Abstract
Two photoactivatable dicarbonyl ruthenium(II) complexes based on an amide‐functionalised bipyridine scaffold (4‐position) equipped with an alkyne functionality or a green‐fluorescent BODIPY (boron‐dipyrromethene) dye have been prepared and used to investigate their light‐induced decarbonylation. UV/Vis, FTIR and 13C NMR spectroscopies as well as gas chromatography and multivariate curve resolution alternating least‐squares analysis (MCR‐ALS) were used to elucidate the mechanism of the decarbonylation process. Release of the first CO molecule occurs very quickly, while release of the second CO molecule proceeds more slowly. In vitro studies using two cell lines A431 (human squamous carcinoma) and HEK293 (human embryonic kidney cells) have been carried out in order to characterise the anti‐proliferative and anti‐apoptotic activities. The BODIPY‐labelled compound allows for monitoring the cellular uptake, showing fast internalisation kinetics and accumulation at the endoplasmic reticulum and mitochondria.
Highlights
Carbon-monoxide-releasing molecules (CORMs) represent a promising prodrug approach since it is known that CO plays a beneficial role in mammals, showing anti-bacterial, anti-apoptotic, anti-proliferative and anti-inflammatory effects.[1]
RuII dicarbonyl complexes based on 2,2’-bipyridine derivatives substituted at 4,4’-1 and 5,5’-positions 2 (Scheme 1) are known as effective CO releasers,[10] surprisingly, little if any biological studies on this class of Ru-CORMs are reported so far. These systems are characterised to undergo a stepwise decarbonylation upon UV irradiation with relatively high rate constants.[10b,c] Previously, we reported about the influence of the electron-withdrawing carboxyl and electron-donating methyl groups attached to the bipyridyl ligand of RuII dicarbonyl complexes 1 on the rate of photolysis in organic and aqueous solvent systems
The alkyne-functionalised bipyridyl ligand 4 was prepared in 61 % yield from the commercially available carboxylic acid-containing precursor 1 b, which was reacted with propargyl amine under peptide coupling conditions with EDC and HOBt (Scheme 3)
Summary
Carbon-monoxide-releasing molecules (CORMs) represent a promising prodrug approach since it is known that CO plays a beneficial role in mammals, showing anti-bacterial, anti-apoptotic, anti-proliferative and anti-inflammatory effects.[1] To control the administration of the highly toxic gas in a safe manner, certain carbonyl compounds have been designed in which CO is either covalently bound in organic molecules[2] or coordinated to metal centres[1b,f,3] in inorganic complexes. Hruby Supramolecular Polymer Systems, Institute of Macromolecular Chemistry Heyrovsky Square 2, 16206 Prague (Czech Republic)
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