Diazadien-Nickel-Komplexe, I: Bis(diazadien)-nickel(O) und Bromo-diazadien-nickel(I) / Diazadiene Nickel Complexes, I: Bis(diazadiene) Nickel(O) and Bromo-diazadiene Nickel(I)

Abstract

<jats:title>Abstract</jats:title><jats:p> Reduction of anhydrous nickel(II) compounds in the presence of diazadienes RN=CR'-CR' = NR, |(DAD), yields (DAD)<jats:sub>2</jats:sub>Ni(0). This complex 1 with R = CH(i-C<jats:sub>3</jats:sub>H<jats:sub>7</jats:sub>)<jats:sub>2</jats:sub> is especially reactive and comproportionates with DADNiBr<jats:sub>2</jats:sub> (2) to yield the bromobridged dimeric nickel(I) species (DADNiBr)<jats:sub>2</jats:sub> (3). The crystal and molecular structure of 3 has been determined by single crystal X-ray diffraction: Space group Pbca with a = 1225.8(12), b = 1474.8(14) and c = 2167.4(22) pm; Ra = 0.076, 1034 reflections. Catalytic tetramerisation of substituted alkynes with 1 is discussed in view of the very easy formation of dimers 3.</jats:p>

An Alternative Mechanistic Concept for Homogeneous Selective Ethylene Oligomerization of Chromium‐Based Catalysts: Binuclear Metallacycles as a Reason for 1‐Octene Selectivity?

“…[40][41][42] Evidence for the proposed mechanism was found for nickel [40,42] and for chromium, in which even a binuclear intermediate was characterized by X-ray measurements. [41] Besides the alkyne tetramerization, cyclotrimerization of acetylene to benzene could also be realized by two bridged chromium centers.…”

“…Mechanism for the selective alkyne tetramerization to cyclooctatetraene proposed by Wilke and co-workers. [40][41][42] Scheme 7. Concept for a binuclear mechanism for the selective ethylene tetramerization.…”

From Hein to Hexene: Recent Advances in the Chemistry of Organochromium π-Complexes

“…This suggestion has as its forerunner one made by G. Wilke in 1978 for the nickel-catalyzed cyclotetramerization of acetylene to cyclooctatetraene. 39,40…”

Molecular and Electronic Structures of Homoleptic Nickel and Cobalt Complexes with Non‐Innocent Bulky Diimine Ligands Derived from Fluorinated 1,4‐Diaza‐1,3‐butadiene (DAD) and Bis(arylimino)acenaphthene (BIAN)

“…The class of [M(DAD) 2 ] complexes was expanded by the groups of tom Dieck (M = Fe, [3] Ni [4] ) and von Walther (M = Fe, [5] Co, [5,6] Ni [7] ). Later, several [Ni(DAD) 2 ] complexes were characterized by single-crystal X-ray analysis.…”