Department of Chemistry, Imperial College London, London, UK SW7 2AZ.
Dalton Trans. 2011 Jun 21;40(23):6210-5. doi: 10.1039/c0dt01614d. Epub 2011 Feb 11.
(R-DAB)FeI(2) complexes containing bidentate diimide ligands (R-DAB = RN=CH-CH=NR; R = (i)Pr, c-C(6)H(11)) have been investigated for their ability to react with carbon monoxide to form iron(II) dicarbonyl complexes, (R-DAB)FeI(2)(CO)(2). Solution IR spectroscopy revealed two νCO stretches between 2000 and 2040 cm(-1) corresponding to a cis-arrangement of the carbonyl ligands around the iron. Photochemical decarbonylation was achieved by UV irradiation (365 nm), which occurred within 5 min as evidenced by solution IR spectroscopy. (c-C(6)H(11)-DAB)FeI(2) has been characterised by X-ray crystallography. Reactions using (11)C-labelled carbon monoxide were investigated and revealed that both (R-DAB)FeI(2) species were not effective as trapping complexes due to the low concentrations of [(11)C]CO used in these experiments. A Fe(TPP)(THF)(x) (TPP = tetraphenylporphyrin) complex was investigated with unlabelled CO and the monocarbonyl adduct Fe(TPP)(THF)CO was formed in situ as identified by IR spectroscopy (νCO = 1966 cm(-1)) yet was stable to CO loss upon UV irradiation. Carbonylation reactions of in situ-generated Fe(TPP)(THF)(x) using [(11)C]CO revealed that 97% of the [(11)C]CO stream could be trapped in one pass of the gas at room temperature and at atmospheric pressure.
(R-DAB)FeI2 配合物含有双齿二酰亚胺配体（R-DAB = RN=CH-CH=NR；R = (i)Pr, c-C6H11），研究其与一氧化碳反应生成铁（II）二羰基配合物（R-DAB）FeI2（CO）2 的能力。溶液红外光谱显示，两个 νCO 伸缩在 2000 和 2040 cm-1 之间，对应于羰基配体在铁周围的顺式排列。光化学脱羰作用通过紫外线照射（365nm）实现，这在 5 分钟内通过溶液红外光谱得到证明。（c-C6H11-DAB）FeI2 已通过 X 射线晶体学进行了表征。使用 11C 标记的一氧化碳进行了反应研究，结果表明由于在这些实验中使用的 [(11)C]CO 的浓度较低，两种 (R-DAB)FeI2 物质都不是有效的捕集配合物。研究了 Fe(TPP)(THF)(x)（TPP = 四苯基卟啉）配合物与未标记的 CO 的反应，通过红外光谱（νCO = 1966 cm-1）原位形成了一羰基加合物 Fe(TPP)(THF)CO，但在紫外线照射下稳定，不会失去 CO。使用 [(11)C]CO 对原位生成的 Fe(TPP)(THF)(x)进行羰基化反应表明，在室温下和大气压下，[11C]CO 气流的 97%可以在一次气体通过中被捕获。
