Abstract
A cyclic tri-nuclear α-diimine nickel(0) complex [{Ni(μ-L Me-2,4 )} 3 ] (2) was synthesized from a “pre-organized”, trimerized trigonal LNiBr 2 -type precursor [Ni 3 (μ 2 -Br) 3 (μ 3 -Br) 2 (L Me-2,4 ) 3 ]·Br (1; L Me-2,4 = [(2,4-Me 2 C 6 H 3 )NC(Me)] 2 ). In complex 2, the α-diimine ligands not only exhibit the normal N,N′-chelating mode, but they also act as bridges between the Ni atoms through an unusual π-coordination of a C═N bond to Ni. Complex 2 is able to catalyze the cyclotrimerization of alkynes to form substituted benzenes in good yield and regio-selectivity for the 1,3,5-isomers, which is found to vary with the nature of the alkyne employed. This complex represents a convenient self-supported nickel(0) catalyst with no need for additional ligands and reducing agent.
Original language | English |
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Pages (from-to) | 4643-4649 |
Number of pages | 7 |
Journal | Dalton Transactions |
Volume | 48 |
Issue number | 14 |
DOIs | |
Publication status | Published - 2019 |
Externally published | Yes |