Highly Stable Mesoporous Zirconium Porphyrinic Frameworks with Distinct Flexibility

Article abstract of DOI:10.1002/chem.201600447

The construction of highly stable metal-porphyrinic frameworks (MPFs) is appealing as these materials offer great opportunities for applications in artificial light-harvesting systems, gas storage, heterogeneous catalysis, etc. Herein, we report the synthesis of a novel mesoporous metal-porphyrinic framework (denoted as NUPF-1) and its catalytic properties. NUPF-1 is constructed from a new porphyrin linker and a Zr₆O₈ structural building unit, possessing an unprecedented doubly interpenetrating scu net. The structure exhibits not only remarkable chemical and thermal stabilities, but also a distinct structural flexibility, which is seldom seen in metal-organic framework (MOF) materials. By the merit of high chemical stability, NUPF-1 could be easily post-metallized with [Ru₃(CO)₁₂], and the resulting {NUPF-1-RuCO} is catalytically active as a heterogeneous catalyst for intermolecular C(sp³)-H amination. Excellent yields and good recyclability for amination of small substrates with various organic azides have been achieved.

Full text of DOI:10.1002/chem.201600447

DOI: 10.1002/chem.201600447
Full Paper
&
Metal–Organic Frameworks
Highly Stable Mesoporous Zirconium Porphyrinic Frameworks
with Distinct Flexibility
Lei Xu,[a] Yan-Ping Luo,[b] Lin Sun,[a] Yan Xu,[c] Zhong-Sheng Cai,[a] Min Fang,*[b]
Rong-Xin Yuan,[b, d] and Hong-Bin Du*[a]
Chem. Eur. J. 2016, 22, 6268 – 6276
6268
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Abstract: The construction of highly stable metal–porphyrin-
ic frameworks (MPFs) is appealing as these materials offer
great opportunities for applications in artificial light-harvest-
ing systems, gas storage, heterogeneous catalysis, etc.
Herein, we report the synthesis of a novel mesoporous
metal–porphyrinic framework (denoted as NUPF-1) and its
catalytic properties. NUPF-1 is constructed from a new por-
phyrin linker and a Zr6O8 structural building unit, possessing
an unprecedented doubly interpenetrating scu net. The
structure exhibits not only remarkable chemical and thermal
stabilities, but also a distinct structural flexibility, which is
seldom seen in metal–organic framework (MOF) materials.
By the merit of high chemical stability, NUPF-1 could be
easily post-metallized with [Ru3(CO)12], and the resulting
{NUPF-1–RuCO} is catalytically active as a heterogeneous cat-
alyst for intermolecular C(sp3)ÀH amination. Excellent yields
and good recyclability for amination of small substrates with
various organic azides have been achieved.
Introduction
strategy, many stable Zr-MPFs have been constructed, which
have greatly promoted the development of MPFs.[4e,5a,7c,f,j,12]
Meanwhile, it is believed that the central metal of the porphy-
rin units in MPFs play a vital role in its properties.[7i] For exam-
ple, MMPF-5(Cd) has a low catalytic activity toward epoxidation
of trans-stilbene, but replacing Cd2+ by Co2+ in MMPF-5 drasti-
cally improved its catalytic performance.[13] Although the cen-
tral porphyrin sites of MPFs are essential for catalysis, these
sites can be easily blocked by metal coordination during the
hydrothermal synthesis, which make MPFs inefficient for cataly-
sis.[4a,7b,14] More importantly, for some metalloporphyrin-cata-
lyzed reactions,[15] the catalytically-active metalloporphyrin cen-
ters are sensitive to water, oxygen, or other coordinating sol-
vents, which would be destroyed in the MPFs synthesis pro-
cess. Therefore, such reactions have rarely been explored using
MPFs as the catalyst. To develop the applications of MPFs as
catalysts for such reactions, the catalytic sites can only be
made by post-metalation of the core-free MPFs. Because of the
high oxophilicity, ZrIV prefers to form Zr–O clusters rather than
in-situ metallizing the porphyrin core during the solvothermal
synthesis,[12a,16] which leads to core-free Zr-MPFs. The resulting
core-free Zr-MPFs could be facilely post-metalized by various
metals, imparting their multifunctionality.[4e,7f,12a,17] Therefore, in
addition to the apparent desirable stability, the core-free
nature of Zr-MPFs makes them versatile platforms for various
applications.
