第6卷‧第3期,
198207
, pp. 298-307
零價錳的有機金屬自由基
- 作者:
陳秋炳; 洪愛娜; 熊葆楨
- 作者服務機構:
國立清華大學化學系
- 中文摘要:
光照射在Mn (CO) 加 phosphine 或 phosphite 的庚烷溶液可產生Mn(O)的自由基,其構造式為Mn(CO) L ,L 為烷基的 phosphine 或 phosphite。L的大小影響了自由基的動態活力,當L為 pMe ,P(OE+) 或(n-BuO) P時, EPR 信號的強度隨溫度變化,並且 Hyperfine Splitting 有平均現象,當L為PE+ ,P(iso-Bu) 或(iso-PrO) P時,只有 Hyperfine Splitting 的平均現象可見。當L更大時,平均現象亦不可見,凝固液體的 EPR,以計算機比擬的方法探討,結果可與溶液資料相比。不配對電子的軌道結構,亦可以 EPR 資料分析。
- 英文摘要:
Photolytically generated Mn(CO) L radicals, which were stabilized with the introduction of abulky phosphine or phosphite ligand L into the coordination sphere, were studied by EPR spectroscopy.Depending on the steric requirement of the phosphines or phosphites, the radical EPR spectra exhibit dif-ferent degrees of electron exchange process, which involve the dynamic monomer-dimer equilibrium. Thisexchange process can be clearly observed when L is Et P, (iso-Bu) P, Me P, (EtO) P, (n-BuO) P and (iso-PrO) P. When the size of the ligand is increased, such as L=(cyclohexyl) P, the exchange process does notshow up in the EPR spectra. When L is small, such as Me P, (EtO) P and (n-BuO) P, the EPR signal inten-sities are temperature dependent. It can be explained based on the stability of Mn (CO) L , with Mn-Mnbond energy ca. 14 Kcal/mole. When L is a triarylphosphine, such as P Ph and P(o-tolyl) ,the photoly-tically generated radicals are different from the trialkylphosphine or trialkylphosphite substituted Mn(O)radicals. The MO of the unpaired electron in the Mn(O) radical is discussed in light of the EPR parameters.
- 中文關鍵字:
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- 英文關鍵字:
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