Metalloporphyrin-based inclusion materials: Exploiting ligating topologies and hydrogen-bonding backbones in generating new supramolecular architectures

Article abstract of DOI:10.1021/ic0702163

By coordination of the metal center of tetraphenylmetalloporphyrins (TPMP) [metal center = Zn(II) or Mn(II)] with pyridyl-based bidentate ligands, namely, N,N′-bis(4-pyridyl)urea (4BPU), N,N′-bis(3-pyridyl)urea (3BPU), and N-(4-pyridyl)isonicotinamide (4PIN), various axially modified tetraarylmetalloporphyrins (AMTAMPs) have been crystallographically characterized in their corresponding lattice inclusion complexes. Nine such inclusion crystals are prepared by crystallizing TPMP and the corresponding bidentate ligands in 1:2 molar ratio from suitable solvent systems. While the metal center Zn(II) of TPMP leads to the formation of both dimeric and monomeric AMTAMPs due to its preference for pentacoordinated geometry, the Mn(II) metal center of TPMP forms both polymeric and discrete hexacoordinated AMTAMPs due to its preference for hexacoordinated geometry. However, there seem to be no control on the formation of a particular AMTAMP. Structural analyses suggest that most of the AMTAMPs display new types of packing in the corresponding inclusion crystals.

Full text of DOI:10.1021/ic0702163

Inorg. Chem. 2007, 46, 7351−7361
Metalloporphyrin-Based Inclusion Materials: Exploiting Ligating
Topologies and Hydrogen-Bonding Backbones in Generating New
Supramolecular Architectures
D. Krishna Kumar,† Amitava Das,*,† and Parthasarathi Dastidar*,‡
Department of Organic Chemistrty, Indian Association for the CultiVation of Science, 2A&2B Raja
S. C. Mullick Road, JadaVpur, Kolkata-700032, West Bengal, India, and Analytical Science
Discipline, Central Salt & Marine Chemicals Research Institute (CSIR), G. B. Marg,
BhaVnagar-364 002, Gujarat, India
Received February 5, 2007
By coordination of the metal center of tetraphenylmetalloporphyrins (TPMP) [metal center
) Zn(II) or Mn(II)] with
pyridyl-based bidentate ligands, namely, N,N -bis(4-pyridyl)urea (4BPU), N,N -bis(3-pyridyl)urea (3BPU), and N-(4-
′
′
pyridyl)isonicotinamide (4PIN), various axially modified tetraarylmetalloporphyrins (AMTAMPs) have been crystal-
lographically characterized in their corresponding lattice inclusion complexes. Nine such inclusion crystals are prepared
by crystallizing TPMP and the corresponding bidentate ligands in 1:2 molar ratio from suitable solvent systems.
While the metal center Zn(II) of TPMP leads to the formation of both dimeric and monomeric AMTAMPs due to its
preference for pentacoordinated geometry, the Mn(II) metal center of TPMP forms both polymeric and discrete
hexacoordinated AMTAMPs due to its preference for hexacoordinated geometry. However, there seem to be no
control on the formation of a particular AMTAMP. Structural analyses suggest that most of the AMTAMPs display
new types of packing in the corresponding inclusion crystals.
Introduction
jugated symmetrical macrocycles possess high rigidity and
high molecular symmetry that are essential for the design
of good building blocks.2 Moreover, they are relatively easily
synthesized and chemically modified, thermally stable, and
largely unreactive; all these qualities are conducive for
developing efficient lattice inclusion host3 and other useful
materials.4 Single-crystal X-ray diffraction studies on a large
number of TAP- and TAMP-based clathrates revealed that
the organization of the porphyrin building blocks is strongly
conserved.5 In the absence of specific nonbonded interactions,
the tetraphenylporphyrins (TPPs) are packed efficiently in
2D via topological complementarity thereby creating voids
in the supramolecular organization which are further filled
Molecules/building blocks that are unable to pack ef-
ficiently in all the three dimensions tend to form supramo-
lecular architecture with voids, open channels that are filled
with guest molecules during crystal formation resulting in
lattice inclusion materials;1 these are important materials
because of their several applications that include conversion
of liquids to solids, molecular separation, controlled release
of guests, and supramolecular storage of reagents. The key
to the design of a lattice inclusion host lies in the judicial
choice of the building block that would self-assemble
primarily via nonbonded interactions generating a supramo-
lecular architecture with voids and/or channels within which
the guest molecules are occluded. The foremost characteristic
of a good building block is its rigidity. Tetraarylporphyrins
(TAPs) and tetraarylmetalloporphyrins (TAMPs) being con-
(2) Byrn, M. P.; Curtis, C. J.; Hsiou, Y.; Khan, S. I.; Sawin, P. A.; Terzis,
A.; Strouse, C. E. In ComprehensiVe Supramolecular Chemistry;
MacNicol, D. D., Toda, F., Bishop, R., Eds.; Pergamon: Oxford, U.K.,
1996; Vol. 6, p 715.
(3) (a) Harada, R.; Matsuda, Y.; Kawa, H.; Kojima, T. Angew. Chem.,
Int. Ed. 2004, 43, 1825. (b) Sharma, C. V. K.; Broker, G. A.;
Huddleston, J. G.; Baldwin, J. W.; Metzger, R. M.; Rogers, R. D. J.
Am. Chem. Soc. 1999, 121, 1137. (c) Kosal, M. E.; Suslick, K. S. J.
Solid State Chem. 2000, 152, 87. (d) Abrahams, B. F.; Hoskins, B.
F.; Michail, D. M.; Robson, R. Nature 1994, 369, 727. (e) Goldberg,
I. Chem.sEur. J. 2000, 6, 3863. (d) Goldberg, I. Chem. Commun.
2005, 1243 and references cited therein. (e) Wojaczyn´ski, J.; Latos-
Gra×c0yn´ski, L. Coord. Chem. ReV. 2000, 204, 113.
* To whom correspondence should be addressed. E-mail: parthod123@
rediffmail.com, ocpd@iacs.res.in (P.D.), amitava@csmcri.org (A.D.). Fax:
+91-33-2473 2805 (P.D.).
† Central Salt & Marine Chemicals Research Institute (CSIR).
‡ Indian Association for the Cultivation of Science.
(1) ComprehensiVe Supramolecular Chemistry; MacNicol, D. D., Toda,
F., Bishop, R., Eds.; Pergamon: Oxford, U.K., 1996; Vol. 6.
10.1021/ic0702163 CCC: $37.00
Published on Web 08/07/2007
© 2007 American Chemical Society
Inorganic Chemistry, Vol. 46, No. 18, 2007 7351

Kumar et al.