Metal–porphyrinic frameworks (MPFs), which contain (metallo)-
porphyrin-decorated ligands as linkers, are a subclass of
metal–organic frameworks (MOFs).[1] Since the first report in
the early 1990s,[2] MPFs have attracted escalating research in-
terest owing to the unique electronic, chemical, and physical
properties of the (metallo)porphyrins. In recent years, an in-
creasing number of MPFs have been elaborately fabricated
and exhibited fascinating chemical/physical properties, which
made them eligible candidates for artificial light-harvesting sys-
tems,[3] gas storage/separation,[4] sensing,[5] photodynamic ther-
apy,[6] catalysis,[7] etc. Nonetheless, the development of MPFs is
still in its infancy. The total number of MPFs is rather small
given the vast family of MOFs and the applications of MPFs
remain largely unexplored.[8] Therefore, the exploration of
novel porphyrinic building blocks and the underlying MPFs
structures as well as their potential applications are still highly
desirable.[9]
In pursuing MPFs, those with high chemical and thermal sta-
bilities are much more appealing as these materials could not
only diversify the applications of MPFs when subjected to
harsh experimental environments,[7j] but also provide a robust
platform for further post modification/functionalization.[10]
Thanks to its high charge density, ZrIV can coordinate to the
carboxylate groups of the ligand to form MOFs with extraordi-
narily high chemical and thermal stabilities.[11] By adopting this
One major motivation for constructing MPFs is their unique
catalytic properties in heterogeneous catalysis. The use of
MPFs as heterogeneous catalysts could not only overcome the
drawbacks of separation and re-utilization of porphyrin mole-
cules in homogeneous catalysis,[14,18] but also make the catalyt-
ically active porphyrinic units highly dispersed and accessible,
overcoming the solubility issue that homogeneous porphyrinic
catalysts often encounter,[7j] thus resulting in superior catalytic
performance. Recently, metalloporphyrins have been found to
exhibit good catalytic activities for both intramolecular and in-
termolecular CÀH aminations, which has attracted tremendous
research interest.[19] However, these reactions were performed
in homogeneous solutions, which cause problems for product
purification and catalyst recycling. The latter has long been an
aspiration because of the synthetic difficulties related to (met-
allo)porphyrins.[19c,20] Immobilizing the active sites of metallo-
porphyrins onto the pore surfaces of stable MPFs, that is, use
of porous MPFs as heterogeneous catalysts for CÀH amination,
[a] L. Xu, L. Sun, Z.-S. Cai, Prof. H.-B. Du
State Key Laboratory of Coordination Chemistry
Collaborative Innovation Center of Chemistry for Life Sciences
School of Chemistry and Chemical Engineering
Nanjing University, Nanjing, 210023 (P. R. China)
E-mail: hbdu@nju.edu.cn
[b] Y.-P. Luo, Prof. M. Fang, Prof. R.-X. Yuan
School of Chemistry and Materials Science
Nanjing Normal University, Nanjing, 210023 (P. R. China)
E-mail: fangmin@njnu.edu.cn
[c] Prof. Y. Xu
College of Chemistry and Chemical Engineering
State Key Laboratory of Materials-Oriented Chemical Engineering
Nanjing Tech University, Nanjing, 210009 (P. R. China)
[d] Prof. R.-X. Yuan
School of Chemistry and Materials Engineering
Changshu Institute of Technology, Changshu, 215500 (P. R. China)
Supporting information for this article is available on the WWW under
http://dx.doi.org/10.1002/chem.201600447.
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6269
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
would address the issues of product purification and catalyst
recycling. However, previous attempts to construct MPFs with
large pores for this purpose have not been successful.[21]
Herein, we report the synthesis of a novel mesoporous, core-
free Zr-MPF, denoted as NUPF-1 (NUPF: Nanjing University Por-
phyrinic Framework no. 1). NUPF-1 possesses exceptionally
high chemical and thermal stabilities. After post-metallization
with [Ru3CO12], {NUPF-1–RuCO} acted as a heterogeneous cata-
lyst for intermolecular C(sp3)ÀH amination, exhibiting good cat-
alytic performance and recyclability.
UiO series.[11a] Each Zr6O8 SBU in NUPF-1 is in a cuboid coordi-
nation geometry, connected by eight porphyrin ligands, while
each porphyrin ligand is coordinated to four Zr6O8 SBUs
through its carboxylate groups. The linkage of the elongated
porphyrin ligands and Zr6O8 SBUs leads to a highly opened
three-dimensional (4,8)-scu net with very large rhombic chan-
nels of ꢀ5.1”2.3 nm (atom-to-atom distance) running along
the c axis. Interestingly, the scu net in NUPF-1 is doubly inter-
penetrated, which is unprecedented. An empirical pattern is
that interpenetration often occurs to topologies with lower
connectivity, and a framework with connectivity larger than six
should not encounter interpenetration.[22] However, the voids
in NUPF-1 are large enough to accommodate another individu-
al network, resulting in an unprecedented twofold interpene-
trating scu net (see the Supporting Information, Section S5).
The interpenetration partitions each large rhombic channel
into four smaller ones with the window sizes of 2.66”1.78 nm,
2.00”0.72 nm, and 1.91”0.67 nm (Figure 1c and d). The calcu-
lated solvent-accessible pore volume is 73.6% of the unit cell
volume (Figure S5 in the Supporting Information).[23]
Results and Discussion
Dark-purple rod-like single crystals of NUPF-1 were obtained
by solvothermal reactions of a novel porphyrin ligand H4L (Fig-
ure 1a) with ZrOCl2·8H2O in DMF and formic acid at 1208C for
48 h (see the Supporting Information, Sections S2 and S3).
Single-crystal X-ray diffraction studies revealed that NUPF-
1 crystalizes in the orthorhombic Cmcm space group. As
shown in Figure 1a, the porphyrin ligand in NUPF-1 is com-
prised of a tetraphenylporphyrin and benzoic acid moieties
linked by amido units, with a span of ꢀ2.4 nm between the
two neighboring carboxylate groups. The porphyrin macrocy-
cle is core-free and almost planar with a maximum out-of-
plane deformation of 0.071 Š. The two phenyl rings in each of
its arms tilt away from the porphyrin macrocycle with dihedral
angles of 72.18 and 49.98 or 80.18 and 57.18, respectively. ZrIV
forms an eight-connected Zr6O8 structural building unit (SBU)
(Figure 1b), similar to those found in PCN-225,[5a] but different
to the commonly observed 12-connected Zr6O8 cluster in the
NUPF-1 exhibits both high chemical and thermal stabilities.
After the crystals of NUPF-1 were immersed into common or-
ganic solvents, boiling water, HCl (pH 1, 2, 3; 1m and concen-
trated), and NaOH solutions (pH 9 and 10) for three days, all
the samples except those in pH 10 solutions retained their
crystallinity and morphology, as shown by powder XRD and
optical images (Figure 2 and Figure S9a in the Supporting In-
formation). The durability of NUPF-1 against acid is outstand-
ing, and to the best of our knowledge, NUPF-1 is one of the
rare MOFs that could resist concentrated HCl.[24] Even in aqua
Figure 1. a) The square porphyrin carboxylate ligand in NUPF-1. b) The eight-connected Zr6(m3-O)4(m3-OH)4(OH)4(H2O)4(OOC)8 SBU in NUPF-1. c) The two-fold in-
terpenetrating scu framework of NUPF-1. d) Large channels of 2.66”1.78 nm (green), 2.00”0.72 nm (orange), and 1.91”0.6 nm (pink) in NUPF-1 viewed
along the c axis. The Connolly surfaces were calculated by using a 1.4 Š probe radius.
