Journal of Inorganic and General Chemistry
Zeitschrift für anorganische und allgemeine Chemie
www.zaac.wiley-vch.de ARTICLE
DOI: 10.1002/zaac.201600361
Syntheses and Structures of Monomeric and Dimeric Ternary Complexes of
Copper(II) with 2,2'-Bipyridyl and Carboxylate Ligands
Syeda Shahzadi Batool,*
[a]
Syeda Rubina Gilani,
[a]
Muhammad Nawaz Tahir,
[b]
and
William T. A. Harrison*
[c]
Dedicated to Prof Anthony K. Cheetham on the Occadion of his 70th Birthday
Keywords: Cinnamic acid; p-Amino benzoic acid; Isomers; Copper; Supramolecular architecture
Abstract. The syntheses and crystal structures of Cu(C
10
H
8
N
2
)
(C
9
H
7
O
2
)(H
2
O) (1) and [Cu
2
(C
10
H
8
N
2
)
2
(C
7
H
6
NO
2
)
3
(C
7
H
7
NO
2
)]·
Cl·3H
2
O(2) are described [C
10
H
8
N
2
= 2,2'-bipyridine (bipy), C
9
H
7
O
2
–
= cinnamate anion (cinn
–
), C
7
H
6
NO
2
–
= p-amino benzoate anion
(paba
–
), and C
7
H
7
NO
2
= p-amino benzoic acid (Hpaba)]. Complex 1
[triclinic, space group P1
¯
(no. 2), a = 12.0357 (7) Å, b = 13.8799
(8) Å, c = 16.3225 (9) Å, α = 84.916 (3)°, β = 88.551 (3)°, γ = 67.877
(3)°, V = 2516.0 (2) Å
3
, Z = 4] contains two molecules in the asymmet-
ric unit: both feature a distorted square-pyramidal CuN
2
O
3
chromo-
phore arising from the coordination of a bidentate bipy ligand, two
monodentate cinn
–
anions, and a water molecule to the metal ion. The
1 Introduction
Ternary copper(II) carboxylate complexes incorporating
N,N-chelating ligands such as 2,2-bipyridine (bipy) and 1,10-
phenanthroline (phen) have been reported to exhibit rich struc-
tural diversity in their ligand coordination modes, metal-ion
arrangements and their various nuclearities including mononu-
clear,
[1]
dinuclear,
[2–4]
trinuclear,
[5]
tetranuclear,
[6]
hexanu-
clear,
[7]
and polynuclear
[8]
species. From the point of view of
the ligand, the coordination modes adopted by the carboxylate
moieties in mixed-ligand complexes include monodentate, bi-
dentate (chelating), and bridging modes.
[9]
For example, in the
mononuclear complex [Cu(C
10
H
8
N
2
)(C
8
H
5
O
3
)
2
], the 4-for-
mylbenzoate (C
8
H
5
O
3
–
) anion coordinates to the metal
ion in a monodentate manner,
[10]
whereas the complex
* Dr. S. S. Batool
E-Mail: syeda_shahzadi_uet@yahoo.com
* Dr. W. T. A. Harrison
E-Mail: w.harrison@abdn.ac.uk
[a] Department of Chemistry
University of Engineering and Technology
Lahore 54890, Pakistan
[b] Department of Physics
Sargodha University
Sargodha, Pakistan
[c] Department of Chemistry
University of Aberdeen
Aberdeen AB24 3UE, Scotland
Supporting information for this article is available on the WWW
under http://dx.doi.org/10.1002/zaac.201600361 or from the au-
thor.
Z. Anorg. Allg. Chem. 0000, ,(), 0–0 © 0000 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim 1
cation in complex 2 [orthorhombic, space group P2
1
2
1
2
1
(no. 19), a =
13.5061 (10) Å, b = 18.1441 (11) Å, c = 18.9671 (13) Å, V = 4648.1
(5) Å
3
, Z = 4] is dimeric with square pyramidal CuN
2
O
3
and CuN
3
O
2
metal coordination polyhedra: each metal ion is coordinated by a bi-
dentate bipy ligand and two bridging paba
–
anions; the apical coordina-
tion site of one is occupied by an O-bonded paba
–
anion and the other
by an N-bonded Hpaba neutral molecule. The cation in 2 is isomeric
with the previously reported [Cu
2
(C
10
H
8
N
2
)
2
(C
7
H
6
NO
2
)
2
(C
7
H
7
NO
2
)
2
]
2+
cation, in which both apical Hpaba molecules are N-bonded to their
metal ions.
[Cu(C
8
H
7
O
3
)
2
(C
10
H
8
N
2
)]·H
2
O
[11]
can be cited as an example
in which the 3-methoxybenzoate (C
8
H
7
O
3
–
) anion assumes a
bidentate or chelating mode. The bridging coordination mode
is more frequent in carboxylic acids having more than one
carboxylate grouping, but mono-carboxylates can also act as
bridging ligands. The different modes of coordination of carb-
oxylate O atoms to Cu
II
may include any of the syn-syn, syn-
anti, and anti-anti conformations, which further increases the
structural versatility of these compounds. In the extended
structures, self-assembly of these monomeric and dimeric units
leads to supramolecular networks, interwoven by non-covalent
interactions such as π–π stacking and classical and “weak”
hydrogen-bonding interactions.
[8,10,11]
As part of our ongoing studies in this area,
[12,13]
we
now report the syntheses and single-crystal structures of
the title complexes Cu(C
10
H
8
N
2
)(C
9
H
7
O
2
)(H
2
O) (1) and
[Cu
2
(C
10
H
8
N
2
)
2
(C
7
H
6
NO
2
)
3
(C
7
H
7
NO
2
)]·Cl·3H
2
O (2)
[C
10
H
8
N
2
= 2,2'-bipyridine (bipy), C
9
H
7
O
2
–
= cinnamate
anion (cinn
–
), C
7
H
6
NO
2
–
= p-amino benzoate anion (paba
–
),
and C
7
H
7
NO
2
= p-amino benzoic acid (Hpaba)].
2 Experimental Section
Synthesis of Cu(C
10
H
8
N
2
)(C
9
H
7
O
2
)(H
2
O) (1): To prepare complex
1, a solution of 2,2'-bipyridine (0.157 g, 1.00 mmol) 15 mL in meth-
anol was slowly added with stirring to a solution of CuCl
2
·2H
2
O
(0.170 g, 1.00 mmol) in 15 mL H
2
O to yield a light blue solution.
Afterwards, cinnamic acid (0.297 g, 2.00 mmol) dissolved in 5 mL of