Halogen-donor Ligands

Organometallic Titaniam(iv) Compounds.—Charge-transfer interactions between TiC and aromatic hydrocarbons and fluorocarbons have been characterized by spectrophotometric studies. The other work described here will mainly be concerned with selected aspects of the chemistry of Ti -alkyl and -cyclopentadienyl derivatives. 

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Halogen-donor Ligands. The a- and p-modifications of LiVF have been obtained by reaction of LiF and VF3 (3 1) and quenching or slowly cooling the products, respectively." Hyperfme and superhyperfine interactions of V " ions in MFj crystals (M = Ca. Sr, or Cd) have been studied at 4.2 K. " ... 

Halogen-donor Ligands. Xep2 reacts with excess VF5 at 90 °C to give XeF2,VF5 as colourless transparent crystals, m.p. 22—28°C. The i.r. spectrum of the vapour indicates that the compound is completely dissociated in this phase. The phase diagram for the HF—VF system has been presented. 

Typical inorganic oxygen- and halogen-donor ligands. 

The elements of first transition series form stable complexes with N, O, F donor ligands whereas the elements of second and third transition series form stable complexes with P, S and halogen donor ligands. 

Group IVA Donor Ligands. The anomalous reactions of PhaSiCl with metal carbonyl anions are discussed on p. 180. Only in the case of [Co(CO)3PPh3] was the normal substitution product obtained. GeH3Br reacts with Na-[Co(CO)4] in ether to produce [H3GeCo(CO)4]. The trideuterio-compound has also been prepared and spectroscopic properties reported for both compounds. The preparation and attempted preparation of halogen-bridged Ge-M compounds is referred to on pp. 180 and 200. In the case of cobalt. 

In these complexes, the gold-metal bonds are apparently weak and polar and, in man cases, the metal carbonyl anion can be displaced by donor ligands (equation go)716 726>732,733 a well as by halogens and similar reagents.721... 

In the case of the complex [Au(Fmes)(NCMe)], containing a poorer donor ligand, it must be obtained by removing halogen from NBu4[Au(Fmes)Cl] with T1BF4 in the presence of the desired ligand [see Eq. (5)]. 

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