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6270
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Figure 2. PXRD patterns of NUPF-1 soaked in different concentrations of a) HCl solutions and b) NaOH solutions for three days. The diffraction peak at
2q=5.71 belongs to the (200) peak of NUPF-1, which was not evident in the calculated pattern. c) Optical images of NUPF-1 after soaking in acidic or alkaline
solutions for three days.
regia, the crystalline structure of NUPF-1 could be maintained
for 24 h (Figure S9b), further demonstrating its remarkable acid
resistance. Thermogravimetric (TG) analysis (Figure S10a in the
Supporting Information) and PXRD studies (Figure S10b) re-
vealed that NUPF-1 was stable up to ~4508C, demonstrating
its high thermal stability. Moreover, NUPF-1 retained its crystal-
linity after exposure to 12.5 tonscmÀ2 of uniaxial pressure (Fig-
ure S11 in the Supporting Information), suggesting that it pos-
sesses excellent mechanical stability. The unusual structural sta-
bility of NUPF-1 laid the foundation for further exploration of
its applications.
and analyzed by GC-MS with triphenylmethane as an internal
standard. The results show that the adsorption capacities of
the as-synthesized NUPF-1, and those treated with concentrat-
ed HCl and pH 9 solution were almost the same (ꢀ32 ethyl-
benzene per formula unit, see the Supporting Information, Sec-
tion S13), indicating that the voids of NUPF-1 were preserved
under harsh conditions. Indeed, as shown in Figure 3a–c, the
activated NUPF-1 could absorb 107, 154, and 182 cm3 gÀ1 (STP)
of ethanol, methanol, and water vapor, respectively, at 298 K
and 1 atm. The samples treated with concentrated HCl ab-
sorbed 119, 174, and 280 cm3gÀ1 (STP) of ethanol, methanol,
and water under the same conditions increased by a factor of
11.2%, 13.0%, and 53.8% compared with the as-synthesized
sample, respectively. The enhancement in the adsorption by
the HCl-treated sample may be ascribed to the removal of
trace amount of trapped ligands in NUPF-1, which made the
structure more open and thus improved the adsorption capaci-
ty.[7g] It is also possible that part of the amino or pyrrole moiet-
ies in NUPF-1 might be protonated in concentrated HCl solu-
tion, which could make the framework cationic and increase
the affinity of NUPF-1 toward adsorbates.[5a,27] Notably, all the
adsorption/desorption isotherms of ethanol, methanol, and
water vapor over NUPF-1 showed unusually large desorption
hysteresis loops. Such phenomenon have been found in flexi-
Interestingly, the porous NUPF-1 shows negligible N2 adsorp-
tion. PXRD analyses revealed that the structure was not de-
composed after the adsorption measurements (Figure S12 in
the Supporting Information). Many attempts to acquire large
N2 adsorption have not been successful (see the Supporting In-
formation, Section S13). The limited N2 adsorption is likely due
to the low affinity of the NUPF-1 framework toward N2, similar
to other reported porous MPFs such as UNLPF-1 or ZnMn-RPM,
etc., which have potential solvent-accessible volumes but no
N2 uptake is seen with them.[4a,c,7b,25] Alternatively, for many
MPFs, such as ZJU-18, CZJ-1, CZJ-4, etc., substrate adsorption
has been used to probe their pore volumes.[7e,14,26] To probe
the pores of NUPF-1, ethylbenzene adsorption was conducted
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6271
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
Figure 3. Adsorption (solid symbols) and desorption (open symbols) isotherms of activated NUPF-1 (squares) and HCl-treated NUPF-1 (circles) for: a) ethanol,
b) methanol, and c) water. d) Powder XRD patterns of NUPF-1: (i) simulated based on crystal structure, (ii) pristine sample, (iii) evacuated at room temperature,
(iv) heated at 4508C under vacuum, and (v) heated at 4508C and then soaked in DMF for 8 h.
ble MOFs,[28] suggesting that the highly stable NUPF-1 frame-
work may exhibit some flexibility.
XRD measurements show that NUPF-1-Ni was still flexible, indi-
cating metallization did not affect the flexibility of NUPF-1. The
flexible nature of NUPF-1 likely arises from the interpenetration
of the two extra-large-pored scu nets and the semi-rigid por-
phyrinic carboxylate ligand. The resulting highly porous NUPF-
1 in its pristine form was swollen by guest solvents. The re-
moval of guest solvents upon evacuation or heating would
lead to sliding between the two interpenetrated nets and thus
contraction of the framework.[28b,31] Meanwhile, the amido
units in the elongated porphyrin ligands were flexible, which
may twist under external stimuli, leading to the framework
flexibility.[32]
To verify this hypothesis, in situ variable-temperature X-ray
diffraction (VT-XRD) measurements were conducted. Impres-
sively, the flexibility of NUPF-1 was distinctly evident from the
VT-XRD patterns. When the temperature gradually increased to
4508C under vacuum, the main diffraction peak of NUPF-1 was
maintained, confirming the high thermal stability (Figure S15a
in the Supporting Information). However, upon evacuation at
room temperature, the (220) diffraction peak of the pristine
NUPF-1 at around 6.598 (2q) shifted to a Bragg angle of 6.768
(2q), indicating that solvent extraction induced a structural
shrinkage (Figure 3d).[29] As the sample was heated up, the
(220) peak sequentially moved to higher Bragg angles, up to
7.528 (2q) at 4508C (Figure S15b). These results demonstrate
that the framework of NUPF-1 contracted upon evacuation or
heating. Interestingly, the contracted framework of NUPF-
1 could reversibly transfer back to the initial structure upon
soaking the sample in DMF or EtOH. It is noted that only a few
Zr-MOFs with high chemical and thermal stabilities accompa-
nied by evident structural flexibility have been reported so
far.[30] Recently, Hupp et al. reported the core-free Zr-MPF, NU-
1104(H2), could undergo a structural transformation triggered
by gas adsorption.[30b] The flexibility of NU-1104(H2) was attrib-
uted to the conformational changes in the core-free porphyrin
linkers. Metallization of the porphyrin linkers in NU-1104 sup-
pressed such flexibility. To check out whether metallization
could eliminate the flexibility of NUPF-1, we prepared the met-
alized NUPF-1 with Ni, similar to NU-1104 (see the Supporting
Information, Section S15).[4e] In contrast to NU-1104, in situ VT-
Considering that most catalytic reactions are carried out in
solvents,[33] and its high chemical stability, mesoporosity, and
porphyrin core-free nature, NUPF-1 may be used as a versatile
platform for heterogeneous catalysis. Among the metallopor-
phyrin-catalyzed reactions, intermolecular C(sp3)ÀH amination
is an attractive but challenging one.[19] To explore the use of
NUPF-1 in intermolecular C(sp3)ÀH amination, the {RuCO} units
of the metalloporphyrins, which are sensitive to water and
other coordinating solvents[34] and cannot be pre-planted or in
situ metalized during the MPFs synthesis, were inserted into
the free porphyrin core by post-metallization. The metallization
process was easily accomplished by heating the archetypal
crystals of NUPF-1 with [Ru3(CO)12] under reflux and a subse-
quent filtration operation, which bypassed the laborious chro-
matography purification process encountered in homogeneous
catalyst preparation (see the Supporting Information, Sec-
tion S16). The resulting {NUPF-1–RuCO} also exhibited high
chemical/thermal stabilities, which were inherited from its
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6272
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
parent structure NUPF-1 (see the Supporting Information, Sec-
tion S16). Such desirable stabilities would be beneficial for the
further heterogeneous catalytic explorations.
