First mixed fluoro-chloro group 4 organometallics: Synthesis and spectroscopic and structural characterization of [{(C(5)Me(5))ZrF2Cl}(4)], [{(C(5)Me(5))HfF2Cl}(4)], [(C(5)Me(5))(4)Zr-4(mu-F)(mu-F-2)(2)(mu-Cl)(2)Cl-4], [(C(5)Me(5))(4)Hf-4(mu-F)(2)(mu-F-2)(2)(mu Cl)(2)Cl-4], [(C(5)Me(4)Et)(2)ZrClF], and [(C(5)Me(5))(2)HfClF]

Tetrameric [{(C(5)Me(5))MF(3)}(4)] (M = Zr, Hf) react smoothly with Me(3)SiCl in CH2Cl2 at room temperature to give [{(C(5)Me(5))ZrF2Cl}(4)] (1) and [{(C(5)Me(5))HfF2Cl}(4)] (2), respectively, in high yield. Treatment of [{(C(5)Me(5))MF(3)}(4)] (M = Zr, Hf) with Me(2)AlCl in toluene gives mixtures of 1 and [(C(5)Me(5))(4)Zr-4(mu-F)(2)(mu-F-2)(2)(mu-Cl)(2)Cl-4] (3), and 2 and [(C(5)Me(5))(4)Hf-4(mu-F)(2)(mu-F-2)(2)(mu-Cl)(2)C-4] (4), respectively, in an approximately 1:1 molar ratio. Metallocene type complexes [(C(5)Me(4)Et)(2)ZrCl2] and [(C(5)Me(5))(2)HfCl2] react with 1 equiv of Me(3)SnF to give [(C(5)Me(4)Et)(2)ZrCIF] (5) and [(C(5)Me(5))(2)HfCIF] (6), respectively. The complexes 1-6 were characterized by spectroscopic methods (H-1 and F-19 NMR and mass spectroscopy). The solid state structures of 1, 3, and 5 were determined by single-crystal X-ray diffraction analyses.