Hydrothermal synthesis of polymeric metal carboxylates from benzene-1,2,4,5-tetracarboxylic acid and benzene-1,2,4-tricarboxylic acid

Article abstract of DOI:10.1016/S0020-1693(01)00318-8

Crystallisation of benzene-1,2,4,5-tetracarboxylic acid or benzene-1,2,4-tricarboxylic acid with divalent metal-ions Co, Mn or Zn and 2,2-bipyridyl gives coordination solids of composition [Co₂(C₁₀H₂O₈)(C₁₀ H₈N₂)₂(H₂O)] (1), [Co₃(C₉H₃O₆)₂ (C₁₀H₈N₂)₂ (H₂O)₂] (2), [Mn₃(C₉H₃O₆)₂ (C₁₀H₈N₂)₂ (H₂O)₂] (3) or [Zn₃(C₉H₃O₆)₂ (C₁₀H₈N₂)₂ (H₂O)₂] (4). Each has a sheet structure with a distorted octahedral coordination environment.

Full text of DOI:10.1016/S0020-1693(01)00318-8

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Inorganica Chimica Acta 315 (2001) 126–132
Note
Hydrothermal synthesis of polymeric metal carboxylates
from benzene-1,2,4,5-tetracarboxylic acid
and benzene-1,2,4-tricarboxylic acid
M. John Plater a,*, Mark R. St J. Foreman a, R. Alan Howie a, Janet M.S. Skakle a,
Alexandra M.Z. Slawin b
a Department of Chemistry, Uni6ersity of Aberdeen, Meston Walk, Aberdeen, AB24 3UE, UK
b Molecular Structure Laboratory, Uni6ersity of St Andrews, St Andrews, Fife, KY16 9ST, UK
Received 12 September 2000; accepted 20 December 2000
Abstract
Crystallisation of benzene-1,2,4,5-tetracarboxylic acid or benzene-1,2,4-tricarboxylic acid with divalent metal-ions Co, Mn or
Zn and 2,2-bipyridyl gives coordination solids of composition [Co2(C10H2O8)(C10H8N2)2(H2O)] (1), [Co3(C9H3O6)2(C10H8N2)2-
(H2O)2] (2), [Mn3(C9H3O6)2(C10H8N2)2(H2O)2] (3) or [Zn3(C9H3O6)2(C10H8N2)2(H2O)2] (4). Each has a sheet structure with a
distorted octahedral coordination environment. © 2001 Elsevier Science B.V. All rights reserved.
Keywords: Hydrothermal; Coordination polymers; CRystal engineering
tals for characterisation purposes1. In this paper we
1. Introduction
report the structures of Co(II), Mn(II) and Zn(II) salts
of benzene-1,2,4,5-tetracarboxylic acid and benzene-
1,2,4-tricarboxylic acid.
Coordination networks crystallised from polyaro-
matic acids and metal-ions are of interest for their
polymeric network structure and their porous proper-
ties [1–6]. Our early studies and those of others showed
the capability of metal-ion salts of 1,3,5-benzenetricar-
boxylic acid to maintain void volume after the removal
of co-crystallised solvent. Our studies showed that net-
worked solids can remain crystalline after the desorp-
tion of non-co-ordinating water molecules. Leaving the
metal-ion coordination environment intact maintains
structural rigidity or crystallinity of the lattice despite
the creation of void volume in the lattice [4,5]. Dehy-
dration of the metal-ion coordination environment in-
evitably leads to a partial loss of crystallinity that can
be easily restored by rehydration. Hydrothermal meth-
ods of synthesis are used to obtain suitably sized crys-
2. Experimental
All organic chemicals were purchased from either
Aldrich or Lancaster while metal salts were purchased
from Aldrich. Hydrothermal reactions were performed
using previously desribed equipment [4]. All infra-red
spectra were recorded on KBr discs using a ATI
Mattson Genesis series FTIR spectrometer. Thermal
gravimetric analyses were performed in an atmosphere
1 Larger crystals have a lower surface area to weight ratio com-
pared to smaller crystals so are expected to form on extended heating
for thermodynamic reasons. Re-dissolution of a large crystal would
be slower than for an equivalent weight of smaller crystals. By
examination of hydrothermal reactions of polyaromatic acids per-
formed in pyrex tubes it can be seen that the bulk of the material
remains undissolved.
