Synthese von ansa‐[2]Boracyclopentadienylcycloheptatrienylchrom und Reaktion zum ansa‐Platinabis(boryl)‐Komplex durch oxidative Addition der Bor‐Bor‐Bindung

Abstract

Chromsandwich mit „Henkel“: Ein [2]Boratrochrocenophan mit Dibor‐Brücke (Schema links) wurde synthetisiert und an [Pt(PEt3)4] oxidativ addiert. Das so erhaltene [3]Boraplatinatrochrocenophan, das erste Beispiel eines ansa‐[3]Boraplatina‐Sandwichkomplexes, wurde in Lösung und im Kristall charakterisiert.

Cycloheptatrienyl Zirconium Sandwich Complexes with Lewis Basic Phospholyl Ligands (Phosphatrozircenes): Synthesis, Structure, Bonding and Coordination Chemistry

“…[12] Alternatively, the cyclopentadienyl system can also be extended by one or more CH units. Following extensive studies by Green and Ng in the 1990s, [13] independent reports from the groups of Braunschweig, [14] Elschenbroich, [15] Girolami [16] and Tamm [17] have recently revitalised interest in early-transition-metal complexes containing the cycloheptatrienyl (Cht) ligand. Our group has especially focused on Group 4 Cht-Cp sandwich complexes, [18] in which-based on experimental and theoretical results-a formal + 4 oxidation state can be assigned to the metal atom, implying that the C 7 H 7 ligand is best considered as a trianion.…”

Intramolecular Activation of a Disila[2]molybdenocenophanedihydride: Synthesis and Structure of a [1],[1]Metalloarenophane

“…In 1992, Manners and coworkers reported the first Pd-catalyzed insertion of alkynes into the SiÀSi bridge of tetramethyldisila[2]ferrocenophane, [4] Herberhold et al described in 1997 the first oxidative addition of a Pt 0 fragment into the SnÀSn bridge of an ansaferrocene and the subsequent insertion of an alkyne, [5] whereas our group accomplished oxidative additions of Pt 0 fragments as well as homogeneously and heterogeneously catalyzed insertions of alkynes and diazobenzene into BÀB and SiÀSi bonds of various [2]metalloarenophanes. [6] Motivated by this facile activation of the EÀE bridge, we wondered whether a corresponding oxidative addition can be achieved intramolecularly and turned our attention to tetramethyldisila[2]molybdenocenophanedihydride (1) as a promising starting material. Herein we report the synthesis and full characterization of this species and its conversion into an unprecedented twofold-bridged [1],[1]metalloarenophane.…”

Ansa‐Complexes of [Mn(η5‐C5H5)(η6‐C6H6)]: Preparation, Characterization, and Reactivity of [n]Manganoarenophanes (n=1, 2, 3)

“…Moreover,t he data indicatet hat only one of the possible B=Nd ouble-bondi somers is formed. Similart oo ther boron-substituted sandwich species, the ipso-carbona tom could not be detected in the 13 CNMR spectrum, [15,29,35,36] whereas the 13 CNMR resonances of the ring CH groups appear in the range d = 76.0 to 88.1 ppm. Furthermore, we were ablet od etermine the solid-state structure of 1 by X-ray diffraction analysis.…”

“…[1][2][3] Typically,t he incorporation of the bridge to give such ansa-complexesi sa chievedb y salt elimination of dilithiated sandwich compounds with appropriate element dihalides. Examples include the preparation of metalloarenophanes derived from [M(h 5 -C 5 H 5 )(h 7 -C 7 H 7 )],t hat is, troticene (M = Ti), [3][4][5][6][7][8] trovacene( M= V), [9][10][11][12] and trochrocene (M = Cr), [13][14][15][16] [Ti(h 5 -C 5 H 5 )(h 8 -C 8 H 8 )] [17] or [Co(h 4 -C 4 Me 4 )(h 5 -C 5 H 5 )]. [18] Reactivity studies on these metalloarenophanes revealed their potential for further transformations, such as ringopeningp olymerization [7,[10][11][12] to produce metallopolymers or the functionalization of unsaturated organic substrates.…”