Cymantrene-based tris(1-pyrazolyl)borates: synthesis and structural characterization of di- and trimetallic complexes

Abstract

The di- and trinuclear complexes Mn(CO)₃[CymB(pz)₃] 6, Mn(CO)₃[CymB(pz)₂(OH)] 7 and Zn[CymB(pz)₃]₂8 have been synthesized and structurally characterized by X-ray crystallography (Cym = cymantrenyl, pz = pyrazolyl). 6 and 8 are easily accessible from the corresponding Tl^I salt Tl[CymB(pz)₃] 2 and Mn(CO)₅Br or ZnBr₂, respectively. IR spectroscopy and X-ray crystallography on 6, which features a cyclopentadienyl ring together with a scorpionate moiety in the same molecule, indicate both ligand types to exert a very similar electronic influence on the respective Mn(CO)₃ fragment. The heteroscorpionate complex 7 is obtained when the reaction of Tl[CymB(pz)₃] 2 and Mn(CO)₅Br is performed without exclusion of air and moisture. Complex 6 undergoes photolysis (with UV light, λ = 254 nm) leading to the liberation of carbon monoxide and the formation of larger aggregates of unknown molecular structure.