Scheme 1
by the guest molecules. The porphyrin core can be judicially
modified by introducing suitable supramolecular synthons6
at strategic positions to achieve desired control and robust-
ness in the structure.7 Another strategy to gain control over
the resultant supramolecular structure is to modify the TAMP
core via axial coordination to the metal center with a suitable
ligand. In this strategy, AMTAMPs (monomer, dimer,
oligomers, and polymers) are synthesized and used as novel
lattice inclusion hosts. We8 along with others9 have shown
that by coordinating the metal center of the porphyrin core
with pyridyl based ligands, novel AMTAMPs can be created
that act as efficient lattice inclusion hosts. The packing of
the TPP/TAMP hosts is generally governed by intermolecular
porphyrin-porphyrin interactions characterized by primarily
C-H···π interactions; parallel chains of porphyrin units are
arranged in layers and channels are located between the
phenyl arms of the porphyrins (Scheme 1). Similar supramo-
Scheme 2
(4) (a) Tao, S.; Li, G.; Zhub, H. J. Mater. Chem. 2006, 16, 4521. (b)
Ogawa, K.; Zhang, T.; Yoshihara, K.; Yoshiaki, K. J. Am. Chem. Soc.
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Science 1994, 264, 1105. (d) Linke, W.; Chambron, J.-C.; Heitz, V.;
Sauvage, J.-P. J. Am. Chem. Soc. 1997, 119, 11329. (e) Wynn, C.
M.; Girtu, M. A.; Sugiura, K.-I.; Brandon, E. J.; Manson, J. L.; Miller,
J. S.; Epstein, A. J. Synth. Met. 1997, 85, 1695. (f) Fox, M. A. Acc.
Chem. Res. 1992, 25, 569. (g) Meunier, B. In Metalloporphyrins
Catalysed Oxidations; Monanari, F., Casella, L., Eds.; Kluwer
Academic: Boston, MA, 1994; p 1. (h) Suslick, K. S. Van Deusen-
Jefries, S. In ComprehensiVe Supramolecular Chemistry: Bioinorganic
Systems; Suslick, K. S., Ed.; Elsevier Science: Oxford, U.K., 1996;
Vol. 5, p 733. (i) Harvey, P. D. In The Porphyrin Handbook; Kadish,
K. M., Smith, K. M., Guilard, R., Eds.; Academic: San Diego, CA,
2003; Vol. 18, Chapter 113.
(5) (a) Byrn, M. P.; Curtis, C. J.; Khan, S. I.; Sawin, P. A.; Tsurumi, R.;
Strouse, C. E. J. Am. Chem. Soc. 1990, 112, 1865. (b) Byrn, M. P.;
Curtis, C. J.; Goldberg, I.; Hsiou.; Khan, S. I.; Sawin, P. A.; Tendick,
S. K.; Strouse, C. E. J. Am. Chem. Soc. 1991, 113, 6549. (c) Byrn,
M. P.; Curtis, C. J.; Hsiou, Y.; Khan, S. I.; Sawin, P. A.; Tendick, S.
K.; Terzis, A.; Strouse, C. E. J. Am. Chem. Soc. 1993, 115, 9480.
(6) Desiraju, G. R. Angew. Chem., Int. Ed. 1995, 34, 2311.
(7) (a) Carlucci, L.; Ciani, G.; Proserpio, D. M.; Porta, F. Angew. Chem.,
Int. Ed. 2003, 42, 317. (b) Pan, L.; Huang, X.; Phan, H.-L. N.; Emge,
T. J.; Li, J.; Wang, X. Inorg. Chem. 2004, 43, 6878. (c) Hagrman, D.;
Hagrman, P. J.; Zubieta, J. Angew. Chem., Int. Ed. 1999, 38, 3165.
(d) Kumar, R. K.; Goldberg, I. Angew. Chem., Int. Ed. 1998, 37, 3027.
(e) Deiters, E.; Bulach, V.; Hosseini, M. W. Chem. Commun. 2005,
3906. (f) Ohmura, T.; Usuki, A.; Fukumori, K.; Ohta, T.; Ito, M.;
Tatsumi, K. Inorg. Chem. 2006, 45, 7988. (g) Kosal, M. E.; Chou,
J.-H.; Wilson, S. R.; Suslick, K. S. Nat. Mater. 2002, 1, 118. (h)
Diskin-Posner, Y.; Dahal, S.; Goldberg, I. Chem. Commun. 2000, 585.
(i) Goldberg, I.; Muniappan, S.; George, S.; Lipstman, S. CrystEng-
Comm 2006, 8, 784. (j) Ring, D. J.; Aragoni, M. C.; Champness, N.
R.; Wilson, C. CrystEngComm 2005, 7, 621. (k) Kempea, R.; Z. Anorg.
Allg. Chem. 2005, 631, 1038. (l) Bharyappa, P.; Wilson, S. R.; Suslick,
K. S. J. Am. Chem. Soc. 1997, 119, 8492.
lecular self-assembly is also observed in many such inclusion
materials derived from AMTAMPs; while penta- and hexa-
coordinated TAMP monomeric species are packed in a
manner wherein the axial ligands occupy the channel space
of the porphyrin arrays along with the guest molecules (if
any),5 the dimer8,9a-c and trimer8 analogues generated by
anchoring two and three TAMP units, respectively, also pack
in the similar fashion (Scheme 2).
However, the AMTAMPs that have been reported thus
far are based on axial modification using pyridyl-based
bidentate ligands with linear ligating topology and an
innocent backbone. In this context, we are interested in
maneuvering the resultant supramolecular organization of
AMTAMPs by exploring the study with pyridyl-based
bidentate ligands with various angular ligating topologies and
a hydrogen bond functionalized (noninnocent) backbone;
angular ligating topology of the bidentate ligand is expected
to generate a bent multicomponent AMTAMP building block
to induce different packing mode, and the hydrogen-bonding
backbones would either recognize each other via comple-
mentary hydrogen bonding in suitable cases or stabilize the
hydrogen bonding capable guest molecules or counteranions,
if any, in the resultant lattice.
(8) Shukla, A. D.; Dave, P. C.; Suresh, E.; Das, A.; Dastidar, P. J. Chem.
Soc., Dalton Trans. 2000, 4459.
(9) (a) Diskin-Posner, Y.; Patra, G. K.; Goldberg, I. J. Chem. Soc., Dalton
Trans. 2001, 2775. (b) Kumar, R. K.; Diskin-Posner, Y.; Goldberg, I.
J. Inclusion Phenom. Macrocyclic Chem. 2000, 37, 219. (c) Kumar,
R. K.; Balasubramanian, S.; Goldberg, I. Chem. Commun. 1998, 1435.
(d) Konarev, D. V.; Litvinov, A. L.; Neretin, I. S.; Drichko, N. V.;
Slovokhotov, Y. L.; Lyubovskaya, R. N.; Howard, J. A. K.; Yufit, D.
S. Cryst. Growth Des. 2004, 4, 643. (e) Alessio, E.; Geremia, S.;
Mestroni, S.; Iengo, E.; Srnova, I.; Slouf, M. Inorg. Chem. 1999, 38,
869. (f) Tat, F. T.; Zhu, Z.; MacMahon, S.; Song, F.; Rheingold, A.