* Corresponding author. Tel.: +44-1224-272943; fax: +44-1224-
272921.
E-mail address: m.j.plater@abdn.ac.uk (M.J. Plater).
0020-1693/01/$ - see front matter © 2001 Elsevier Science B.V. All rights reserved.
PII: S0020-1693(01)00318-8

M.J. Plater et al. / Inorganica Chimica Acta 315 (2001) 126–132
127
of either flowing nitrogen gas or air using a Stanton
Redcroft STA-780. Microanalyses was preformed by
Butterworth Laboratories Ltd while cobalt analyses
was carried out using a Varian Spectra AA-10 using an
air/acetylene flame.
1604m, 1578s, 1561s, 1489w, 1470m, 1439s, 1420m,
1386s, 1320w, 1311m, 1247w, 1166w, 1152w, 1135m,
1114w, 1110w, 1055w, 1025m, 945m, 896w, 882w,
858m, 823w, 802m, 767s, 735m, 722w, 662m, 653m,
634w, 590w, 542m, 454m and 416m (cm−1); TGA (air)
no change occurred until at 300°C a vigorous exother-
mic mass loss commenced.
2.1. Synthesis of [Co2(C10H2O8)(C10H8N2)2(H2O)] (1)
Benzene-1,2,4,5-tetracarboxylic acid (100 mg, 0.39
mmol), cobalt acetate tetrahydrate (196 mg, 0.787
mmol), and 2,2%-bipyridyl (123 mg, 0.788 mmol) were
placed together in a 45 ml bomb with water (20 ml).
After sealing the bomb was heated at a rate of 100°C
2.2. Synthesis of [Co3(C9H3O6)2(C10H8N2)2(H2O)2] (2)
Benzene-1,2,4-tricarboxylic acid (101 mg, 0.481
mmol), cobalt acetate tetrahydrate (119 mg, 0.480
mmol), 2,2-bipyridyl (76 mg, 0.487 mmol) and water
(10 ml) were placed in a 23 ml bomb. After sealing the
bomb was heated at 20°C h−1 to 230°C. After main-
taining at this temperture for 2 h the bomb was cooled
at a rate of 5°C h−1 to 180°C. After a further 6 h the
bomb was cooled at 2°C h−1 to 90°C before cooling to
50°C at 4°C h−1 and then cooling at 5°C h−1 to room
h
−1 to 180°C. After maintaining at this temperature for
2 h the bomb was cooled at a rate of 2°C h−1 to 20°C.
The dark red product (248 mg, 93%) was collected by
filtration and air dried. (Anal. Found: C, 52.1; H, 2.9;
N, 8.0; Co, 17.4. [Co2(C10H2O8)(2,2%-bipy)2(H2O)] re-
quires: C, 51.6; H, 2.9; N, 8.0; Co, 16.9%); IR (KBr)
Fig. 1. Top: Drawing of the Co coordination environment in 1. Bottom: Drawing showing a water binding to two Co cations.

128
M.J. Plater et al. / Inorganica Chimica Acta 315 (2001) 126–132
Fig. 2. Drawing showing the 2-D sheets in 1. 2,2-Bipyridyl ligands are omitted for clarity.
temperture (r.t.). Red crystals were harvested (209 mg,
81%). (Anal. Found: C, 48.3; H, 2.6; N, 5.7.
