H u r s t h o u s e 2 , 3
1
WestCHEM, School of Chemistry, University of Glasgow, Glasgow, United Kingdom
E-mail: Daniel.Price@glasgow.ac.uk
2
School of Chemistry, University of Southampton, Southampton, United Kingdom
3
Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
Received October, 20, 2011
Revised — February, 7, 2012
Reaction of cobalt hydroxide with the D,Z-dicarboxylic acid and 1,12-dodecanedioic acid under ambient conditions results in the formation of a trihydrate Co(C12H20O4)(H2O)3 (1). <...> The structure has a
very pronounced two dimensional character, with a separation of hydrophobic n-alkyl chains
from the carboxylate groups, the Co2+ cations and the water of crystallisation. <...> The structure is
discussed in respect of the structures of other known compositionally related compounds, including the dihydrate Co(C12H20O4)(H2O)2. <...> K e y w o r d s: cobalt, layered compound, carboxylate bridge, pseudopolymorphism. <...> The interest in the chemical and physical properties of transition metal coordination networks
(now often referred to as MOFs — metal organic frameworks) is rapidly increasing. <...> In the design of new materials there are many strategies and parameters that can be exploited. <...> We can use
ligands with well defined chelating coordination modes to produce well defined arrays of metal ions,
whether they are discreet clusters [ 7 ] or infinite arrays [ 8 ]. <...> A reduction of specificity of the coordination mode introduces some flexibility in the possible metal coordination geometries, but can still retain
predictable gross structural features in the metal atom distribution. <...> This is certainly seen with aryl carboxylate ligands such as the rigid 1,2,4,5-benzene tetracarboxylate [ 9 ]. <...> With alkyl carboxylates we
introduce a conformational flexibility to the ligand, and we also introduce the hydrophobic alkyl-alkyl
interactions which when the alky chain is long enough, result in a layered 2D lamella character to a
material. <...> We describe here the structure of Co(O2C(CH2)10CO2)(H2O)3 (1) and comment on its structural relationship to a growing family of transition metal soaps. <...> Powder X-ray diffraction was
performed <...>
CRYSTAL_STRUCTURE_OF_COBALT(II)_1,12-DODECANEDIOATE_TRIHYDRATE_A_NEW_LAYERED_COORDINATION_NETWORK.pdf
2013. 54, 2
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– -
UDC 548.73:547.13:546.73
CRYSTAL STRUCTURE OF COBALT(II) 1,12-DODECANEDIOATE TRIHYDRATE:
A NEW LAYERED COORDINATION NETWORK
D.J. Price1, S.J. Coles2, M.B. Hursthouse2, 3
1WestCHEM, School of Chemistry, University of Glasgow, Glasgow, United Kingdom
E-mail: Daniel.Price@glasgow.ac.uk
Received October, 20, 2011
. 411 – 415
2School of Chemistry, University of Southampton, Southampton, United Kingdom
3Department of Chemistry, Faculty of Science, King Abdulaziz University, Jeddah, Saudi Arabia
Revised — February, 7, 2012
Reaction of cobalt hydroxide with the h,-dicarboxylic acid and 1,12-dodecanedioic acid under
ambient conditions results in the formation of a trihydrate Co(C12H20O4)(H2O)3 (1). Single
crystal X-ray diffraction studies show 1 to crystallise in the orthorhombic space group Pccn
with cell parameters a = 40.2343(7) Å, b = 8.1519(1) Å, c = 9.1011(2) Å. The structure has a
very pronounced two dimensional character, with a separation of hydrophobic n-alkyl chains
from the carboxylate groups, the Co2+ cations and the water of crystallisation. The structure is
discussed in respect of the structures of other known compositionally related compounds, including
the dihydrate Co(C12H20O4)(H2O)2.
Keywords: cobalt, layered compound, carboxylate bridge, pseudopolymorphism.
The interest in the chemical and physical properties of transition metal coordination networks
(now often referred to as MOFs — metal organic frameworks) is rapidly increasing. This is because
many have characteristics that make them appealing as candidate materials in areas such as gas absorption
[ 1 ], gas separation [ 2 ], catalysis [ 3 ], luminescence [ 4 ], and magnetism [ 5, 6 ]. In the design
of new materials there are many strategies and parameters that can be exploited. We can use
ligands with well defined chelating coordination modes to produce well defined arrays of metal ions,
whether they are discreet clusters [ 7 ] or infinite arrays [ 8 ]. A reduction of specificity of the coordination
mode introduces some flexibility in the possible metal coordination geometries, but can still retain
predictable gross structural features in the metal atom distribution. This is certainly seen with aryl carboxylate
ligands such as the rigid 1,2,4,5-benzene tetracarboxylate [ 9 ]. With alkyl carboxylates we
introduce a conformational flexibility to the ligand, and we also introduce the hydrophobic alkyl-alkyl
interactions which when the alky chain is long enough, result in a layered 2D lamella character to a
material. We describe here the structure of Co(O2C(CH2)10CO2)(H2O)3 (1) and comment on its structural
relationship to a growing family of transition metal soaps.
Experimental. C and H analysis was obtained using an Exeter Analytical Inc. CE-440 Elemental
Analyser. Infrared spectra were recorded on a Perkin Elmer Spectrum One FTIR spectrometer as
pressed KBr pellets; UV-visible spectra were recorded on a Perkin Elmer Lambda 19 spectrometer in
diffuse reflectance mode, using powdered BaSO4 as a diluting matrix. Powder X-ray diffraction was
performed using a Bruker D5000 instrument with CuKh radiation.
Synthesis of Co[O2C(CH2)10CO2](H2O)3 (1). A solution of NaOH (0.033 g, 0.83 mmol) in distilled
water (4 ml) was added to a solution of CoCl26H2O (0.152 g, 0.64 mmol) in distilled water
(3 ml), producing a blue precipitate of Co(OH)2. To this mixture, 1,12-dodecanedioic acid (0.096 g,
© Price D.J., Coles S.J., Hursthouse M.B., 2013
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