Method of Establishing the Lewis Acidity of a Metal Fragment Based on the Relative Binding Strengths of Ar-BIAN Ligands (Ar-BIAN = Bis(aryl)acenaphthenequinonediimine)
作者:Michela Gasperini、Fabio Ragaini
DOI:10.1021/om034370i
日期:2004.3.1
coordination strengths of a series of differently substituted Ar-BIAN ligands (Ar-BIAN = bis(aryl)acenaphthenequinonediimine) to a series of palladium complexes in both the formal 0 and 2 oxidation states have been determined. In all cases a good to excellent linearity of log Keq with respect to the Hammett σ constants of the substituents on the aryl fragments of the ligands was observed. The resulting
已经确定了一系列不同取代的Ar-BIAN配体(Ar-BIAN =双(芳基)ac萘醌二亚胺)对一系列处于正式0和2氧化态的钯配合物的相对配位强度。在所有情况下,都观察到log K eq相对于配体芳基片段上取代基的Hammettσ常数具有良好的线性关系。建议将所得的ρ常数很好地表明金属碎片的路易斯酸度,这是仅针对有限种类的化合物确定实验参数的物理量。所获得的参数不仅可以将它们之间的不同烯烃配合物进行比较,还可以针对不同的金属片段(如Pd(OAc)2)进行比较。,Pd(Me)Cl和π-烯丙基配合物。烯烃络合物的路易斯酸度变化很大,其范围从酸性较低的(Pd(Ar-BIAN)(DMFU); DMFU =富马酸二甲酯)到酸性最高的两种(Pd(Ar-BIAN)(TCNE)和Pd (Ar-BIAN)(FN); TCNE =四氰基乙烯,FN =富马腈衍生物)配合物。阳离子π-烯丙基配合物在所检查的配合物中具
Synthesis of Ar-BIAN Ligands (Ar-BIAN = Bis(aryl)acenaphthenequinonediimine) Having Strong Electron-Withdrawing Substituents on the Aryl Rings and Their Relative Coordination Strength toward Palladium(0) and -(II) Complexes
作者:Michela Gasperini、Fabio Ragaini、Sergio Cenini
DOI:10.1021/om020147u
日期:2002.7.1
The synthesis of Ar-BIAN ligands (Ar-BIAN = bis(aryl)acenaphthenequinonediimine) having strong electron-withdrawing substituents on the aryl ring is reported. Most of these derivatives had escaped isolation in a pure form up to now. A quantitative scale of coordination strength of the newly synthesized ligands in the complexes Pd0(L)(DMFU) (DMFU = dimethylfumarate) and PdII(L)(OAc)2 has been measured
Ethylene Oligomerization and Propylene Dimerization Using Cationic (α-Diimine)nickel(II) Catalysts
作者:Steven A. Svejda、Maurice Brookhart
DOI:10.1021/om980736t
日期:1999.1.1
modified MAO (MMAO), or Et2AlCl in toluene generates active cationic catalysts in situ that oligomerizeethylene to a Schulz−Flory distribution of linearα-olefins. Reaction conditions can be adjusted that lead to selectivities as high as 96% for linearα-olefins. These catalysts are highly active, with ethylene turnover frequencies as high as 1.4 × 105 mol of C2H4/((mol of Ni)h) observed. Schulz−Flory
描述了镍催化的乙烯低聚和丙烯二聚反应。一系列芳基取代的α-二亚胺配体1(ArN C(R)C(R)NAr,R,R≡1,8-萘二基,Ar≡XC 6 H 4,X = p -CF 3(a),p -H(b),p -Me(c),p -OMe(d),o -Me(e))及其相应的二溴化Ni(II)配合物2的制备。二溴化镍(II)配合物的处理2用烷基铝活化剂如MAO(甲基铝氧烷),改性的MAO(MMAO),或Et 2的AlCl在甲苯产生活性阳离子催化剂在 原位即乙烯低聚至α线性烯烃的舒尔茨-弗洛里分布。可以调节反应条件,以使直链α-烯烃的选择性高达96%。这些催化剂具有很高的活性,乙烯的转化频率高达1.4×10 5 mol C 2 H 4。/((Ni的摩尔)h)。Schulz-Floryα值的范围从0.59到0.81,并且取决于反应温度,乙烯压力和铝助催化剂的性质。活性催化剂使丙烯二聚,产生具有大致相等的正己烯和2-甲基戊烯组成的产物混合物。2
Easy Entry into Reduced Ar-BIANH<sub>2</sub>Compounds: A New Class of Quinone/Hydroquinone-Type Redox-Active Couples with an Easily Tunable Potential
redox properties of these molecules, highlighting their analogies with quinone/hydroquinone systems. Such analogies, in combination with the much more negative reduction potential range of Ar‐BIAN compounds with respect to quinones, can afford to extend the range of reduction potentials so far obtainable by the use of quinones.
通过还原相应的双(芳基)ac萘醌二亚胺(Ar-BIAN)化合物,可以高收率合成在芳基环上带有不同取代基的Ar-BIANH 2。固态p -CH 3 C 6 H 4 -BIANH 2的结构通过X射线衍射确定。两个平行的BIAN和BIANH 2的详尽伏安法研究系列提供了这些分子的氧化还原特性的首次合理化,突出了它们与醌/对苯二酚体系的相似性。这种类比,再加上Ar-BIAN化合物相对于醌具有更大的负还原电位范围,可以提供迄今为止通过使用醌可获得的还原电位范围的扩展。