends are apparent within the
group of 37 organocation guest molecules employed in this study
(Table 4). The SSZ-36 material is generally favored by the
mono- and bicyclic ring systems (Tables 1 and 2) with ring
methylation beyond the charged nitrogen and tends to prefer-
entially form at higher heteroatom lattice substitutions; no pure
silica example has been found. The SSZ-36 product can be
crystallized at high lattice substitution with SAR ) 10-4021
and can also be crystallized in the presence of a number of guest
molecules when the synthesis conditions are rich in borate. It

270 J. Am. Chem. Soc., Vol. 122, No. 2, 2000
Wagner et al.
structure indicates a space group assignment consistent with
C2/c (No. 15). The structure solution of the new aluminosilicate
SSZ-39 is obtained by the isomorphic substitution of the non-
oxygen framework atoms in the SAPO-18 structure23 with
silicon atoms.
For the Rietveld refinements of SSZ-39 from the synchrotron
powder XRD data (SPXRD), 10 background parameters (shifted
Chebychev function), the scale factor, and the zero shift were
first refined, followed by the refinement of the lattice parameters,
six profile parameters (Simpson’s rule integration of the pseudo-
Voight function), and finally, the atomic positions and the
isotropic temperature factors for all the atoms were refined.
Ninety-four variables were refined in the final Rietveld
refinement over a profile range of 2.0-50.0° (l ) 1.20106 Å,
step sizes ) 0.005°, resulting in 9600 observables) containing
649 reflections. Fifty-seven soft constraints were employed (24,
d(Si-O) ) 1.61(01) Å; 33, d(O-O) ) 2.61 Å), resulting in an
average d(Si-O) of 1.611 Å with a maximum of 1.644 Å and
minimum of 1.588 Å (minimum of 105.5°), and the average
Si-O-Si angle being 148.57° with a maximum of 152.6°
dimension and a minimum of 141.3°. The final residual values
were wRp ) 11.338% and Rp ) 9.30%. The Fourier difference
map showed maximum peak heights all less than 0.5 e-/Å. The
refinement data are presented in Figure 5. The atomic position
together with the isotropic temperature factors are presented in
the Supporting Information.
The structure of SSZ-39 is composed of columns of double
six-ring units that stack along the [001] direction (Figure 6a).
These columns interconnect through bridging oxygen atoms to
form layers that connect through other oxygen atoms (Figure
6b). The layerlike units stack along the [010] direction and are
related through mirror planes (Figure 6c). This layer stacking
of the sheets of double six-ring units gives rise to a cage system
similar in volume to the cages found in the SSZ-35 structure.
They are interconnected in three dimensions by eight-ring unitss
as shown in Figure 6d and e.
c. SSZ-36. Twin faulting and intergrowth occurs frequently
in zeolitic materials due in part to the poor specificity of the
structure-directing agent for a particular end-member polymorph
of the fault series. Twin faulting in zeolites is commonly
manifested as a stacking disorder of a layerlike unit in which
the successively stacked layers can be related through either
mirror planes or inversion centers. As the density of the twin
faults increases, i.e., the distance between the twin faults
decrease, broadening or streaking of reflection intensities in the
diffraction data occurs.
As seen in Figure 3a, the SSZ-36 material synthesized from
entry 9 in Table 2 contains a distribution of reflection widths
that, together with SEMs showing uniform crystal morphology,
indicate that the crystals contain a high density of twin faults.
The reflections at smaller scattering angles lack significant
broadening in comparison to the reflections near 18° 2θ. These
sharp reflections resemble the low scattering angle portion of
the powder X-ray diffraction pattern observed for the RUB-13
material (RTH).24
Figure 4. Framework representation of SSZ-35 showing the 10-ring
portals leading into larger cavities.
is important to note that certain reflection intensities and breadths
observed in the SSZ-36 powder X-ray diffraction data depend
on the degree of lattice substitution and the organocation
employed in the SSZ-36 syntheses. Such preferential line
broadening in the powder X-ray data is indicative of faulting
and will be discussed in greater detail below in the context of
the SSZ-36 structure.
SSZ-35 is most effectively crystallized in the presence of tri-
and tetracyclic charged compounds (Table 3) with no additional
ring derivatization and tends to be favored at low lattice
substitution. The calculated SDA/zeolite interaction energy
indicates that the tri- and tetracyclic quaternized amine mol-
ecules provide favorable van der Waals stabilization of the SSZ-
35 cages, as will be discussed in more detail in Section 3. The
distinct preference for forming this new zeolite structure via
the tri- and tetracyclic organocations indicates that not only the
overall size of the molecule but also the shape of the molecule
are important in considering new molecules as SDAs for zeolite
synthesis. Conspicuously absent in these results are SDA
candidates with pendant Me3N+ groups. Only entry 10, in one
particular reaction, produces SSZ-36. To date, there are no
examples of these kinds of SDAs crystallizing SSZ-35.