L.; Echegoyen, L.; Schuster, D. I.; Wilson, S. R. J. Org. Chem. 2004,
69, 4602. (g) Choi, M. T. M.; Choi, C.-F.; Ng, D. K. P Tetrahedron
2004, 60, 6889. (h) D’Souza, F.; Rath, N. P.; Deviprasad, G. R.;
Zandler, M. E. Chem. Commun. 2001, 267. (i) Wyllie, G. R. A.;
Schulz, C. E.; Scheidt, W. R. Inorg. Chem. 2003, 42, 5722. (j) Burrell,
A. K.; Jones, B. M.; Hall, S. B.; Officer, D. L.; Reid, D. C. W.; Wild,
K. Y. J. Inclusion Phenom. Macrocyclic Chem. 1999, 35, 185. (k)
Ikeda, T.; Asakawa, M.; Goto, M.; Nagawa, Y.; Shimizu, T. Eur. J.
Org. Chem. 2003, 3744.
7352 Inorganic Chemistry, Vol. 46, No. 18, 2007

Metalloporphyrin-Based Inclusion Materials
ZnTPP is found to be a much better general purpose host
corresponding X-ray structures of the inclusion materials,
the composition of the inclusion materials thus derived, and
the solvent combination used for crystallization (given in
parentheses) reported in this study. As expected, except 2
and 5, all the building blocks are dimers in ZnTPP-based
compounds; relatively high thermodynamic stability of the
binuclear complex13 along with strong affinity of pentaco-
ordination of Zn2+ ion probably induces the formation of a
dimeric building block. However, pentacoordinated mono-
meric building blocks derived from ZnTAP and bidentate
ligands are rare and 2 and 5 are probably the first such
examples in the literature.14 It is interesting to note that when
the crystals of 12 comprised of monomeric building block 2
are dissolved in DMF and recrystallized, inclusion crystals
of 11 containing the dimeric building block 1 are formed
indicating the preferences for forming dimeric building block
in ZnTPP-based materials. On the other hand, Mn3+ in
MnTPP·Cl prefers a hexacoordinated geometry of the metal
center and, thus, formation of either coordination polymer
or discrete hexcoordinated monomer is expected. Out of three
inclusion materials based on MnTPP·Cl reported herein (18-
20), inclusion material 18 is based on coordination of a
polymeric building block, namely, 7; the other two, 19 and
20, are based on hexacoordinated monomeric building
block 8.
for the design of inclusion materials. Double occupation of
2+
2
2
the dx -y orbital of the Zn complex tends to increase the
metal-nitrogen bond distances and destabilizes the ruffled
conformation of the porphyrin plane observed in TPP
complexes with other first row transition metals. Thus, the
more planar ZnTPP has higher symmetry and provides fewer
orientational degrees of freedom, thereby making it a
potential building block. Moreover, Zn2+ displays high
affinity for pentacoordinated environment thereby making
it a suitable candidate for dimeric AMTAMPs and in some
rare occasion trimeric8 AMTAMPs wherein both penta- and
hexacoordinated metal centers are present, whereas Mn3+
has a strong tendency to form hexacoordinated environment
thereby making it a good candidate for polymeric AMTAMPs
although only few TPP-based coordination polymers are thus
far reported.7d,9a,c We have been studying the role of various
bis(pyridyl) ligands having different hydrogen bonding
capable backbones and ligating topologies on the resulting
supramolecular structures of various metal-organic frame-
works (MOFs).10 In this context, we considered it worthwhile
to modify TAMP by axially coordinating the porphyrin core
using some of these bis(pyridyl) ligands.
Thus, we have studied nine inclusion crystals derived from
AMTAMPs generated by axially modifying ZnTPP/MnTPP·
Cl by three pyridyl-based ligands, namely N,N′-bis(4-
pyridyl)urea (4BPU),11 N,N′-bis(3-pyridyl)urea (3BPU),11
and N-(4-pyridyl)isonicotinamide (4PIN).12 Supramolecular
structures of these AMTAMPs in the resultant inclusion
crystals and their thermal behavior are reported.
Molecular Structure of the AMTAMPs As Observed
for the Corresponding Inclusion Crystals. The porphyrin
cores are found to be reasonably planar in all the building
blocks. While pentacoordinated Zn2+ metal ions of the
AMTAMPs 1-5 are slightly away from the porphyrin core
by 0.211-0.416 Å, hexacoordinated Mn3+ ions are located
on the mean porphyrin plane in 7 and 8. Zn-Naxial and Mn-
Results and Discussion
N
axial bond distances are within the usually observed ranges
Synthesis. Our previous encounter with AMTAMPs
synthesis suggests that stoichiometric amount of the reactants
namely TAMP and a bidentate ligand does not yield dimeric
building block;8 twice an excess of the bidentate ligand is a
requirement. Thus, in this study, the reactants are taken in
TAMP-bidentate ligand (1:2) ratio and crystallized from
suitable solvent systems with the hope of obtaining dimeric
AMTAMPs. A total of 11 inclusion crystals namely 10-20
were isolated (Scheme 3). Crystals suitable for single-crystal
X-ray diffraction are chosen and structurally characterized.
However, crystal structures of 10 and 17 could not be fully
determined. Crystal data for 11-16 and 18-20 are listed in
Table 1. Thermogravimetric analyses of all the inclusion
crystals except 12 and 15 are listed in Table 2. Crystals of
12 and 15 are found to be too unstable to perform TGA
experiments.
of 2.105(6)-2.217(6) and 2.216(6)-2.224(5) Å, respectively.
Dimeric AMTAMPs. Among the axial ligands used in
this study, the ligating topologies of 4PIN and 4BPU are
conformation independent and almost linear although not as
linear as their counter analogue, namely, 4,4′-bipyridine,
whereas 3BPU which is a positional isomer of 4BPU that
can have different ligating topologies depending on its
conformation. While syn-syn conformation would lead to
an angular ligating topology, anti-anti conformation will
result into a linear ligating topology in 3BPU. Thus, the
AMTAMPs derived from 4PIN and 4BPU are expected to
form slightly bent dumbbell-shaped dimeric complexes
whereas the shape of the building block generated by syn-
syn 3BPU would be a severely bent dumbbell and that
generated by anti-anti 3BPU would be a linear dumbbell.
When analyzed, it is observed that the dimeric building block
4 in 15 generated by 4PIN is a perfectly linear dumbbell
displaying 0.0° angle between the terminal porphyrin cores.
Meanwhile 3, the building block observed in the inclusion
crystals 13 and 14, displays a severely bent dumbbell shape
Scheme 3 depicts the chemical structure of the reactants,
molecular structures of the AMTAMPs as observed in the
(10) (a) Krishna Kumar, D.; Jose, D. A.; Das, A.; Dastidar, P. Inorg. Chem.
2005, 44, 6933. (b) Krishna Kumar, D.; Das, A.; Dastidar, P. New J.
Chem. 2006, 30, 1267. (c) Krishna Kumar, D.; Das, A.; Dastidar, P.
Cryst. Growth Des. 2006, 6, 1903. (d) Krishna Kumar, D.; Das, A.;
Dastidar, P. J. Mol. Struct. 2006, 796, 139. (e) Krishna Kumar, D.;
Das, A.; Dastidar, P. CrystEngComm. 2006, 805.
(13) Das, A.; Maher, J. P.; McCleverty, J. A.; Badiola, J. A. N.; Ward, M.
