1404564-06-2Relevant articles and documents
Preparation and structures of coordination complexes of the very hard Lewis acids ZrF4 and HfF4
Benjamin, Sophie L.,Levason, William,Pugh, David,Reid, Gillian,Zhang, Wenjian
, p. 12548 - 12557 (2012)
[MF4(dmso)2] (M = Zr or Hf) and [MF 4(dmf)2], prepared by dissolving MF4· nH2O in the appropriate solvent, have been used as synthons for a range of complexes of these otherwise intractable tetrafluorides. These reagents react with OPR3 (R = Me or Ph) or OAsPh3 (L) in anhydrous CH2Cl2 to form six-coordinate [MF4L 2] which exist as a mixture of cis (predominant form) and trans isomers in CH2Cl2 solution but which crystallise as trans (OPPh3, OAsPh3) or cis (OPMe3) forms. Cis-[ZrF4(OAsPh3)2] crystals were obtained from MeCN. Cis-[MF4(pyNO)2] and eight-coordinate (distorted dodecahedral) [MF4(L-L)2] (L-L = 2,2′-bipy, or 1,10-phen), and [MF4(Me4-cyclam)] were also obtained. Attempts to prepare complexes with the N-heterocyclic carbene, 1,3-(2,6-di-isopropylphenyl)imidazol-2-ylidene (IDiPP) or alkyl diphosphines were unsuccessful. Crystal structures are reported for trans-[ZrF 4(OPPh3)2], cis- and trans-[ZrF 4(OAsPh3)2], cis-[HfF4(OPMe 3)2], [ZrF4(2,2′-bipy)2], cis-[HfF4(dmf)2], and geometric isomers (both pentagonal bipyramidal) of [(dmso)2F3M(μ-F)2MF 3(dmso)2]. The failed attempts to make IDiPP adducts led to crystals of [IDiPPH]3[M3F15] containing discrete anions based upon a triangle of M atoms with single F bridges. The results are compared with previous work on TiF4 adducts and with complexes of MCl4, and demonstrate that the MF4 are very hard Lewis acids, with a marked preference for O- over N-donors.
