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Investigations on the synthesis of molecular rectangles based on rhenium
Author
Wong, Li Peng
Supervisor
Yan, Yaw Kai
Abstract
In this study, a series of rhenium (I) carbonyl complexes bridged by bis(bidentate) ligands (dithiooxalate, tetrathiooxalate, and dithiooxamide) were synthesised. These complexes were then reacted with linear, rigid, bifunctional N-donor ligands (4,4'- bipyridine, and pyrazine), with the aim of producing rectangular metallacycles through molecular self-assembly.
The complex [{Re(CO)5}2(μ,ŋ1: ŋ1-C2S2O2)]was thermally decarbonylated to give [{Re(CO)3}2(μ,ŋ2: ŋ2-C2S2O2]n, which was reacted with an equivalent amount of 4,4'-bipyridine (bpy) and pyrazine (pyz), respectively. The infiared and 'H-NMR spectroscopic data of the products were consistent with them being [{Re(CO)3}2(μ,ŋ1: ŋ1-bpy)((μ,ŋ2: ŋ2-C2S2O2]n and [{Re(CO)3}2(μ,ŋ1: ŋ1-pyz)((μ,ŋ2: ŋ2-C2S2O2]n respectively, i.e. they could either be macrocycles or linear polymers, and electrospray mass spectrometric (ESMS) measurements provided strong evidence for the formation of rectangles.
The dithiooxamidate-bridged rhenium carbonyl intermediate was prepared and reacted in analogous fashion with 4,4'-bipyridine to give a product that could be formulated, based on infrared, 1H-NMR and ESMS data, as [{Re(CO)3}2(μ,ŋ1: ŋ1-bpy)((μ,ŋ2: ŋ2-C2S2O2]2.
Reactions involving the tetrathiooxalate-bridged rhenium carbonyl intermediate with either 4,4'-bipyridine or pyrazine consistently gave complex mixtures, as indicated by their 'H-NMR spectra. The product mixture obtained from the reaction of tetrathiooxalate-bridged rhenium carbonyl complex with 4,4'-bipyridine could include, based on infrared, 'H-NMR and ESMS data, [{Re(CO)3}2(μ,ŋ1: ŋ1-bpy)((μ,ŋ2: ŋ2-C2S4]2.
The complex [{Re(CO)5}2(μ,ŋ1: ŋ1-C2S2O2)]was thermally decarbonylated to give [{Re(CO)3}2(μ,ŋ2: ŋ2-C2S2O2]n, which was reacted with an equivalent amount of 4,4'-bipyridine (bpy) and pyrazine (pyz), respectively. The infiared and 'H-NMR spectroscopic data of the products were consistent with them being [{Re(CO)3}2(μ,ŋ1: ŋ1-bpy)((μ,ŋ2: ŋ2-C2S2O2]n and [{Re(CO)3}2(μ,ŋ1: ŋ1-pyz)((μ,ŋ2: ŋ2-C2S2O2]n respectively, i.e. they could either be macrocycles or linear polymers, and electrospray mass spectrometric (ESMS) measurements provided strong evidence for the formation of rectangles.
The dithiooxamidate-bridged rhenium carbonyl intermediate was prepared and reacted in analogous fashion with 4,4'-bipyridine to give a product that could be formulated, based on infrared, 1H-NMR and ESMS data, as [{Re(CO)3}2(μ,ŋ1: ŋ1-bpy)((μ,ŋ2: ŋ2-C2S2O2]2.
Reactions involving the tetrathiooxalate-bridged rhenium carbonyl intermediate with either 4,4'-bipyridine or pyrazine consistently gave complex mixtures, as indicated by their 'H-NMR spectra. The product mixture obtained from the reaction of tetrathiooxalate-bridged rhenium carbonyl complex with 4,4'-bipyridine could include, based on infrared, 'H-NMR and ESMS data, [{Re(CO)3}2(μ,ŋ1: ŋ1-bpy)((μ,ŋ2: ŋ2-C2S4]2.
Date Issued
2005
Call Number
QD181.R4 Won
Date Submitted
2005