D. J. Chem. Soc., Dalton Trans. 1993, 681.
(11) Krishna Kumar, D.; Jose, D. A.; Das, A.; Dastidar, P. Chem. Commun.
2005, 4059.
(12) Krishna Kumar, D.; Jose, D. A.; Dastidar, P.; Das, A. Langmuir 2004,
20, 10413.
(14) CCDC search (CSD 5.27, Nov 2005 release) of a fragment containing
metalated TPP (any transition metal) coordinated by pyridyl fragment
did not show any report of pentacoordinated monomer wherein the
axial ligand is a pyridyl-based bidentate ligand.
Inorganic Chemistry, Vol. 46, No. 18, 2007 7353

Kumar et al.
Scheme 3
with the corresponding porphyrin-porphyrin angles of 74.5
and 75.2°, respectively, which is expected because of the
syn-syn conformation of 3BPU. On the other hand, the
dimeric building block 1 in 11 displays a porphyrin-
porphyrin angle of 23.4°, which appears to be as a result of
the slightly angular ligating topology of 4BPU.
Polymeric AMTAMPs. 3BPU results in a polymeric
building block owing to the fact that Mn3+ prefers a
hexacoordinated environment. The polymeric AMTAMP 7,
found in inclusion crystal 18, displays a linear propagation
due to the linear ligating topology of the anti-anti confor-
mation of 3BPU. Thus, the porphyrin-porphyrin angle in
this polymeric AMTAMP is found to be 36.5°.
Monomeric Pentacoordinated AMTAMPs. As discussed
earlier, generating pentacoordinated AMTAMPs using ZnT-
PP and/or MnTPP and a bidentate ligand is extremely
difficult and there is no guarantee of its successful synthesis.
However, in this study, two such pentacoordinated mono-
mers, namely, 2 and 5 are observed in the inclusion crystals
12 and 16, respectively. In both the cases, the molecular
topology of the building block can be best described as a
“board pin” shaped complex emphasizing the fact that the
bidentate pyridyl ligands approached the metal center in a
near perfect axial direction which is characterized by ∼90.0°
angle involving pyridyl N, metal center, and pyrrole N of
the porphyrin core.
7354 Inorganic Chemistry, Vol. 46, No. 18, 2007

Metalloporphyrin-Based Inclusion Materials
Table 1. Crystal Data
Crystal data
11
12
13
14
15
Empirical formula
Formula weight
Crystal size (mm)
Crystal system
Space group
a (Å)
C
158H122N21O6Zn3
C62.33H46.33ClN8OZn
1024.23
C61.50H44Br2N6OZn
1108.22
0.26 × 0.21 × 0.06
Monoclinic
C2
18.5409(17)
11.9085(11)
23.836(2)
C63.5H50N6OZn
978.47
0.30 × 0.12 × 0.05
Monoclinic
C2
18.5279(11)
11.8843(7)
23.8153(15)
C56.5H40N5.5O0.5Zn
869.31
2606.88
0.40 × 0.18 × 0.06
0.26 × 0.22 × 0.12
0.30 × 0.24 × 0.08
Triclinic
Trigonal
Triclinic
P-1
R-3
39.6465(13)
P-1
13.3651(8)
17.5105(10)
28.9961(17)
92.6800(10)
91.1970(10)
93.4930(10)
6764.0(7)
2
11.170(3)
11.284(3)
22.556(6)
80.641(4)
86.847(6)
73.517(5)
2689.8(12)
2
b (Å)
c (Å)
17.0551(12)
R (0)
â (0)
110.051(2)
109.5620(10)
γ (0)
120.00
23216(2)
18
Volume (Å3)
Z
4943.9(8)
4
1.489
4941.2(5)
4
1.315
D
calc.(g/cm3)
1.280
1.319
1.073
F(000)
2710
0.594
298(2)
-17/17, -23/23,
-38/38
1.17/28.29
78134/31309/22287
9564
0.579
100(2)
2252
2.164
100(2)
2044
0.548
100(2)
903
0.495
100(2)
-14/12, -14/9,
-28/29
1.83/28.37
15586/11589/5117
µ MoKR (mm-1
)
Temperature (K)
Range of h, k, l
-47/45, -41/47,
-22/22, -14/14,
-19/24, -15/14,
-18/20
-28/28
-30/26
θ min/max
1.68/25.00
38435/9092/7356
1.82/25.00
23414/4580/4125
2.07/28.26
14456/5946/5452
Reflections collected/
unique/observed
Data/restraints/
parameters
31309/0/1665
9092/0/650
4580/1/650
5946/1/652
11589/1/524
Goodness of fit on F2
Final R indices
[I > 2σ(I)]
1.043
R1 ) 0.0655
0.965
R1 ) 0.0692
1.012
R1 ) 0.0378
1.017
R1 ) 0.0351
0.872
R1 ) 0.0819
wR2 ) 0.1604
R1 ) 0.0939
wR2 ) 0.1730
wR2 ) 0.2063
R1 ) 0.0787
wR2 ) 0.2149
wR2 ) 0.0893
R1 ) 0.0440
wR2 ) 0.0924
wR2 ) 0.0798
R1 ) 0.0395
wR2 ) 0.0817
wR2 ) 0.2005
R1 ) 0.1723
wR2 ) 0.2361
R indices (all data)
Crystal data
16
18
19
20
Empirical formula
Formula weight
Crystal size (mm)
Crystal system
Space group
a (Å)
C72H57N7O2Zn
1117.62
0.40 × 0.18 × 0.05
Monoclinic
P21/c
11.682(2)
23.694(5)
22.016(4)
C67H48ClMnN10O6
1179.54
C74H53Cl4MnN12O2
1339.02
C78H63ClMnN12O3
1306.79
0.20 × 0.13 × 0.02
0.40 × 0.28 × 0.05
0.34 × 0.18 × 0.04
Triclinic
Triclinic
Triclinic
P-1
P-1
P-1
12.9200(12)
13.9061(12)
16.0531(14)
93.852(2)
94.519(2)
96.530(2)
2848.1(4)
2
12.9146(17)
15.739(2)
17.626(2)
92.632(2)
110.355(2)
105.793(2)
3192.7(7)
2
12.8727(11)
13.0713(11)
20.0292(16)
82.5140(10)
84.0510(10)
78.2670(10)
3261.3(5)
2
b (Å)
c (Å)
R (0)
â (0)
104.749(3)
γ (0)
Volume (Å3)
Z
5894(2)
4
1.260
D
calc.(g/cm3)
1.375
1.393
1.331
F(000)
2336
0.470
150(2)
1220
0.343
100(2)
1380
0.433
150(2)
1362
0.305
100(2)
µ MoKR (mm-1
)
Temperature (K)
Range of h, k, l
θ min/max
Reflections collected/
unique/observed
-15/15, -23/31, -28/27
-15/15, -16/16,-19/19
1.28/25.00
20614/9972/6407
-15/17, -18/20, -23/20
1.25/28.26
17942/13606/8192
-16/16, -16/17, -26/26
1.60/28.34
36619/14928/10100
1.29/28.41
34323/13576/6859
Data/restraints/parameters
Goodness of fit on F2
Final R indices [I > 2σ(I)]
13576/0/731
0.939
R1 ) 0.0579
wR2 ) 0.1506
R1 ) 0.1308
wR2 ) 0.1910
9972/0/699
1.042
R1 ) 0.0964
wR2 ) 0.2091
R1 ) 0.1468
wR2 ) 0.2323
13606/0/836
1.022
R1 ) 0.0686
wR2 ) 0.1637
R1 ) 0.1273
wR2 ) 0.1887
14928/0/878
1.042
R1 ) 0.0575
wR2 ) 0.1462
R1 ) 0.0955
wR2 ) 0.1659
R indices (all data)
Monomeric Hexacoordinated AMTAMPs. Hexacoor-
dinated monomeric AMTAMPs are observed only in the
inclusion materials of MnTPP·Cl since Mn3+ prefers a
hexacoordinated environment. Hexacoordinated monomeric
building block 8 is observed in the corresponding inclusion
crystals 19 and 20. The axial ligand 3BPU in both the
crystallographically independent building blocks located in
the asymmetric unit of 19 displays a nonplanar syn-syn
conformation with pyridyl-pyridyl angles of 33.6 and 58.2°,
respectively. An almost identical molecular topology of the
building block is observed in 20 except that here the pyridyl-
pyridyl angles of 3BPU observed in the two crystallographi-
cally independent building blocks are 31.3 and 51.8°,
respectively.
