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]28 have been synthesized and structurally characterized by X-ray crystallography (Cym = cymantrenyl, pz = pyrazolyl). 6 and 8 are easily accessible from the corresponding TlI 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, (lambda)= 254 nm) leading to the liberation of carbon monoxide and the formation of larger aggregates of unknown molecular structure.