Structural study of few p-phenylenediacetate complexes of Mn2+, Cu2+, Zn2+ and Cd2+

Article abstract of DOI:10.1016/j.ica.2009.06.002

Different metal carboxylate complexes are prepared by reactions of manganese (+2) acetate, copper (+2) acetate, zinc (+2) acetate and cadmium (+2) acetate with p-phenylenediacetic acid under ambient condition with or without a nitrogen donor ligands and e

Full text of DOI:10.1016/j.ica.2009.06.002

Inorganica Chimica Acta 362 (2009) 4268–4271
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Note
Structural study of few p-phenylenediacetate complexes
of Mn2+, Cu2+, Zn2+ and Cd2+
*
W. Marjit Singh, Jubaraj B. Baruah
Department of Chemistry, Indian Institute of Technology Guwahati, Guwahati 39, 781 039 Assam, India
a r t i c l e i n f o
a b s t r a c t
Article history:
Different metal carboxylate complexes are prepared by reactions of manganese (+2) acetate, copper (+2)
acetate, zinc (+2) acetate and cadmium (+2) acetate with p-phenylenediacetic acid under ambient condi-
tion with or without a nitrogen donor ligands and each of them are characterized by conventional spec-
troscopic techniques along with crystallography.
Received 24 April 2009
Received in revised form 2 June 2009
Accepted 3 June 2009
Available online 9 June 2009
Ó 2009 Elsevier B.V. All rights reserved.
Keywords:
Dicarboxylic acid
Coordination polymer
Nitrogen donor ligand
Crystal structure
1. Introduction
(0.245 g, 1 mmol) in methanol (3 ml) was added. The reaction mix-
ture was stirred for 5 min, a white precipitate was obtained. The
The formation of polymeric metal carboxylate complexes is
guided by various factors [1–3] and the dimensionality of such
coordination polymers can be changed by substituents on the li-
gand and/or by solvents [4]. The structural features of metal car-
boxylate coordination polymers originate from different types of
geometries constructed around a metal center by coordinated car-
boxylate ligand/s [5]. Structurally rigid dicarboxylate, for example,
terephthalate anion leads to interesting metallo-organic frame-
work [6], whereas flexible carboxylates, such as malonate anion
is useful in making polymers with different dimensions [7–10].
There is good numbers of studies on coordination complexes of
p-phenylenediacetate [11] and most of the study is directed to-
wards making porous materials through solvothermal process. In
this study, a series of carboxylate complexes are prepared by reac-
tions carried out at ambient condition with different metal ions in
the presence and absence of nitrogen containing ligands. The reac-
tions through which these complexes are prepared are presented
in Scheme 1. We discuss the structures of each of these complexes.
white solid was filtered and the residue was re-dissolved in
milli-Q water (10 ml). The aqueous solution on slow evaporation
gave crystalline product I. The complex II or III were prepared from
I by reacting with corresponding nitrogen donor ligand. For their
synthesis an aqueous solution of I was prepared as described above
and to this solution a solution of 1,10-phenanthroline (0.180 g,
1 mmol) or 2,20-bipyridine (0.158 g, 1 mmol) in milli-Q water
(10 ml) were added to make a homogeneous solution. The solution
on slow evaporation gave the corresponding complex II or III as per
the nitrogen donor ligand.
2.2. Synthesis of coordination polymers IV, V and VI
To a solution of 1,4-phenylenediacetic acid (0.2 g, 1 mmol) in
methanol (7 ml) a solution of the corresponding hydrated metal
(+2) acetate (1 mmol) was added. The reaction mixture on stirring
for 5 min gave precipitate (green in the case of copper, white in the
case of zinc or cadmium). The precipitate was filtered and it was
dissolved in pyridine/methanol (1:5 v/v, 5 ml). A homogeneous
solution was obtained in each case. The solution was allowed to
evaporate slowly for 4–5 days at room temperature, which yielded
the desired coordination polymer IV–VI in pure crystalline form.
2. Experimental
2.1. Synthesis of coordination polymer I and complexes II and III
2.3. Spectral properties of the complexes
To a well stirred solution of 1,4-phenylenediacetic acid (0.2 g,
1 mmol) in methanol (7 ml) a solution of manganese (+2) acetate
Coordination polymer I : Yield: 93%. IR (KBr, cmꢀ1) 3625(s), 3092
(bw), 2926(w), 1552(s), 1405(s), 1283(w), 1203(m), 1164(m),
930(w), 797(m), 720(s), 622(m). Elemental Anal. Calc. for
* Corresponding author. Tel.: +91 361 2582082; fax: +91 361 2690762.
E-mail address: juba@iitg.ernet.in (J.B. Baruah).
0020-1693/$ - see front matter Ó 2009 Elsevier B.V. All rights reserved.
doi:10.1016/j.ica.2009.06.002

