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LUND UNIVERSITY LIBRARIES

Synthesis and Characterization of some Photo-CORM and Photosensitizers

Björklund, Joachim LU (2019) KEML12 20182
Department of Chemistry
Abstract
It is well known that Carbon monoxide is a toxic and hazardous gas, but during recent years it has been proven that using a controlled concentration, carbon monoxide can in fact be used as a therapeutic agent, and can contribute to decrease malaria, treat cardiovascular and lung diseases and potentially even treat cancer, among other things. The main problem in using carbon monoxide directly is the fact that it is not trivial to control the volume of gas inhaled, compromising its use as a therapeutic agent. Much effort has been made to synthesize molecules that can release carbon monoxide, so-called CORMs. The release of the carbon monoxide present in these molecules can occur in different ways: a) exchanging the carbon monoxide with... (More)
It is well known that Carbon monoxide is a toxic and hazardous gas, but during recent years it has been proven that using a controlled concentration, carbon monoxide can in fact be used as a therapeutic agent, and can contribute to decrease malaria, treat cardiovascular and lung diseases and potentially even treat cancer, among other things. The main problem in using carbon monoxide directly is the fact that it is not trivial to control the volume of gas inhaled, compromising its use as a therapeutic agent. Much effort has been made to synthesize molecules that can release carbon monoxide, so-called CORMs. The release of the carbon monoxide present in these molecules can occur in different ways: a) exchanging the carbon monoxide with solvent (e.g. water). Although this is an easy and controlled method to release a known quantity of carbon monoxide, it is not possible to guarantee the time and tissue the CO is released. b) triggering the release of carbon monoxide, for example by light exposure (Photo-CORMs). This can be an efficient method, since metal carbonyls are well known as photosensitive systems.
Two Photo-CORMs complexes, Re(aaz)(CO)3]Cl (aaz = 6-amino-6-methylperhydro-1,4-diazepine) and [Re(tacn)(CO)3]Cl (tacn = 1,4,7-triazacyclononane), were synthesized, fully characterized and tested for their ability to release carbon monoxide when exposed to light radiation. By determining the change in oxidation potential through square wave electrochemistry, as well as UV- and IR-spectra, there was enough proof to conclude that the complexes release at least 2 equivalents of carbon monoxide per Photo-CORM when radiated by UV light.
Four new complexes, containing photosensitizers were also synthesized and characterized [Ru(Me2bpy)2Cl2] (bpy = 2,2’-bipyridine) , [Ru(phen)2Cl2] (phen = 1,10-phenanthroline), [Cu(Me2-bpy)2]BF4 (4,4’-dimethyl-2,2’-bipyridine) and [Fe(η5-C5H4CHO)(η6-C6H6)]PF6 ((η5-C5H4CHO)(η6-C6H6) = η6-benzene,η5-cyclopentadienyl). All the four complexes absorb IR radiation and excite the Photo-CORM through triplet energy transfer. The IR spectroscopy showed that all photosensitizers were formed, since there were displacements of the bands and formation of new bands. (Less)
Popular Abstract (Swedish)
Det är väl känt att kolmonoxid (CO) är en giftig och hälsofarlig gas som är luktlös, färglös och smaklös vilket gör den svår att detektera utan analytisk utrustning. Men under senaste åren så har forskning bevisat att i små doser så kan kolmonoxid användas som en terapeutisk substans för att lindra malaria, cancer, lung-, hjärt- och kärlsjukdomar men även reducera mängden inflammatoriska substanser i kroppen. Hur får man då in kolmonoxiden i kroppen? Det mest självklara valet är att andas in gasen i små mängder men där uppstår ett problem, då man inte kan kontrollera vart i kroppen kolmonoxiden kommer att distribueras. Istället så kan man då använda så kallade CORMs (Carbon monoxide releasing molecules) för att kunna kontrollera mängden,... (More)
Det är väl känt att kolmonoxid (CO) är en giftig och hälsofarlig gas som är luktlös, färglös och smaklös vilket gör den svår att detektera utan analytisk utrustning. Men under senaste åren så har forskning bevisat att i små doser så kan kolmonoxid användas som en terapeutisk substans för att lindra malaria, cancer, lung-, hjärt- och kärlsjukdomar men även reducera mängden inflammatoriska substanser i kroppen. Hur får man då in kolmonoxiden i kroppen? Det mest självklara valet är att andas in gasen i små mängder men där uppstår ett problem, då man inte kan kontrollera vart i kroppen kolmonoxiden kommer att distribueras. Istället så kan man då använda så kallade CORMs (Carbon monoxide releasing molecules) för att kunna kontrollera mängden, och distributionen av kolmonoxid i patientens kropp. Dessa CORMs består av ett metall-center (i detta fall rhenium) med kolmonoxid bundet direkt till metallen med diverse ligander bundna till metallen för att ändra hur CORM:en beter sig.
