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Molecular squares based on 3,3′-Diamino-4,4′-Bipyridine : synthesis and chemical sensing properties
Author
Kwek, Kah Hwee
Supervisor
Yan, Yaw Kai
Teo, Yong Chua
Abstract
The 3,3′-diamino-4,4′-bipyridine (dabpy) ligand was synthesized in accordance to literature procedures: Ullmann coupling of 4-chloro-3-nitropyridine was first carried out to obtain 3,3′-dinitro-4,4′-bipyridine, which was then reduced to dabpy by hydrogenation. Reaction of the dabpy ligand with [ReCl(CO)5] yielded the molecular square compound, [ReCl(CO)3(dabpy)]4, which was characterized by 1H-NMR, IR and UV-Vis spectroscopy, ESIMS and elemental analysis. Molecular recognition studies were conducted by adding dicarboxylic acids (oxalic, malonic, succinic and fumaric acids) to (CD3)2CO solutions of [ReCl(CO)3(dabpy)]4 in a 1:1 molar ratio, and monitoring the effect by 1H-NMR spectroscopy. Results showed that the [ReCl(CO)3(dabpy)]4 molecular square was responsive to only oxalic acid molecules. Further changes in the 1H-NMR spectrum with increasing amounts of oxalic acid suggest that each Re(I)-dabpy molecular square is able to interact with a total of four oxalic acid molecules.
The Pt(II) square complex, [(en)Pt(dabpy)]4(NO3)8, was synthesized using the literature procedure for the synthesis of [(en)Pt(bpy)]4(NO3)8 (bpy = 4,4′-bipyridine), and characterized by ESIMS, UV-Vis and 1H-NMR spectroscopy. Proton NMR peaks characteristic of the aromatic protons of a symmetrically bridging dabpy ligand were observed, providing support for the successful synthesis of [(en)Pt(dabpy)]48+. The acidic solution of the Pt(II) square complex is dark yellowish green in colour, and turns red upon neutralization.
The Pt(II) square complex, [(en)Pt(dabpy)]4(NO3)8, was synthesized using the literature procedure for the synthesis of [(en)Pt(bpy)]4(NO3)8 (bpy = 4,4′-bipyridine), and characterized by ESIMS, UV-Vis and 1H-NMR spectroscopy. Proton NMR peaks characteristic of the aromatic protons of a symmetrically bridging dabpy ligand were observed, providing support for the successful synthesis of [(en)Pt(dabpy)]48+. The acidic solution of the Pt(II) square complex is dark yellowish green in colour, and turns red upon neutralization.
Date Issued
2011
Call Number
QD878 Kwe
Date Submitted
2011