Supramolecular Architectures of the AMTAMPs In-
clusion Host in the Crystal Structures of the Correspond-
ing Inclusion Materials. Dimeric AMTAMPs. Dimeric
building blocks are observed in the inclusion materials
derived from ZnTPP. All the three axial ligands, namely,
4BPU, 3BPU, and 4PIN result in dimeric building blocks
Inorganic Chemistry, Vol. 46, No. 18, 2007 7355

Kumar et al.
Table 2. Thermogravimetric Data
wt loss %
obsd
calcd
peak temp/°C
11
146.0
212.8
loss of
14.8
10.8
14.1
10.5
5 DMF, 1 H2O
1 DMF, 1 4BPU
13
14
16
30.5
10.8
29.1
9.6
122.9
247.4
4 bromobenzene, 1 H2O
1 3BPU
10.9
20.8
10.3
20.3
131.6
250.1
2 toluene, 1 H2O
2 toluene, 1 3BPU
21.5
18.6
21.4
17.8
151.0
1 p-xylene, 1 2-p-tolylethenol
1 4PIN
264.6, 303.4
18
20.8
18.6
23.5
17.8
110.1
281.5
2 nitrobenzene, 2 H2O
1 3BPU
19
15.7
31.9
15.7
31.9
144.7
1 toluene, 1 CHCl3
2 3BPU
229.6, 287.0
20
12.9
34.8
12.1
34.1
67.5, 136.6
1.5 p-xylene
2 3BPU, 1 H2O
216.2, 266.5
in the corresponding inclusion materials, namely, 11, 13 and
14, and 15, respectively.
[{(ZnTPP)24BPU}·{(ZnTPP)DMF}·4DMF·X] (11). One
dimeric building block 1, one pentacoordinated ZnTPP
wherein the axial site is occupied by the O atom of DMF,
three DMF guests, one disordered DMF, and unaccountable
electron densities presumably from disordered DMF are
located in the asymmetric unit of 11. Since the smeared
electron densities could not be modeled properly, the overall
contribution of the unaccounted electron densities to the
diffraction pattern is subtracted from the observed data using
a “bypass” technique, namely, SQUEEZE;15 subsequent
refinement with these relatively “noisefree” data enabled a
reasonable refinement of the structure.
The slightly bent dumbbell shaped dimers are packed in
a linear fashion via porphyrin-porphyrin interactions result-
ing into the formation of a microporous ladder architecture.
The ladders are then further packed in an offset fashion
thereby blocking the pores of the ladders. However, a
multipore architecture is formed along the ladder axis and
pores are located between the offsetly packed ladder as-
semblies. Smaller voids are located between the axial ligands
of the building blocks whereas the bigger one is located
among the porphyrin arms. While one of the three ordered
DMF molecules forms a bifurcated hydrogen bonding with
the urea funcationality [N···O ) 2.786(3)-3.122(3) Å; N-
H···O ) 169.2-146.2°], the other two are located in the
bigger void. The disordered DMF is located near the smaller
void. The bigger void is also occupied by the pentacoordi-
nated ZnTPP-DMF complex as guest. The disordered DMFs
for which no suitable model could be refined are located in
the smaller voids (Figure 1). Squeezed electrons (97 e/unit
cell) probably indicate the presence of two DMF’s and two
water molecules. Thermal analyses also support these data
(Table 2).
Figure 1. Crystal structure illustration of 11: (a) 1D ladder type array of
the dimeric building block 1 showing open voids; (b) offset pack of the
ladder blocking the voids; (c) overall packing viewed down the ladder
propagation axis displaying multipore architecture wherein the guest
molecules (green, ZnTPP-DMF; red, ordered DMF; blue, disordered DMF)
are located.
[{(ZnTPP)23BPU}·Br-benzene·H2O] (13). The asym-
metric unit of 13 contains half of the dimer 3 (the urea Cd
O of which is sitting on a 2-fold axis), a half-water molecule
[also sitting on the 2-fold and hydrogen bonded to urea
functionality via N-H···O interactions (N···O ) 2.930(8) Å;
N-H···O ) 158.9°)], and two bromobenzenes located on
general positions. The dimers are found to be propagating
along c-axis in a linear fashion apparently directed by
porphyrin-porphyrin interactions. The 1D arrays of the
dimer are then packed in a parallel fashion resulting in a 2D
porous architecture. The guest molecules, namely, bro-
mobenzene are located within the pores. Such 2D layers are
further packed in an offset fashion (Figure 2). TGA data
match well with the X-ray results (Table 2).
Thedimer3seenintheinclusionmaterial[{(ZnTPP)23BPU}·
toluene·H2O] (14) also adopts a near identical supramolecular
assembly as observed in 13. In fact, both these inclusion
materials 13 and 14 display an identical space group (C2)
and very similar cell dimensions. In this inclusion crystal of
14, the guest molecules are toluene and water. TGA analyses
(Table 2) also support the crystallographic finding.
[{(ZnTPP)24PIN}·toluene·X] (15). The dimeric building
block 4 is found to be disordered in the crystal structure of
15 around a center of symmetry which may be arising due
to the statistical centrosymmetric arrangement of the axial
(15) Van der Sluis, P.; Spek, A. L. Acta Crystallogr. 1990, A46, 194.
7356 Inorganic Chemistry, Vol. 46, No. 18, 2007

Metalloporphyrin-Based Inclusion Materials
Figure 3. Crystal structure illustration of 15: (a) 1D ladder type of array
of the dimeric building block 4 displaying pores; (b) overall packing viewed
down the ladder propagation axis. The ordered toluene guests (red) are
located in the cages generated by the porphyrin moieties; disordered guest
molecule (not shown) are located in the bigger channels generated near the
axial ligand moieties.