80% with 8 mmol% catalyst loading reported in the litera-
ture).[35] Catalyst recycling tests revealed that {NUPF-1–RuCO}
can be easily separated and re-used for further ethylbenzene
amination, showing the advantages of a heterogeneous cata-
lyst. Good yields of 89% and 84% were obtained in the 2nd
and 3rd runs, respectively (entries 6 and 7). In addition, the
crystalline nature of {NUPF–1-RuCO} was retained after the 3rd
catalytic cycle (Figure S19 in the Supporting Information). The
slight deactivation compared with the previous run is likely
due to the exposure of the catalyst to water, oxygen, or other
coordinating solvents during the handling, which destroyed
some of the catalytically active intermediates.[34]
Amination of ethylbenzene with p-nitrophenyl azide was
chosen to evaluate the catalytic performance of {NUPF-1–
RuCO}. As listed in Table 1, compared with the trials with the
blank, the pristine NUPF-1, and [Ru3CO12] catalysts (entries 1, 2,
and 3), {NUPF-1–RuCO} unequivocally exhibited catalytic activi-
ty toward ethylbenzene C(sp3)ÀH amination (entry 4). The yield
is 94%, higher than that of the homogeneous catalyst
[(tpp)RuCO] (ꢀ73%, entry 5) under the same conditions (c.f.
To further explore the catalytic performance of
{NUPF-1–RuCO}, more azidobenzenes with different
Table 1. Amination of ethylbenzene with various azides.
functional groups (entries 8–14) were used to ami-
nate ethylbenzene. The catalytic results show that ex-
cellent yields of 72–89% have been achieved. The ex-
Entry
1
Azide
Catalyst
blank
Product
Yield [%]
cellent catalytic performance of {NUPF-1–RuCO} may
be attributed to the good dispersion of catalytic cen-
ters in the mesoporous NUPF-1, which resulted in ef-
fective utilization of the active sites.[7j] In fact, MPFs
as heterogeneous catalysts can, in many case-
s,[7a,d,13,36] generate higher catalytic yields than their
counterparts in homogeneous catalysis. Moreover,
{NUPF-1–RuCO} was shown not only to be catalytical-
ly active toward aryl azides, but also active in the re-
actions between ethylbenzene and sulfonyl or acyl
azides to form aminated compounds with good
yields of 83% and 72%, respectively (entries 15–16),
demonstrating a good catalytic competence.
0[a]
2
3
4
5
6
7
NUPF-1
0[a]
[Ru3CO12]
6[a]
{NUPF-1–RuCO}
[(tpp)RuCO]
{NUPF-1–RuCO}
{NUPF-1–RuCO}
94[a]
73[a,b]
89
(2nd run)[a]
84
Similar to other heterogeneous reactions catalyzed
by MOFs,[37] a slower conversion rate was observed in
the amination of ethylbenzene with p-nitrophenyl
azide catalyzed by {NUPF-1–RuCO}. Time-course plots
reveal that full consumption of the azide needed
nearly 18 h (see the Supporting Information, Sec-
tion S20), whereas the same reaction catalyzed by
[(tpp)RuCO] was accomplished in 5 h (Table 1,
entry 5). These results indicate that the catalytic reac-
tion occurred in the channels of {NUPF-1–RuCO}
rather than on the external surface, as substrate-diffu-
sion processes may be the bottleneck for the {NUPF-
1–RuCO}-catalyzed reaction. To verify this, a “standard
protocol” that gradually increased the size of sub-
strates was followed.[33,38] If the catalysis indeed
occurs mainly inside the pores of MOFs rather than
on the surface, no or slow conversion of large sub-
strates would be encountered. As shown in Table 2,
the yields indeed gradually dropped with increasing
size of the substrates. For example, an excellent yield
of 93% was achieved in the amination of cyclohex-
ene, whereas the yield decreased to 53% for 1,2,3,4-
tetrahydronaphthalene. A low yield of 17% was ob-
served for diphenylmethane, even with a prolonged
reaction time. The exception was toluene, which has
a smaller size but gave a good yield of 77.6%
(Table 2, entry 2); this could be attributed to the un-
(3rd run)[a]
8
9
{NUPF-1–RuCO}
{NUPF-1–RuCO}
87[c]
72[c]
10
11
12
13
14
{NUPF-1–RuCO}
{NUPF-1-RuCO}
{NUPF-1–RuCO}
{NUPF-1–RuCO}
{NUPF-1–RuCO}
87[c]
87[c]
85[c]
89[c]
78[c]
15
16
{NUPF-1–RuCO}
{NUPF-1–RuCO}
83[c]
72[c]
Reactions were run under a high-purity Ar atmosphere with 3.0 mL of substrate,
0.3 mmol of azide, and 6 mmol% catalyst at 1008C for 24 h unless stated otherwise.
