IR Spectroscopic Methods for the Investigation of the CO Release from CORMs

详细信息    查看全文

• 作者：Moritz Klein ; Ute Neugebauer ; Ali Gheisari ; Astrid Malassa ; Taghreed M. A. Jazzazi ; Frank Froehlich ; Matthias Westerhausen ; Michael Schmitt ; J眉rgen Popp
• 刊名：Journal of Physical Chemistry A
• 出版年：2014
• 出版时间：July 24, 2014
• 年：2014
• 卷：118
• 期：29
• 页码：5381-5390
• 全文大小：396K
• ISSN：1520-5215

文摘

Carbon monoxide (CO) is a toxic gas for mammals, and despite this fact, it is naturally produced in these organisms and has been proven to be beneficial in medical treatments, too. Therefore, CO-releasing molecules (CORMs) are intensively developed to administer and dose CO for physiological applications. Nearly all of these compounds are metal carbonyl complexes, which have been synthesized and investigated. However, for most of these CORMs, the exact reaction mechanisms of CO release is not completely elucidated, although it is of utmost importance. The widely used myoglobin assay for testing the CO release has several disadvantages, and therefore, different methods have to be applied to characterize CORMs. In this work, different setups of IR absorption spectroscopy are used to analyze and quantify the CO release during the decay of various CORMs: IR spectroscopy of the gas phase is applied to follow the CO liberation, and attenuated total reflection (ATR) IR spectroscopy is used to record the decay of the metal carbonyl. IR spectroscopy supported by DFT calculations yields valuable insights in the CO release reaction mechanism. The focus is set on two different CORMs: CORM-2 (Ru₂(CO)₆Cl₄) and on the photoactive CORM-S1 (photoCORM [Fe(CO)₂(SCH₂CH₂NH₂)₂]). Our results indicate that the CO liberation from CORM-2 strongly depends on sodium dithionite, which is required for the commonly applied myoglobin assay and that CORM-S1 loses all its bound CO molecules upon irradiation with blue light.