W.M. Singh, J.B. Baruah / Inorganica Chimica Acta 362 (2009) 4268–4271
4269
[Mn(Bipy)(H2O)4]L
reported structure [7]. Coordination polymer IV: Yield: 69%. IR
(KBr, cmꢀ1) 3409(bs), 2925 (w), 1578 (s), 1562(s), 1450(m),
1384(s), 1217(m), 1159(w), 1071(w), 763(w), 698(m). Elemental
Anal. Calc. for C20H22N2O6Cu: C, 53.34; H, 4.89. Found: C, 53.52;
H, 5.01%. Magnetic moment (RT) 1.70BM. Coordination polymer V
: Yield: 80%. IR (KBr, cmꢀ1) 3067(bw), 2966(w), 1599(s), 1557(s),
1414(m), 1392(s), 1305(m), 1222(w), 1142(m), 1070(w), 817(w),
770(s), 701(s), 663(m). Elemental Anal. Calc. for C15H15NO5Zn: C,
50.75; H, 4.23. Found: C, 50.81; H, 4.31%. Coordination polymer
VI: Yield: 88%. IR (KBr, cmꢀ1) 3400(bs), 3039 (bw), 2950(w),
1595(s), 1573(s), 1444(m), 1397(s), 1215(w), 1151(w), 753(m),
751(m), 699(s). Elemental Anal. Calc. for C20H24N2O7Cd: C, 46.44;
H, 4.64. Found: C, 46.45; H, 4.62%.
II
[Mn2(L)2(H2O)2]n
[Mn2L(Phen)2(H2O)6]L
I
III
Mn(OAc)2.4H2O
Bipy
Bipy =
Phen
N
N
Mn(OAc)2.4H2O
O
O
Phen =
Py =
Zn(OAc)2.2H2O
Py
HO
OH
N
N
Cu(OAc)2.H2O
Py
N
LH2
Cd(OAc)2.2H2O
[Zn(L)(Py)(H2O)]n
Py
{[Cu(L)(Py)2]2H2O}n
V
IV
{[Cd(L)(Py)2(H2O)](H2O)}n
VI
Scheme 1.
3. Results and discussion
C10H12O6Mn: C, 42.38; H, 4.24. Found: C, 42.44; H, 4.23%. Magnetic
moment (RT) 4.3BM. Complex II : Yield: 68%. IR (KBr, cmꢀ1) 3307
(bw), 3126(bw), 1557(s), 1426(s), 1385(s), 1305(w), 1176(m),
1141(m), 848(s), 772(m), 726(s), 715(w). Elemental Anal. Calc. for
C20H24N2O8Mn: C, 50.49, H, 5.05. Found: C, 50.47; H, 5.10%. Mag-
netic moment (RT) 5.78BM. Complex III: Yield: 67%. It is identified
by comparing its spectroscopic data and crystal structure with
The reaction of p-phenylenediacetic acid with manganese (+2)
acetate tetrahydrate under ambient condition leads to a coordina-
tion polymer I as shown in Scheme 1. The coordination polymer
has six coordinated environments around the manganese centers.
Each of the carboxylate group bridges two manganese centers
and each manganese ion is anchored by four carboxylate groups
Fig. 1. (a) Repeated units in the structure of coordination polymer derived from manganese (+2) with p-phenylenediacetate (I), (b) coordination geometry around manganese
ion, (c) the packing pattern of the coordination polymer. Bond distances (Å): Mn1–O1, 2.15(9); Mn1–O3, 2.19(9); Mn1–O2, 2.21(1). Bond angles (°): O1–Mn1–O3, 85.5(4);
O1–Mn1–O30, 94.5(4); O1–Mn1–O2, 92.0(4); O1–Mn1–O20, 88.0(4); O3–Mn1–O2, 88.5(5); O3–Mn1–O20, 91.5(5); O3–Mn1–O2, 91.5(5).

