10170-68-0Relevant articles and documents
Herwig, W.,Zeiss, H. H.
, p. 1404 - 1404 (1958)
Synthesis and molecular structure of the tetranuclear μ4-oxo-centered chromium complex [Cr4(CH2CH2CH2NMe2) 4(μ4-O)(μ-Cl)6]
Ossola, Franco,Benetollo, Franco
, p. 56 - 59 (1999)
The complex [CrCl3(THF)3] reacts with Li(CH2CH2CH2NMe2) in THF at room temperature (r.t.) to form the tetranuclear complex [Cr4(CH2CH2CH2NMe2) 4(μ4-O)(μ-Cl)6] (1) where each chromium atom has a distorted octahedral coordination geometry with an oxygen atom shared among the four metal ions.
Kurras, E.
, p. 171 - 171 (1959)
N-Phosphanyl- and N,N′-Diphosphanyl-Substituted N-Heterocyclic Carbene Chromium Complexes: Synthesis, Structures, and Catalytic Ethylene Oligomerization
Ai, Pengfei,Danopoulos, Andreas A.,Braunstein, Pierre
, p. 4109 - 4116 (2015)
The chromium(II) complexes [CrCl2(t-BuNHC,P-κC)2] (1), [CrCl2(MesNHC,P-κC)2] (2), [CrCl2(DippNHC,P-κC)2] (3), and [CrCl2(P,NHC,P-κC)2] (4) containing the N-phosphanyl- or N,N′-diphosphanyl-substituted N-heterocyclic carbene (NHC) hybrid ligands t-BuNHC,P (1-(di-tert-butylphosphino)-3-tert-butylimidazol-2-ylidene), MesNHC,P (1-(di-tert-butylphosphino)-3-mesitylimidazol-2-ylidene), DippNHC,P (1-(di-tert-butylphosphino)-3-(2,6-diisopropylphenyl)imidazol-2-ylidene), and P,NHC,P (1,3-bis(di-tert-butylphosphino)imidazol-2-ylidene), respectively, were prepared from CrII ([CrCl2(thf)2]) or CrIII ([CrCl3(thf)3] or [Cr(Me)Cl2(thf)3]) precursors. The solid-state structures of these four complexes show square-planar CrII centers, with two trans chloride and two monodentate CNHC donors. Alkylation of 3 and 4 with [Mg(benzyl)2(thf)2] led to the formation of the σ complexes [Cr(benzyl)3(DippNHC,P-κC,κP)] (5) and [Cr(benzyl)3(P,NHC,P-κC,κP)] (6), respectively, with five-coordinate distorted-square-pyramidal CrIII coordination, comprising a chelating ligand through the CNHC and one P donor and three benzyl groups. These complexes were used as precatalysts in ethylene oligomerization, and it was found that the nature of the cocatalyst used and the metal oxidation state have a remarkable influence on the catalytic properties. The CrIII/MAO systems displayed superior catalytic performance (TOF values up to 16320 mol of C2H4/((mol of Cr) h) for 6) and gave mostly oligomers. Interestingly, the oligomers obtained with complex 3 were almost exclusively 1-hexene and 1-butene when the reaction was initiated at 30 °C. The overall activities and selectivities were also affected by the initial reaction temperature and the nature of the solvent. With AlEtCl2 (EADC) as cocatalyst, polyethylene was predominately formed. (Chemical Equation Presented).
Reductive Preparation of Bis(arene)metal Complexes from Metal Halides in Solution using Potassium Atoms
Hawker, Pelham N.,Timms, Peter L.
, p. 1123 - 1126 (1983)
Some known bis(arene) complexes of zerovalent Ti, V, Cr and Mo have been synthesised in a new way by stepwise reduction of solutions of the metal chlorides in tetrahydrofuran and arene, using K atoms condensed into the solutions at -110 deg C under vacuum in a rotary reactor.The extent of reduction was followed by observing colour changes in the solutions.With Ti and V, the initial products were anionic forms of the bis(arene) complexes, which were oxidised to give the zerovalent compounds.The method is a useful way of making 0.1-1 g samples of some bis(arene)titanium complexes and bis(naphthalene) complexes of V, Cr, and Mo which are otherwise accessible only by using the transition-metal atoms as reagents.
Spin structure of surface-supported single-molecule magnets from isomorphous replacement and X-ray magnetic circular Dichroism
Mannini, Matteo,Tancini, Erik,Sorace, Lorenzo,Sainctavit, Philippe,Arrio, Marie-Anne,Qian, Yu,Otero, Edwige,Chiappe, Daniele,Margheriti, Ludovica,Cezar, Julio C.,Sessoli, Roberta,Cornia, Andrea
, p. 2911 - 2917 (2011/06/18)
Surface-supported arrays of Fe4-type Single-Molecule Magnets retain a memory effect and are of current interest in the frame of molecule-based information storage and spintronics. To reveal the spin structure of [Fe4(L)2(dpm)6] (1) on Au, an isomorphous compound [Fe3Cr(L)2(dpm)6] was synthesized and structurally and magnetically characterized (H3L is tripodal ligand 11-(acetylthio)-2,2-bis(hydroxymethyl)undecan-1-ol and Hdpm is dipivaloylmethane). The new complex contains a central Cr3+ ion and has a S = 6 ground state as opposed to S = 5 in 1. Low-temperature X-ray Magnetic Circular Dichroism studies at Fe- and Cr-L2,3 edges revealed that the antiparallel alignment between Fe and Cr spins is preserved on surfaces. Moreover, the different Fe-L2,3 spectral features found in the homo- and heterometallic species disclose the opposing contribution of the central Fe3+ ion in the former compound, proving that its ferrimagnetic spin structure is retained on surfaces.
