Synthesis and characterisation of a series of 1,2-phenylenedioxoborylcyclopentadienyl-metal complexes [Ti(IV), Zr(IV), Hf(IV), La(III), Ce(III), Yb(III), Sn(II) and Fe(II)]

The preparation of a series of 1,2-phenylenedioxoborylcyclopentadienyl–metal complexes is described. These are of formula [M{g5-C5H4(BX)}Cl3] [M = Ti and X = CAT (2a), CATt (2b) or CATtt (2c); X = CATtt and M = Zr (4a) or Hf (4b)], [M{g5- C5H4(BX)}2Cl2] [M = Zr, X = CAT (3a) or CATt (3c); orM = Hf, X = CAT (3b) or CATt (3d)], [M{(l-g5-C5H3BCAT)2 SiMe2}Cl2] [M = Zr (5a) or Hf (5b)], [M{g5-C5H3(BCAT)2}Cl3] [M = Zr (6a) or Hf (6b)], [M{g5-C5H4BCAT}3(THF)] [M = La (7a), Ce (7b) or Yb (7c)], [Sn{g5-C5 H4(BCATt)}Cl](8) and [Fe{g5-C5H4(BCATt)}2] (9). The abbreviations refer to BO2C6H4-1,2 (BCAT) and the 4- But (BCATt) and the 3; 5-But 2 (BCATtt) analogues. The compounds 2a–9 have been characterised by microanalysis, multinuclear NMR and mass spectra. The single crystal X-ray structure of the lanthanum compound 7a is presented.