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

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)](2) 8 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)(5)Br 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)(5)Br is performed without exclusion of air and moisture. Complex 6 undergoes photolysis (with UV light, = 254 nm) leading to the liberation of carbon monoxide and the formation of larger aggregates of unknown molecular structure.