Synthesis and characterisation of [CU2(P-H2NC6H4COO)N(Rcoo)4-N] as low temperature functional metallomesogens / Ahmad Nazeer bin Che Mat

• Main Author: Ahmad Nazeer, Che Mat
• Format: Thesis
• Published: 2011
• Subjects: QD Chemistry
• Online Access: http://studentsrepo.um.edu.my/3752/1/FIRST_COVER_(INSIDE).pdf; http://studentsrepo.um.edu.my/3752/2/FRONT_COVER_(RED_HARD_COVER).pdf; http://studentsrepo.um.edu.my/3752/3/Acknowledge%2C_Abstract%2C_Abstrak_%26_Content.pdf; http://studentsrepo.um.edu.my/3752/4/CHAPTER_1_INTRODUCTION.pdf; http://studentsrepo.um.edu.my/3752/5/CHAPTER_2_THEORY_AND_REVIEW_150411.pdf; http://studentsrepo.um.edu.my/3752/6/CHAPTER_3_EXPERIMENTAL_nazeer.pdf; http://studentsrepo.um.edu.my/3752/7/CHAPTER_4_RESULTS_AND_DISCUSSIONS.pdf; http://studentsrepo.um.edu.my/3752/8/CHAPTER_5_CONCLUSION.pdf; http://studentsrepo.um.edu.my/3752/9/APPENDIX_1.pdf; http://studentsrepo.um.edu.my/3752/10/APPENDIX_2.pdf; http://pendeta.um.edu.my/client/default/search/results?qu=Synthesis+and+characterisation+of+%5BCU2%28P-H2NC6H4COO%29N%28Rcoo%294-N%5D+as+low+temperature+functional+metallomesogens&te=; http://studentsrepo.um.edu.my/3752/

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, iii respectively. All complexes were redox active. The redox reactions were quasi-reversible involving extensive structural reorganization and chemical reactions (the EC mechanism).