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[Ni(NHC) 2 ] as a Scaffold for Structurally Characterized trans [H−Ni−PR 2 ] and trans [R 2 P−Ni−PR 2 ] Complexes
Author(s) -
Sabater Sara,
Schmidt David,
Schmidt Heidi née Schneider,
KuntzeFechner Maximilian W.,
Zell Thomas,
Isaac Connie J.,
Rajabi Nasir A.,
Grieve Harry,
Blackaby William J. M.,
Lowe John P.,
Macgregor Stuart A.,
Mahon Mary F.,
Radius Udo,
Whittlesey Michael K.
Publication year - 2021
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.202101484
Subject(s) - diphosphines , phosphine , moiety , chemistry , carbene , adduct , nickel , stereochemistry , ligand (biochemistry) , substituent , medicinal chemistry , dissociation (chemistry) , crystallography , catalysis , biochemistry , receptor , organic chemistry
The addition of PPh 2 H, PPhMeH, PPhH 2 , P( para ‐Tol)H 2 , PMesH 2 and PH 3 to the two‐coordinate Ni 0 N‐heterocyclic carbene species [Ni(NHC) 2 ] (NHC=I i Pr 2 , IMe 4 , IEt 2 Me 2 ) affords a series of mononuclear, terminal phosphido nickel complexes. Structural characterisation of nine of these compounds shows that they have unusual trans [H−Ni−PR 2 ] or novel trans [R 2 P−Ni−PR 2 ] geometries. The bis‐phosphido complexes are more accessible when smaller NHCs (IMe 4 >IEt 2 Me 2 >I i Pr 2 ) and phosphines are employed. P−P activation of the diphosphines R 2 P−PR 2 (R 2 =Ph 2 , PhMe) provides an alternative route to some of the [Ni(NHC) 2 (PR 2 ) 2 ] complexes. DFT calculations capture these trends with P−H bond activation proceeding from unconventional phosphine adducts in which the H substituent bridges the Ni−P bond. P−P bond activation from [Ni(NHC) 2 (Ph 2 P−PPh 2 )] adducts proceeds with computed barriers below 10 kcal mol −1 . The ability of the [Ni(NHC) 2 ] moiety to afford isolable terminal phosphido products reflects the stability of the Ni−NHC bond that prevents ligand dissociation and onward reaction.