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for manganese dicarboxylate coordination polymers from different
dicarboxylates depending on the ancillary ligand (see Fig. 1).
Metal dicarboxylate coordination polymers with nitrogen con-
taining bidentate chelate ligands are reported in literature; such li-
gands also have advantages to control the dimensionality of
coordination polymers [14–17]. Thus, a few complexes as well as
coordination polymes of metal p-phenylenediacetate that has
2,20-bipyridine and 1,10-phenanthroline as ancillary ligand are
prepared for structural study. The reaction of manganese (+2) ace-
tate tetrahydrate with p-phenylenediacetic acid in the presence of
ancillary ligands such as 2,20-bipyridine or 1,10-phenanthroline
leads to the formation of mononuclear (II) (Fig. 2) and dinuclear
complex (III) as illustrated in Scheme 1. The dinuclear complex
III was reported in the literature [11] and it was earlier prepared
through a solvothermal process, however we obtained this com-
plex under ambient condition. Each of these complexes has six
coordination environments. In these complexes the two carboxyl-
ate groups of the ligands are anti to each other across the pheny-
lene ring. These complexes have very low solubility in common
solvents making it difficult to perform spectroscopic study in
solution.
While formation of these complexes the nitrogen donor ligands
competes with the carboxylate for coordination to the metal ion
and upon coordination they block some of the coordination sites
to prevent coordination polymerization. Bis-chelated mononuclear
complex of manganese with 1,10-phenanthroline having carboxyl-
ate anion are reported in literature [18]. The nickel (2+) meditated
ring opening reactions of pyromellitic dianhydride in the presence
of 2,20-bipyridine leads to mononuclear cationic complex of nickel
(+2) [16] that has structural similarity to complex II. Coordination
polymer of p-phenylene diacetate of manganese [19] and nickel
[20] containing 1,10-phenanthroline are reported in literature.
From these available data on formation of coordination polymer
as well low nuclearity metal complexes of manganese in the ab-
sence or presence of nitrogen containing chelates, it may be said
that it is the reaction condition along with coordination effect
Fig. 2. Structure of manganese (+2) p-phenylenediacetate complex with 4,40-
bipyridine ligand (II).
of four independent dicarboxylate anions. The manganese centers
are also associated with two water ligands. The manganese poly-
mer has a two dimensional network structure. This is in contrast
to the manganese dicarboxylate coordination polymer having pyr-
idine as ancillary ligand that has one dimensional aqua-bridged
dinuclear manganese cores [12]. Grid-like structures containing
dinuclear manganese cores are also reported in literature [13].
These suggest that the different types of structures are possible
Fig. 3. (a) Structure of p-phenylenediacetate copper (+2) coordination polymer (IV). (b) The coordination environment around copper (+2) ion. Selected bond distances (Å):
Cu1–O1, 1.96(2), Cu1–N1, 2.00(2), Cu1–O3 2.83. Bond angles (°): O1–Cu1–O1, 180.0; O1–Cu1–N1, 92.6(9); O1–Cu1–N1, 87.4(9); O1–Cu1–N1, 87.4(9); O1–Cu1–N1, 92.6(9);
N1–Cu1–N1, 180.0.
Fig. 4. (a) Structure of p-phenylenediacetate zinc (+2) complex (V), (b) coordination environment around zinc (selected bond distances (Å): Zn1–O4, 1.96(1); Zn1–O1,
1.97(1); Zn1–O3, 1.98(1); Zn1–N1, 2.05(1); selected bond angles (°) : O4–Zn1–O1, 98.2(5); O4–Zn1–O3, 123.0(5); O1–Zn1–O3, 105.8(5); O4–Zn1–N1, 100.2(5); O1–Zn1–N1,
128.1(5); O3–Zn1–N1, 103.7(5).

