An investigation of the reactivity and chromatographic separation of some ruthenium bis (2, 2' - bibyridyl) compounds
McGovern, Evin
(1988)
An investigation of the reactivity and chromatographic separation of some ruthenium bis (2, 2' - bibyridyl) compounds.
Master of Science thesis, Dublin City University.
The complex [Ru(bpy)2(CO)H]PF6 .l/2Acetone was
synthesised in 50% yield. The reaction of this complex with a number of aldehydes, ketones and esters in buffered aqueous media and in an acidic acetonitrile environment revealed the reactivity to decrease in this order:
Aldehydes > Ketones > Esters
A kinetic study into the general acid catalysed
reaction of this hydride complex with bgnzal^e^ydj was carried out and a rate coefficient of 1.3 10~ mol 1_| was
calculated. An activation energy of 11.5 kJmol was
calculated. High Performance Liquid Chromatography (H£LC) was used to demonstrate the conversion of [Ru(bpy)2 (CO)H] to [Ru(bpy)2 (CO)Cl] in acetonitrile by addition of HC1.
Reverse phase ion pair chromatography (RP.IPC) and
cation exchange chromatography were used for the analysis of
ruthenium bis (2,21-bipyridyl), (bpy), complexes using a range
of mobile phases with lithium perchlorate, (LiClO^), as an
additive. A C18 and a CN column were not suitable for the
analysis due to peak distortion problems. A cation exchange,
(CX), column provided a useful method for the separation of
these compounds. Plots of %acetonitrile, (MeCN), vs. retention time at given LiCl04 concentration suggested a change in the dominant retention mechanism, possibly from cation exchange to RP.IPC with increaing water content in the mobile phase. The presence of split peaks for the dicationic complexes at 80%MeCN : 20%H20 ; 0.1M LiC104 as mobile phase was attributed to competing retention mechanisms. The optimum system for the separation of the compounds examined was 80%MeCN : 20%H„0 ; 0.08M LiC104 at a flow rate of 2.5ml/min.
The Photolyses of [Ru(bpy)2L2]2+ [Ru(bpy)2 (L)C1]+ , (L = imidazole / vinylimidazole), in MeCN was studied on an ODS and a CX column using the system developed. The ligand was replaced in these reactions to give [Ru(bpy)2(MeCN)2 ] + for the dicationic compounds and [Ru(bpy)2 (MeCN)Cl] for the monocationic compounds as the major final products. Other unidentified products were present in significant levels. The potential applications of HPLC in the study of ruthenium bis (2,21-bipyridine) complexes were demonstrated by these experiments.