Catalysis on Photoinduced Electron Transfer

We have found that Sc^<3+> ion is highly effective for the reduction of benzaldehyde and its derivatives by an NADH analogue at room temperature。这种明显的反应性显然是可以与酶相比较的。您的位置：知道173>> on the electron transfer reactions of carbonyl compounds。从10-甲基-9，10-二氢丙烯啶（AcrH_2）到对苯并喹酮（Q）的氢化物转移反应已被催化成乙腈（MeCN）中的各种金属，如Mg^<2+>和稀土金属。在测试金属盐中， Sc （OTf） _3是最有效的。观察到的第二顺序速率恒定增加与[Sc^<3+>]低浓度的增加，改变到高浓度的第二顺序依赖性。在MeCN中观察到相同的催化行为的Sc^<3+>在CoTPP中减少Q的电子转移（TPP=四苯ylporphyrin dianion）。与[Sc^<3+>]相比，速率常数的次要依赖于[Sc^<3+>]被归类为形成一个1 ： 2复杂之间的Q^<·->和Sc^<3+>。您的位置：知道173>>-2 Sc ^<3+> is confirmed by the ESR spectrum which exhibits the super hyperManagement interaction with two equivalent Sc n\i。因此，从AcrH_2到Q可以通过Sc^<3+>催化的电子转移从AcrH_2到Q.当AcrH_2被1-苯并-1，4-二氢氯丁胺（BNAH）替换时，它是一个比AcrH_2、苯并醛和其衍生物被BNAH有效地减少在Sc^<3+>的MeCN在房间温度上相应的相应酒精含量。Sc^<3+>也可以从Ru （bpy）的兴奋状态中提取金属。

We have found that Sc^<3+> ion is highly effective for the reduction of benzaldehyde and its derivatives by an NADH analogue at room temperature. The apparent reactivity is shown to be comparable with the enzyme. The catalytic mechanism is discussed based on the comparison of the catalysis of Sc^<3+> on the electron transfer reactions of carbonyl compounds. The hydride transfer reaction from 10-methyl-9,10-dihydroacridine (AcrH_2) to p-benzoquinone (Q) is catalyzed by various metal ions such as Mg^<2+> and rare-earth metal ions in acetonitrile (MeCN). Among triflate salts of metal ions examined, Sc (OTf) _3 was the most effective. The observed second-order rate constant increases with an increase in [Sc^<3+>] at low concentrations, changing to second order dependence at high concentrations. Essentially the same catalytic behavior of Sc^<3+> was observed in the electron transfer reduction of Q by CoTPP (TPP=tetraphenylporphyrin dianion) in MeCN.The second-order dependence of the rate constant with respect to [Sc^<3+>] is ascribed to formation of a 1 : 2 complex between Q^<・-> and Sc^<3+>. The formation of Q^<・->-2Sc^<3+> is confirmed by the ESR spectrum which exhibits the super hyperfine interaction with two equivalent Sc nuclei. Thus, the hydride transfer from AcrH_2 to Q may proceed via Sc^<3+>-catalyzed electron transfer from AcrH_2 to Q.When AcrH_2 is replaced by 1-benzyl-1,4-dihydronicotinamide (BNAH) which is a stronger electron donor than AcrH_2, benzaldehyde and its derivatives are reduced by BNAH efficiently in the presence of Sc^<3+> in MeCN at room temperature to yield the corresponding alcohols. The Sc^<3+> also catalyzes photoinduced electron transfer from the excited state of Ru (bpy) _3^<2+> to benzaldehydes in MeCN.Catalysis of metal ions on various thermal and photoinduced electron transfer reactions has been examined in detail.