Butenyl‐Substituted Alkaline‐Earth Metallocenes: A First Step towards Olefin Complexes of the Alkaline‐Earth Metals

Schumann, Herbert; Schutte, Stefan; Kroth, Heinz‐Jürgen; Lentz, Dieter

doi:10.1002/anie.200460927

Cited by 55 publications

(48 citation statements)

References 38 publications

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“…In some cases, convincing NMR spectroscopic evidence has been reported, while in others, compounds were sufficiently crystalline for X-ray structure determination. 11,13,26,44 Based on the Dewar-Chatt-Duncanson model, it is easy to understand why olefin complexes of d 0 metals are more label than olefin complexes of metals with d-electrons. Less obvious, however, is the reason for the scarcity of olefin complexes with certain d 10 metals.…”

Section: Introductionmentioning

confidence: 99%

Unprecedented Alkene Complex of Zinc(II): Structures and Bonding of Divinylzinc Complexes

et al. 2006

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This report describes the solid state structures of a series of divinylzinc complexes, one of which represents the only structurally characterized zinc(II) π-complex. Vinylzinc reagents, Zn[C(Me) =CH 2 ] 2 (1) and Zn[C(H)=CMe 2 ] 2 (2), have been synthesized and isolated as white crystalline solids in 66% and 72% yield, respectively. Each compound exhibits an infinite polymeric architecture in the solid state via a series of zinc-π (1) and zinc-σ-bonded (2)

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Section: Introductionmentioning

confidence: 99%

Unprecedented Alkene Complex of Zinc(II): Structures and Bonding of Divinylzinc Complexes

et al. 2006

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“…It should be noted that first alkene derivatives of alkaline earth metals were synthesized and structurally characterized in 2004. 5 The coordination of alkenes to metal atoms in these com pounds was confirmed not only by X ray diffraction data but also by 1 H NMR spectra.…”

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confidence: 75%

“…1,2 Bis[(2,6 diisopropylphenyl)imino]acenaphthenediethyl aluminum sodium diethyl etherate, Na(Et 2 O)(dpp BIAN)AlEt 2 (5). A solution of (C 2 H 5 ) 2 AlCl (1.0 mol L -1 ) in hexane (1.0 mL) was added to a solution of Na 2 (dpp BIAN), which was prepared from dpp BIAN (0.5 g, 1.0 mmol) in Et 2 O (30 mL).…”

Section: Methodsmentioning

confidence: 99%

“…Hence, is seemed reasonable to perform the experimental study of the influence of the alkyl groups at the aluminum atom on both the position of the sodium cation with respect to the dpp BIAN dianion and the coordination of arene by the sodium cation. In the present study, we synthesized the ethyl derivatives Na(Et 2 O)(dpp BIAN)AlEt 2 (5) and Na(C 6 H 6 )(dpp BIAN)AlEt 2 (6) and characterized them by X ray diffraction.…”

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confidence: 99%

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Coordination of benzene to a sodium cation

et al. 2007

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The complexes Na(Et 2 O)(dpp BIAN)AlEt 2 (5) and Na(η 6 C 6 H 6 )(dpp BIAN)AlEt 2 (6) were synthesized by reactions of the disodium salts of dpp BIAN (dpp BIAN is 1,2 bis[(2,6 di isopropylphenyl)imino]acenaphthene) with 1 equiv. of Et 2 AlCl in diethyl ether and benzene, respectively. The structures of both complexes were established by X ray diffraction. In mol ecules 5 and 6, diethylaluminum is chelated by the dianionic dpp BIAN ligand. The sodium cations in molecules 5 and 6 are located above the plane of the diimine fragments and coordi nate the Et 2 O or benzene molecule, respectively.The coordination of unsaturated hydrocarbons by metal complexes and the reactivities of organic molecules bound to metal atoms are among fundamental problems of coordination and organometallic chemistry. A great diversity of organic reactions catalyzed by transition metal compounds is based on the ability of these metals to coor dinate unsaturated substrates, such as olefins or arenes. Main group metals do not form stable π complexes be cause they have no electrons for the back donation to the antibonding orbitals of π ligands, which strengthens metal-π ligand interactions. Nevertheless, the coordi nation of arenes to alkali metal cations was documented. All structurally characterized complexes, in which arenes are coordinated to alkali metal cations, can be divided into two classes. One class (A) includes complexes, in which the arene fragment (substituted or unsubstituted Ph ring) is involved in an anionic ligand coordinated to any other metal. Numerous examples of this "forced" co ordination of arenes to alkali metal cations were pub lished in the literature. 1Another class (B) includes complexes, in which a neu tral free arene ligand is coordinated exclusively to an al kali metal cation. The K[Al 7 O 6 Me 16 ](η 6 C 6 H 6 ) complex is the first structurally characterized compound of this class. 2 In recent years, several analogous Na and K com pounds were synthesized and characterized by X ray dif fraction. 3 The nature of interactions between alkali metal cations and arenes was investigated by quantum chemi cal methods in several studies. 4 The coordination of arenes to Group I metal cations is described as the attraction between the metal cation and the dipole of the arene π system. Complexes of Group I metal cations with arenes do not exist in donor solvents. As a rule, these complexes can be prepared by crystallization of organic derivatives of alkali metals from arenes. The dissolution of these com plexes in donor solvents, for example, in Et 2 O, leads to the replacement of arene by a solvent molecule. In spite of the fact that the reactions of arenes with alkali metal cations can play an important role in the development of such a fundamental concept of chemistry as the chemical bond, the X ray diffraction analysis is the only experi mental method used for investigation of these interac tions. Moreover, data on the reactivities of arenes coordi nated to alkali metal atoms are lacking. It should be noted that first al...

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“…Sensitisers used in PVC membranes typically also are organic metal-complexing agents at low concentration [12,13], including the membrane used by List-Kratochvil et al [5] which is described in [14]. The ability of alkaline earth metals to form organometallic complexes is established [15], they may therefore compete with Pd for complexation with tris(dibenzylideneacetone). ZnO, in contrast, is impermeable and does not contain catalyst residue.…”

Section: Discussionmentioning

confidence: 99%