As discussed previously, SSZ-39 is able to be crystallized
from a wide range of the SDA molecules in Tables 1-3 at very
high lattice substitution. The reactions employing high alumina
content also require a high hydroxide concentration in order to
solubilize the alumina and tend to result in cage-based zeolites
with small portals such as SSZ-39 due to the ordering of
aluminum in the framework; the details of the SSZ-39 structure
are presented below. Highly lattice substituted even-membered-
ring-containing zeolites such as CHA and SSZ-39 tend to be
observed when the inorganic gel composition predominates over
the organic/inorganic interactions.
2. Zeolite Structures. a. SSZ-35. The details of the structure
solution of the high-silica, molecular sieve SSZ-35 are described
in a recent publication.22 The structure contains an unusual, one-
dimensional channel system with pore openings that alternate
between rings containing 10 tetrahedral atoms (T-atoms) and
18 tetrahedral atoms (Figure 4a). This alternating pore diameter
can also be viewed as arising from the stacking of [445866102]
cages with 10 T-atom openings at the top and bottom of the
cages (Figure 4b).
The RTH topology possesses a two-dimensional pore system
circumscribed by eight-membered rings and contains large cages
that are interconnected through the eight-membered rings. The
RUB-13 structure can be viewed as resulting from the stacking
of layerlike units related through mirror planes that can twin
parallel to c*.24 This twin fault gives rise to layerlike units that
b. SSZ-39. The refined17 unit cell parameters for SSZ-39
obtained from the synchrotron powder XRD data are a )
13.629692 Å, b ) 12.674772 Å, c ) 18.473045 Å, and â )
89.9288°. Analysis of the systematic absences for the monoclinic
(22) (a) Wagner, P.; Medrud, R. C.; Davis, M. E.; Zones, S. I.
Proceedings of the 12th International Zeolite Conference, Baltimore, MD,
July 1998; Recent Progress Reports Poster Abstract, RR. (b) Wagner, P.;
Medrud, R. C.; Davis, M. E.; Zones, S. I. Angew. Chem., Int. Ed. 1999, 38,
1269-1272.
(23) Simmen, A.; McCusker, L. B.; Baerlocher, Ch.; Meier, W. M.
Zeolites 1991, 11, 654.
(24) Vortman, S.; Marler, B.; Gies, H.; Daniels, P. Microporous Mater.
1995, 4, 111.

Synthesis of NoVel Cage-Based Zeolites
J. Am. Chem. Soc., Vol. 122, No. 2, 2000 271
Figure 6. Linkages for the chains and connectivities used to construct
the cavities in SSZ-39. See the text for greater discussion.
Figure 7. Comparison of the cage constructions for ITE and RTH
(left). It can be seen that a difference of one symmetry operator results
in the two unique structures (taken from ref 25).
Figure 8. DIFFaX analysis for simulation of polymorph intergrowth
from end members ITE and RTH.
Figure 5. Calculated and experimental (synchrotron data) diffraction
patterns for SSZ-39.
Simulations of powder X-ray diffraction (PXRD) data for
crystals containing varying RTH-ITE twin fault densities were
performed using DiFFaX26 (Figure 8). At the low twin fault
densities, the PXRD data closely match the PXRD data resulting
from the pure end-member polymorph; however, as the twin
fault density increases, broad reflection intensities arise due to
the decreasing distance between the twin faults, as previously
discussed.
are related through inversion centers and results in the formation
of a new large cage structure that differs in shape from the cages
found in the RUB-13 structure but that possesses a similar
volume. The synthesis and structure solution of this other
material has recently been reported25 and has been given the
IZC code ITE. Figure 7 (adapted from ref 25) shows the
comparison of the symmetry differences for the two cage types
generated for these two end-member structures. The representa-
tion shows the two-dimensional eight-ring pores system that
intersects into sizable cages.
SSZ-36 has been synthesized from a number of different
organic structure-directing agents, and depending on the par-
ticular SDA and the degree of heteroatom substitution, the
(25) Camblor, M. A.; Corma, A.; Lightfoot, P.; Villaescusa, L. A.;
Wright, P., A. Angew. Chem., Int. Ed. 1997, 36, 2659.