[a] Yield determined by 1H NMR with 2,4-dinitrotoluene as the internal standard.
[b] Reaction time=5 h. [c] Isolated yield.
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6273
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
NUPF-1 with large pores and desired chemical and
thermal stabilities provides an ideal platform for het-
erogeneous catalysis. After post-metallization, {NUPF-
1–RuCO} exhibits excellent, size-selective catalytic
performance and good recyclability as a heterogene-
ous catalyst for intermolecular C(sp3)ÀH amination of
small substrates with various organic azides. The
unique structural features and properties of NUPF-
1 will make it a promising candidate for a variety of
applications.
Table 2. Amination of various substrates with p-nitrophenyl azide.
Entry
1
Substrate
Catalyst
Product
Yield [%]
93[a]
{NUPF-1–RuCO}
2
4
{NUPF-1–RuCO}
{NUPF-1–RuCO}
77.6[a]
69[b]
Experimental Section
Synthesis of NUPF-1
5
6
7
{NUPF-1–RuCO}
{NUPF-1–RuCO}
{NUPF-1–RuCO}
53[b]
Porphyrin ligand H4L (13 mg, 0.01 mmol) was transferred
into N,N-dimethylformamide (DMF, 2 mL) in a small
capped vial and sonicated for 10 min for dissolution.
ZrOCl2·8H2O (10 mg, 0.03 mmol) and anhydrous formic
acid (0.3 mL) were then added to the resulting solution
and further sonicated for 10 min. The vial was placed
into a Teflon-lined acid-digestion bomb and heated at
1208C for 2 days and then allowed to cool to room tem-
perature naturally. Small dark-purple rod-like crystals
(Figure S3 in the Supporting Information) were harvest-
ed: yieldꢀ12 mg (ꢀ72%, based on porphyrin ligand).
31[b,c]
17[b,c]
Reactions were run under a high-purity Ar atmosphere with 3.0 mL of substrate,
0.3 mmol of p-nitrophenyl azide, and 6 mmol% catalyst at 1008C for 24 h unless
stated otherwise. [a] Yield determined by 1H NMR with 2,4-dinitrotoluene as the inter-
nal standard. [b] Isolated yield. [c] Reaction time=48 h.
Crystal data for NUPF-1: C152H108N16O40Zr6, Mr =3345.86,
dark-purple rod-like crystal, 0.15”0.13”0.12 mm3, ortho-
rhombic, space group Cmcm, a=30.6210(7) Š,
b=55.6255(9) Š,
c=24.4120(4) Š,
a=b=g=908,
desired conversion of toluene to byproducts.[35] These results
V=41581.2(13) Š3, Z=4, 1cald =0.534 g cmÀ3, F000 =6768, 57649 re-
flections collected, 16888 unique, (Rint =0.0779), final GooF=1.056,
R1 =0.0769, wR2 =0.2372. CCDC 1058125 contains the supplemen-
tary crystallographic data for this paper. These data are provided
free of charge by The Cambridge Crystallographic Data Centre.
clearly prove that the catalytic reactions indeed occur in the in-
ternal pores of {NUPF-1–RuCO}.
It has been proposed that the metalloporphyrin-catalyzed
intermolecular CÀH amination requires the coordination of the
ArN3 moiety to the metal site to generate an active metal–
imido complex.[19e] When a hydrocarbon substrate subsequent-
ly approaches to the active center, the nitrene transfer reaction
takes place to form the adductive product. For {NUPF-1–
RuCO}-catalyzed intermolecular CÀH amination, the reaction
occurs when the organic substrates and aryl azides effectively
diffuse into the pores and approach the active metal sites.
Meanwhile, the formed bulky products must diffuse out of the
pores to regenerate the metal catalytic centers and make
room for incoming substrates. The relatively large sizes of the
molecules involved in the reactions likely resulted in diffusion
bottlenecks during the {NUPF-1–RuCO}-catalyzed heterogene-
ous C(sp3)ÀH aminations, resulting in the characteristic slow
conversion and shape selective catalysis.
Post-metalation of NUPF-1 with [Ru3(CO)12]
Toluene was dried before use. Under an argon atmosphere, NUPF-
1 (80 mg, 0.05 mmol) and [Ru3(CO)12] (60 mg, 0.09 mmol) were sus-
pended in dry toluene (15 mL) and heated at reflux at 1208C for
24 h with shaking at 220 rpm by using a thermo-shaker. After the
reaction flask cooled down to room temperature, the resulting
crystals were collected in a filter, and washed thoroughly with dry
toluene. The obtained {NUPF-1–RuCO} was used immediately.
Catalytic reactions
All the reactions were carried out in a high-purity Ar atmosphere
by employing standard Schlenk techniques and vacuum-line ma-
nipulations. All glassware was dried in an oven at 1208C prior to
use. Organic azides were synthesized by following the reported
methods (see the Supporting Information, Section S1). Liquid sub-
strates were distilled over sodium/benzophenone or dried by 4 Š
molecular sieves. For a typical catalysis, organic azide (0.3 mmol)
and catalyst (6 mmol%), that is, 53 mg for {NUPF-1–RuCO}, 14 mg
for [(tpp)RuCO] (tpp=dianion of tetraphenylporphyrin), 12 mg for
[Ru3CO12], 30 mg for NUPF-1, were added to a Schlenk flask. The
flask was evacuated and backfilled with high-purity Ar three times.