Polymeric AMTAMPs. Polymeric building blocks are
observed in the inclusion materials derived from MnTPP·
Cl. 3BPU results in a polymeric AMTAMP in the corre-
sponding inclusion crystals 18.
Figure 2. Crystal structure illustration of 13: (a) 1D array of the bent
dimer 3; (b) 2D sheet structure of the 1D array (shown in alternating orange
and purple color) displaying voids; (c) offset packing of the 2D sheets
(shown in purple and orange) and guest occlusion (blue-white-magenta,
bromobenzene). The water guest is embedded within the dimer via hydrogen
bond with urea functionality and not seen here.
[{(MnTPP)3BPU}Cl·2-nitrobenezene·H2O·X]n (18). One
axial ligand 3BPU, two half-MnTPP moieties for which the
Mn centers lie on center of symmetries, a Cl- ion, two
nitrobenzenes, and one water molecule are located in the
asymmetric unit of 18. At the end of the final cycles of
refinement, some disordered electron densities were also
located. SQUEEZE15 calculation (see above) indicated the
presence of 11 e/unit cell which amounts to one disordered
water molecule. TGA results are also commensurate with
these findings (Table 2). In the crystal structure, the axial
ligand which shows an anti-anti conformation coordinates
to the adjacent MnTPP moieties resulting in the formation
of a linear coordination polymer which passes through the
center of the a-c plane and center of the b-axis. The 1D
linear polymeric chains are further packed in a parallel
fashion resulting in the formation of a 2D layer structure.
The porphyrin moieties are approximately perpendicular to
the layer. Thus, when these layers pack in the third
dimension, it results in the formation of cage architecture
within which the guest molecules (nitrobenzene and water)
are accommodated (Figure 4).
ligand, namely, 4PIN. Thus, the asymmetric unit is com-
prised of half of the disordered dimer, one toluene molecule,
and a disordered toluene molecule. In the final refinement,
however, the disordered toluene molecule is squeezed15 out
(see above) because it could not be refined; only the
disordered dimer and one toluene guest are refined. The
dimers are packed via porphyrin-porphyrin interactions
approximately along the diagonal of the a-b plane thereby
creating a 1D ladder type microporous architecture. The 1D
arrays are further packed in an offset manner so that various
voids are created in the hierarchical assembly. The toluene
guest is found to be arrested in the cage type of voids among
the porphyrin moieties. Open channels are also seen between
the offsetly packed ladders; the channels are most probably
accommodated by the disordered toluene (Figure 3). How-
ever, SQUEEZE15 calculations (see above) indicated the
presence of 72 e/unit cell, which is 28 e less than that
expected for two disordered toluene molecules in the unit
cell. This is not surprising as the crystal mounted for X-ray
diffraction was deteriorating fast and, therefore, the residual
electron densities for the disordered toluene was less than
expected. TGA analyses could not be performed for these
crystals because of their fast deterioration.
Pentacoordinated Monomeric AMTAMPs. Pentacoor-
dinated monomeric building blocks are observed only in two
cases, namely, in the crystals of 12 and 16.
[{(ZnTPP)4BPU}·toluene·CHCl3·X] (12). The asym-
metric unit contains one monomer 2, one toluene, one CHCl3
sitting on a 3-fold axis, and several electron density peaks
Inorganic Chemistry, Vol. 46, No. 18, 2007 7357

Kumar et al.
Figure 5. Crystal structure illustration of 12: (a) hydrogen-bonded 1D
array of pentacoordinated dimeric building block 2 (inset: axial view of
1D chain displaying 3-fold symmetry); (b) association of the hydrogen-
bonded chains (interacting chains shown in orange, purple, and green); (c)
overall packing displaying cage architecture within which the guest
molecules (toluene, blue/white; CHCl3, green/white; disordered guest, red)
are located.
Figure 4. Crystal structure illustration of 18: (a) 1D linear coordination
polymeric building block 7; (b) parallel packing of the polymeric chains
resulting in 2D layer structure displaying Cl- ions association with the urea
functionality; (c) packing of the 2D layers creating cage architecture within
which guest molecules (pink and blue ) nitrobenzene; red ) water) are
located; (d) another view of the overall packing.
which appear to be a disordered toluene. In the final
refinement, the unaccounted electron densities are squeezed15
out (see above) and only the host moiety and ordered guest
molecules, namely, toluene and CHCl3 are refined.
In the crystal structure, each monomer is involved in
hydrogen bonding with two neighboring monomers via N-H·
··N hydrogen bonding involving N-H of urea and N of the
pyridyl moiety [N···N ) 2.901(5) Å; N-H···N ) 163.7°].
Such interactions lead to the formation of a 1D hydrogen-
bonded chain displaying 3-fold symmetry. The 1D chains
are further packed in a parallel fashion resulting in the
formation of an architecture containing voids within which
the guest molecules are occluded (Figure 5). SQUEEZE15
calculations (see above) showed the presence of 380 e/unit
cell which may be attributed to 8 toluene molecules. TGA
analyses did not give satisfactory results presumably due to
the escape of the guest molecules at room temperature.
Figure 6. Crystal structure illustration of 16: (a) hydrogen-bonded guest
(2-p-tolylethenol, green) mediated dimer of pentacoordinated monomeric
building block 5; (b) herringbone packing of the hydrogen-bonded dimer
(purple-orange) displaying entrapment of the guest (p-xylene, red).
Hexacoordinated Monomers of AMTAMPs. Hexaco-
ordinated AMTAMPs are observed in MnTPP-derived inclu-
sion crystals 19 and 20.
[{(MnTPP)(3BPU)2}Cl·toluene·CHCl3] (19). The asym-
metric unit of 19 contains two half-moieties of MnTPP, one
CHCl3, one toluene (the Me group of which is disordered
over two places), and a Cl- ion. The counterion Cl- forms
a hydrogen bond with both the monomers via N-H···Cl
hydrogen bonding, while it is involved in hydrogen-bonding
interactions with both the N-H of one monomer [N···Cl )
3.163(3)-3.237(4) Å; N-H···Cl ) 150.8-153.9°] and the
other monomer interacts with the Cl- ion via one N-H of
the urea moiety [N···Cl ) 3.220(4) Å; N-H···Cl )163.6)°].
The metal centers Mn of both the MnTPP moieties sit on a
center of symmetry. There are two crystallographically
independent monomers in the crystal structure. One of the
monomers packs along the b-c plane generating an archi-
tecture containing voids. Further packing analyses reveals
that these voids are occupied by the second monomers as
well as the guest molecules (Figure 7). TGA data (Table 2)
also support these findings.
