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Synthesis, characterization and thermal studies of Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate: the single crystal structure of [(C(6)H(5))(CH(3))NCS(2)](4)Hg(2).

Onwudiwe DC, Ajibade PA - Int J Mol Sci (2011)

Bottom Line: Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, (1)H and (13)C-NMR).One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring.Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Fort Hare, Private Bag X1314, ALICE 5700, South Africa; E-Mail: donwudiwe@ufh.ac.za.

ABSTRACT
Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, (1)H and (13)C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films.

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DSC curves of the complexes (in nitrogen) at a heating rate of 5 °C min−1.
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f2-ijms-12-01964: DSC curves of the complexes (in nitrogen) at a heating rate of 5 °C min−1.

Mentions: The thermal properties of the complexes were studied by TGA and DSC in the temperature ranging from 20 to 800 °C under nitrogen atmosphere. The content of a particular component in a complex changes with its composition and structure. These can be determined based on mass losses of these components in the thermogravimetric plots of the complex. The pertinent thermal decomposition data for the complexes are presented in Table 1, Figure 1 shows their degradation pattern and the DSC curves of the complexes are presented in Figure 2. The compounds start decomposing above 210 °C and the thermogram for each complex exhibits two distinct decomposition steps at 219, 270, 168 and 450, 430, 361 °C for the Zn, Cd and Hg complexes respectively. The first decomposition step stretches beyond 50 °C and exhibits 65–70% weight loss. This corresponds to decomposition of the organic moiety [30] leaving behind metal sulfide as the end product. The slight weight loss (<2%) observed in the mercury complex around 185 °C could be ascribed to the presence of entrapped water or solvent molecule [31]. The absence of any thermal change before this temperature is reached indicates that samples restructuring did not take place before the degradation processes started [32], and also demonstrates their high thermal stability. The second decomposition temperature stretches to around 650 °C in Zn and Cd complexes but less than 600 °C in Hg complex. The products correspond to the respective metal oxides except in the Hg complex where the thermogram indicates volatilization). The presence of oxygen and sulfur in the end product of the zinc and cadmium complexes at 800 °C, as shown by the EDX result (Figures 3 and 4), may indicate oxysulfate which probably have formed due to the oxidation of the sulfide. It is evident from the thermogram (Figure 1) that the Hg complex has the least thermal stability as previously observed [33]. The calculated mass change agrees favorably with the experimental values. The anomaly observed in the mercury complex may be due to the volatility in the second phase of decomposition. The stability trend [34] of the complexes could be said to follow: Hg < Zn < Cd.


Synthesis, characterization and thermal studies of Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate: the single crystal structure of [(C(6)H(5))(CH(3))NCS(2)](4)Hg(2).

Onwudiwe DC, Ajibade PA - Int J Mol Sci (2011)

DSC curves of the complexes (in nitrogen) at a heating rate of 5 °C min−1.
© Copyright Policy - open-access
Related In: Results  -  Collection

License 1 - License 2
Show All Figures
getmorefigures.php?uid=PMC3111644&req=5

f2-ijms-12-01964: DSC curves of the complexes (in nitrogen) at a heating rate of 5 °C min−1.
Mentions: The thermal properties of the complexes were studied by TGA and DSC in the temperature ranging from 20 to 800 °C under nitrogen atmosphere. The content of a particular component in a complex changes with its composition and structure. These can be determined based on mass losses of these components in the thermogravimetric plots of the complex. The pertinent thermal decomposition data for the complexes are presented in Table 1, Figure 1 shows their degradation pattern and the DSC curves of the complexes are presented in Figure 2. The compounds start decomposing above 210 °C and the thermogram for each complex exhibits two distinct decomposition steps at 219, 270, 168 and 450, 430, 361 °C for the Zn, Cd and Hg complexes respectively. The first decomposition step stretches beyond 50 °C and exhibits 65–70% weight loss. This corresponds to decomposition of the organic moiety [30] leaving behind metal sulfide as the end product. The slight weight loss (<2%) observed in the mercury complex around 185 °C could be ascribed to the presence of entrapped water or solvent molecule [31]. The absence of any thermal change before this temperature is reached indicates that samples restructuring did not take place before the degradation processes started [32], and also demonstrates their high thermal stability. The second decomposition temperature stretches to around 650 °C in Zn and Cd complexes but less than 600 °C in Hg complex. The products correspond to the respective metal oxides except in the Hg complex where the thermogram indicates volatilization). The presence of oxygen and sulfur in the end product of the zinc and cadmium complexes at 800 °C, as shown by the EDX result (Figures 3 and 4), may indicate oxysulfate which probably have formed due to the oxidation of the sulfide. It is evident from the thermogram (Figure 1) that the Hg complex has the least thermal stability as previously observed [33]. The calculated mass change agrees favorably with the experimental values. The anomaly observed in the mercury complex may be due to the volatility in the second phase of decomposition. The stability trend [34] of the complexes could be said to follow: Hg < Zn < Cd.

Bottom Line: Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, (1)H and (13)C-NMR).One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring.Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films.

View Article: PubMed Central - PubMed

Affiliation: Department of Chemistry, University of Fort Hare, Private Bag X1314, ALICE 5700, South Africa; E-Mail: donwudiwe@ufh.ac.za.

ABSTRACT
Zn(II), Cd(II) and Hg(II) complexes of N-methyl-N-phenyl dithiocarbamate have been synthesized and characterized by elemental analysis and spectral studies (IR, (1)H and (13)C-NMR). The single crystal X-ray structure of the mercury complex revealed that the complex contains a Hg centre with a distorted tetrahedral coordination sphere in which the dinuclear Hg complex resides on a crystallographic inversion centre and each Hg atom is coordinated to four S atoms from the dithiocarbamate moiety. One dithiocarbamate ligand acts as chelating ligand while the other acts as chelating bridging ligand between two Hg atoms, resulting in a dinuclear eight-member ring. The course of the thermal degradation of the complexes has been investigated using thermogravimetric and differential thermal analyses techniques. Thermogravimetric analysis of the complexes show a single weight loss to give MS (M = Zn, Cd, Hg) indicating that they might be useful as single source precursors for the synthesis of MS nanoparticles and thin films.

Show MeSH
Related in: MedlinePlus