Tris(tri-o-tolyl phosphite-κP)nickel: a coordinatively unsaturated nickel(0) complex

Abstract

A previously reported complex, [Ni(C(21)H(21)O(3)P)(3)] or Ni[P(O-o-tolyl(3))(3)] [Gosser & Tolman (1970). Inorg. Chem. 9, 2350-2353], crystallized in the monoclinic space group C2/c, and its solid-state structure was determined. The Ni(0) atom adopts an essentially trigonal-planar geometry as a consequence of the steric congestion of the ligands. Three of the phenoxy rings on two phosphite ligands were modelled as being disordered over two sets of sites, and the occupancy factors were set at 0.5 after trial refinement and intramolecular contact considerations. The exact ligand cone angle has been calculated to be 163.6°.

The Synthesis and Catalytic Activity of New Mixed NHC-Phosphite Nickel(0) Complexes

“…Two related nickel complexes, Ni­(SIMes)­[P­(O- o -tol) 3 ] 2 ( 3 ) and Ni­(IMes)­[P­(O- o -tol) 3 ] 2 ( 4 ) were synthesized using the IMes and SIMes NHC ligands and the sterically bulkier tri­( o -tolyl)­phosphite ligand analogue (Scheme b). The more reactive unsaturated tris­(tri- o -tolyl phosphite) nickel was used as the precursor for these reactions, allowing these transformations to be carried out in less time and under slightly reduced temperatures. Through this methodology the red crystalline solids of nickel complex 3 and 4 were isolated in 67% and 57% yields, respectively …”

Nickel Phosphite-Catalyzed Tetradehydro-Diels–Alder Reactions of (E)-3-ene-1,8-diynes

“… Unfortunately, the reaction involving the sterically encumbered di- ortho -isopropyl arylphosphite was unsuccessful at a range of temperatures, and it was thought that the observed ensuing purple reaction mixture was due to the tris -complex Ni­[P­(O-2,6- i Pr-Ph) 3 ] 3 and not the desired tetrakis complex Ni­[P­(O-2,6- i Pr-Ph) 3 ] 4 . Given that nickel(0) tris -complexes are often unstable, decomposition of this complex was assumed . Treating the nickel nitrate with meta -dimethyl phosphite 14b , at 40 °C, furnished the Ni­[P­(O-3,5-Me-Ph) 3 ] 4 15b in reasonable yield, 61%.…”