Abstract
The synthesis of a full series of group 4/nickel complexes supported by a 2-(diphenylphosphino)pyrrolide (NP) ligand is reported. Treatment of the homoleptic, 8-coordinate M(NP)4 monometallic precursors with Ni(COD)2 (COD = 1,5-cyclooctadiene) yielded the heterobimetallic complexes (κ2-NP)M(μ2-NP)3Ni (M = Ti, Zr, Hf). Although X-ray crystallographic analysis reveals similarly short metal-metal distances in all three complexes, quantum chemical calculations indicate that ZrNi (5) and HfNi (6) contain only single Ni → M dative bonds while TiNi (4) has an additional Ti-Ni π-bond. All three complexes have quasireversible reductions by cyclic voltammetry, and 1-electron chemical reduction of 4 by Na(Hg) yields the anion, [Na][(κ2-NP)Ti(μ2-NP)3Ni] (7). X-ray and computational analysis indicate that the 1-electron reduction of 4 completely breaks the metal-metal bond, yielding a formally TiIII-Ni0 complex. Ti-Ni bonding can also be disrupted by coordination of CO, wherein Ni → CO backbonding effectively outcompetes Ni → Ti dative bonding.
| Original language | English (US) |
|---|---|
| Pages (from-to) | 9892-9901 |
| Number of pages | 10 |
| Journal | Dalton Transactions |
| Volume | 45 |
| Issue number | 24 |
| DOIs | |
| State | Published - 2016 |
Bibliographical note
Publisher Copyright:© 2016 The Royal Society of Chemistry.