[Co3(C9H3O6)2(C10H8N2)2(H2O)2] requires: C, 48.6; H,
2.8; N, 6.0%); IR (KBr) 3467br, 1620s, 1599m, 1577m,
1561m, 1534w, 1508w, 1491m, 1474m, 1438m, 1401s,
1384sh, 1314w, 1286w, 1249w, 822w, 806m, 770m,
736m (cm−1); TGA above 200°C decomposition
occurs.
783w, 769m, 730m, 666w, 650w, 627w, 607w, 505m and
411m (cm−1); TGA above 170°C decomposition oc-
curs.
2.4. Synthesis of [Zn3(C9H3O6)2(C10H8N2)2(H2O)2] (4)
Benzene-1,2,4-tricarboxylic acid (99.9 mg, 0.476
mmol), zinc acetate dihydrate (158 mg, 0.720 mmol),
2,2-bipyridyl (113 mg, 0.723 mmol) and water (10 ml)
were placed in a 23 ml bomb and heated as for struc-
ture 2. The product was harvested as a white solid (170
mg, 74%). (Anal. Found: C, 47.6; H, 2.3; N, 5.4.
[Zn3(C9H3O6)2(C10H8N2)2(H2O)2] requires: C, 47.6; H,
2.7; N, 5.8%); IR (KBr) 3419br, 1621s, 1599s, 1585s,
1567s, 1544m, 1491m, 1476w, 1438m, 1396s, 1384s,
1317w, 1288w, 1251w, 1223w, 1173w, 1156w, 1131w,
1101w, 1076w, 1057w, 1025w, 1012w, 972w, 944w,
933w, 906w, 872w, 824m, 725w, 669w, 652w, 630w,
609w, 540w and 415m (cm−1); TGA above 170°C
decomposition occurs.
2.3. Synthesis of [Mn3(C9H3O6)2(C10H8N2)2(H2O)2] (3)
Benzene-1,2,4-tricarboxylic acid (151 mg, 0.722
mmol), manganese acetate tetrahydrate (178 mg, 0.726
mmol), 2,2-bipyridyl (114 mg, 0.730 mol) and water (20
ml) were placed in a 45 ml bomb. After sealing the
bomb was heated at 20°C h−1 to 230°C. After main-
taining at this temperature for 2 h the bomb was cooled
at a rate of 5°C h−1 to 180°C. After a further 6 h the
bomb was cooled at 2°C h−1 to 90°C before cooling to
50°C at 4°C h−1 and then cooling at 5°C h−1 to r.t.
Crystals were harvested (178 mg, 80%). (Anal. Found:
C, 48.8; H, 2.4; N, 6.1. [Mn3(C9H3O6)2(C10H8N2)2-
(H2O)2] requires: C, 49.2; H, 2.8; N, 6.0%); IR (KBr)
