Trifluorophosphine as a Bridging Ligand in Homoleptic Binuclear Nickel Complexes^†

Abstract

The stable tetrahedral derivative Ni(PF(3))(4) is reported to generate binuclear Ni(2)(PF(3))(n) ions in its mass spectrum emerging from ion-molecule reactions. Theoretical studies on such binuclear complexes indicate Ni(2)(PF(3))(7) to be energetically unfavorable with respect to decomposition into Ni(PF(3))(4) + Ni(PF(3))(3). However, viable rather unsymmetrical structures with two PF(3) bridges for Ni(2)(PF(3))(n) (n = 6, 5, 4) are reported here as well as a triply semibridged Ni(2)(PF(3))(5) structure. The nickel-nickel distances in these Ni(2)(PF(3))(n) derivatives suggest a formal double bond (2.51 A), a formal triple bond (2.26 A), and a formal double bond (2.34 A) for n = 6, 5, and 4, respectively. The mononuclear Ni(PF(3))(n) derivatives are predicted to have tetrahedral, trigonal planar, and bent (139 degrees ) structures for n = 4, 3, and 2, respectively.

Construction of the Tetrahedral Trifluorophosphine Platinum Cluster Pt4(PF3)8 from Smaller Building Blocks

“…Comparison of the preferred structures of the binuclear platinum trifluorophosphine complexes Pt 2 (PF 3 ) n ( n = 6, 5, 4) with their previously studied nickel analogues indicates a lower tendency of the platinum derivatives to form structures with bridging PF 3 groups than the corresponding nickel derivatives. Thus, both low-energy Ni 2 (PF 3 ) 6 structures are predicted to have two bridging PF 3 groups with normal Ni–P distances.…”

σ‐Accepting Properties of a Chlorobismuthine Ligand

“…[24] In the case of the chlorobismuthine described herein, the 6s bismuth lone pair is too inert to be involved in bonding, thus unveiling an essentially pure electron-accepting behavior. The emergence of this ligative behavior is correlated to the presence of an electronegative chloro substituent, which enhances the acidity of the bismuth center.…”

Metal–Metal (MM) Bond Distances and Bond Orders in Binuclear Metal Complexes of the First Row Transition Metals Titanium Through Zinc

“…All three systems gave singlet global minima with Ni(0)−Ni(0) bonds of length 2.521 to 2.672 Å of orders 1, 2, and 3, respectively. BP86 results on the homoleptic binuclear nickel trifluorophosphine series Ni 2 (PF 3 ) n (n = 6, 5, 4) 507 gave singlet global minima for the three systems with n = 6, 5, and 4, each with two bridging PF 3 ligands. The singlet structure S-1 for Ni 2 (PF 3 ) 6 has a Ni(0)Ni(0) double bond of length 2.483 4 which showed no appreciable 3d covalent interactions.…”