I detta arbete så syntetiserades ett par photo-CORMs, alltså en molekyl som släpper ifrån sig kolmonoxid genom ljusstrålning, för att testa dess effektivitet i att släppa kolmonoxid i lösning. Det gjordes med UV-strålning då CORM:en endast reagerar med UV-strålning. Experimenten var lyckade och kolmonoxid släpptes i lösning och kunde detekteras med hjälp av IR, UV-vis spektroskopi och elektrokemi.
Det är inte alltid gynnsamt att använda UV-strålning då det är farligt för celler, och har en dålig penetrationsförmåga. Det är mycket mer gynnande att använda IR-strålning, men det går inte att ändra beteendet på en CORM så drastiskt så då syntetiserades några PS (Photosensitizers) för att lösa det problemet. En photosensitizer är en molekyl som tar emot elektromagnetisk strålning som exciterar sina elektroner, och överför sedan den exciterade energin till en annan molekyl genom kollision, bland annat. Syntetiseringen av ett par rutenium, järn och koppar komplex var lyckade, men hann aldrig testas i lösning med CORMs, så effektiviteten är ännu okänd. (Less)
Please use this url to cite or link to this publication:
author
Björklund, Joachim LU
supervisor
organization
course
KEML12 20182
year
type
M2 - Bachelor Degree
subject
keywords
Inorganic Chemistry, Bioinorganic Chemistry, CORM, Photo-CORM, Photosensitizers, Synthesis, Characterization, Oorganisk kemi
language
English
id
8987601
date added to LUP
2019-07-04 14:36:36
date last changed
2019-07-04 14:36:36
@misc{8987601,
  abstract     = {{It is well known that Carbon monoxide is a toxic and hazardous gas, but during recent years it has been proven that using a controlled concentration, carbon monoxide can in fact be used as a therapeutic agent, and can contribute to decrease malaria, treat cardiovascular and lung diseases and potentially even treat cancer, among other things. The main problem in using carbon monoxide directly is the fact that it is not trivial to control the volume of gas inhaled, compromising its use as a therapeutic agent. Much effort has been made to synthesize molecules that can release carbon monoxide, so-called CORMs. The release of the carbon monoxide present in these molecules can occur in different ways: a) exchanging the carbon monoxide with solvent (e.g. water). Although this is an easy and controlled method to release a known quantity of carbon monoxide, it is not possible to guarantee the time and tissue the CO is released. b) triggering the release of carbon monoxide, for example by light exposure (Photo-CORMs). This can be an efficient method, since metal carbonyls are well known as photosensitive systems. 
Two Photo-CORMs complexes, Re(aaz)(CO)3]Cl (aaz = 6-amino-6-methylperhydro-1,4-diazepine) and [Re(tacn)(CO)3]Cl (tacn = 1,4,7-triazacyclononane), were synthesized, fully characterized and tested for their ability to release carbon monoxide when exposed to light radiation. By determining the change in oxidation potential through square wave electrochemistry, as well as UV- and IR-spectra, there was enough proof to conclude that the complexes release at least 2 equivalents of carbon monoxide per Photo-CORM when radiated by UV light. 
Four new complexes, containing photosensitizers were also synthesized and characterized [Ru(Me2bpy)2Cl2] (bpy = 2,2’-bipyridine) , [Ru(phen)2Cl2] (phen = 1,10-phenanthroline), [Cu(Me2-bpy)2]BF4 (4,4’-dimethyl-2,2’-bipyridine) and [Fe(η5-C5H4CHO)(η6-C6H6)]PF6 ((η5-C5H4CHO)(η6-C6H6) = η6-benzene,η5-cyclopentadienyl). All the four complexes absorb IR radiation and excite the Photo-CORM through triplet energy transfer. The IR spectroscopy showed that all photosensitizers were formed, since there were displacements of the bands and formation of new bands.}},
  author       = {{Björklund, Joachim}},
  language     = {{eng}},
  note         = {{Student Paper}},
  title        = {{Synthesis and Characterization of some Photo-CORM and Photosensitizers}},
  year         = {{2019}},
}