Unraveling the photochemistry of Fe(CO)5 in solution: observation of Fe(CO)3 and the conversion between 3Fe(CO)4 and 1Fe(CO)4(Solvent).
Unraveling the photochemistry of Fe(CO)5 in solution: observation of Fe(CO)3 and the conversion between 3Fe(CO)4 and 1Fe(CO)4(Solvent).
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DOI：
10.1021/ja048411t
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发表时间：
2004-09
影响因子：
15
通讯作者：
Peter Portius;Jixin Yang;Xue-Zhong Sun;D. Grills;P. Matousek;A. Parker;M. Towrie;M. George
中科院分区：
文献类型：
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作者：
Peter Portius;Jixin Yang;Xue-Zhong Sun;D. Grills;P. Matousek;A. Parker;M. Towrie;M. George
用时间分辨红外光谱法研究了Fe（CO）_5（5）在庚烷、超临界Ar、ScCl_4和scCH_4中的光化学反应。3Fe（CO）4（（3）4）和Fe（CO）3（溶剂）（3）在最初的几皮秒内作为初级光产物形成。配合物3通过单光子过程形成。在庚烷、SCCH 4和SCCH 3中，（3）4衰变形成（1）4 x L（L =庚烷、CH 4或CH 3），并与5反应形成Fe 2（CO）9。在庚烷中，3与CO反应形成（1）4 x L。第一次直接监测了（3）4向（1）4 × L的转化率（L =庚烷，kobs = 7.8（+/-0.3）× 10（7）s（-1）; scCH 4，5（+/-1）× 10（6）s（-1）; scCH 4，2.1（+/-0.1）× 10（7）s（-1））。在scAr中，（3）4和3分别与CO反应生成5和（3）4。我们测定了（3）4与CO在scAr中反应的速率常数（kCO = 1.2 × 10（7）dm ~ 3 mol ~（-1）s ~（-1）），这与以前在气相中得到的值非常相似。将scAr掺杂有NH 4或CH 4导致（3）4与NH 4或CH 4反应以形成（1）4 x NH 4或（1）4 x CH 4。相对产率[（3）4]：[3]以庚烷> scO 2> scCH 4>> scAr的顺序降低，并且scAr和scCH 4中的压力依赖性测量表明溶剂密度对该比率的影响。
The photochemistry of Fe(CO)5 (5) has been studied in heptane, supercritical (sc) Ar, scXe, and scCH4 using time-resolved infrared spectroscopy (TRIR). 3Fe(CO)4 ((3)4) and Fe(CO)3(solvent) (3) are formed as primary photoproducts within the first few picoseconds. Complex 3 is formed via a single-photon process. In heptane, scCH4, and scXe, (3)4 decays to form (1)4 x L (L = heptane, CH4, or Xe) as well as reacting with 5 to form Fe2(CO)9. In heptane, 3 reacts with CO to form (1)4 x L. The conversion of (3)4 to (1)4 x L has been monitored directly for the first time (L = heptane, kobs = 7.8(+/- 0.3) x 10(7) s(-1); scCH4, 5(+/- 1) x 10(6) s(-1); scXe, 2.1(+/- 0.1) x 10(7) s(-1)). In scAr, (3)4 and 3 react with CO to form 5 and (3)4, respectively. We have determined the rate constant (kCO = 1.2 x 10(7) dm3 mol(-1) s(-1)) for the reaction of (3)4 with CO in scAr, and this is very similar to the value obtained previously in the gas phase. Doping the scAr with either Xe or CH4 resulted in (3)4 reacting with Xe or CH4 to form (1)4 x Xe or (1)4 x CH4. The relative yield, [(3)4]:[3] decreases in the order heptane > scXe > scCH4 >> scAr, and pressure-dependent measurements in scAr and scCH4 indicate an influence of the solvent density on this ratio.