Case Study of N‐ⁱPr versus N‐Mes Substituted NHC Ligands in Nickel Chemistry: The Coordination and Cyclotrimerization of Alkynes at [Ni(NHC)₂]

Abstract

A case study on the effect of the employment of two different NHC ligands in complexes [Ni(NHC) 2 ] (NHC = i Pr 2 Im Me 1 Me , Mes 2 Im 2) and their behavior towards alkynes is reported. The reaction of a mixture of [Ni 2 ( i Pr 2 Im Me ) 4 (μ-(η 2 : η 2 )-COD)] B/ [Ni( i Pr 2 Im Me ) 2 (η 4 -COD)] B' or [Ni(Mes 2 Im) 2 ] 2, respectively, with alkynes afforded complexes [Ni(NHC) 2 (η 2 -alkyne)] (NHC = i Pr 2 Im Me : alkyne = MeC�CMe 3, H 7 C 3 C�CC 3 H 7 4,

Nickel boryl complexes and nickel-catalyzed alkyne borylation

“…Both complexes adopt a pseudo-trigonal planar structure with Ni–C NHC distances of 1.9454(14)–1.9560(13) Å in a typical range. 22 The C3–C4 distances of the coordinated alkene of 1.453(2) Å ( 15a ) and 1.4550(17) Å ( 15b ) are in line with those of coordinated olefins reported previously 22 a , j and are much larger compared to those of alkyne complexes ( c.f. 14a : 1.285(2) Å).…”

Revealing the Role of the Cyaphide Ion as a Bridging Ligand in Heterometallic Complexes

“…For this purpose, we chose to study the reactivity of A towards electron‐rich late transition metal complexes. Nickel(0) centers are known to form complexes with electrophilic π‐acceptor ligands such as alkynes and phosphaalkynes; [20, 21] thus we envisioned that the nickel(0) carbene complex Ni( Me I i Pr) 2 (COD) x could be used to prepare a bridging cyaphide complex [22] . Ni( Me I i Pr) 2 (COD) 0.7 [prepared as a mixture of Ni( Me I i Pr) 2 (COD) and {Ni( Me I i Pr) 2 } 2 (μ 2 ‐COD)] reacts with A at room temperature, resulting in the displacement of COD and immediate, quantitative formation of the heterobimetallic compound Au(IDipp)(μ 2 ‐C≡P)Ni( Me I i Pr) 2 ( 2 ; Scheme 2).…”

N-Heterocyclic carbene and cyclic (alkyl)(amino)carbene complexes of vanadium(iii) and vanadium(v)

“…We have demonstrated recently for complexes [Ni(NHC) 2 ] that NHC ligands of different size influence the reactivity pattern of such complexes often beyond the more obvious steric factors. 19…”