(26) Treacy, M. M. J.; Deem, M. W.; Newsam, J. M. DIFFaX Version
1.801, 1995.

272 J. Am. Chem. Soc., Vol. 122, No. 2, 2000
Wagner et al.
Table 5. Stabilization Energy for Compound 29 (Table 3) in the
Cages of the Competing Zeolite Phases
zeolite
compound 29, kcal/cage
ITE
RTH
SSZ-39
SSZ-35
-19.9
-18.8591
-6.79554
-20.87
As discussed previously, the SSZ-36 material that results from
entry 9 is a faulted intermediate between the RTH and the ITE
structures. To gain a better understanding of the effects of the
SDA molecule on zeolite faulting, entry 9 was modeled in the
cages of both ITE and RTH. The resulting VDW energies of
stabilization for 9 in the RTH cages is -14.9 kcal/cage, while
the stabilization energy of 9 in the ITE cages is -14.03 kcal/
cage. The similarities of the nonbonded van der Waals energy
of stabilization for entry 9 within both the ITE and RTH cages
suggest that this compound may lead to a structure that is a
faulted intermediate between the RTH and ITE structures. The
experimentally observed powder X-ray data for the SSZ-36
material that results from entry 9 reveals that it is faulted and
possesses a fault probability toward the RTH structure of
approximately 80% (Figure 9).
Additional insight into the phase selectivity of the organic
guests for a particular silicate framework is gained by examining
the behavior of the tri- and tetracyclic molecules in Table 3.
With the lone exception of entry 37, these guest molecules all
produce SSZ-35. These molecules must therefore possess the
correct size and geometry to stabilize the SSZ-35 cages.
An interesting case of SSZ-35 phase selectivity is observed
for the tetracyclic entry 29, which crystallizes SSZ-35 over the
entire lattice substitution range. Molecular modeling was
employed to determine the effects of the van der Waals (VDW)
energy of interaction between entry 29 and the cages of the
SSZ-35 phase and the cages of the competing phases (ITQ-3,
RUB-13, and SSZ-39). The calculation results are given in Table
5 and indicate that entry 29 strongly stabilizes SSZ-35 relative
to these competing phases. The significant stabilization of SSZ-
35 over SSZ-39 (-20.87 vs -6.79 kcal/cage) is particularly
interesting. This result is consistent with the experimental
observation that, even at high aluminum substitution, entry 29
stabilizes the SSZ-35 structure over the six-ring-rich structures
that commonly result from syntheses containing high alumina
content and high OH/Si ratios (entry 29, Table 4, SAR ) 30).
Figure 9. Comparison of the experimental XRD powder data from
Figure 3a and the DIFFaX modeling of polymorph mixtures in the range
of RTH having 80% probability.
PXRD data are affected to varying degrees by twin faulting
between the RUB-13 and the ITQ-3 structures. For example,
comparison of the experimental powder X-ray diffraction pattern
of SSZ-36 synthesized from entry 9, Table 2 (Figure 3a), to
the fault simulations indicates that this material is a faulted
intermediate between the RTH and the ITE structures with a
fault probability of approximately 80% RTH (Figure 9). In
contrast, Figure 3b shows the powder X-ray diffraction pattern
that results from the use of entry 18 in Table 2. Comparison of
these PXRD data with the fault simulations in Figure 8 indicates
that the material is nearly fault-free. The PXRD pattern is
characteristic of a material consisting predominantly of the
structure of the pure end-member polymorph ITQ-3. The product
here is not pure silica, as is the case for the published ITE.
3. Correlations between Guest Molecules and Phase
Selectivities. Here, we present several molecular modeling
studies in which the nonbonded SDA/zeolite energy of interac-
tion is correlated with the observed zeolite phase selectivity from
a particular SDA. These results provide insights into the factors
that affect the specificity for the observed zeolite phases from
the designed SDA molecules.
