Synthesis and Characterization of the Stable Dicarbonyl(cyclopentadienyl)iron Radical [(C₅R₅)Fe(CO)₂] (R  CHMe₂)

Abstract

COMMUNICATIONS materials causes the condensation of the silicate layers, giving the zeolite structures MCM-22 and ferrierite. Similar behavior can also be expected for RUB-15, since the silicate layer terminated with silanol groups should be the perfect subunit for the formation of the silica framework of the zeolite sodalite. Experimental ProcedureRUB-15 crystallized from a reaction mixture with the following composition: SiO,:TMAOH:H,O = 1.00:0.75:55.52 The solution was filled in Teflon-lined autoclaves (60% filling factor) and kept in an oven at a temperature between 120 and 140 C for about four weeks. The reaction product was filtered, washed with distilled water. dried at 80 c. and subsequently identified by X-ray powder diffraction.

Iron‐Mediated Coupling of Two Ethyl Anions to Form a 2‐Butyne Ligand

“…The methyne carbon atoms, however, may occupy the positions shown in Figure 1 or positions arrived at by application of an individual mirror plane defined for each isopropyl substituent by its two methyl carbon atoms and the ring carbon atom connected to the respective isopropyl group. The ellipsoids shown in Figure 1 illustrate this disorder, which has also been found for other 5 Cp complexes9–12 and has been discussed in detail for decaisopropylstannocene 11. Despite this disorder, the structures usually refine quite well, and the wR 2 value for all data was 0.0721 in this case (cf.…”

“…Pentaisopropylcyclopentadienyliron(II) bromide [ 5 CpFe(μ‐Br)] 2 ( 1 ) has been known since 1996,9 but a crystal structure analysis of this starting compound could be performed only recently (Figure 1). The structure suffers from a disorder of all isopropyl groups, whose methyl groups occupy the positions shown in Figure 1.…”

Chromium(III) and Chromium(II) Phenolate Complexes with Bulky Alkylcyclopentadienyl Ligands

“…Many examples show, that the steric bulk of the four isopropyl groups of the 4 Cp ligand leaves space for one additional ligand close to the only ring CH position and a second one between two isopropyl groups rotated away from each other. There are also examples with three additional ligands like [ 4 CpFe(CO) 2 Br], [10] but the dissociation of the tricarbonyl-pentamethylcyclopentadienylchromium dimer in [Cp*Cr(CO) 3 ] · radicals [11] and the complete dissociation of solid [ 5 CpFeCO(μ-CO)] 2 in dicarbonylpentaisopropylcyclopentadienyliron radicals in solution even at low temperatures [10] show the limited capacity of 3d transition metals for a growing number of "legs" in half sandwich complexes with bulky alkylcyclopentadienyl ligands. also the chromium(III) bis(phenolate) complex 5, this work].…”

The Shrinking World of Innocent Ligands: Conventionaland Non‐Conventional Redox‐Active Ligands

“…• acting as true cyclopentadienyl radicals), [56] (2) σ-and π bonding, ligands include reducible CO (Ǟ oligomerization [46] ), non-innocent carbenes, [57] or metalcapped C n chains, [58] and (3) σ bonding dominates the interaction of metals with hydride, alkyl, and aryl groups.…”