Thermochimica Acta 419 (2004) 115–117
Simultaneous thermal analysis of a cobalt(II) complex with nicotinate
∗
Yanhua Liu, Jiehui Yu, Jingzhe Zhao, Hui Zhang, Yanhui Deng, Zichen Wang
Department of Chemistry, Jilin University, 119 Jie Fang Road, Changchun 130023, PR China
Received 27 August 2003; received in revised form 1 February 2004; accepted 17 February 2004
Available online 9 April 2004
Abstract
Dynamic kinetic analyses were performed on Co(NIA)
2
2 4 5 4
(H O) (NIA: nicotinate (C H NCOOH)) using thermogravimetry (TG) and dif-
ferential thermal analysis (DTA) measurements in air atmosphere. The thermal behavior and the kinetics of decomposition were studied. The
effect of the heating rate on the thermal decomposition process was investigated. The Friedman method was applied to estimate the activation
energy of decomposition.
©
2004 Elsevier B.V. All rights reserved.
Keywords: Cobalt complex; Decomposition kinetics
1
. Introduction
2. Experimental
Co(NIA)2(H2O)4 (NIA: nicotinate) is a transition metal
The synthesis of Co(NIA)2(H2O)4 is described elsewhere
[1]. The product was submitted to thermal analysis. All the
experiments were performed on a Mettler Toledo simultane-
ous thermal analyzer (TGA/SDTA851e) with system inter-
face device and a computer workstation. All samples were
placed in aluminum crucibles. Experiments were performed
using sample sizes of 3 ± 0.3 mg. All the experiments were
conducted under air as the purge gas. The flow rate of the
gas was 50 ml/min. The range of temperature studied was
organic–inorganic composite compound with a novel
three-dimensional supramolecular structure. It displays re-
markably a cavity structure and ladder-type hydrogen bond
chains of carboxylates and water molecules. The design-
ing, synthesizing and determination of the structure of the
compound has been reported [1], but no study on thermo-
chemistry, so far as we know, has been done.
Thermogravimetry (TG) and differential thermal analy-
sis (DTA) are valuable techniques for studying the thermal
properties of various compounds. Materazzi et al. [2] had
reported the thermoanalytical studies of unusual adrenaline
complexes with Co(II), Ni(II) and Cu(II). Thermogravimet-
ric analysis of complexes of Co(II) chelates with Schiff
base reagents were studied by Madhu et al. [3]. Arshad
et al. [4] reported the thermal decomposition pattern of
◦
from 50 to 700 C, at the heating rates of 20, 30, 40 and
◦
50 C/min.
3. Results and discussion
Fig. 1 represent TG-DTA curves of the compound, for an
◦
1
,2-dipiperidinoethane complexes of Co(II), Ni(II), Cu(II),
experiment carried out at 30 C/min with a sample size of
3.224 mg in air. The curves show that the non-isothermal de-
composition of the compound occurs in two separate steps.
Zn(II) and Cd(II). The present study is aimed at the ther-
mal decomposition process of Co(NIA)2(H2O)4 in air at-
mosphere. The activation energy for the decomposition of
compound was also evaluated.
◦
The first weight loss starts at about 100 C; the first de-
composition stage ends with weight loss of 20.57% due to
the loss of water (calculated value is 19.10%). The second
◦
weight loss starts at about 370 C ending with a weight loss
of 59.98% due to the loss of nicotinate and the formation of
CoO (calculated value is 61.01%). The DTA curve shows an
endothermic peak for the first weight loss and an exothermic
peak for the second weight loss.
∗
Corresponding author. Tel.: +86-431-894-9334;
fax: +86-431-894-9334.
E-mail address: wangzc@mail.jlu.edu.cn (Z. Wang).
0
040-6031/$ – see front matter © 2004 Elsevier B.V. All rights reserved.
doi:10.1016/j.tca.2004.02.005