As mentioned in the Discussion section, the SSZ-36 material
is favored by the mono- and bicyclic ring systems with ring
methylation beyond the charged nitrogen (Table 4). The SDAs
that possess ring methylation beyond the charged nitrogen show
a strong selectivity for SSZ-36 over SSZ-35. Entries 19 and 20
(Table 2) present an interesting example of this phenomenon,
in which the addition of one methyl group to the carbon ring
of the [4.1.1] octane molecule (entry 19) dramatically shifts the
phase selectivity from SSZ-35 to SSZ-36. (A similar comparison
can be made for 14 vs 17.) Molecular modeling calculations
were employed in order to gain a better understanding of the
strong specificity of the [4.1.1] octane molecule with and without
the ring methyl group. The calculated nonbonded energy of the
entry 20/SSZ-35 interaction indicates that entry 20 strongly
stabilizes the SSZ-35 cage structure (-11.81 kcal/cage). How-
ever, the addition of the methyl group to the carbon ring (entry
19) results in a positive energy of interaction (0.69 kcal/cage),
indicating that the molecule is too large to fit into the cages of
the SSZ-35 material. The modeling calculations suggest that
the mono- and bicyclic ring SDA molecules with ring methy-
lation beyond the charged nitrogen are either too large or of
the wrong shape to fit within the cages of the competing SSZ-
35 phase. These results support the design strategy outlined in
the Introduction for developing rigid molecules that are too large
to fit into the cage or pore system of competing phases.
Conclusions
Here, we have presented the results of the design strategy
for organic structure-directing agents that lead to three novel
zeolite phases: SSZ-35, SSZ-36, and SSZ-39. The strategy
involves synthesizing rigid bulky organocations that are too large
or of the wrong geometry to fit into the cavities or pores of
commonly encountered competing phases such as the clathrates
or the straight one-dimensional channel system zeolites, e.g.,
SSZ-31 and MTW.
The tri- and tetracyclic charged compounds with no additional
ring derivatization (Table 3) are found to be very effective
structure-directing agents for the novel zeolitic phase, SSZ-35.
This new material also tends to be favored at low lattice
substitution. The molecular modeling results indicate that the
tri- and tetracyclic quaternized amine molecules are particularly
effective in stabilizing the SSZ-35 cages. The structure of SSZ-
35 contains an unusual, one-dimensional channel system
containing an alternating 10- and 18-MR pore diameter that can
also be viewed as arising from the stacking of cages with 10
T-atom openings at the top and bottom of the cages.

Synthesis of NoVel Cage-Based Zeolites
J. Am. Chem. Soc., Vol. 122, No. 2, 2000 273
The novel zeolitic phase, SSZ-36, is favored by the mono-
and bicyclic SDA molecules in Tables 1 and 2 that possess ring
methylation beyond the nitrogen. Molecular modeling results
indicate that these molecules are typically too large or are of
the wrong geometry to fit within the cages of potentially
competing phases such as SSZ-35. The SSZ-36 phase also tends
to be favored at higher lattice substitutions; no all-silica SSZ-
36 materials were synthesized. The structure of SSZ-36 is found
to be a faulted intermediate between the two end-member
polymorphs RTH and ITE, that possess two-dimensional pore
systems circumscribed by eight-membered rings and that
intersect into large cavities.
The SSZ-39 material is a frequently observed product of the
high-alumina-containing syntheses (SAR ) 30) using the
organic molecules in Tables 1-3. If the inorganic gel composi-
tion predominates over the organic/inorganic interactions in the
high-alumina-containing zeolite synthesis, then cage-based
zeolites containing even-membered ring constructions and small
portals such as SSZ-39 tend to form. The structure of SSZ-39
was found to be isomorphous with the aluminophosphate
molecular sieve, SAPO-18 (AEI).
zeolite phase selectivities of the designed SDA molecules.
Understanding the effects of the nonbonded energy of the
organic SDA/zeolite interaction on zeolite phase selectivity and
fault probability will play a fundamental role in the future
discovery of new zeolite phases through rational SDA design.
Acknowledgment. We thank Dr. Guang Zhang and Mr. Ken
Ong for help in preparation and data collection at the synchro-
tron source. For the gathering of X-ray data from Beamline
X7A, the research was carried out at the National Synchrotron
Light Source at the Brookhaven National Laboratory. This
facility is supported by the U.S. Department of Energy, Division
of Materials Science and Division of Chemical Sciences. We
appreciate the help of Dr. D. E. Cox in the data collection. Dr.
Peter Crozier, from the High Resolution Electron Microscopy
Center at Arizona State University, is thanked for his work on
SSZ-35. P.W. thanks Dow Chemical Co. Foundation for a Dow
Graduate Fellowship.
Supporting Information Available: Details of the syntheses
of the organocations 1-37 and relevant references, and a table
of atomic positions and isotropic temperature factors for SSZ-
39 (PDF). This material is available free of charge via the
Internet at http://pubs.acs.org.
The successful strategy of designing organic zeolite directing
molecules that are too large or of the wrong geometry to stabilize
commonly encountered competing phases in order to synthesize
novel zeolite materials is complemented by the computational
modeling results that provide useful insights into the observed
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