Bimetallic π‐Allyl Complexes of Nickel and Palladium

First-Row Transition Metals in Binuclear Cyclopentadienylmetal Derivatives of Tetramethyleneethane: η3,η3 versus η4,η4 Ligand–Metal Bonding Related to Spin State and Metal–Metal Bonds

“…This mode of TME bonding occurs in the three complexes depicted in Figure 1. The complex trans-(η 4 ,η 4 -TME)Co 2 Cp* 2 illustrates an alternative trans-η 4 ,η 4 -TME mode of bonding to a pair of metal atoms. In this latter mode of bonding of the TME ligand to a pair of metal atoms, each metal atom is bonded to four carbon atoms of the TME ligand so that the two central TME carbon atoms bridge the M 2 unit.…”

“…This led to the synthesis of trans-(η 3 ,η 3 -TME)[Co(CO) 3 ] 2 from the reaction of NaCo(CO) 4 with 2,3-bis(bromomethyl)butadiene (TMEBr 2 ). In addition, trans-(η 4 ,η 4 -TME)Co 2 Cp* 2 (Cp* = η 5 -Me 5 C 5 ) was synthesized from TMEK 2 , Cp*Li, and Co(acac) 2 (Figure 2).…”

“…The cobalt complexes trans-(η 3 ,η 3 -TME*)Co 2 (CO) 6 and trans-(η 4 ,η 4 -TME)Co 2 Cp* 2 (Figure 2) synthesized by O'Hare and co-workers 12 exemplify two distinctly different ways that the TME ligand can bond to a pair of metal atoms. Most commonly, the TME ligand is a bis(allylic) ligand, bonding to each metal atom as a η 3 ligand similar to the allyl ligand in the long-known 13,14 (η 3 -C 3 H 5 )Co(CO) 3 .…”

Chapter 13. Transition-metal carbonyls and organometallic complexes

“…C(CH2)2 has been prepared in which one allylic group is n-bonded to nickel and the other to palladium. 385 n Complexes of Straight-chain Mono-and Poly-enes.-The structure of ethylenebis(triphenyIphosphinejnicke1 has been determined twice by X-ray crystallography and the unit cell was defined differently in the two reports.38c In this crystal system (triclinicj, the choice of unit cell is arbitrary until a Delauney reduction is calculated; however in this case, there may be a real difference between the two crystals since the cell volume is slightly different. These two crystals may be simply crystal modifications of the same compound or one may not be the ethylene adduct.…”

Chromium Complexes Supported by Phenyl Ether‐Pyrazolyl [N,O] Ligands as Catalysts for the Oligo‐ and Polymerization of Ethylene

“…[ 1–8 ] LAOs are generally produced with a broad range of olefins from C 4 to C 20 featured by Schulz‐Flory distributions manufactured by Shell, Ineos, SABIC, and Chevron‐Phillips. [ 9–12 ] Among all the transition‐metal‐based catalysts, chromium catalysts have proven to be the most promising candidates for selective ethylene oligomerization. [ 13–16 ] In this way, significant efforts have been dedicated to the synthesis of new families of ligands based on a wide variety of donor‐group combinations aiming to generate more efficient chromium catalyst systems that are capable of selectively forming α‐olefins with high productivities.…”