Nickel(II) Cyanoborates and Cyanoborate-Ligated Nickel(II) Complexes

Abstract

Nickel(II) cyanoborates Ni[BH 2 (CN) 2 ] 2 •H 2 O (1b•H 2 O), Ni[BH(CN) 3 ] 2 •0.5H 2 O (1c•0.5H 2 O), and Ni[B(CN) 4 ] 2 • 0.5H 2 O (1d•0.5H 2 O) were synthesized, and their reactivity with respect to dppeO 2 (=1,2-bis-(diphenylphosphinoethane dioxide)), pyNO (=pyridine-N-oxide), dppe (=1,2-bis-(diphenylphosphinoethane), and DMSO (=dimethyl sulfoxide) was examined. Using these ligands, either cyanoborate (CB) complex salts of [Ni(dppe) 2 ] 2+ (2b−d) and [Ni(pyNO) 6 ] 2+ (3c−d) were isolated or complexes [Ni(DMSO) 4 {NC-B(CN) 3 } 2 ] (1d DMSO ) and [Ni(dppeO 2 ) 2 {NC-B(CN) 3 } 2 ] (1d dppeO2 ) were formed. Salt metathesis of [Ni(dppe)Cl 2 ] with alkali metal cyanoborates resulted in mono-and disubstituted coordination compounds [Ni(dppe){NC-BH(CN) 2 }Cl] (5c) and [Ni(dppe){NC-BH 2 CN) 2 }] (4b), which decomposed to salts 2b−d. The synthetical pathways explored offer convenient routes to nickel(II) cyanoborates, nickel(II) complexes ligated with cyanoborates, and nickel(II) complex salts of cyanoborates. Further, our studies demonstrate the diverse character of cyanoborates in coordination chemistry as noncoordinating counteranions and also as medium coordinating anions forming novel transition-metal complexes and salts.