[{(ZnTPP)4PIN}·p-xylene·2-p-tolylethenol] (16). The
asymmetric unit of 16 contains one monomer 5, one
p-xylene, and one 2-p-tolylethenol. The presence of 2-p-
tolylethenol in the crystal structure is a surprise inclusion of
the alcohol impurity presumably coming from the p-xylene
used for crystallization. In the crystal structure, the mono-
meric unit is involved in hydrogen-bonding interactions with
the alcohol guest via N-H···O and O-H···N interactions [N·
··O ) 2.949(5) Å; N-H···O ) 156.9°; O···N ) 2.762(4) Å;
O-H···N ) 171.0(4)°] around a center of symmetry so that
a guest-mediated hydrogen-bonded dimer of the monomer
5 is formed. The hydrogen-bonded dimers are further packed
in herringbone fashion entrapping the p-xylene guest mol-
ecules in the lattice (Figure 6). TGA data match well with
the X-ray structure (Table 2).
7358 Inorganic Chemistry, Vol. 46, No. 18, 2007

Metalloporphyrin-Based Inclusion Materials
hydrogen bonding with both the urea N-H’s of one
monomer [N···Cl ) 3.212-3.227 Å; N-H···Cl ) 159.0-
(3)-161.0(3)°], it also acts as hydrogen bond acceptor and
interacts with one of the urea N-H’s of the other monomer
[N···Cl ) 3.201(3) Å; N-H···Cl ) 169(3)°]. TGA data also
corroborate well with the X-ray structure (Table 2).
A CSD (CSD 5.27, Nov 2005 release) search conducted
with a search fragment containing a metallo-TPP (only
transition metal) coordinated with a pyridyl moiety results
in 63 hits out of which 7 pentacoordinated monomers, 5
hexacoordinated monomers, 13 dimers, and 3 polymers are
observed; there is only one structure (reference code:
HALXIB) wherein the axial ligand is 4-methylpyridine
conforms to the packing mode depicted for pentacoordinated
momomeric species (Scheme 2). The rest of the six structures
(reference codes: MOSFOP, MOSFIJ, HUCNAU, DACNIF,
MOSFUV, NIOJOM) display different packing modes prob-
ably due to strong interactions with the π-surface of the
porphyrin moiety, and C60, C70, and porphyrin moieties used
in the axial ligand thereby display significant consequences
on the packing modes.
Figure 7. Crystal structure illustration of 19: (a) void containing 2D array
of one of the hexacoordinated monomers in the asymmetric unit; (b) overall
packing showing the other crystallographically independent monomer
occupying the voids. The guest molecules toluene and CHCl3 (red) also
occupy the voids.
The monomeric building block 2 observed in the inclusion
crystal 12 does not conform to the packing modes of
pentacoordinated monomeric species as depicted in Scheme
2. Due to hydrogen-bonding interactions among the axial
ligands 4BPU, it forms a 1D chain with 3-fold symmetry
resulting in the formation of an intriguing packing mode.
On the other hand, the monomeric building block 5 observed
in the inclusion crystal 16 self-assembles to form a hydrogen-
bonded dimer involving the alcohol guest. However, such
dimers do not pack in the way depicted in Scheme 2. It rather
prefers to pack in a herringbone fashion maximizing the
interactions between the axial ligand moieties (in the present
case, both axial ligand 4PIN and the alcohol guest) with the
porphyrin moiety of the building block as also observed in
some dimeric structures such as BABBIQ. It may be noted
that both the structures 12 and 16 display porphyrin-
porphyrin interactions characterized by various C-H···π
interactions17 (3.601-3.808 Å) as observed in many TPP-
based inclusion crystals.
Figure 8. Crystal structure illustration of 20: (a) 2D array of one of the
hexacoordinated monomers displaying two differently sized voids; (b)
overall packing showing how the other monomer (purple) and p-xylene
(blue) occupy the voids.
[{(MnTPP)(3BPU)2}Cl·p-xylene·H2O] (20). Structural
analyses reveal that inclusion crystal 20 is a supramolecular
isomer16 of 19. The asymmetric unit is comprised of two
independent monomers like in 19, two p-xylenes (one of
them residing on a center of symmetry), one water, and a
Cl- ion. Thus, the host building block is identical with that
observed in 19. However, the supramolecular architecture
of the host building block in 20 is entirely different from
that observed in 19 thereby making it a supramolecular
isomer of 19. In this structure, one of the crystallographically
independent dimers packs along the a-c plane resulting in
the formation of a 2D layer structure containing two different
types of voids. The larger voids are then occupied by the
second monomer, and the smaller one is filled with p-xylene
(Figure 8). The water molecule is found to be hydrogen
bonded with the uncoordinated pyridine moiety of the one
of the monomers via O-H···N interactions [O···N ) 2.928
Å (H of water could not be located; thus, the angular
parameter is not available)]. The counterion Cl- is involved
in hydrogen bonding with both the monomers. While it forms
The dimer in 11 adopts a slightly bent topology and
displays a similar, although not identical, packing observed
for linear dimers (Scheme 2); the little difference appears to
be arising due to its need to accommodate a guest as large
as a DMF-coordinated ZnTPP.
Dimer 3 (as observed in both 13 and 14) displays a
severely bent topology. However, it packs in a manner never
observed before in a pyridyl-based metallo-TPP dimer. C-H·
··π mediated (3.732-3.987 Å) porphyrin-porphyrin interac-
tions lead to the formation of a linear array of the dimer
that further self-assembles into offset packed 2D layers with
voids. Dimer 4 (as observed in 15), on the other hand, is
derived from a linear ligand 4PIN and displays a perfectly
(17) (a) Steiner, T.; Starikov, E. B.; Amado, A. M.; Teixeira-Dias, J. J. C.
J. Chem. Soc., Perkin Trans. 2 1995, 1321. (b) Cochran, J. E.; Parrott,
T. J.; Whitlock, B. J.; Whitiock, H. W. J. Am. Chem. Soc. 1992, 114,
2269.
(16) Moulton, B.; Zaworotko, M. J. Chem. ReV. 2001, 101, 1629.
Inorganic Chemistry, Vol. 46, No. 18, 2007 7359

Kumar et al.
linear topology. Thus, it packs the way a linear dimer
generally packs (Scheme 2).
blocks 1 and 4 as observed in 11 and 15, respectively,
conserve the packing mode of dimeric AMTAMPs. However,
the bent AMTAMP 3 as observed in 13 and 14 displays
intriguing packing modes not observed thus far. Board pin
shaped AMTAMP 2 in 12 does not conserve the packing
mode of pentacoordinated monomeric building block; the
hydrogen-bonding backbone, namely, urea of 4BPU influ-
ences the self-assembly of the building block involving the
hydrogen-bonding interactions of the type N-H···N resulting
in a new type of packing. The amide hydrogen-bonding
backbone 5 in 16 interacts with the hydrogen bond capable
guest 2-p-tolylethenol resulting in a supramolecular dimer
that packs in a herringbone fashion. It is worth noting that
the hydrogen-bonding backbones urea and amide did not
show their usual self-complementary hydrogen-bonding
interactions18 in the dimeric building block presumably
because of the fact that the hydrogen-bonding functionalities
are not sterically accessible for such interactions. Hydrogen-
bonding functionalities, however, are able to interact with
the hydrogen bonding capable guests. In the MnTPP-based
materials, the hydrogen-bonding backbone is mainly interact-
ing with the counterion Cl- via N-H···Cl interactions.
