NOVEL FERROCENE-BASED MONOFUNCTIONAL AND BIFUNCTIONAL TRI-1-PYRAZOLYLBORATE LIGANDS

The reaction of (dibromoboryl)ferrocene (1a) with pyrazole/NEt(3) gave the ferrocenyltri-1-pyrazolylborate ligand 2. Its thallium(I) derivat ive 2-Tl provides the first example of a polymeric structure with brid ging tri-1-pyrazolylborate units in the solid state. The trinuclear ir on complex 2-Fe, which is related to 1,1'-terferrocene, was obtained b y reaction of 2 with FeCl2. The bis(polydentate) ligand 1,1'-ferrocene diyl-bis(tri-1-pyrazolylborate) (3-Li) was prepared from 1,1'-bis-[bis (dimethylamino)boryl]ferrocene (1c) and a mixture of lithium pyrazolid e/pyrazole in refluxing toluene/THF. 3-Li reacts with TlNO3 to give th e thallium(I) complex 3-Tl.