Bis-nickel-bridged p-terphenyl dianion – Synthesis and structures

•Bis-nickelacyclic-dilithium complex exhibits paramagnetic properties.•Different behavior of bis-nickelacyclic-dilithium complex from nickelafluorenyllithium.•Catalytic properties of nickelacycles in C–C bond formation.

In this paper we present the synthesis and characterisation of novel bisnickelacyclic complexes. We carried out the reaction between 2,2′,2″,5′-tetralithio-1,1′,4′,1″-terphenyl and nickelocene in which bisnickelacyclic–dilithium complex was formed. It represented the contact ion pair that consisted of nickelacyclic dianion (the first of it's kind) and lithium cations. Exchange of solvent from diethyl ether to DME (1,2-dimethoxyethane) afforded solvent separated ionic pair. Both of these complexes exhibited paramagnetic behaviour, so structural investigations had to be carried out by means of X-ray diffraction. DFT calculations were employed for better understanding of electronic structure of these complexes.

Graphical abstractThe paper describes the synthesis and characterisation of novel bisnickelacyclic complex isolated from the reaction between 2,2′,2″,5′-tetralithio-1,1′,4′,1″-terphenyl and nickelocene. It represents the contact ion pair that consists of nickelacyclic dianion and lithium cations. Exchange of solvent from diethyl ether to DME affords solvent separated ionic pair.Figure optionsDownload full-size imageDownload as PowerPoint slide