The liquid substrate (3 mL) was then added by a syringe under an
Ar stream. The resulting mixture was shaken at 220 rpm by
a thermo-shaker and heated at 1008C for a certain period. After
Conclusion
A new mesoporous zirconium-based metal–porphyrinic frame-
work, named NUPF-1, has been synthesized, which possesses
an unprecedented doubly interpenetrated scu framework.
NUPF-1 not only exhibits remarkably high chemical and ther-
mal stabilities, but also possesses a distinct structural flexibility.
The flexibility likely originates from the interpenetration of the
two large-pored scu nets and the flexible amido ligands.
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6274
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
2014, 136, 15881–15884; j) D. Feng, Z.-Y. Gu, Y.-P. Chen, J. Park, Z. Wei,
Y. Sun, M. Bosch, S. Yuan, H.-C. Zhou, J. Am. Chem. Soc. 2014, 136,
17714–17717; k) J. Zheng, M. Wu, F. Jiang, W. Su, M. Hong, Chem. Sci.
2015, 6, 3466–3470; l) N. Kornienko, Y. Zhao, C. S. Kley, C. Zhu, D. Kim,
S. Lin, C. J. Chang, O. M. Yaghi, P. Yang, J. Am. Chem. Soc. 2015, 137,
14129–14135; m) T. Toyao, N. Ueno, K. Miyahara, Y. Matsui, T.-H. Kim, Y.
Horiuchi, H. Ikeda, M. Matsuoka, Chem. Commun. 2015, 51, 16103–
16106; n) J. A. Johnson, J. Luo, X. Zhang, Y.-S. Chen, M. D. Morton, E.
Echeverría, F. E. Torres, J. Zhang, ACS Catal. 2015, 5, 5283–5291.
[8] a) B. J. Burnett, P. M. Barron, W. Choe, CrystEngComm 2012, 14, 3839–
3846; b) C. Zou, C.-D. Wu, Dalton Trans. 2012, 41, 3879–3888; c) W.-Y.
Gao, M. Chrzanowski, S. Ma, Chem. Soc. Rev. 2014, 43, 5841–5866; d) Z.
Guo, B. Chen, Dalton Trans. 2015, 44, 14574–14583.
the reaction was complete, the mixture was allowed to cool down
to room temperature and the catalyst was isolated by centrifuga-
tion. The solution was concentrated to dryness, then CHCl3 (3 mL)
was added to redissolve the residue. 2,4-Dinitrotoluene (0.1 mmol)
was added to 1 mL of the above solution as a 1H NMR internal
standard. The resulting solution was concentrated to dryness for
the 1H NMR test. The remaining 2 mL of the above solution was
purified by flash chromatography. For the high boiling point sub-
strates, the solution was purified by silica gel column chromatogra-
phy to give the corresponding products.
Other experimental details and characterizations are given in the
Supporting Information.
[9] Q. Lin, X. Bu, A. Kong, C. Mao, X. Zhao, F. Bu, P. Feng, J. Am. Chem. Soc.
2015, 137, 2235–2238.
[10] K. Sasan, Q. Lin, C. Mao, P. Feng, Chem. Commun. 2014, 50, 10390–
10393.
Acknowledgments
[11] a) J. H. Cavka, S. Jakobsen, U. Olsbye, N. Guillou, C. Lamberti, S. Bordiga,
K. P. Lillerud, J. Am. Chem. Soc. 2008, 130, 13850–13851; b) T. Devic, C.
Serre, Chem. Soc. Rev. 2014, 43, 6097–6115.
The authors are grateful for financial support from the National
Natural Science Foundation of China (grant number 21471075).
[12] a) W. Morris, B. Volosskiy, S. Demir, F. Gµndara, P. L. McGrier, H. Furuka-
wa, D. Cascio, J. F. Stoddart, O. M. Yaghi, Inorg. Chem. 2012, 51, 6443–
6445; b) T.-F. Liu, D. Feng, Y.-P. Chen, L. Zou, M. Bosch, S. Yuan, Z. Wei, S.
Fordham, K. Wang, H.-C. Zhou, J. Am. Chem. Soc. 2015, 137, 413–419.
[13] X.-S. Wang, M. Chrzanowski, L. Wojtas, Y.-S. Chen, S. Ma, Chem. Eur. J.
2013, 19, 3297–3301.
[14] X.-L. Yang, C.-D. Wu, Inorg. Chem. 2014, 53, 4797–4799.
[15] a) C.-Y. Zhou, W.-Y. Yu, P. W. H. Chan, C.-M. Che, J. Org. Chem. 2004, 69,
7072–7082; b) R. Wakabayashi, T. Kurahashi, S. Matsubara, Org. Lett.
2012, 14, 4794–4797; c) P. Zardi, A. Caselli, P. Macchi, F. Ferretti, E. Gallo,
Organometallics 2014, 33, 2210–2218.
Keywords: heterogeneous catalysis · mesoporous materials ·
metal–organic frameworks · zirconium
[1] a) H.-C. Zhou, J. R. Long, O. M. Yaghi, Chem. Rev. 2012, 112, 673–674;
b) H. C. Zhou, S. Kitagawa, Chem. Soc. Rev. 2014, 43, 5415–5418.
[2] B. F. Abrahams, B. F. Hoskins, R. Robson, J. Am. Chem. Soc. 1991, 113,
3606–3607.
[3] a) C. Y. Lee, O. K. Farha, B. J. Hong, A. A. Sarjeant, S. T. Nguyen, J. T.
Hupp, J. Am. Chem. Soc. 2011, 133, 15858–15861; b) A. Fateeva, P. A.
Chater, C. P. Ireland, A. A. Tahir, Y. Z. Khimyak, P. V. Wiper, J. R. Darwent,
M. J. Rosseinsky, Angew. Chem. Int. Ed. 2012, 51, 7440–7444; Angew.
Chem. 2012, 124, 7558–7562; c) H.-J. Son, S. Jin, S. Patwardhan, S. J.
