Synthesis and characterisation of [CU2(P-H2NC6H4COO)N(Rcoo)4-N] as low temperature functional metallomesogens / Ahmad Nazeer bin Che Mat
This research project is focused on the synthesis and characterization of copper(II) mixed carboxylates of general formula, [Cu2(RCOO)n(R’COO)4-n)], where R = p-H2NC6H4, R’ = CH3(CH2)14, and n = 1–3. These mixed carboxylates were specially designed to be low-temperature and thermally stable magnetic...
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| Summary: | This research project is focused on the synthesis and characterization of copper(II) mixed carboxylates of general formula, [Cu2(RCOO)n(R’COO)4-n)], where R = p-H2NC6H4, R’ = CH3(CH2)14, and n = 1–3. These mixed carboxylates were specially designed to be low-temperature and thermally stable magnetic and redox-active metallomesogens.
A total of six binuclear copper(II) mixed-carboxylates were successfully prepared by the one-pot reaction, and their thermal, metallomesogenic, magnetic and redox properties reported. The instrumental analyses used to characterize these complexes were CHN elemental analyses, FTIR and UV-vis spectroscopies, molar conductivity, thermogravimetry, differential scanning calorimetry, optical polarized microscopy, magnetic susceptibility by the Gouy method, and cyclic voltammetry.
All complexes, except for [Cu2(p-H3NC6H4COO)3Cl]Cl3.NH3.3H2O (Complex 4), were non-electrolytes. Complex 4 was a 1:1 electrolyte. Their geometry was square-pyramidal involving syn-syn or syn-anti bridging and/or chelating carboxylates, their thermal stabilities were higher than 200oC, and the melting point ranges from about 118oC, except for Complex 6 which melted at a higher temperature of 166oC.
The complex exhibiting thermotropic metallomesogenic properties was [Cu2(p-H2NC6H4COO)2(CH3(CH2)14COO)2(H2O)(CH3CH2OH)] (Complex 1) with smectic C mesophase. They were either antiferromagnet or ferromagnet, with μeff and 2J values from 2.11 to 3.72 B.M. and from -200 to 109 cm-1,
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respectively. All complexes were redox active. The redox reactions were quasi-reversible involving extensive structural reorganization and chemical reactions (the EC mechanism). |
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