3415br, 1678w, 1635sh, 1621s, 1597s, 1577s, 1561s,
1527m, 1490m, 1475w, 1436m, 1399s, 1355w, 1318w,
1293w, 1246w, 1218w, 1176w 1154w, 1134w, 1076w,
1056w, 1018m, 949w, 931w, 898w, 871w, 823w, 802m,
2.5. X-ray crystallographic studies
Details of the structure determinations are given in
Table 5. X-ray diffraction measurements were made
with graphite-monochromated Mo Ka radiation (u=
,
0.71073 A) using a Bruker SMART diffractometer [7].

M.J. Plater et al. / Inorganica Chimica Acta 315 (2001) 126–132
129
Table 1
a
,
Selected bond distances (A) and angles (°) for structures 1, 2 and 3
Compound 1
Co1–O10
Co1–N1
Co1–O20
Co1c1–O16
Co1–O15c1
Co1–N10
2.013(4)
2.102(5)
2.155(3)
2.326(5)
2.083(5)
2.103(5)
O10–Co1–O15c1
O15c1–Co1–N1
O15c1–Co1–N10
O10–Co1–O20
95.6(2)
97.2(2)
91.2(2)
88.7(2)
113.9(2)
92.9(2)
156.5(2)
89.5(2)
O10–Co1–N1
O10–Co1–N10
N1–Co1–N10
90.0(2)
167.1(2)
78.2(2)
148.7(2)
91.2(2)
59.4(2)
100.0(2)
O15c1–Co1–O20
N1–Co1–O20
N10–Co1–O20
O10–Co1–O16c1
N1–Co1–O16c1
O20–Co1–O16c1
O15c1–Co1–O16c1
N10–Co1–O16c1
Compound 2
Co1–O4c1
Co1–O5c1
Co1–O1
Co1–N1
Co1–N2
2.035(2)
2.065(2)
2.095(2)
2.098(2)
2.143(2)
2.360(2)
2.080(2)
2.118(2)
2.133(2)
O4c1–Co1–O5c1
O4c1–Co1–O1
O5c1–Co1–O1
O4c1–Co1–N1
O5c1–Co1–N1
O1–Co1–N1
O4c1–Co1–N2
O5c1–Co1–N2
O1–Co1–N2
87.0(1)
96.4(1)
103.5(1)
109.8(1)
88.1(1)
151.9(1)
97.7(1)
164.7(1)
90.5(1)
76.6(1)
147.9(1)
80.6(1)
O1–Co1–O2
N1–Co1–O2
N2–Co1–O2
O6c2–Co2–O3c4
O6c3–Co2–O3c4
O6c3–Co2–O3
O6c2–Co2–O7
O6c3–Co2–O7
O3c4–Co2–O7
O3–Co2–O7
58.6(1)
99.3(1)
101.0(1)
86.8(1)
93.3(1)
86.7(1)
86.6(1)
93.4(1)
89.9(1)
90.1(1)
93.4(1)
Co1–O2
Co2–O6c2
Co2–O3
Co2–O7
N1–Co1–N2
O4c1–Co1–O2
O6c2–Co2–O7c4
O5c1–Co1–O2
Compound 3
Mn1–O5cl
Mn1–O3c1
Mn1–O2
Mn1–O1
Mn1–N1
2.258(4)
2.267(4)
2.299(4)
2.342(3)
2.359(4)
2.374(4)
2.250(3)
2.305(4)
2.391(4)
O5c1–Mn1–O3c1
O5c1 –Mn1–O2
O3c1–Mn1–O2
O5c1–Mn1–O1
O3c1–Mn1–O1
O2–Mn1–O1
O5c1–Mn1–N1
O3c1–Mn1–N1
O2–Mn1–N1
82.1(2)
84.4(2)
141.4(1)
110.0(1)
91.4(1)
O5c1–Mn1–N2
O3c1–Mn1–N2
O2–Mn1–N2
O1–Mn1–N2
N1–Mn1–N2
O4c2–Mn2–O6c3
O4–Mn2–O6c3
O4–Mn2–O6c4
O4c2–Mn2–O7
O4–Mn2–O7
O6c3–Mn2–O7
O6c4–Mn2–O7
O4c2–Mn2–O7c2
O4–Mn2–O7c2
O6c3–Mn2–O7c2
O6c4–Mn2–O7c2
160.2(1)
103.4(2)
101.5(2)
89.1(2)
72.3(2)
84.5(1)
95.5(1)
84.5(1)
91.8(1)
88.2(1)
86.3(1)
93.7(1)
88.2(1)
91.8(1)
93.7(1)
86.3(1)
Mn1–N2
Mn2–O4
60.0(1)
88.1(1)
Mn2–O6c3
114.3(1)
101.1(2)
150.8(2)
160.2(1)
103.4(2)
101.1(2)
150.8(2)
Mn2–O7
O1–Mn1–N1
O5c1–Mn1–N2
O3c1–Mn1–N2
O2–Mn1–N1
O1–Mn1–N1
a Symmetry transformations used to generate equivalent atoms: for 1: c1 −x+1, y, −z+3/2; c2 x, −y+1, −z+2; c3 −x+2, y, −z+3/2;
for 2: c1 −x, −y, −z+1; c2 −x, −y−1, −z+1; c3 x−1, y, z; c4 −x−1, −y−1, −z+1; c5 x+1, y, z.