W.M. Singh, J.B. Baruah / Inorganica Chimica Acta 362 (2009) 4268–4271
4271
Fig. 5. (a) Repeated units in the structure of p-phenylenediacetate cadmium (+2) complex (VI). (b) The coordination environment around cadmium (bond distances (Å): Cd1–
O3, 2.26(3); Cd1–O2, 2.35(1); Cd1–N1, 2.38(2); Cd1–O1, 2.56(1); bond angles (°): O3–Cd1–O2, 137.6(4); O2–Cd1–O2, 84.7(9); O3–Cd1–N1, 84.4(5); O2–Cd1–N1, 87.5(6); O2–
Cd1–N1, 100.8(7), N1–Cd1–N1, 168.8(9); O3–Cd1–O1, 86.3(4); O2–Cd1–O1, 52.5(6); O2–Cd1–O10, 134.7(6); N1–Cd1–O1, 92.4(6); N1–Cd1–O1, 86.9(6)).
which decides the dimensionality of the polymerization process in
these manganese dicarboxylate complexes. Thermogravimetric
analysis of the three manganese complexes I–III shows that they
lose water molecules around 80 °C in all the cases.
pyridine ligand favors one dimensional coordination polymer irre-
spective of coordination number of the central metal atom.
Appendix A. Supplementary data
An one dimensional coordination polymer IV of copper(II)
(Fig. 3a) can be prepared from simple reaction of copper(II) acetate
with p-phenylenediacaetic acid followed by crystallization from
pyridine water mixed solvent. It has two pyridine ligands and
two aqua ligands. Two carboxylate ligands act as bridges the cop-
per ions. The polymer has octahedral geometry around the copper
ions (Fig. 3b). In this coordination polymer the pyridine ligands are
trans to each other and the aqua ligands are also trans to each
other. The Cu1–O3 bond (2.83 Å) is much longer than the Cu1–
O1 bond (2.00 Å). This is obvious for copper (+2) which shows
Jahn–Teller distortion.
CCDC 714474, 714475, 714476, 714477, 716805 and 716806
contain the supplementary crystallographic data for this paper.
These data can be obtained free of charge from The Cambridge
Crystallographic Data Centre via www.ccdc.cam.ac.uk/data_re-
quest/cif.
Supplementary data associated with this article can be found, in
the online version, at doi:10.1016/j.ica.2009.06.002.
References
Similarly, the corresponding zinc (2+) p-phenylenediacetate
coordination polymer having pyridine has a distorted tetrahedral
geometry around the zinc (Fig. 4a and b). In the coordination poly-
mer the zinc–nitrogen bond is slightly longer than zinc–oxygen
bonds and it has a chain like structure (Fig. 4a). Similarly, the cad-
mium complex of p-phenylenediacetate and pyridine ligand is also
a one dimensional coordination polymer with all the cadmium ions
having two pyridine and one aqua ligand anchored to them. The
polymer forms a zig-zag chain like structure in which each cad-
mium ions have seven coordination number (Fig. 5). The carboxyl-
ate groups are chelating in this polymer (Fig. 5a). The seven
coordination number for cadmium is common in coordination
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across the rings. Syn or anti arrangements of the carboxylate
groups across the phenylene rings are associated in these metal
complexes. There is a competition between coordination of dicar-
boxylates with aromatic nitrogen containing ligands. The dicarbox-
ylate complexes derived from p-phenylenediacetate having
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