On the Stability of a POCsp3OP‐Type Pincer Ligand in Nickel(II) Complexes |
| |
| Authors: | Dr Jingjun Hao Berline Mougang‐Soumé Boris Vabre Prof?Dr Davit Zargarian |
| |
| Affiliation: | Départment de chimie, Univerrsité de Montréal, 2900 Boul. Edouard‐Montpetit, Montréal, Québec, H3C 3J7 (Canada) |
| |
| Abstract: | We describe the results of a study on the stabilities of pincer‐type nickel complexes relevant to catalytic hydroalkoxylation and hydroamination of olefins, C? C and C? X couplings, and fluorination of alkyl halides. Complexes (POCsp3OP)NiX] are stable for X=OSiMe3, OMes (Mes=1,3,5‐Me3C6H2), NPh2, and CC? H, whereas the O(tBu) and N(SiMe3)2 derivatives decompose readily. The phenylacetylide derivative transforms gradually into the zero‐valent species cis‐{κP,κC,κC′‐(iPr2POCH2CHCH2)}Ni{η2,κC,κC′‐(iPr2P(O)CCPh)}]. Likewise, attempts to prepare (POCsp3OP)NiF] gave instead the zwitterionic trinuclear species {(η3‐allyl)Ni}2‐{μ,κP,κO‐(iPr2PO)4Ni}]. Characterization of these two complexes provides concrete examples of decomposition processes that can dismantle POCsp3OP‐type pincer ligands by facile C? O bond rupture. These results serve as a cautionary tale for the inherent structural fragility of pincer systems bearing phosphinite donor moieties, and provide guidelines on how to design more robust analogues. |
| |
| Keywords: | C O bond cleavage nickel pincer complexes |
|
|