Table 4
Table 2
a
,
Hydrogen bonds (A and °) for structure 3
,
Hydrogen bonds (A and °) for structure 1
D–H···A
d(D–H) d(H···A) d(D···A) Ú(DHA)
D–H···A
d(D–H)
d(H···A)
d(D···A)
Ú(DHA)
O(7)–H(7WA)···O(3)
0.64(8) 2.04(8) 2.677(6)
179(10)
153(6)
118(5)
O20–H20–O11
1.71(1)
151.5(7)
O(7)–H(7WB)···O(2)c6 1.20(9) 1.89(9) 3.005(6)
O(7)–H(7WB)···O(5)c4 1.20(9) 2.44(8) 3.187(6)
Table 3
a Symmetry transformations used to generate equivalent atoms:
c1 −x, −y, −z+1; c2 −x−1, −y−1, −z+1; c3 −x,
−y−1, −z+1; c4 x−1, y, z; c5 x+1, y, z; c6 −x−1, −y,
−z+1.
a
,
Hydrogen bonds (A and °) for structure 2
D–H···A
d(D–H) d(H···A) d(D···A) Ú(DHA)
O(7)–H(7WA)···O(4)
0.74(4) 1.99(4) 2.684(3)
155(4)
142(4)
138(4)
O(7)–H(7WB)···O(2)c6 0.79(5) 2.25(5) 2.910(3)
Intensity data were collected using 0.3° width steps
accumulating area detector frames spanning at least a
hemisphere of reciprocal space for all structures (data
were integrated using the SAINT program [7]). All data
were corrected for Lorentz, polarisation and long-term
O(7)–H(7WB)···O(5)c3 0.79(5) 2.32(5) 2.959(3)
a Symmetry transformations used to generate equivalent atoms:
c1 −x, −y, −z+1; c2 −x, −y−1, −z+1; c3 x−1, y, z; c4
−x−1, −y−1, −z+1; c5 x+1, y, z; c6 −x−1, −y, −z+1.

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M.J. Plater et al. / Inorganica Chimica Acta 315 (2001) 126–132
Table 5
Summary of key crystallographic data for compounds 1–3
Compound
1
2
3
Formula
M
C30H20Co2N4O9
698.4
C
469.7
19H13Co1.5N2O7
C19H13Mn1.5N2O7
463.72
T (K)
293(2)
orthorhombic
C2221
300(2)
triclinic
293(2)
triclinic
Crystal system
Space group
Z
(
(
P1
P1
2
4
2
Unit cell dimensions
,
a (A)
10.9864(10)
19.128(2)
12.4073(11)
7.6299(3)
10.7948(4)
11.6418(5)
81.657(2)
76.043(1)
71.052(2)
877.79(6)
1.777
7.8295(6)
11.3147(9)
12.6076(11)
82.024(2)
75.835(2)
73.651(2)
1036.21(15)
1.486
,
b (A)
,
c (A)
h (°)
i (°)
k (°)
3
,
V (A )
2607.4(4)
1.779
1.342
0.12×0.12×0.14
8135
Density calc. (Mg m−3
)
v (mm−1
)
1.483
0.03×0.02×0.01
10765
0.970
0.2×0.1×0.02
9435
Crystal size (mm3)
Reflections collected
Independent reflections/Rint
Data/restraints/parameters
GoF on F2
3099/0.1075
3047/1/209
0.923
0.0615/0.1237
0.1216/0.1568
0.722/−1.051
4647/0.0109
4647/0/276
0.995
0.0380/0.0873
0.0607/0.0954
0.487/−0.317
6245/0.0868
6245/0/276
0.843
0.0635/0.1409
0.1613/0.2225
0.780/−0.615
R1/wR2 (F2\2|(F2)]
(all data)
−3
,
Largest difference peak and hole (e A
)
.