The only other two polymers reported thus far (as a result
of the CSD search described above) are BABBUC and
PIKKID which packed in a fashion wherein the polymers
are arranged in parallel arrays displaying no usually observed
porphyrin-porphyrin interactions; the adjacent phenyl arms
of the porphyrin moieties embrace the axial ligands coming
from the neighboring polymeric chains. However, the linear
polymeric building 7 found in 18 displays noteworthy
packing modes observed thus far in pyridyl-based metallo-
TPP polymers. The polymeric units 7 in 18 are packed in a
cagelike architecture within which the guest molecules are
accommodated.
The hexacoordinated monomeric unit 8 observed in both
19 and 20 displays a unique feature. In both the crystals 19
and 20, two crystallographically independent monomeric unit
8 are observed in the asymmetric unit. The packing of one
type of monomer creates voids within which the other
monomeric units along with the guest molecules are accom-
modated. Such type of packing mode in pyridyl-based
hexacoordinated metallo-TPP-based inclusion crystals is, to
the best of our knowledge, not reported thus far.
Porphyrin-Porphyrin Interactions. Porphyrin-porphy-
rin interactions characterized by C-H···π type interactions
involving phenyl arms and pyrrole moieties of the porphyrins
are present in all the dimers as observed in the inclusion
crystals 11 and 13-15 and in pentacoordinated monomers
as observed in 12 and 16. The polymeric building block in
18 and hexacoordinated monomers in 19 and 20 do not show
such interactions.
Summary. Pyridyl-based bidentate ligands having various
ligating topologies and hydrogen-bonding backbones (amide/
urea) have been used to modify ZnTPP/MnTPP building
blocks through axial coordination. Thus, single-crystal
structures of nine inclusion crystals derived from ZnTPP-
or MnTPP-based AMTAMPs generated using axial ligands
4BPU, 3BPU, and 4PIN are reported.
Axial Ligand and AMTAMP Topology. While dimeric
AMTAMPs (1, 3, and 4) are formed in ZnTPP-based
materials (11, 13-15), the polymeric 7 and hexacoordinated
monomeric building block 8 are obtained in MnTPP-based
crystals 18 and 19-20, respectively. Pentacoordinated mon-
omeric building blocks 2 and 5 are observed only in ZnTPP-
based materials (in 12 and 16) displaying “board pin”
topology. The building block 1 displays a slightly bent
topology in 11. Severely bent topology is also displayed by
AMTAMP 3 (as observed in 13 and 14) which is derived
from 3BPU wherein the pyridyl N atoms are more angularly
disposed in its syn-syn conformation compared to its
structural isomer 4BPU. Meanwhile the amide-based biden-
tate ligand 4PIN in which the ligating pyridyl N atoms are
linearly disposed results in a linear dimer 4 as observed in
15. Overall topology of the polymeric building block 7
as observed in 18 is found to be effectively linear although
the intra-porphyrin angle is found to be 36.5°. Hexacoordi-
nated monomeric building block 8 as observed in 19 and
20 displays expected topology wherein the axial ligands
coordinate to the metal center with the perpendi-
cular approach. However, the axial ligands are protruding
out of the porphyrin core in 8 due to the angular disposition
of the coordinating pyridyl N atom of the axial ligand
3BPU.
This study clearly demonstrates how the ligating topologies
and hydrogen-bonding backbone influences the final su-
pramolecular architectures of the AMTAMPs in the corre-
sponding inclusion crystals. The AMTAMP topology and
consequently its supramolecular architecture and inclusion
properties can be modulated by choosing appropriate axial
ligands. Thus, these results presented here provide further
insights into the designing of metalloporphyrin-based inclu-
sion materials.
Experimental Section
Materials and Methods. Syntheses, characterization of ligands
4BPU, 3BPU, and 4PIN were previously reported by our group.11-12
Monomeric ZnTPP and MnTPP were synthesized according to the
standard procedure for porphyrin synthesis. All the solvents were
commercially available and used without further purification. FT-
IR spectra were recorded using Perkin-Elmer Spectrum GX, and
TGA analyses were performed on a Mettler Toledo TGA/
SDTA851e.
AMTAMPs derived from ZnTPP and MnTPP were obtained by
reaction of the metalloporphyrins and the corresponding ligands in
1:2 (TAMP:ligand) molar ratio in suitable solvents. Single crystals
suitable for X-ray analysis of 12-16 (yields 15-20%) and 18-20
(yields 40-45%) were obtained by the slow evaporation of these
(18) (a) Hollingsworth, M. D.; Harris, K. D. In ComprehensiVe Supramo-
lecular Chemistry; MacNicol, D. D., Toda, F., Bishop, R., Eds.;
Pergamon: Oxford, U.K., 1996; Vol. 6, p 177. (b) MacDonald, J. C.;
Whitesides, G. M. Chem. ReV. 1994, 94, 2383.
AMTAMP Topologies, Hydrogen-Bonding Backbone
of the Axial Ligand, and Their Influence on the Self-
Assembly of the AMTAMPs. The linear dimeric building
7360 Inorganic Chemistry, Vol. 46, No. 18, 2007

Metalloporphyrin-Based Inclusion Materials
solutions. Slow evaporation of a solution of 12 in DMF over a
period of 1 week resulted in X-ray-quality single crystals of 11.
X-ray Diffration. X-ray single-crystal data were collected using
Mo KR (λ ) 0.7107 Å) radiation on a SMART APEX diffracto-
meter equipped with CCD area detector. All the crystals except 15
were isolated from the mother liquor and immediately immersed
in Paratone oil and then mounted; a suitable crystal of 15 was sealed
in a glass capillary. Data collection, data reduction, and structure
solution/refinement were carried out using the software package
of SMART APEX. Graphics were generated using MERCURY 1.4.
All structures were solved by direct methods and refined in a
routine manner. In most of the cases, non-hydrogen atoms were
treated anisotropically. The phenyl rings of the porphyrin moiety
were refined as a rigid hexagon in suitable cases. Whenever
possible, the hydrogen atoms were located on a difference Fourier
map and refined. In other cases, the hydrogen atoms were
geometrically fixed.
provided in SHELXL. In 18, two carbon atoms, C(43) and C(54),
of the pyrrole moiety of the porphyrin core were refined isotropi-
cally due to high thermal parameters. In 19, the disordered carbon
atom of the guest molecule toluene was refined using the FVAR
facility. In all cases, repeated measurements of the unit-cell
dimensions from different single crystallites were performed, and
the uniform constitution of all AMTAMPs reported herein was
confirmed.
Acknowledgment. D. K.K. thanks the CSIR, New Delhi,
India, for a senior research fellowship. P.D. thanks the
Department of Science and Technology, New Delhi, India,
for financial support.
Supporting Information Available: FT-IR data, hydrogen-
bonding parameters, TGA plots, and CIFs. This material is available
free of charge via the Internet at http://pubs.acs.org.
In 11, one of the solvent DMF molecules was found to be
disordered and was refined with the FVAR second variable facility
IC0702163
Inorganic Chemistry, Vol. 46, No. 18, 2007 7361