Preparation of chelate bis(imine)nickel allyl systems by reaction of their corresponding butadiene complexes with electrophiles
作者:Joachim W Strauch、Gerald Kehr、Gerhard Erker
DOI:10.1016/s0022-328x(03)00699-5
日期:2003.10
activation energy of ΔG‡ (298 K)=22.3±0.2 kcal mol−1. Complex 4a added [Ph3C+] to the butadiene ligand to yield the salt [(lig)Ni(η3-C3H4-CH2CPh3)+][B(C6F5)4−] (Z-12a), that proved isomerically stable under the applied reaction conditions. Similar reactions were carried out starting from the acenaphthylene 1,2-dione derived chelate bis(imine)Ni(butadiene) complex 4b. The systems 6, 7, 9 and 12 were found to
Synthesis and Reactivity of (C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>B−<i>N</i>-Heterocycle Complexes. 1. Generation of Highly Acidic sp<sup>3</sup> Carbons in Pyrroles and Indoles
The reaction of pyrroles and indoles with B(C(6)F(5))(3) and BCl(3) produces 1:1 B-N complexes containing highly acidic sp(3) carbons, for example, N-[tris(pentafluorophenyl)borane]-5H-pyrrole (1) and N-[tris(pentafluorophenyl)borane]-3H-indole (2), that are formed by a new formal N-to-C hydrogen shift, the mechanism of which is discussed. With some derivatives, restricted rotation around the B-N bond
Synthesis and Reactivity of <i>N</i>-Heterocycle-B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub> Complexes. 4. Competition between Pyridine- and Pyrrole-Type Substrates toward B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>: Structure and Dynamics of 7-B(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>-7-azaindole and [7-Azaindolium]<sup>+</sup>[HOB(C<sub>6</sub>F<sub>5</sub>)<sub>3</sub>]<sup>-</sup>
and 5 have been determined both in the solid state and in solution and compared to the structures of other (C6F5)3B-N-heterocycle complexes. Two dynamicprocesses have been found in compound 4. Their activation parameters (DeltaH = 66 (3) kJ/mol, DeltaS = -18 (10) J/mol K and DeltaH = 76 (5) kJ/mol, DeltaS = -5 (18) J/mol K) are comparable with those of other (C6F5)3B-based adducts. The nature of the
7-氮杂吲哚与B(C6F5)3之间的反应定量生成7-(C6F5)3B-7-氮杂吲哚(4),其中B(C6F5)3与7-氮杂吲哚的吡啶氮配位,甚至没有反应的吡咯环在存在第二个等效的B(C6F5)3的情况下。7-氮杂吲哚与H 2 O-B(C 6 F 5)3反应最初产生[7-氮杂吲哚] + [HOB(C 6 F 5)3]-(5),其缓慢转化为4,从而释放出H 2 O分子。吡啶从已知的络合物(C6F5)3B-吡咯(1)和(C6F5)3B-吲哚(2)中除去硼烷,形成游离吡咯或吲哚,得到更稳定的加合物(C6F5)3B-吡啶(3) 。吡啶与7-氮杂吲哚之间与B(C6F5)3配位的竞争再次产生3。化合物4和5的分子结构已在固态和溶液中进行了测定,并与其他(C6F5)3B-N-杂环配合物的结构进行了比较。在化合物4中发现了两个动态过程。它们的活化参数(DeltaH = 66(3)kJ / mol,DeltaS
Protonation of the Heterocyclic Cp-Anion Equivalent [Pyrrolyl-B(C6F5)3]Li − Formation of a Useful Neutral Brønsted Acid for the Generation of Homogeneous Metallocene Ziegler Catalysts
an η5 coordination of the pyrrolyl moiety to the lithium cation. Treatment of 3 with HCl in ether leads to H+ addition at a pyrrolyl α-position to yield the neutral dipolar Bronsted acid system [(C4H5N)B(C6F5)3] (4). The reagent 4 can be used to protonate Cp2Zr(CH3)3 to yield [Cp2Zr(CH3)+(C4H4N)B(C6F5)3−] (6) and methane. H+ transfer from 4 to (butadiene)zirconocene results in the formation of the