Wezenberg, N. C. Jeong, M. So, C. E. Wilmer, A. A. Sarjeant, G. C. Schatz,
R. Q. Snurr, O. K. Farha, G. P. Wiederrecht, J. T. Hupp, J. Am. Chem. Soc.
2012, 134, 9537–9540; d) H.-Q. Xu, J. Hu, D. Wang, Z. Li, Q. Zhang, Y.
Luo, S.-H. Yu, H.-L. Jiang, J. Am. Chem. Soc. 2015, 137, 13440–13443.
[4] a) X.-S. Wang, L. Meng, Q. Cheng, C. Kim, L. Wojtas, M. Chrzanowski, Y.-
S. Chen, X. P. Zhang, S. Ma, J. Am. Chem. Soc. 2011, 133, 16322–16325;
b) X.-S. Wang, M. Chrzanowski, W.-Y. Gao, L. Wojtas, Y.-S. Chen, M. J. Za-
worotko, S. Ma, Chem. Sci. 2012, 3, 2823–2827; c) J. A. Johnson, Q. Lin,
L.-C. Wu, N. Obaidi, Z. L. Olson, T. C. Reeson, Y.-S. Chen, J. Zhang, Chem.
Commun. 2013, 49, 2828–2830; d) Z. Guo, D. Yan, H. Wang, D. Tesfa-
gaber, X. Li, Y. Chen, W. Huang, B. Chen, Inorg. Chem. 2014, 53, 200–
204; e) T. C. Wang, W. Bury, D. A. Gómez-Gualdrón, N. A. Vermeulen, J. E.
Mondloch, P. Deria, K. Zhang, P. Z. Moghadam, A. A. Sarjeant, R. Q.
Snurr, J. F. Stoddart, J. T. Hupp, O. K. Farha, J. Am. Chem. Soc. 2015, 137,
3585–3591; f) O. T. Wilcox, A. Fateeva, A. P. Katsoulidis, M. W. Smith,
C. A. Stone, M. J. Rosseinsky, Chem. Commun. 2015, 51, 14989–14991.
[5] a) H.-L. Jiang, D. Feng, K. Wang, Z.-Y. Gu, Z. Wei, Y.-P. Chen, H.-C. Zhou, J.
Am. Chem. Soc. 2013, 135, 13934–13938; b) B. J. Deibert, J. Li, Chem.
Commun. 2014, 50, 9636–9639; c) J. Yang, Z. Wang, K. Hu, Y. Li, J. Feng,
J. Shi, J. Gu, ACS Appl. Mater. Interfaces 2015, 7, 11956–11964.
[6] K. Lu, C. He, W. Lin, J. Am. Chem. Soc. 2014, 136, 16712–16715.
[7] a) A. M. Shultz, O. K. Farha, J. T. Hupp, S. T. Nguyen, J. Am. Chem. Soc.
2009, 131, 4204–4205; b) O. K. Farha, A. M. Shultz, A. A. Sarjeant, S. T.
Nguyen, J. T. Hupp, J. Am. Chem. Soc. 2011, 133, 5652–5655; c) D. Feng,
Z.-Y. Gu, J.-R. Li, H.-L. Jiang, Z. Wei, H.-C. Zhou, Angew. Chem. Int. Ed.
2012, 51, 10307–10310; Angew. Chem. 2012, 124, 10453–10456; d) L.
Meng, Q. Cheng, C. Kim, W.-Y. Gao, L. Wojtas, Y.-S. Chen, M. J. Zaworot-
ko, X. P. Zhang, S. Ma, Angew. Chem. Int. Ed. 2012, 51, 10082–10085;
Angew. Chem. 2012, 124, 10229–10232; e) X.-L. Yang, M.-H. Xie, C. Zou,
Y. He, B. Chen, M. O’Keeffe, C.-D. Wu, J. Am. Chem. Soc. 2012, 134,
10638–10645; f) D. Feng, W.-C. Chung, Z. Wei, Z.-Y. Gu, H.-L. Jiang, Y.-P.
Chen, D. J. Darensbourg, H.-C. Zhou, J. Am. Chem. Soc. 2013, 135,
17105–17110; g) K. Wang, D. Feng, T.-F. Liu, J. Su, S. Yuan, Y.-P. Chen, M.
Bosch, X. Zou, H.-C. Zhou, J. Am. Chem. Soc. 2014, 136, 13983–13986;
h) M. Zhao, S. Ou, C.-D. Wu, Acc. Chem. Res. 2014, 47, 1199–1207; i) J. A.
Johnson, X. Zhang, T. C. Reeson, Y.-S. Chen, J. Zhang, J. Am. Chem. Soc.
[16] H. J. Kim, D. Whang, K. Kim, Y. Do, Inorg. Chem. 1993, 32, 360–362.
[17] a) I. Hod, M. D. Sampson, P. Deria, C. P. Kubiak, O. K. Farha, J. T. Hupp,
ACS Catal. 2015, 5, 6302–6309; b) C.-W. Kung, T.-H. Chang, L.-Y. Chou,
J. T. Hupp, O. K. Farha, K.-C. Ho, Chem. Commun. 2015, 51, 2414–2417.
[18] Y. Liu, A. J. Howarth, J. T. Hupp, O. K. Farha, Angew. Chem. Int. Ed. 2015,
54, 9001–9005; Angew. Chem. 2015, 127, 9129–9133.
[19] a) H. Lu, H. Jiang, L. Wojtas, X. P. Zhang, Angew. Chem. Int. Ed. 2010, 49,
10192–10196; Angew. Chem. 2010, 122, 10390–10394; b) C.-M. Che,
V. K.-Y. Lo, C.-Y. Zhou, J.-S. Huang, Chem. Soc. Rev. 2011, 40, 1950–1975;
c) H. Lu, X. P. Zhang, Chem. Soc. Rev. 2011, 40, 1899–1909; d) G. Tseberli-
dis, P. Zardi, A. Caselli, D. Cancogni, M. Fusari, L. Lay, E. Gallo, Organome-
tallics 2015, 34, 3774–3781; e) D. Intrieri, P. Zardi, A. Caselli, E. Gallo,
Chem. Commun. 2014, 50, 11440–11453.
