Oxidative P‐P‐Bindungsaddition an Cobalt(−I): Bildung eines Low‐spin‐Cobalt(III)‐Phosphanidokomplexes

Abstract

Die oxidative P‐P‐Bindungsaddition eines ortho‐Carboran‐substituierten 1,2‐Diphosphetans an Cobalt(−I) in [K(thf)0.2][Co(η4‐cod)2)] (cod=1,5‐Cycloctadien) ermöglichte die Darstellung des ersten homoleptischen Cobalt(III)‐Phosphanidokomplexes [K(thf)4][Co{1,2‐(PtBu)2C2B10H12}2] (1). Diese Verbindung ist ein seltenes Beispiel eines verzerrt tetraedrisch koordinierten 3d6‐Komplexes mit einem Low‐spin‐Grundzustand. Magnetische Messungen ergaben, dass 1 zwischen 2 und 270 K im Festkörper und bei 298 K in einer [D8]THF‐Lösung diamagnetisch ist. Dichtefunktionalrechnungen zeigten, dass der diamagnetische Grundzustand durch die starken σ‐Donor‐ und die moderaten π‐Donoreigenschaften der Bisphosphanidoliganden verursacht wird.

Intermolecular Insertion Reactions into the P−P Bond of Oligophosphorus Compounds

“…Activation of P−P bonds in cyclic phosphines is possible through metal interactions. Oxidative addition of a P−P bond to a transition metal may lead to oligophosphorus complexes with specific properties and novel applications [14] . Oxidative addition of oligophosphorus ligand 128 to [Cr(CO) 3 (RCN) 3 ] (where R=Me, Ph) at room temperature in toluene can be followed by the intermolecular insertion of nitriles into a P−P bond to give 129a , b with an eight‐membered cyclic ligand which coordinates through three phosphorus atoms to chromium(0) tricarbonyl (Scheme 51).…”

“…We discuss different insertion reactions of non‐metals, unsaturated organic substrates, carbenes and carbene analogues into the P−P bond of diphosphines, heterocyclic compounds with P−P bonds, complexes with P−P bonds, white phosphorus, cyclooligophosphines and polyphosphanides. Not included are reactions of insertion of metal atoms, e. g., gold(I), [12] rhodium(I), [13] cobalt(−I), [14] gallium(I), [15] titanium(II), [16] aluminum [15b,17] and nickel(0), [18] or phosphorus with expansion of phosphorus chains and rings and formation of P n+1 compounds, [19] since these interactions were widely discussed previously [20] . Carbene analogues based on gallium [17b] and aluminum [15b,17,20a] are mentioned in the discussion to show their similarities to carbenes and silylenes in the insertion reactions into the P−P bond of white phosphorus P 4 .…”

Applications of Low-Valent Transition Metalates: Development of a Reactive Noncarbonyl Rhenium(I) Anion

“…For instance, anionic metal-dinitrogen adducts have been used for the protonation and silylation of dinitrogen to form ammonia and tris(trimethylsilyl)amine, respectively, 20−22 and C−CN bond activation has been achieved with rhodium metalates. 23 The activation of small-molecule phosphorus reagents such as P 4 , 24−26 phosphaalkynes (RCP), 27 and P−P bonds 28,29 has also been demonstrated. Each of these highlighted examples of small-molecule activation is performed with noncarbonyl metalates.…”