Fig. 3. Top: Drawing of the coordination environment of Co1 in structure 2. Bottom: Drawing of the coordination environment of Co2.

M.J. Plater et al. / Inorganica Chimica Acta 315 (2001) 126–132
131
Fig. 4. Drawing of the double layer sheets in structure 2.
intensity fluctuations. Absorption effects were corrected
on the basis of multiple equivalent reflections or by
semi-empirical methods using SADABS [7]. Structure 1
was solved by direct methods and refined by full-matrix
has a distorted octahedral geometry. Two bipyridine
nitrogens bind to the cobalt, one carboxylate chelates
to the cobalt while a second carboxylate binds through
only one oxygen. To complete the coordination sphere
a water is binding to the metal. The water ligand
bridges between two cobalts and the water hydrogen
bonds to a carboxylate oxygen O11. The Co–O–Co
angle is 120.8° (Tables 1–4). The crystal structre con-
sists of infinite layers consisting of cobalt atoms cross
linked by both waters and the carboxylates. Between
these hydrated cobalt carboxylate layers are layers of
2,2%-bipyridine ligands.
least-squares against F2
(SHELXTL). The water hydro-
gen atom was refined isotropically subject to a distance
constraint. All other hydrogen atoms were assigned
riding isotropic displacement parameters and were con-
strained to idealised geometries. Refinements converged
to residuals given in Table 5. All calculations were
made with SHELXTL [7]. For structures 2 and 3, struc-
tures were solved by Patterson methods in SHELXS-86
[8] and refined using SHELXL-97 [8]. These structures
were found to be isostructural, and for these structures
the water hydrogen atoms were located from the differ-
ence Fourier map and refined freely. All other hydro-
gen atoms were constrained as for structure 1. Structure
4 was confirmed to be isostructural with 2 and 3 by
powder diffraction.
3.2. Structural description of [Co3(C9H3O6)2-
(C10H8N2)2(H2O)2] (2)
Compound 2 contains cobalt atoms in two different
coordination environments (Figs. 3 and 4). The two
,
different cobalts are separated by a distance of 5.105 A.
Co1 has a distorted octahedral coordination geometry
and consists of a chelating bipyridine ligand, a
chelating carboxylate group and two more carboxylate
oxygens. The two carboxylates which are binding
through one oxygen to Co1 have an ortho relationship
on the benzene ring. The coordination geometry of
Co2 is also distorted octahedral, and consists of two
waters arranged trans and four carboxylate groups.
3. Results and discussion
3.1. Structural description of [Co2(C10H2O8)-
(C10H8N2)2(H2O)] (1)
The structure is shown in Figs. 1 and 2. The cobalt

132
M.J. Plater et al. / Inorganica Chimica Acta 315 (2001) 126–132
Each of the carboxylates bridges to a cobalt Co1 but no
bridges through a single oxygen are present in contrast
with the solid formed from the isomer 1,3,5-benzenetri-
carboxylic acid, cobalt acetate and 2,2-bipyridyl.
Acknowledgements
We are grateful to the Leverhulme Trust for financial
support.
3.3. Structural description of [Mn3(C9H3O6)2(C10H8N2)2-
(H2O)2] (3) and [Zn3(C9H3O6)2(C10H8N2)2(H2O)2] (4)
References
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Crystallographic data for the structural analyses have
been deposited with the Cambridge Crystallographic
Data Centre, CCDC nos. 157777, 157778 and 157843.
Copies of this information may be obtained free of
charge from the Director, CCDC, 12 Union Road,
Cambridge, CB2 1EZ, UK (fax: +44-1223-336-033;
e-mail: deposit@ccdc.cam.ac.uk or http://www.ccdc.
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