[20] A. Ciammaichella, A. Leoni, P. Tagliatesta, New J. Chem. 2010, 34, 2122–
2124.
[21] L. Carlucci, G. Ciani, S. Maggini, D. M. Proserpio, F. Ragaini, E. Gallo, M.
Ranocchiari, A. Caselli, J. Porphyrins Phthalocyanines 2010, 14, 804–814.
[22] M. Zhang, Y.-P. Chen, M. Bosch, T. Gentle, K. Wang, D. Feng, Z. U. Wang,
H.-C. Zhou, Angew. Chem. Int. Ed. 2014, 53, 815–818; Angew. Chem.
2014, 126, 834–837.
[23] A. L. Spek, J. Appl. Crystallogr. 2003, 36, 7–13.
[24] S. Wang, J. Wang, W. Cheng, X. Yang, Z. Zhang, Y. Xu, H. Liu, Y. Wu, M.
Fang, Dalton Trans. 2015, 44, 8049–8061.
[25] a) L. Zhang, C. Wang, X. Zhao, F. Yu, F.-F. Yao, J. Li, Inorg. Chem.
Commun. 2015, 55, 123–128; b) W.-Y. Gao, Z. Zhang, L. Cash, L. Wojtas,
Y.-S. Chen, S. Ma, CrystEngComm 2013, 15, 9320–9323.
[26] a) C. Zou, T. Zhang, M.-H. Xie, L. Yan, G.-Q. Kong, X.-L. Yang, A. Ma, C.-D.
Wu, Inorg. Chem. 2013, 52, 3620–3626; b) W. Zhang, P. Jiang, Y. Wang,
J. Zhang, J. Zheng, P. Zhang, Chem. Eng. J. 2014, 257, 28–35; c) M.-H.
Xie, X.-L. Yang, Y. He, J. Zhang, B. Chen, C.-D. Wu, Chem. Eur. J. 2013, 19,
14316–14321.
[27] X.-S. Wang, S. Ma, D. Sun, S. Parkin, H.-C. Zhou, J. Am. Chem. Soc. 2006,
128, 16474–16475.
[28] a) C. Serre, C. Mellot-Draznieks, S. SurblØ, N. Audebrand, Y. Filinchuk, G.
FØrey, Science 2007, 315, 1828–1831; b) T. K. Maji, R. Matsuda, S. Kitaga-
wa, Nat. Mater. 2007, 6, 142–148; c) A. Shigematsu, T. Yamada, H. Kita-
gawa, J. Am. Chem. Soc. 2011, 133, 2034–2036.
[29] S. Henke, A. Schneemann, A. Wütscher, R. A. Fischer, J. Am. Chem. Soc.
2012, 134, 9464–9474.
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6275
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim

Full Paper
[30] a) Q. Zhang, J. Su, D. Feng, Z. Wei, X. Zou, H.-C. Zhou, J. Am. Chem. Soc.
2015, 137, 10064–10067; b) P. Deria, D. A. Gómez-Gualdrón, W. Bury,
H. T. Schaef, T. C. Wang, P. K. Thallapally, A. A. Sarjeant, R. Q. Snurr, J. T.
Hupp, O. K. Farha, J. Am. Chem. Soc. 2015, 137, 13183–13190.
[31] a) S. Horike, S. Shimomura, S. Kitagawa, Nat. Chem. 2009, 1, 695–704;
b) S. Bureekaew, H. Sato, R. Matsuda, Y. Kubota, R. Hirose, J. Kim, K.
Kato, M. Takata, S. Kitagawa, Angew. Chem. Int. Ed. 2010, 49, 7660–
7664; Angew. Chem. 2010, 122, 7826–7830; c) Y. Sakata, S. Furukawa, M.
Kondo, K. Hirai, N. Horike, Y. Takashima, H. Uehara, N. Louvain, M. Meili-
khov, T. Tsuruoka, S. Isoda, W. Kosaka, O. Sakata, S. Kitagawa, Science
2013, 339, 193–196.
[35] D. Intrieri, A. Caselli, F. Ragaini, S. Cenini, E. Gallo, J. Porphyrins Phthalo-
cyanines 2010, 14, 732–740.
[36] Y. Chen, T. Hoang, S. Ma, Inorg. Chem. 2012, 51, 12600–12602.
[37] a) J. S. Seo, D. Whang, H. Lee, S. I. Jun, J. Oh, Y. J. Jeon, K. Kim, Nature
2000, 404, 982–986; b) Y. K. Hwang, D.-Y. Hong, J.-S. Chang, S. H. Jhung,
Y.-K. Seo, J. Kim, A. Vimont, M. Daturi, C. Serre, G. FØrey, Angew. Chem.
Int. Ed. 2008, 47, 4144–4148; Angew. Chem. 2008, 120, 4212–4216;
c) A. Corma, H. Garcia, F. X. L. I. Xamena, Chem. Rev. 2010, 110, 4606–
4655; d) I. Luz, F. X. LlabrØs i Xamena, A. Corma, J. Catal. 2012, 285,
285–291.
[38] A. Dhakshinamoorthy, H. Garcia, Chem. Soc. Rev. 2014, 43, 5750–5765.
[32] A. Karmakar, A. V. Desai, B. Manna, B. Joarder, S. K. Ghosh, Chem. Eur. J.
2015, 21, 7071–7076.
[33] M. Yoon, R. Srirambalaji, K. Kim, Chem. Rev. 2012, 112, 1196–1231.
[34] S. Fantauzzi, E. Gallo, A. Caselli, F. Ragaini, N. Casati, P. Macchi, S. Cenini,
Chem. Commun. 2009, 3952–3954.
Received: January 20, 2016
Published online on March 9, 2016
Chem. Eur. J. 2016, 22, 6268 – 6276
www.chemeurj.org
6276
ꢀ 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim